NAME¶
CPAN - query, download and build perl modules from CPAN sites
SYNOPSIS¶
Interactive mode:
perl -MCPAN -e shell
--or--
cpan
Basic commands:
# Modules:
cpan> install Acme::Meta # in the shell
CPAN::Shell->install("Acme::Meta"); # in perl
# Distributions:
cpan> install NWCLARK/Acme-Meta-0.02.tar.gz # in the shell
CPAN::Shell->
install("NWCLARK/Acme-Meta-0.02.tar.gz"); # in perl
# module objects:
$mo = CPAN::Shell->expandany($mod);
$mo = CPAN::Shell->expand("Module",$mod); # same thing
# distribution objects:
$do = CPAN::Shell->expand("Module",$mod)->distribution;
$do = CPAN::Shell->expandany($distro); # same thing
$do = CPAN::Shell->expand("Distribution",
$distro); # same thing
DESCRIPTION¶
The CPAN module automates or at least simplifies the make and install of perl
modules and extensions. It includes some primitive searching capabilities and
knows how to use LWP, HTTP::Tiny, Net::FTP and certain external download
clients to fetch distributions from the net.
These are fetched from one or more mirrored CPAN (Comprehensive Perl Archive
Network) sites and unpacked in a dedicated directory.
The CPAN module also supports named and versioned
bundles of modules.
Bundles simplify handling of sets of related modules. See Bundles below.
The package contains a session manager and a cache manager. The session manager
keeps track of what has been fetched, built, and installed in the current
session. The cache manager keeps track of the disk space occupied by the make
processes and deletes excess space using a simple FIFO mechanism.
All methods provided are accessible in a programmer style and in an interactive
shell style.
CPAN::shell([$prompt, $command]) Starting Interactive Mode¶
Enter interactive mode by running
perl -MCPAN -e shell
or
cpan
which puts you into a readline interface. If "Term::ReadKey" and
either of "Term::ReadLine::Perl" or "Term::ReadLine::Gnu"
are installed, history and command completion are supported.
Once at the command line, type "h" for one-page help screen; the rest
should be self-explanatory.
The function call "shell" takes two optional arguments: one the
prompt, the second the default initial command line (the latter only works if
a real ReadLine interface module is installed).
The most common uses of the interactive modes are
- Searching for authors, bundles, distribution files and
modules
- There are corresponding one-letter commands "a",
"b", "d", and "m" for each of the four
categories and another, "i" for any of the mentioned four. Each
of the four entities is implemented as a class with slightly differing
methods for displaying an object.
Arguments to these commands are either strings exactly matching the
identification string of an object, or regular expressions matched
case-insensitively against various attributes of the objects. The parser
only recognizes a regular expression when you enclose it with slashes.
The principle is that the number of objects found influences how an item is
displayed. If the search finds one item, the result is displayed with the
rather verbose method "as_string", but if more than one is
found, each object is displayed with the terse method
"as_glimpse".
Examples:
cpan> m Acme::MetaSyntactic
Module id = Acme::MetaSyntactic
CPAN_USERID BOOK (Philippe Bruhat (BooK) <[...]>)
CPAN_VERSION 0.99
CPAN_FILE B/BO/BOOK/Acme-MetaSyntactic-0.99.tar.gz
UPLOAD_DATE 2006-11-06
MANPAGE Acme::MetaSyntactic - Themed metasyntactic variables names
INST_FILE /usr/local/lib/perl/5.10.0/Acme/MetaSyntactic.pm
INST_VERSION 0.99
cpan> a BOOK
Author id = BOOK
EMAIL [...]
FULLNAME Philippe Bruhat (BooK)
cpan> d BOOK/Acme-MetaSyntactic-0.99.tar.gz
Distribution id = B/BO/BOOK/Acme-MetaSyntactic-0.99.tar.gz
CPAN_USERID BOOK (Philippe Bruhat (BooK) <[...]>)
CONTAINSMODS Acme::MetaSyntactic Acme::MetaSyntactic::Alias [...]
UPLOAD_DATE 2006-11-06
cpan> m /lorem/
Module = Acme::MetaSyntactic::loremipsum (BOOK/Acme-MetaSyntactic-0.99.tar.gz)
Module Text::Lorem (ADEOLA/Text-Lorem-0.3.tar.gz)
Module Text::Lorem::More (RKRIMEN/Text-Lorem-More-0.12.tar.gz)
Module Text::Lorem::More::Source (RKRIMEN/Text-Lorem-More-0.12.tar.gz)
cpan> i /berlin/
Distribution BEATNIK/Filter-NumberLines-0.02.tar.gz
Module = DateTime::TimeZone::Europe::Berlin (DROLSKY/DateTime-TimeZone-0.7904.tar.gz)
Module Filter::NumberLines (BEATNIK/Filter-NumberLines-0.02.tar.gz)
Author [...]
The examples illustrate several aspects: the first three queries target
modules, authors, or distros directly and yield exactly one result. The
last two use regular expressions and yield several results. The last one
targets all of bundles, modules, authors, and distros simultaneously. When
more than one result is available, they are printed in one-line
format.
- "get", "make", "test",
"install", "clean" modules or distributions
- These commands take any number of arguments and investigate
what is necessary to perform the action. Argument processing is as
follows:
known module name in format Foo/Bar.pm module
other embedded slash distribution
- with trailing slash dot directory
enclosing slashes regexp
known module name in format Foo::Bar module
If the argument is a distribution file name (recognized by embedded
slashes), it is processed. If it is a module, CPAN determines the
distribution file in which this module is included and processes that,
following any dependencies named in the module's META.yml or Makefile.PL
(this behavior is controlled by the configuration parameter
"prerequisites_policy"). If an argument is enclosed in slashes
it is treated as a regular expression: it is expanded and if the result is
a single object (distribution, bundle or module), this object is
processed.
Example:
install Dummy::Perl # installs the module
install AUXXX/Dummy-Perl-3.14.tar.gz # installs that distribution
install /Dummy-Perl-3.14/ # same if the regexp is unambiguous
"get" downloads a distribution file and untars or unzips it,
"make" builds it, "test" runs the test suite, and
"install" installs it.
Any "make" or "test" is run unconditionally. An
install <distribution_file>
is also run unconditionally. But for
install <module>
CPAN checks whether an install is needed and prints module up to date
if the distribution file containing the module doesn't need updating.
CPAN also keeps track of what it has done within the current session and
doesn't try to build a package a second time regardless of whether it
succeeded or not. It does not repeat a test run if the test has been run
successfully before. Same for install runs.
The "force" pragma may precede another command (currently:
"get", "make", "test", or
"install") to execute the command from scratch and attempt to
continue past certain errors. See the section below on the
"force" and the "fforce" pragma.
The "notest" pragma skips the test part in the build process.
Example:
cpan> notest install Tk
A "clean" command results in a
make clean
being executed within the distribution file's working directory.
- "readme", "perldoc", "look"
module or distribution
- "readme" displays the README file of the
associated distribution. "Look" gets and untars (if not yet
done) the distribution file, changes to the appropriate directory and
opens a subshell process in that directory. "perldoc" displays
the module's pod documentation in html or plain text format.
- "ls" author
- "ls" globbing_expression
- The first form lists all distribution files in and below an
author's CPAN directory as stored in the CHECKUMS files distributed on
CPAN. The listing recurses into subdirectories.
The second form limits or expands the output with shell globbing as in the
following examples:
ls JV/make*
ls GSAR/*make*
ls */*make*
The last example is very slow and outputs extra progress indicators that
break the alignment of the result.
Note that globbing only lists directories explicitly asked for, for example
FOO/* will not list FOO/bar/Acme-Sthg-n.nn.tar.gz. This may be regarded as
a bug that may be changed in some future version.
- "failed"
- The "failed" command reports all distributions
that failed on one of "make", "test" or
"install" for some reason in the currently running shell
session.
- Persistence between sessions
- If the "YAML" or the "YAML::Syck"
module is installed a record of the internal state of all modules is
written to disk after each step. The files contain a signature of the
currently running perl version for later perusal.
If the configurations variable "build_dir_reuse" is set to a true
value, then CPAN.pm reads the collected YAML files. If the stored
signature matches the currently running perl, the stored state is loaded
into memory such that persistence between sessions is effectively
established.
- The "force" and the "fforce"
pragma
- To speed things up in complex installation scenarios,
CPAN.pm keeps track of what it has already done and refuses to do some
things a second time. A "get", a "make", and an
"install" are not repeated. A "test" is repeated only
if the previous test was unsuccessful. The diagnostic message when CPAN.pm
refuses to do something a second time is one of Has already been
"unwrapped|made|tested successfully" or something similar.
Another situation where CPAN refuses to act is an "install" if
the corresponding "test" was not successful.
In all these cases, the user can override this stubborn behaviour by
prepending the command with the word force, for example:
cpan> force get Foo
cpan> force make AUTHOR/Bar-3.14.tar.gz
cpan> force test Baz
cpan> force install Acme::Meta
Each forced command is executed with the corresponding part of its
memory erased.
