NAME¶
Net::HTTP - Low-level HTTP connection (client)
SYNOPSIS¶
use Net::HTTP;
my $s = Net::HTTP->new(Host => "www.perl.com") || die $@;
$s->write_request(GET => "/", 'User-Agent' => "Mozilla/5.0");
my($code, $mess, %h) = $s->read_response_headers;
while (1) {
my $buf;
my $n = $s->read_entity_body($buf, 1024);
die "read failed: $!" unless defined $n;
last unless $n;
print $buf;
}
DESCRIPTION¶
The "Net::HTTP" class is a low-level HTTP client. An instance of the
"Net::HTTP" class represents a connection to an HTTP server. The
HTTP protocol is described in RFC 2616. The "Net::HTTP" class
supports "HTTP/1.0" and "HTTP/1.1".
"Net::HTTP" is a sub-class of "IO::Socket::INET". You can
mix the methods described below with reading and writing from the socket
directly. This is not necessary a good idea, unless you know what you are
doing.
The following methods are provided (in addition to those of
"IO::Socket::INET"):
- $s = Net::HTTP->new( %options )
- The "Net::HTTP" constructor method takes the same
options as "IO::Socket::INET"'s as well as these:
Host: Initial host attribute value
KeepAlive: Initial keep_alive attribute value
SendTE: Initial send_te attribute_value
HTTPVersion: Initial http_version attribute value
PeerHTTPVersion: Initial peer_http_version attribute value
MaxLineLength: Initial max_line_length attribute value
MaxHeaderLines: Initial max_header_lines attribute value
The "Host" option is also the default for
"IO::Socket::INET"'s "PeerAddr". The
"PeerPort" defaults to 80 if not provided.
The "Listen" option provided by "IO::Socket::INET"'s
constructor method is not allowed.
If unable to connect to the given HTTP server then the constructor returns
"undef" and $@ contains the reason. After a successful connect,
a "Net:HTTP" object is returned.
- $s->host
- Get/set the default value of the "Host" header to
send. The $host must not be set to an empty string (or "undef")
for HTTP/1.1.
- $s->keep_alive
- Get/set the keep-alive value. If this value is TRUE
then the request will be sent with headers indicating that the server
should try to keep the connection open so that multiple requests can be
sent.
The actual headers set will depend on the value of the
"http_version" and "peer_http_version"
attributes.
- $s->send_te
- Get/set the a value indicating if the request will be sent
with a "TE" header to indicate the transfer encodings that the
server can choose to use. The list of encodings announced as accepted by
this client depends on availability of the following modules:
"Compress::Raw::Zlib" for deflate, and
"IO::Compress::Gunzip" for gzip.
- $s->http_version
- Get/set the HTTP version number that this client should
announce. This value can only be set to "1.0" or
"1.1". The default is "1.1".
- $s->peer_http_version
- Get/set the protocol version number of our peer. This value
will initially be "1.0", but will be updated by a successful
read_response_headers() method call.
- $s->max_line_length
- Get/set a limit on the length of response line and response
header lines. The default is 8192. A value of 0 means no limit.
- $s->max_header_length
- Get/set a limit on the number of header lines that a
response can have. The default is 128. A value of 0 means no limit.
- $s->format_request($method, $uri, %headers,
[$content])
- Format a request message and return it as a string. If the
headers do not include a "Host" header, then a header is
inserted with the value of the "host" attribute. Headers like
"Connection" and "Keep-Alive" might also be added
depending on the status of the "keep_alive" attribute.
If $content is given (and it is non-empty), then a
"Content-Length" header is automatically added unless it was
already present.
- $s->write_request($method, $uri, %headers,
[$content])
- Format and send a request message. Arguments are the same
as for format_request(). Returns true if successful.
- $s->format_chunk( $data )
- Returns the string to be written for the given chunk of
data.
- $s->write_chunk($data)
- Will write a new chunk of request entity body data. This
method should only be used if the "Transfer-Encoding" header
with a value of "chunked" was sent in the request. Note, writing
zero-length data is a no-op. Use the write_chunk_eof() method to
signal end of entity body data.
Returns true if successful.
- $s->format_chunk_eof( %trailers )
- Returns the string to be written for signaling EOF when a
"Transfer-Encoding" of "chunked" is used.
- $s->write_chunk_eof( %trailers )
- Will write eof marker for chunked data and optional
trailers. Note that trailers should not really be used unless is was
signaled with a "Trailer" header.
Returns true if successful.
- ($code, $mess, %headers) = $s->read_response_headers(
%opts )
- Read response headers from server and return it. The $code
is the 3 digit HTTP status code (see HTTP::Status) and $mess is the
textual message that came with it. Headers are then returned as key/value
pairs. Since key letter casing is not normalized and the same key can even
occur multiple times, assigning these values directly to a hash is not
wise. Only the $code is returned if this method is called in scalar
context.
As a side effect this method updates the 'peer_http_version' attribute.
Options might be passed in as key/value pairs. There are currently only two
options supported; "laxed" and "junk_out".
The "laxed" option will make read_response_headers() more
forgiving towards servers that have not learned how to speak HTTP
properly. The "laxed" option is a boolean flag, and is enabled
by passing in a TRUE value. The "junk_out" option can be used to
capture bad header lines when "laxed" is enabled. The value
should be an array reference. Bad header lines will be pushed onto the
array.
The "laxed" option must be specified in order to communicate with
pre-HTTP/1.0 servers that don't describe the response outcome or the data
they send back with a header block. For these servers peer_http_version is
set to "0.9" and this method returns (200, "Assumed
OK").
The method will raise an exception (die) if the server does not speak proper
HTTP or if the "max_line_length" or
"max_header_length" limits are reached. If the "laxed"
option is turned on and "max_line_length" and
"max_header_length" checks are turned off, then no exception
will be raised and this method will always return a response code.
- $n = $s->read_entity_body($buf, $size);
- Reads chunks of the entity body content. Basically the same
interface as for read() and sysread(), but the buffer offset
argument is not supported yet. This method should only be called after a
successful read_response_headers() call.
The return value will be "undef" on read errors, 0 on EOF, -1 if
no data could be returned this time, otherwise the number of bytes
assigned to $buf. The $buf is set to "" when the return value is
-1.
You normally want to retry this call if this function returns either -1 or
"undef" with $! as EINTR or EAGAIN (see Errno). EINTR can happen
if the application catches signals and EAGAIN can happen if you made the
socket non-blocking.
This method will raise exceptions (die) if the server does not speak proper
HTTP. This can only happen when reading chunked data.
- %headers = $s->get_trailers
- After read_entity_body() has returned 0 to indicate
end of the entity body, you might call this method to pick up any
trailers.
- $s->_rbuf
- Get/set the read buffer content. The
read_response_headers() and read_entity_body() methods use
an internal buffer which they will look for data before they actually
sysread more from the socket itself. If they read too much, the remaining
data will be left in this buffer.
- $s->_rbuf_length
- Returns the number of bytes in the read buffer. This should
always be the same as:
length($s->_rbuf)
but might be more efficient.
SUBCLASSING¶
The
read_response_headers() and
read_entity_body() will invoke the
sysread() method when they need more data. Subclasses might want to
override this method to control how reading takes place.
The object itself is a glob. Subclasses should avoid using hash key names
prefixed with "http_" and "io_".
SEE ALSO¶
LWP, IO::Socket::INET, Net::HTTP::NB
COPYRIGHT¶
Copyright 2001-2003 Gisle Aas.
This library is free software; you can redistribute it and/or modify it under
the same terms as Perl itself.