The "fforce" pragma is a variant that emulates a "force
get" which erases the entire memory followed by the action specified,
effectively restarting the whole get/make/test/install procedure from
scratch.
- Lockfile
- Interactive sessions maintain a lockfile, by default
"~/.cpan/.lock". Batch jobs can run without a lockfile and not
disturb each other.
The shell offers to run in downgraded mode when another process is
holding the lockfile. This is an experimental feature that is not yet
tested very well. This second shell then does not write the history file,
does not use the metadata file, and has a different prompt.
- Signals
- CPAN.pm installs signal handlers for SIGINT and SIGTERM.
While you are in the cpan-shell, it is intended that you can press
"^C" anytime and return to the cpan-shell prompt. A SIGTERM will
cause the cpan-shell to clean up and leave the shell loop. You can emulate
the effect of a SIGTERM by sending two consecutive SIGINTs, which usually
means by pressing "^C" twice.
CPAN.pm ignores SIGPIPE. If the user sets "inactivity_timeout", a
SIGALRM is used during the run of the "perl Makefile.PL" or
"perl Build.PL" subprocess. A SIGALRM is also used during module
version parsing, and is controlled by "version_timeout".
CPAN::Shell¶
The commands available in the shell interface are methods in the package
CPAN::Shell. If you enter the shell command, your input is split by the
Text::ParseWords::shellwords() routine, which acts like most shells do.
The first word is interpreted as the method to be invoked, and the rest of the
words are treated as the method's arguments. Continuation lines are supported
by ending a line with a literal backslash.
autobundle¶
"autobundle" writes a bundle file into the
"$CPAN::Config->{cpan_home}/Bundle" directory. The file contains
a list of all modules that are both available from CPAN and currently
installed within @INC. The name of the bundle file is based on the current
date and a counter.
hosts¶
Note: this feature is still in alpha state and may change in future versions of
CPAN.pm
This commands provides a statistical overview over recent download activities.
The data for this is collected in the YAML file "FTPstats.yml" in
your "cpan_home" directory. If no YAML module is configured or YAML
not installed, no stats are provided.
mkmyconfig¶
mkmyconfig() writes your own CPAN::MyConfig file into your
"~/.cpan/" directory so that you can save your own preferences
instead of the system-wide ones.
recent ***EXPERIMENTAL COMMAND***¶
The "recent" command downloads a list of recent uploads to CPAN and
displays them
slowly. While the command is running, a $SIG{INT} exits
the loop after displaying the current item.
Note: This command requires XML::LibXML installed.
Note: This whole command currently is just a hack and will probably
change in future versions of CPAN.pm, but the general approach will likely
remain.
Note: See also smoke
recompile¶
recompile() is a special command that takes no argument and runs the
make/test/install cycle with brute force over all installed dynamically
loadable extensions (a.k.a. XS modules) with 'force' in effect. The primary
purpose of this command is to finish a network installation. Imagine you have
a common source tree for two different architectures. You decide to do a
completely independent fresh installation. You start on one architecture with
the help of a Bundle file produced earlier. CPAN installs the whole Bundle for
you, but when you try to repeat the job on the second architecture, CPAN
responds with a "Foo up to date" message for all modules. So you
invoke CPAN's recompile on the second architecture and you're done.
Another popular use for "recompile" is to act as a rescue in case your
perl breaks binary compatibility. If one of the modules that CPAN uses is in
turn depending on binary compatibility (so you cannot run CPAN commands), then
you should try the CPAN::Nox module for recovery.
report Bundle|Distribution|Module¶
The "report" command temporarily turns on the "test_report"
config variable, then runs the "force test" command with the given
arguments. The "force" pragma reruns the tests and repeats every
step that might have failed before.
smoke ***EXPERIMENTAL COMMAND***¶
*** WARNING: this command downloads and executes software from CPAN to
your computer of completely unknown status. You should never do this
with your normal account and better have a dedicated well separated and
secured machine to do this. ***
The "smoke" command takes the list of recent uploads to CPAN as
provided by the "recent" command and tests them all. While the
command is running $SIG{INT} is defined to mean that the current item shall be
skipped.
Note: This whole command currently is just a hack and will probably
change in future versions of CPAN.pm, but the general approach will likely
remain.
Note: See also recent
upgrade [Module|/Regex/]...¶
The "upgrade" command first runs an "r" command with the
given arguments and then installs the newest versions of all modules that were
listed by that.
The four "CPAN::*" Classes: Author, Bundle, Module,
Distribution¶
Although it may be considered internal, the class hierarchy does matter for both
users and programmer. CPAN.pm deals with the four classes mentioned above, and
those classes all share a set of methods. Classical single polymorphism is in
effect. A metaclass object registers all objects of all kinds and indexes them
with a string. The strings referencing objects have a separated namespace
(well, not completely separated):
Namespace Class
words containing a "/" (slash) Distribution
words starting with Bundle:: Bundle
everything else Module or Author
Modules know their associated Distribution objects. They always refer to the
most recent official release. Developers may mark their releases as unstable
development versions (by inserting an underbar into the module version number
which will also be reflected in the distribution name when you run 'make
dist'), so the really hottest and newest distribution is not always the
default. If a module Foo circulates on CPAN in both version 1.23 and 1.23_90,
CPAN.pm offers a convenient way to install version 1.23 by saying
install Foo
This would install the complete distribution file (say BAR/Foo-1.23.tar.gz) with
all accompanying material. But if you would like to install version 1.23_90,
you need to know where the distribution file resides on CPAN relative to the
authors/id/ directory. If the author is BAR, this might be
BAR/Foo-1.23_90.tar.gz; so you would have to say
install BAR/Foo-1.23_90.tar.gz
The first example will be driven by an object of the class CPAN::Module, the
second by an object of class CPAN::Distribution.
Integrating local directories¶
Note: this feature is still in alpha state and may change in future versions of
CPAN.pm
Distribution objects are normally distributions from the CPAN, but there is a
slightly degenerate case for Distribution objects, too, of projects held on
the local disk. These distribution objects have the same name as the local
directory and end with a dot. A dot by itself is also allowed for the current
directory at the time CPAN.pm was used. All actions such as "make",
"test", and "install" are applied directly to that
directory. This gives the command "cpan ." an interesting touch:
while the normal mantra of installing a CPAN module without CPAN.pm is one of
perl Makefile.PL perl Build.PL
( go and get prerequisites )
make ./Build
make test ./Build test
make install ./Build install
the command "cpan ." does all of this at once. It figures out which of
the two mantras is appropriate, fetches and installs all prerequisites, takes
care of them recursively, and finally finishes the installation of the module
in the current directory, be it a CPAN module or not.
The typical usage case is for private modules or working copies of projects from
remote repositories on the local disk.
Redirection¶
The usual shell redirection symbols " | " and ">" are
recognized by the cpan shell
only when surrounded by whitespace. So
piping to pager or redirecting output into a file works somewhat as in a
normal shell, with the stipulation that you must type extra spaces.
CONFIGURATION¶
When the CPAN module is used for the first time, a configuration dialogue tries
to determine a couple of site specific options. The result of the dialog is
stored in a hash reference $CPAN::Config in a file CPAN/Config.pm.
Default values defined in the CPAN/Config.pm file can be overridden in a user
specific file: CPAN/MyConfig.pm. Such a file is best placed in
"$HOME/.cpan/CPAN/MyConfig.pm", because "$HOME/.cpan" is
added to the search path of the CPAN module before the
use() or
require() statements. The mkmyconfig command writes this file for you.
The "o conf" command has various bells and whistles:
- completion support
- If you have a ReadLine module installed, you can hit TAB at
any point of the commandline and "o conf" will offer you
completion for the built-in subcommands and/or config variable names.
- displaying some help: o conf help
- Displays a short help
- displaying current values: o conf [KEY]
- Displays the current value(s) for this config variable.
Without KEY, displays all subcommands and config variables.
Example:
o conf shell
If KEY starts and ends with a slash, the string in between is treated as a
regular expression and only keys matching this regex are displayed
Example:
o conf /color/
- changing of scalar values: o conf KEY VALUE
- Sets the config variable KEY to VALUE. The empty string can
be specified as usual in shells, with '' or ""
Example:
o conf wget /usr/bin/wget
- changing of list values: o conf KEY
SHIFT|UNSHIFT|PUSH|POP|SPLICE|LIST
- If a config variable name ends with "list", it is
a list. "o conf KEY shift" removes the first element of the
list, "o conf KEY pop" removes the last element of the list.
"o conf KEYS unshift LIST" prepends a list of values to the
list, "o conf KEYS push LIST" appends a list of valued to the
list.
Likewise, "o conf KEY splice LIST" passes the LIST to the
corresponding splice command.
Finally, any other list of arguments is taken as a new list value for the
KEY variable discarding the previous value.
Examples:
o conf urllist unshift http://cpan.dev.local/CPAN
o conf urllist splice 3 1
o conf urllist http://cpan1.local http://cpan2.local ftp://ftp.perl.org
- reverting to saved: o conf defaults
- Reverts all config variables to the state in the saved
config file.
- saving the config: o conf commit
- Saves all config variables to the current config file
(CPAN/Config.pm or CPAN/MyConfig.pm that was loaded at start).
The configuration dialog can be started any time later again by issuing the
command " o conf init " in the CPAN shell. A subset of the
configuration dialog can be run by issuing "o conf init WORD" where
WORD is any valid config variable or a regular expression.
Config Variables¶
The following keys in the hash reference $CPAN::Config are currently defined:
applypatch path to external prg
auto_commit commit all changes to config variables to disk
build_cache size of cache for directories to build modules
build_dir locally accessible directory to build modules
build_dir_reuse boolean if distros in build_dir are persistent
build_requires_install_policy
to install or not to install when a module is
only needed for building. yes|no|ask/yes|ask/no
bzip2 path to external prg
cache_metadata use serializer to cache metadata
check_sigs if signatures should be verified
colorize_debug Term::ANSIColor attributes for debugging output
colorize_output boolean if Term::ANSIColor should colorize output
colorize_print Term::ANSIColor attributes for normal output
colorize_warn Term::ANSIColor attributes for warnings
commandnumber_in_prompt
boolean if you want to see current command number
commands_quote preferred character to use for quoting external
commands when running them. Defaults to double
quote on Windows, single tick everywhere else;
can be set to space to disable quoting
connect_to_internet_ok
whether to ask if opening a connection is ok before
urllist is specified
cpan_home local directory reserved for this package
curl path to external prg
dontload_hash DEPRECATED
dontload_list arrayref: modules in the list will not be
loaded by the CPAN::has_inst() routine
ftp path to external prg
ftp_passive if set, the environment variable FTP_PASSIVE is set
for downloads
ftp_proxy proxy host for ftp requests
ftpstats_period max number of days to keep download statistics
ftpstats_size max number of items to keep in the download statistics
getcwd see below
gpg path to external prg
gzip location of external program gzip
halt_on_failure stop processing after the first failure of queued
items or dependencies
histfile file to maintain history between sessions
histsize maximum number of lines to keep in histfile
http_proxy proxy host for http requests
inactivity_timeout breaks interactive Makefile.PLs or Build.PLs
after this many seconds inactivity. Set to 0 to
disable timeouts.
index_expire refetch index files after this many days
inhibit_startup_message
if true, suppress the startup message
keep_source_where directory in which to keep the source (if we do)
load_module_verbosity
report loading of optional modules used by CPAN.pm
lynx path to external prg
make location of external make program
make_arg arguments that should always be passed to 'make'
make_install_make_command
the make command for running 'make install', for
example 'sudo make'
make_install_arg same as make_arg for 'make install'
makepl_arg arguments passed to 'perl Makefile.PL'
mbuild_arg arguments passed to './Build'
mbuild_install_arg arguments passed to './Build install'
mbuild_install_build_command
command to use instead of './Build' when we are
in the install stage, for example 'sudo ./Build'
mbuildpl_arg arguments passed to 'perl Build.PL'
ncftp path to external prg
ncftpget path to external prg
no_proxy don't proxy to these hosts/domains (comma separated list)
pager location of external program more (or any pager)
password your password if you CPAN server wants one
patch path to external prg
patches_dir local directory containing patch files
perl5lib_verbosity verbosity level for PERL5LIB additions
prefer_external_tar
per default all untar operations are done with
Archive::Tar; by setting this variable to true
the external tar command is used if available
prefer_installer legal values are MB and EUMM: if a module comes
with both a Makefile.PL and a Build.PL, use the
former (EUMM) or the latter (MB); if the module
comes with only one of the two, that one will be
used no matter the setting
prerequisites_policy
what to do if you are missing module prerequisites
('follow' automatically, 'ask' me, or 'ignore')
For 'follow', also sets PERL_AUTOINSTALL and
PERL_EXTUTILS_AUTOINSTALL for "--defaultdeps" if
not already set
prefs_dir local directory to store per-distro build options
proxy_user username for accessing an authenticating proxy
proxy_pass password for accessing an authenticating proxy
randomize_urllist add some randomness to the sequence of the urllist
scan_cache controls scanning of cache ('atstart', 'atexit' or 'never')
shell your favorite shell
show_unparsable_versions
boolean if r command tells which modules are versionless
show_upload_date boolean if commands should try to determine upload date
show_zero_versions boolean if r command tells for which modules $version==0
tar location of external program tar
tar_verbosity verbosity level for the tar command
term_is_latin deprecated: if true Unicode is translated to ISO-8859-1
(and nonsense for characters outside latin range)
term_ornaments boolean to turn ReadLine ornamenting on/off
test_report email test reports (if CPAN::Reporter is installed)
trust_test_report_history
skip testing when previously tested ok (according to
CPAN::Reporter history)
unzip location of external program unzip
urllist arrayref to nearby CPAN sites (or equivalent locations)
use_sqlite use CPAN::SQLite for metadata storage (fast and lean)
username your username if you CPAN server wants one
version_timeout stops version parsing after this many seconds.
Default is 15 secs. Set to 0 to disable.
wait_list arrayref to a wait server to try (See CPAN::WAIT)
wget path to external prg
yaml_load_code enable YAML code deserialisation via CPAN::DeferredCode
yaml_module which module to use to read/write YAML files
You can set and query each of these options interactively in the cpan shell with
the "o conf" or the "o conf init" command as specified
below.
- "o conf <scalar option>"
- prints the current value of the scalar option
- "o conf <scalar option> <value>"
- Sets the value of the scalar option to
value
- "o conf <list option>"
- prints the current value of the list option in
MakeMaker's neatvalue format.
- "o conf <list option> [shift|pop]"
- shifts or pops the array in the list option
variable
- "o conf <list option> [unshift|push|splice]
<list>"
- works like the corresponding perl commands.
- interactive editing: o conf init [MATCH|LIST]
- Runs an interactive configuration dialog for matching
variables. Without argument runs the dialog over all supported config
variables. To specify a MATCH the argument must be enclosed by slashes.
Examples:
o conf init ftp_passive ftp_proxy
o conf init /color/
Note: this method of setting config variables often provides more
explanation about the functioning of a variable than the manpage.
CPAN::anycwd($path): Note on config variable getcwd¶
CPAN.pm changes the current working directory often and needs to determine its
own current working directory. By default it uses Cwd::cwd, but if for some
reason this doesn't work on your system, configure alternatives according to
the following table:
- cwd
- Calls Cwd::cwd
- getcwd
- Calls Cwd::getcwd
- fastcwd
- Calls Cwd::fastcwd
- backtickcwd
- Calls the external command cwd.
urllist parameters are URLs according to RFC 1738. We do a little guessing if
your URL is not compliant, but if you have problems with "file"
URLs, please try the correct format. Either:
file://localhost/whatever/ftp/pub/CPAN/
or
file:///home/ftp/pub/CPAN/
The urllist parameter has CD-ROM support¶
The "urllist" parameter of the configuration table contains a list of
URLs used for downloading. If the list contains any "file" URLs,
CPAN always tries there first. This feature is disabled for index files. So
the recommendation for the owner of a CD-ROM with CPAN contents is: include
your local, possibly outdated CD-ROM as a "file" URL at the end of
urllist, e.g.
o conf urllist push file://localhost/CDROM/CPAN
CPAN.pm will then fetch the index files from one of the CPAN sites that come at
the beginning of urllist. It will later check for each module to see whether
there is a local copy of the most recent version.
Another peculiarity of urllist is that the site that we could successfully fetch
the last file from automatically gets a preference token and is tried as the
first site for the next request. So if you add a new site at runtime it may
happen that the previously preferred site will be tried another time. This
means that if you want to disallow a site for the next transfer, it must be
explicitly removed from urllist.
Maintaining the urllist parameter¶
If you have YAML.pm (or some other YAML module configured in
"yaml_module") installed, CPAN.pm collects a few statistical data
about recent downloads. You can view the statistics with the "hosts"
command or inspect them directly by looking into the "FTPstats.yml"
file in your "cpan_home" directory.
To get some interesting statistics, it is recommended that
"randomize_urllist" be set; this introduces some amount of
randomness into the URL selection.
The "requires" and "build_requires"
dependency declarations¶
Since CPAN.pm version 1.88_51 modules declared as "build_requires" by
a distribution are treated differently depending on the config variable
"build_requires_install_policy". By setting
"build_requires_install_policy" to "no", such a module is
not installed. It is only built and tested, and then kept in the list of
tested but uninstalled modules. As such, it is available during the build of
the dependent module by integrating the path to the "blib/arch" and
"blib/lib" directories in the environment variable PERL5LIB. If
"build_requires_install_policy" is set ti "yes", then both
modules declared as "requires" and those declared as
"build_requires" are treated alike. By setting to
"ask/yes" or "ask/no", CPAN.pm asks the user and sets the
default accordingly.
Configuration for individual distributions
(Distroprefs)¶
(
Note: This feature has been introduced in CPAN.pm 1.8854 and is still
considered beta quality)
Distributions on CPAN usually behave according to what we call the CPAN mantra.
Or since the advent of Module::Build we should talk about two mantras:
perl Makefile.PL perl Build.PL
make ./Build
make test ./Build test
make install ./Build install
But some modules cannot be built with this mantra. They try to get some extra
data from the user via the environment, extra arguments, or
interactively--thus disturbing the installation of large bundles like
Phalanx100 or modules with many dependencies like Plagger.
The distroprefs system of "CPAN.pm" addresses this problem by allowing
the user to specify extra informations and recipes in YAML files to either
- •
- pass additional arguments to one of the four commands,
- •
- set environment variables
- •
- instantiate an Expect object that reads from the console,
waits for some regular expressions and enters some answers
- •
- temporarily override assorted "CPAN.pm"
configuration variables
- •
- specify dependencies the original maintainer forgot
- •
- disable the installation of an object altogether
See the YAML and Data::Dumper files that come with the "CPAN.pm"
distribution in the "distroprefs/" directory for examples.
Filenames¶
The YAML files themselves must have the ".yml" extension; all other
files are ignored (for two exceptions see
Fallback Data::Dumper and
Storable below). The containing directory can be specified in
"CPAN.pm" in the "prefs_dir" config variable. Try "o
conf init prefs_dir" in the CPAN shell to set and activate the
distroprefs system.
Every YAML file may contain arbitrary documents according to the YAML
specification, and every document is treated as an entity that can specify the
treatment of a single distribution.
Filenames can be picked arbitrarily; "CPAN.pm" always reads all files
(in alphabetical order) and takes the key "match" (see below in
Language Specs) as a hashref containing match criteria that determine
if the current distribution matches the YAML document or not.
Fallback Data::Dumper and Storable¶
If neither your configured "yaml_module" nor YAML.pm is installed,
CPAN.pm falls back to using Data::Dumper and Storable and looks for files with
the extensions ".dd" or ".st" in the "prefs_dir"
directory. These files are expected to contain one or more hashrefs. For
Data::Dumper generated files, this is expected to be done with by defining
$VAR1, $VAR2, etc. The YAML shell would produce these with the command
ysh < somefile.yml > somefile.dd
For Storable files the rule is that they must be constructed such that
"Storable::retrieve(file)" returns an array reference and the array
elements represent one distropref object each. The conversion from YAML would
look like so:
perl -MYAML=LoadFile -MStorable=nstore -e '
@y=LoadFile(shift);
nstore(\@y, shift)' somefile.yml somefile.st
In bootstrapping situations it is usually sufficient to translate only a few
YAML files to Data::Dumper for crucial modules like "YAML::Syck",
"YAML.pm" and "Expect.pm". If you prefer Storable over
Data::Dumper, remember to pull out a Storable version that writes an older
format than all the other Storable versions that will need to read them.
Blueprint¶
The following example contains all supported keywords and structures with the
exception of "eexpect" which can be used instead of
"expect".
---
comment: "Demo"
match:
module: "Dancing::Queen"
distribution: "^CHACHACHA/Dancing-"
not_distribution: "\.zip$"
perl: "/usr/local/cariba-perl/bin/perl"
perlconfig:
archname: "freebsd"
not_cc: "gcc"
env:
DANCING_FLOOR: "Shubiduh"
disabled: 1
cpanconfig:
make: gmake
pl:
args:
- "--somearg=specialcase"
env: {}
expect:
- "Which is your favorite fruit"
- "apple\n"
make:
args:
- all
- extra-all
env: {}
expect: []
commandline: "echo SKIPPING make"
test:
args: []
env: {}
expect: []
install:
args: []
env:
WANT_TO_INSTALL: YES
expect:
- "Do you really want to install"
- "y\n"
patches:
- "ABCDE/Fedcba-3.14-ABCDE-01.patch"
depends:
configure_requires:
LWP: 5.8
build_requires:
Test::Exception: 0.25
requires:
Spiffy: 0.30
Language Specs¶
Every YAML document represents a single hash reference. The valid keys in this
hash are as follows:
- comment [scalar]
- A comment
- cpanconfig [hash]
- Temporarily override assorted "CPAN.pm"
configuration variables.
Supported are: "build_requires_install_policy",
"check_sigs", "make",
"make_install_make_command", "prefer_installer",
"test_report". Please report as a bug when you need another one
supported.
- depends [hash] *** EXPERIMENTAL FEATURE ***
- All three types, namely "configure_requires",
"build_requires", and "requires" are supported in the
way specified in the META.yml specification. The current implementation
merges the specified dependencies with those declared by the
package maintainer. In a future implementation this may be changed to
override the original declaration.
- disabled [boolean]
- Specifies that this distribution shall not be processed at
all.
- features [array] *** EXPERIMENTAL FEATURE ***
- Experimental implementation to deal with optional_features
from META.yml. Still needs coordination with installer software and
currently works only for META.yml declaring "dynamic_config=0".
Use with caution.
- goto [string]
- The canonical name of a delegate distribution to install
instead. Useful when a new version, although it tests OK itself, breaks
something else or a developer release or a fork is already uploaded that
is better than the last released version.
- install [hash]
- Processing instructions for the "make install" or
"./Build install" phase of the CPAN mantra. See below under
Processing Instructions.
- make [hash]
- Processing instructions for the "make" or
"./Build" phase of the CPAN mantra. See below under
Processing Instructions.
- match [hash]
- A hashref with one or more of the keys
"distribution", "modules", "perl",
"perlconfig", and "env" that specify whether a
document is targeted at a specific CPAN distribution or installation. Keys
prefixed with "not_" negates the corresponding match.
The corresponding values are interpreted as regular expressions. The
"distribution" related one will be matched against the canonical
distribution name, e.g. "AUTHOR/Foo-Bar-3.14.tar.gz".
The "module" related one will be matched against all
modules contained in the distribution until one module matches.
The "perl" related one will be matched against $^X (but with the
absolute path).
The value associated with "perlconfig" is itself a hashref that is
matched against corresponding values in the %Config::Config hash living in
the "Config.pm" module. Keys prefixed with "not_"
negates the corresponding match.
The value associated with "env" is itself a hashref that is
matched against corresponding values in the %ENV hash. Keys prefixed with
"not_" negates the corresponding match.
If more than one restriction of "module",
"distribution", etc. is specified, the results of the separately
computed match values must all match. If so, the hashref represented by
the YAML document is returned as the preference structure for the current
distribution.
- patches [array]
- An array of patches on CPAN or on the local disk to be
applied in order via an external patch program. If the value for the
"-p" parameter is 0 or 1 is determined by reading the patch
beforehand. The path to each patch is either an absolute path on the local
filesystem or relative to a patch directory specified in the
"patches_dir" configuration variable or in the format of a
canonical distro name. For examples please consult the distroprefs/
directory in the CPAN.pm distribution (these examples are not installed by
default).
Note: if the "applypatch" program is installed and
"CPAN::Config" knows about it and a patch is written by
the "makepatch" program, then "CPAN.pm" lets
"applypatch" apply the patch. Both "makepatch" and
"applypatch" are available from CPAN in the
"JV/makepatch-*" distribution.
- pl [hash]
- Processing instructions for the "perl
Makefile.PL" or "perl Build.PL" phase of the CPAN mantra.
See below under Processing Instructions.
- test [hash]
- Processing instructions for the "make test" or
"./Build test" phase of the CPAN mantra. See below under
Processing Instructions.
Processing Instructions¶
- args [array]
- Arguments to be added to the command line
- commandline
- A full commandline to run via "system()". During
execution, the environment variable PERL is set to $^X (but with an
absolute path). If "commandline" is specified, "args"
is not used.
- eexpect [hash]
- Extended "expect". This is a hash reference with
four allowed keys, "mode", "timeout",
"reuse", and "talk".
You must install the "Expect" module to use "eexpect".
CPAN.pm does not install it for you.
"mode" may have the values "deterministic" for the case
where all questions come in the order written down and
"anyorder" for the case where the questions may come in any
order. The default mode is "deterministic".
"timeout" denotes a timeout in seconds. Floating-point timeouts
are OK. With "mode=deterministic", the timeout denotes the
timeout per question; with "mode=anyorder" it denotes the
timeout per byte received from the stream or questions.
"talk" is a reference to an array that contains alternating
questions and answers. Questions are regular expressions and answers are
literal strings. The Expect module watches the stream from the execution
of the external program ("perl Makefile.PL", "perl
Build.PL", "make", etc.).
For "mode=deterministic", the CPAN.pm injects the corresponding
answer as soon as the stream matches the regular expression.
For "mode=anyorder" CPAN.pm answers a question as soon as the
timeout is reached for the next byte in the input stream. In this mode you
can use the "reuse" parameter to decide what will happen with a
question-answer pair after it has been used. In the default case (reuse=0)
it is removed from the array, avoiding being used again accidentally. If
you want to answer the question "Do you really want to do that"
several times, then it must be included in the array at least as often as
you want this answer to be given. Setting the parameter "reuse"
to 1 makes this repetition unnecessary.
- env [hash]
- Environment variables to be set during the command
- expect [array]
- You must install the "Expect" module to use
"expect". CPAN.pm does not install it for you.
"expect: <array>" is a short notation for this
"eexpect":
eexpect:
mode: deterministic
timeout: 15
talk: <array>
Schema verification with "Kwalify"¶
If you have the "Kwalify" module installed (which is part of the
Bundle::CPANxxl), then all your distroprefs files are checked for syntactic
correctness.
Example Distroprefs Files¶
"CPAN.pm" comes with a collection of example YAML files. Note that
these are really just examples and should not be used without care because
they cannot fit everybody's purpose. After all, the authors of the packages
that ask questions had a need to ask, so you should watch their questions and
adjust the examples to your environment and your needs. You have been
warned:-)
PROGRAMMER'S INTERFACE¶
If you do not enter the shell, shell commands are available both as methods
("CPAN::Shell->install(...)") and as functions in the calling
package ("install(...)"). Before calling low-level commands, it
makes sense to initialize components of CPAN you need, e.g.:
CPAN::HandleConfig->load;
CPAN::Shell::setup_output;
CPAN::Index->reload;
High-level commands do such initializations automatically.
There's currently only one class that has a stable interface - CPAN::Shell. All
commands that are available in the CPAN shell are methods of the class
CPAN::Shell. Each of the commands that produce listings of modules
("r", "autobundle", "u") also return a list of
the IDs of all modules within the list.
- expand($type,@things)
- The IDs of all objects available within a program are
strings that can be expanded to the corresponding real objects with the
"CPAN::Shell->expand("Module",@things)" method.
Expand returns a list of CPAN::Module objects according to the @things
arguments given. In scalar context, it returns only the first element of
the list.
- expandany(@things)
- Like expand, but returns objects of the appropriate type,
i.e. CPAN::Bundle objects for bundles, CPAN::Module objects for modules,
and CPAN::Distribution objects for distributions. Note: it does not expand
to CPAN::Author objects.
- Programming Examples
- This enables the programmer to do operations that combine
functionalities that are available in the shell.
# install everything that is outdated on my disk:
perl -MCPAN -e 'CPAN::Shell->install(CPAN::Shell->r)'
# install my favorite programs if necessary:
for $mod (qw(Net::FTP Digest::SHA Data::Dumper)) {
CPAN::Shell->install($mod);
}
# list all modules on my disk that have no VERSION number
for $mod (CPAN::Shell->expand("Module","/./")) {
next unless $mod->inst_file;
# MakeMaker convention for undefined $VERSION:
next unless $mod->inst_version eq "undef";
print "No VERSION in ", $mod->id, "\n";
}
# find out which distribution on CPAN contains a module:
print CPAN::Shell->expand("Module","Apache::Constants")->cpan_file
Or if you want to schedule a cron job to watch CPAN, you could list
all modules that need updating. First a quick and dirty way:
perl -e 'use CPAN; CPAN::Shell->r;'
If you don't want any output should all modules be up to date, parse the
output of above command for the regular expression "/modules are up
to date/" and decide to mail the output only if it doesn't match.
If you prefer to do it more in a programmerish style in one single process,
something like this may better suit you:
# list all modules on my disk that have newer versions on CPAN
for $mod (CPAN::Shell->expand("Module","/./")) {
next unless $mod->inst_file;
next if $mod->uptodate;
printf "Module %s is installed as %s, could be updated to %s from CPAN\n",
$mod->id, $mod->inst_version, $mod->cpan_version;
}
If that gives too much output every day, you may want to watch only for
three modules. You can write
for $mod (CPAN::Shell->expand("Module","/Apache|LWP|CGI/")) {
as the first line instead. Or you can combine some of the above tricks:
# watch only for a new mod_perl module
$mod = CPAN::Shell->expand("Module","mod_perl");
exit if $mod->uptodate;
# new mod_perl arrived, let me know all update recommendations
CPAN::Shell->r;
Methods in the other Classes¶
- CPAN::Author::as_glimpse()
- Returns a one-line description of the author
- CPAN::Author::as_string()
- Returns a multi-line description of the author
- CPAN::Author::email()
- Returns the author's email address
- CPAN::Author::fullname()
- Returns the author's name
- CPAN::Author::name()
- An alias for fullname
- CPAN::Bundle::as_glimpse()
- Returns a one-line description of the bundle
- CPAN::Bundle::as_string()
- Returns a multi-line description of the bundle
- CPAN::Bundle::clean()
- Recursively runs the "clean" method on all items
contained in the bundle.
- CPAN::Bundle::contains()
- Returns a list of objects' IDs contained in a bundle. The
associated objects may be bundles, modules or distributions.
- CPAN::Bundle::force($method,@args)
- Forces CPAN to perform a task that it normally would have
refused to do. Force takes as arguments a method name to be called and any
number of additional arguments that should be passed to the called method.
The internals of the object get the needed changes so that CPAN.pm does
not refuse to take the action. The "force" is passed recursively
to all contained objects. See also the section above on the
"force" and the "fforce" pragma.
- CPAN::Bundle::get()
- Recursively runs the "get" method on all items
contained in the bundle
- CPAN::Bundle::inst_file()
- Returns the highest installed version of the bundle in
either @INC or "$CPAN::Config->{cpan_home}". Note that this
is different from CPAN::Module::inst_file.
- CPAN::Bundle::inst_version()
- Like CPAN::Bundle::inst_file, but returns the $VERSION
- CPAN::Bundle::uptodate()
- Returns 1 if the bundle itself and all its members are
up-to-date.
- CPAN::Bundle::install()
- Recursively runs the "install" method on all
items contained in the bundle
- CPAN::Bundle::make()
- Recursively runs the "make" method on all items
contained in the bundle
- CPAN::Bundle::readme()
- Recursively runs the "readme" method on all items
contained in the bundle
- CPAN::Bundle::test()
- Recursively runs the "test" method on all items
contained in the bundle
- CPAN::Distribution::as_glimpse()
- Returns a one-line description of the distribution
- CPAN::Distribution::as_string()
- Returns a multi-line description of the distribution
- CPAN::Distribution::author
- Returns the CPAN::Author object of the maintainer who
uploaded this distribution
- CPAN::Distribution::pretty_id()
- Returns a string of the form "AUTHORID/TARBALL",
where AUTHORID is the author's PAUSE ID and TARBALL is the distribution
filename.
- CPAN::Distribution::base_id()
- Returns the distribution filename without any archive
suffix. E.g "Foo-Bar-0.01"
- CPAN::Distribution::clean()
- Changes to the directory where the distribution has been
unpacked and runs "make clean" there.
- CPAN::Distribution::containsmods()
- Returns a list of IDs of modules contained in a
distribution file. Works only for distributions listed in the
02packages.details.txt.gz file. This typically means that just most recent
version of a distribution is covered.
- CPAN::Distribution::cvs_import()
- Changes to the directory where the distribution has been
unpacked and runs something like
cvs -d $cvs_root import -m $cvs_log $cvs_dir $userid v$version
there.
- CPAN::Distribution::dir()
- Returns the directory into which this distribution has been
unpacked.
- CPAN::Distribution::force($method,@args)
- Forces CPAN to perform a task that it normally would have
refused to do. Force takes as arguments a method name to be called and any
number of additional arguments that should be passed to the called method.
The internals of the object get the needed changes so that CPAN.pm does
not refuse to take the action. See also the section above on the
"force" and the "fforce" pragma.
- CPAN::Distribution::get()
- Downloads the distribution from CPAN and unpacks it. Does
nothing if the distribution has already been downloaded and unpacked
within the current session.
- CPAN::Distribution::install()
- Changes to the directory where the distribution has been
unpacked and runs the external command "make install" there. If
"make" has not yet been run, it will be run first. A "make
test" is issued in any case and if this fails, the install is
cancelled. The cancellation can be avoided by letting "force"
run the "install" for you.
This install method only has the power to install the distribution if there
are no dependencies in the way. To install an object along with all its
dependencies, use CPAN::Shell->install.
Note that install() gives no meaningful return value. See
uptodate().
- CPAN::Distribution::install_tested()
- Install all distributions that have tested successfully but
not yet installed. See also "is_tested".
- CPAN::Distribution::isa_perl()
- Returns 1 if this distribution file seems to be a perl
distribution. Normally this is derived from the file name only, but the
index from CPAN can contain a hint to achieve a return value of true for
other filenames too.
- CPAN::Distribution::look()
- Changes to the directory where the distribution has been
unpacked and opens a subshell there. Exiting the subshell returns.
- CPAN::Distribution::make()
- First runs the "get" method to make sure the
distribution is downloaded and unpacked. Changes to the directory where
the distribution has been unpacked and runs the external commands
"perl Makefile.PL" or "perl Build.PL" and
"make" there.
- CPAN::Distribution::perldoc()
- Downloads the pod documentation of the file associated with
a distribution (in HTML format) and runs it through the external command
lynx specified in "$CPAN::Config->{lynx}". If
lynx isn't available, it converts it to plain text with the
external command html2text and runs it through the pager specified
in "$CPAN::Config->{pager}".
- CPAN::Distribution::prefs()
- Returns the hash reference from the first matching YAML
file that the user has deposited in the "prefs_dir/" directory.
The first succeeding match wins. The files in the "prefs_dir/"
are processed alphabetically, and the canonical distro name (e.g.
AUTHOR/Foo-Bar-3.14.tar.gz) is matched against the regular expressions
stored in the $root->{match}{distribution} attribute value.
Additionally all module names contained in a distribution are matched
against the regular expressions in the $root->{match}{module} attribute
value. The two match values are ANDed together. Each of the two attributes
are optional.
- CPAN::Distribution::prereq_pm()
- Returns the hash reference that has been announced by a
distribution as the "requires" and "build_requires"
elements. These can be declared either by the "META.yml" (if
authoritative) or can be deposited after the run of "Build.PL"
in the file "./_build/prereqs" or after the run of
"Makfile.PL" written as the "PREREQ_PM" hash in a
comment in the produced "Makefile". Note: this method
only works after an attempt has been made to "make" the
distribution. Returns undef otherwise.
- CPAN::Distribution::readme()
- Downloads the README file associated with a distribution
and runs it through the pager specified in
"$CPAN::Config->{pager}".
- CPAN::Distribution::reports()
- Downloads report data for this distribution from
www.cpantesters.org and displays a subset of them.
- CPAN::Distribution::read_yaml()
- Returns the content of the META.yml of this distro as a
hashref. Note: works only after an attempt has been made to
"make" the distribution. Returns undef otherwise. Also returns
undef if the content of META.yml is not authoritative. (The rules about
what exactly makes the content authoritative are still in flux.)
- CPAN::Distribution::test()
- Changes to the directory where the distribution has been
unpacked and runs "make test" there.
- CPAN::Distribution::uptodate()
- Returns 1 if all the modules contained in the distribution
are up-to-date. Relies on containsmods.
- CPAN::Index::force_reload()
- Forces a reload of all indices.
- CPAN::Index::reload()
- Reloads all indices if they have not been read for more
than "$CPAN::Config->{index_expire}" days.
- CPAN::InfoObj::dump()
- CPAN::Author, CPAN::Bundle, CPAN::Module, and
CPAN::Distribution inherit this method. It prints the data structure
associated with an object. Useful for debugging. Note: the data structure
is considered internal and thus subject to change without notice.
- CPAN::Module::as_glimpse()
- Returns a one-line description of the module in four
columns: The first column contains the word "Module", the second
column consists of one character: an equals sign if this module is already
installed and up-to-date, a less-than sign if this module is installed but
can be upgraded, and a space if the module is not installed. The third
column is the name of the module and the fourth column gives maintainer or
distribution information.
- CPAN::Module::as_string()
- Returns a multi-line description of the module
- CPAN::Module::clean()
- Runs a clean on the distribution associated with this
module.
- CPAN::Module::cpan_file()
- Returns the filename on CPAN that is associated with the
module.
- CPAN::Module::cpan_version()
- Returns the latest version of this module available on
CPAN.
- CPAN::Module::cvs_import()
- Runs a cvs_import on the distribution associated with this
module.
- CPAN::Module::description()
- Returns a 44 character description of this module. Only
available for modules listed in The Module List
(CPAN/modules/00modlist.long.html or 00modlist.long.txt.gz)
- CPAN::Module::distribution()
- Returns the CPAN::Distribution object that contains the
current version of this module.
- CPAN::Module::dslip_status()
- Returns a hash reference. The keys of the hash are the
letters "D", "S", "L", "I", and
<P>, for development status, support level, language, interface and
public licence respectively. The data for the DSLIP status are collected
by pause.perl.org when authors register their namespaces. The values of
the 5 hash elements are one-character words whose meaning is described in
the table below. There are also 5 hash elements "DV",
"SV", "LV", "IV", and <PV> that carry
a more verbose value of the 5 status variables.
Where the 'DSLIP' characters have the following meanings:
D - Development Stage (Note: *NO IMPLIED TIMESCALES*):
i - Idea, listed to gain consensus or as a placeholder
c - under construction but pre-alpha (not yet released)
a/b - Alpha/Beta testing
R - Released
M - Mature (no rigorous definition)
S - Standard, supplied with Perl 5
S - Support Level:
m - Mailing-list
d - Developer
u - Usenet newsgroup comp.lang.perl.modules
n - None known, try comp.lang.perl.modules
a - abandoned; volunteers welcome to take over maintenance
L - Language Used:
p - Perl-only, no compiler needed, should be platform independent
c - C and perl, a C compiler will be needed
h - Hybrid, written in perl with optional C code, no compiler needed
+ - C++ and perl, a C++ compiler will be needed
o - perl and another language other than C or C++
I - Interface Style
f - plain Functions, no references used
h - hybrid, object and function interfaces available
n - no interface at all (huh?)
r - some use of unblessed References or ties
O - Object oriented using blessed references and/or inheritance
P - Public License
p - Standard-Perl: user may choose between GPL and Artistic
g - GPL: GNU General Public License
l - LGPL: "GNU Lesser General Public License" (previously known as
"GNU Library General Public License")
b - BSD: The BSD License
a - Artistic license alone
2 - Artistic license 2.0 or later
o - open source: approved by www.opensource.org
d - allows distribution without restrictions
r - restricted distribution
n - no license at all
- CPAN::Module::force($method,@args)
- Forces CPAN to perform a task it would normally refuse to
do. Force takes as arguments a method name to be invoked and any number of
additional arguments to pass that method. The internals of the object get
the needed changes so that CPAN.pm does not refuse to take the action. See
also the section above on the "force" and the "fforce"
pragma.
- CPAN::Module::get()
- Runs a get on the distribution associated with this
module.
- CPAN::Module::inst_file()
- Returns the filename of the module found in @INC. The first
file found is reported, just as perl itself stops searching @INC once it
finds a module.
- CPAN::Module::available_file()
- Returns the filename of the module found in PERL5LIB or
@INC. The first file found is reported. The advantage of this method over
"inst_file" is that modules that have been tested but not yet
installed are included because PERL5LIB keeps track of tested
modules.
- CPAN::Module::inst_version()
- Returns the version number of the installed module in
readable format.
- CPAN::Module::available_version()
- Returns the version number of the available module in
readable format.
- CPAN::Module::install()
- Runs an "install" on the distribution associated
with this module.
- CPAN::Module::look()
- Changes to the directory where the distribution associated
with this module has been unpacked and opens a subshell there. Exiting the
subshell returns.
- CPAN::Module::make()
- Runs a "make" on the distribution associated with
this module.
- CPAN::Module::manpage_headline()
- If module is installed, peeks into the module's manpage,
reads the headline, and returns it. Moreover, if the module has been
downloaded within this session, does the equivalent on the downloaded
module even if it hasn't been installed yet.
- CPAN::Module::perldoc()
- Runs a "perldoc" on this module.
- CPAN::Module::readme()
- Runs a "readme" on the distribution associated
with this module.
- CPAN::Module::reports()
- Calls the reports() method on the associated
distribution object.
- CPAN::Module::test()
- Runs a "test" on the distribution associated with
this module.
- CPAN::Module::uptodate()
- Returns 1 if the module is installed and up-to-date.
- CPAN::Module::userid()
- Returns the author's ID of the module.
Cache Manager¶
Currently the cache manager only keeps track of the build directory
($CPAN::Config->{build_dir}). It is a simple FIFO mechanism that deletes
complete directories below "build_dir" as soon as the size of all
directories there gets bigger than $CPAN::Config->{build_cache} (in MB).
The contents of this cache may be used for later re-installations that you
intend to do manually, but will never be trusted by CPAN itself. This is due
to the fact that the user might use these directories for building modules on
different architectures.
There is another directory ($CPAN::Config->{keep_source_where}) where the
original distribution files are kept. This directory is not covered by the
cache manager and must be controlled by the user. If you choose to have the
same directory as build_dir and as keep_source_where directory, then your
sources will be deleted with the same fifo mechanism.
Bundles¶
A bundle is just a perl module in the namespace Bundle:: that does not define
any functions or methods. It usually only contains documentation.
It starts like a perl module with a package declaration and a $VERSION variable.
After that the pod section looks like any other pod with the only difference
being that
one special pod section exists starting with (verbatim):
=head1 CONTENTS
In this pod section each line obeys the format
Module_Name [Version_String] [- optional text]
The only required part is the first field, the name of a module (e.g. Foo::Bar,
i.e.
not the name of the distribution file). The rest of the line is
optional. The comment part is delimited by a dash just as in the man page
header.
The distribution of a bundle should follow the same convention as other
distributions.
Bundles are treated specially in the CPAN package. If you say 'install
Bundle::Tkkit' (assuming such a bundle exists), CPAN will install all the
modules in the CONTENTS section of the pod. You can install your own Bundles
locally by placing a conformant Bundle file somewhere into your @INC path. The
autobundle() command which is available in the shell interface does
that for you by including all currently installed modules in a snapshot bundle
file.
PREREQUISITES¶
The CPAN program is trying to depend on as little as possible so the user can
use it in hostile environment. It works better the more goodies the
environment provides. For example if you try in the CPAN shell
install Bundle::CPAN
or
install Bundle::CPANxxl
you will find the shell more convenient than the bare shell before.
If you have a local mirror of CPAN and can access all files with
"file:" URLs, then you only need a perl later than perl5.003 to run
this module. Otherwise Net::FTP is strongly recommended. LWP may be required
for non-UNIX systems, or if your nearest CPAN site is associated with a URL
that is not "ftp:".
If you have neither Net::FTP nor LWP, there is a fallback mechanism implemented
for an external ftp command or for an external lynx command.
UTILITIES¶
Finding packages and VERSION¶
This module presumes that all packages on CPAN
- •
- declare their $VERSION variable in an easy to parse manner.
This prerequisite can hardly be relaxed because it consumes far too much
memory to load all packages into the running program just to determine the
$VERSION variable. Currently all programs that are dealing with version
use something like this
perl -MExtUtils::MakeMaker -le \
'print MM->parse_version(shift)' filename
If you are author of a package and wonder if your $VERSION can be parsed,
please try the above method.
- •
- come as compressed or gzipped tarfiles or as zip files and
contain a "Makefile.PL" or "Build.PL" (well, we try to
handle a bit more, but with little enthusiasm).
Debugging¶
Debugging this module is more than a bit complex due to interference from the
software producing the indices on CPAN, the mirroring process on CPAN,
packaging, configuration, synchronicity, and even (gasp!) due to bugs within
the CPAN.pm module itself.
For debugging the code of CPAN.pm itself in interactive mode, some debugging aid
can be turned on for most packages within CPAN.pm with one of
- o debug package...
- sets debug mode for packages.
- o debug -package...
- unsets debug mode for packages.
- o debug all
- turns debugging on for all packages.
- o debug number
which sets the debugging packages directly. Note that "o debug 0"
turns debugging off.
What seems a successful strategy is the combination of "reload cpan"
and the debugging switches. Add a new debug statement while running in the
shell and then issue a "reload cpan" and see the new debugging
messages immediately without losing the current context.
"o debug" without an argument lists the valid package names and the
current set of packages in debugging mode. "o debug" has built-in
completion support.
For debugging of CPAN data there is the "dump" command which takes the
same arguments as make/test/install and outputs each object's Data::Dumper
dump. If an argument looks like a perl variable and contains one of
"$", "@" or "%", it is
eval()ed and fed
to Data::Dumper directly.
Floppy, Zip, Offline Mode¶
CPAN.pm works nicely without network access, too. If you maintain machines that
are not networked at all, you should consider working with "file:"
URLs. You'll have to collect your modules somewhere first. So you might use
CPAN.pm to put together all you need on a networked machine. Then copy the
$CPAN::Config->{keep_source_where} (but not $CPAN::Config->{build_dir})
directory on a floppy. This floppy is kind of a personal CPAN. CPAN.pm on the
non-networked machines works nicely with this floppy. See also below the
paragraph about CD-ROM support.
Basic Utilities for Programmers¶
- has_inst($module)
- Returns true if the module is installed. Used to load all
modules into the running CPAN.pm that are considered optional. The config
variable "dontload_list" intercepts the "has_inst()"
call such that an optional module is not loaded despite being available.
For example, the following command will prevent "YAML.pm" from
being loaded:
cpan> o conf dontload_list push YAML
See the source for details.
- has_usable($module)
- Returns true if the module is installed and in a usable
state. Only useful for a handful of modules that are used internally. See
the source for details.
- instance($module)
- The constructor for all the singletons used to represent
modules, distributions, authors, and bundles. If the object already
exists, this method returns the object; otherwise, it calls the
constructor.
SECURITY¶
There's no strong security layer in CPAN.pm. CPAN.pm helps you to install
foreign, unmasked, unsigned code on your machine. We compare to a checksum
that comes from the net just as the distribution file itself. But we try to
make it easy to add security on demand:
Cryptographically signed modules¶
Since release 1.77, CPAN.pm has been able to verify cryptographically signed
module distributions using Module::Signature. The CPAN modules can be signed
by their authors, thus giving more security. The simple unsigned MD5 checksums
that were used before by CPAN protect mainly against accidental file
corruption.
You will need to have Module::Signature installed, which in turn requires that
you have at least one of Crypt::OpenPGP module or the command-line
gpg
tool installed.
You will also need to be able to connect over the Internet to the public key
servers, like pgp.mit.edu, and their port 11731 (the HKP protocol).
The configuration parameter check_sigs is there to turn signature checking on or
off.
EXPORT¶
Most functions in package CPAN are exported by default. The reason for this is
that the primary use is intended for the cpan shell or for one-liners.
ENVIRONMENT¶
When the CPAN shell enters a subshell via the look command, it sets the
environment CPAN_SHELL_LEVEL to 1, or increments that variable if it is
already set.
When CPAN runs, it sets the environment variable PERL5_CPAN_IS_RUNNING to the ID
of the running process. It also sets PERL5_CPANPLUS_IS_RUNNING to prevent
runaway processes which could happen with older versions of Module::Install.
When running "perl Makefile.PL", the environment variable
"PERL5_CPAN_IS_EXECUTING" is set to the full path of the
"Makefile.PL" that is being executed. This prevents runaway
processes with newer versions of Module::Install.
When the config variable ftp_passive is set, all downloads will be run with the
environment variable FTP_PASSIVE set to this value. This is in general a good
idea as it influences both Net::FTP and LWP based connections. The same effect
can be achieved by starting the cpan shell with this environment variable set.
For Net::FTP alone, one can also always set passive mode by running libnetcfg.
POPULATE AN INSTALLATION WITH LOTS OF MODULES¶
Populating a freshly installed perl with one's favorite modules is pretty easy
if you maintain a private bundle definition file. To get a useful blueprint of
a bundle definition file, the command autobundle can be used on the CPAN shell
command line. This command writes a bundle definition file for all modules
installed for the current perl interpreter. It's recommended to run this
command once only, and from then on maintain the file manually under a private
name, say Bundle/my_bundle.pm. With a clever bundle file you can then simply
say
cpan> install Bundle::my_bundle
then answer a few questions and go out for coffee (possibly even in a different
city).
Maintaining a bundle definition file means keeping track of two things:
dependencies and interactivity. CPAN.pm sometimes fails on calculating
dependencies because not all modules define all MakeMaker attributes
correctly, so a bundle definition file should specify prerequisites as early
as possible. On the other hand, it's annoying that so many distributions need
some interactive configuring. So what you can try to accomplish in your
private bundle file is to have the packages that need to be configured early
in the file and the gentle ones later, so you can go out for coffee after a
few minutes and leave CPAN.pm to churn away untended.
WORKING WITH CPAN.pm BEHIND FIREWALLS¶
Thanks to Graham Barr for contributing the following paragraphs about the
interaction between perl, and various firewall configurations. For further
information on firewalls, it is recommended to consult the documentation that
comes with the
ncftp program. If you are unable to go through the
firewall with a simple Perl setup, it is likely that you can configure
ncftp so that it works through your firewall.
Three basic types of firewalls¶
Firewalls can be categorized into three basic types.
- http firewall
- This is when the firewall machine runs a web server, and to
access the outside world, you must do so via that web server. If you set
environment variables like http_proxy or ftp_proxy to values beginning
with http://, or in your web browser you've proxy information set, then
you know you are running behind an http firewall.
To access servers outside these types of firewalls with perl (even for ftp),
you need LWP or HTTP::Tiny.
- ftp firewall
- This where the firewall machine runs an ftp server. This
kind of firewall will only let you access ftp servers outside the
firewall. This is usually done by connecting to the firewall with ftp,
then entering a username like "user@outside.host.com".
To access servers outside these type of firewalls with perl, you need
Net::FTP.
- One-way visibility
- One-way visibility means these firewalls try to make
themselves invisible to users inside the firewall. An FTP data connection
is normally created by sending your IP address to the remote server and
then listening for the return connection. But the remote server will not
be able to connect to you because of the firewall. For these types of
firewall, FTP connections need to be done in a passive mode.
There are two that I can think off.
- SOCKS
- If you are using a SOCKS firewall, you will need to compile
perl and link it with the SOCKS library. This is what is normally called a
'socksified' perl. With this executable you will be able to connect to
servers outside the firewall as if it were not there.
- IP Masquerade
- This is when the firewall implemented in the kernel (via
NAT, or networking address translation), it allows you to hide a complete
network behind one IP address. With this firewall no special compiling is
needed as you can access hosts directly.
For accessing ftp servers behind such firewalls you usually need to set the
environment variable "FTP_PASSIVE" or the config variable
ftp_passive to a true value.
Configuring lynx or ncftp for going through a firewall¶
If you can go through your firewall with e.g. lynx, presumably with a command
such as
/usr/local/bin/lynx -pscott:tiger
then you would configure CPAN.pm with the command
o conf lynx "/usr/local/bin/lynx -pscott:tiger"
That's all. Similarly for ncftp or ftp, you would configure something like
o conf ncftp "/usr/bin/ncftp -f /home/scott/ncftplogin.cfg"
Your mileage may vary...
FAQ¶
- 1)
- I installed a new version of module X but CPAN keeps
saying, I have the old version installed
Probably you do have the old version installed. This can happen if a
module installs itself into a different directory in the @INC path than it
was previously installed. This is not really a CPAN.pm problem, you would
have the same problem when installing the module manually. The easiest way
to prevent this behaviour is to add the argument "UNINST=1" to
the "make install" call, and that is why many people add this
argument permanently by configuring
o conf make_install_arg UNINST=1
- 2)
- So why is UNINST=1 not the default?
Because there are people who have their precise expectations about who may
install where in the @INC path and who uses which @INC array. In fine
tuned environments "UNINST=1" can cause damage.
- 3)
- I want to clean up my mess, and install a new perl along
with all modules I have. How do I go about it?
Run the autobundle command for your old perl and optionally rename the
resulting bundle file (e.g. Bundle/mybundle.pm), install the new perl with
the Configure option prefix, e.g.
./Configure -Dprefix=/usr/local/perl-5.6.78.9
Install the bundle file you produced in the first step with something like
cpan> install Bundle::mybundle
and you're done.
- 4)
- When I install bundles or multiple modules with one command
there is too much output to keep track of.
You may want to configure something like
o conf make_arg "| tee -ai /root/.cpan/logs/make.out"
o conf make_install_arg "| tee -ai /root/.cpan/logs/make_install.out"
so that STDOUT is captured in a file for later inspection.
- 5)
- I am not root, how can I install a module in a personal
directory?
As of CPAN 1.9463, if you do not have permission to write the default perl
library directories, CPAN's configuration process will ask you whether you
want to bootstrap <local::lib>, which makes keeping a personal perl
library directory easy.
Another thing you should bear in mind is that the UNINST parameter can be
dangerous when you are installing into a private area because you might
accidentally remove modules that other people depend on that are not using
the private area.
- 6)
- How to get a package, unwrap it, and make a change before
building it?
Have a look at the "look" (!) command.
- 7)
- I installed a Bundle and had a couple of fails. When I
retried, everything resolved nicely. Can this be fixed to work on first
try?
The reason for this is that CPAN does not know the dependencies of all
modules when it starts out. To decide about the additional items to
install, it just uses data found in the META.yml file or the generated
Makefile. An undetected missing piece breaks the process. But it may well
be that your Bundle installs some prerequisite later than some depending
item and thus your second try is able to resolve everything. Please note,
CPAN.pm does not know the dependency tree in advance and cannot sort the
queue of things to install in a topologically correct order. It resolves
perfectly well if all modules declare the prerequisites correctly
with the PREREQ_PM attribute to MakeMaker or the "requires"
stanza of Module::Build. For bundles which fail and you need to install
often, it is recommended to sort the Bundle definition file manually.
- 8)
- In our intranet, we have many modules for internal use. How
can I integrate these modules with CPAN.pm but without uploading the
modules to CPAN?
Have a look at the CPAN::Site module.
- 9)
- When I run CPAN's shell, I get an error message about
things in my "/etc/inputrc" (or "~/.inputrc") file.
These are readline issues and can only be fixed by studying readline
configuration on your architecture and adjusting the referenced file
accordingly. Please make a backup of the "/etc/inputrc" or
"~/.inputrc" and edit them. Quite often harmless changes like
uppercasing or lowercasing some arguments solves the problem.
- 10)
- Some authors have strange characters in their names.
Internally CPAN.pm uses the UTF-8 charset. If your terminal is expecting
ISO-8859-1 charset, a converter can be activated by setting term_is_latin
to a true value in your config file. One way of doing so would be
cpan> o conf term_is_latin 1
If other charset support is needed, please file a bug report against CPAN.pm
at rt.cpan.org and describe your needs. Maybe we can extend the support or
maybe UTF-8 terminals become widely available.
Note: this config variable is deprecated and will be removed in a future
version of CPAN.pm. It will be replaced with the conventions around the
family of $LANG and $LC_* environment variables.
- 11)
- When an install fails for some reason and then I correct
the error condition and retry, CPAN.pm refuses to install the module,
saying "Already tried without success".
Use the force pragma like so
force install Foo::Bar
Or you can use
look Foo::Bar
and then "make install" directly in the subshell.
- 12)
- How do I install a "DEVELOPER RELEASE" of a
module?
By default, CPAN will install the latest non-developer release of a module.
If you want to install a dev release, you have to specify the partial path
starting with the author id to the tarball you wish to install, like so:
cpan> install KWILLIAMS/Module-Build-0.27_07.tar.gz
Note that you can use the "ls" command to get this path
listed.
- 13)
- How do I install a module and all its dependencies from the
commandline, without being prompted for anything, despite my CPAN
configuration (or lack thereof)?
CPAN uses ExtUtils::MakeMaker's prompt() function to ask its
questions, so if you set the PERL_MM_USE_DEFAULT environment variable, you
shouldn't be asked any questions at all (assuming the modules you are
installing are nice about obeying that variable as well):
% PERL_MM_USE_DEFAULT=1 perl -MCPAN -e 'install My::Module'
- 14)
- How do I create a Module::Build based Build.PL derived from
an ExtUtils::MakeMaker focused Makefile.PL?
http://search.cpan.org/dist/Module-Build-Convert/
- 15)
- I'm frequently irritated with the CPAN shell's inability to
help me select a good mirror.
CPAN can now help you select a "good" mirror, based on which ones
have the lowest 'ping' round-trip times. From the shell, use the command
'o conf init urllist' and allow CPAN to automatically select mirrors for
you.
Beyond that help, the urllist config parameter is yours. You can add and
remove sites at will. You should find out which sites have the best
up-to-dateness, bandwidth, reliability, etc. and are topologically close
to you. Some people prefer fast downloads, others up-to-dateness, others
reliability. You decide which to try in which order.
Henk P. Penning maintains a site that collects data about CPAN sites:
http://www.cs.uu.nl/people/henkp/mirmon/cpan.html
Also, feel free to play with experimental features. Run
o conf init randomize_urllist ftpstats_period ftpstats_size
and choose your favorite parameters. After a few downloads running the
"hosts" command will probably assist you in choosing the best
mirror sites.
- 16)
- Why do I get asked the same questions every time I start
the shell?
You can make your configuration changes permanent by calling the command
"o conf commit". Alternatively set the "auto_commit"
variable to true by running "o conf init auto_commit" and
answering the following question with yes.
- 17)
- Older versions of CPAN.pm had the original root directory
of all tarballs in the build directory. Now there are always random
characters appended to these directory names. Why was this done?
The random characters are provided by File::Temp and ensure that each
module's individual build directory is unique. This makes running CPAN.pm
in concurrent processes simultaneously safe.
- 18)
- Speaking of the build directory. Do I have to clean it up
myself?
You have the choice to set the config variable "scan_cache" to
"never". Then you must clean it up yourself. The other possible
values, "atstart" and "atexit" clean up the build
directory when you start or exit the CPAN shell, respectively. If you
never start up the CPAN shell, you probably also have to clean up the
build directory yourself.
COMPATIBILITY¶
OLD PERL VERSIONS¶
CPAN.pm is regularly tested to run under 5.004, 5.005, and assorted newer
versions. It is getting more and more difficult to get the minimal
prerequisites working on older perls. It is close to impossible to get the
whole Bundle::CPAN working there. If you're in the position to have only these
old versions, be advised that CPAN is designed to work fine without the
Bundle::CPAN installed.
To get things going, note that GBARR/Scalar-List-Utils-1.18.tar.gz is compatible
with ancient perls and that File::Temp is listed as a prerequisite but CPAN
has reasonable workarounds if it is missing.
CPANPLUS¶
This module and its competitor, the CPANPLUS module, are both much cooler than
the other. CPAN.pm is older. CPANPLUS was designed to be more modular, but it
was never intended to be compatible with CPAN.pm.
CPANMINUS¶
In the year 2010 App::cpanminus was launched as a new approach to a cpan shell
with a considerably smaller footprint. Very cool stuff.
SECURITY ADVICE¶
This software enables you to upgrade software on your computer and so is
inherently dangerous because the newly installed software may contain bugs and
may alter the way your computer works or even make it unusable. Please
consider backing up your data before every upgrade.
BUGS¶
Please report bugs via <
http://rt.cpan.org/>
Before submitting a bug, please make sure that the traditional method of
building a Perl module package from a shell by following the installation
instructions of that package still works in your environment.
AUTHOR¶
Andreas Koenig "<andk@cpan.org>"
LICENSE¶
This program is free software; you can redistribute it and/or modify it under
the same terms as Perl itself.
See <
http://www.perl.com/perl/misc/Artistic.html>
TRANSLATIONS¶
Kawai,Takanori provides a Japanese translation of a very old version of this
manpage at <
http://homepage3.nifty.com/hippo2000/perltips/CPAN.htm>
SEE ALSO¶
Many people enter the CPAN shell by running the cpan utility program which is
installed in the same directory as perl itself. So if you have this directory
in your PATH variable (or some equivalent in your operating system) then
typing "cpan" in a console window will work for you as well. Above
that the utility provides several commandline shortcuts.