.\" Automatically generated by Pod::Man 2.25 (Pod::Simple 3.16)
.\"
.\" Standard preamble:
.\" ========================================================================
.de Sp \" Vertical space (when we can't use .PP)
.if t .sp .5v
.if n .sp
..
.de Vb \" Begin verbatim text
.ft CW
.nf
.ne \\$1
..
.de Ve \" End verbatim text
.ft R
.fi
..
.\" Set up some character translations and predefined strings.  \*(-- will
.\" give an unbreakable dash, \*(PI will give pi, \*(L" will give a left
.\" double quote, and \*(R" will give a right double quote.  \*(C+ will
.\" give a nicer C++.  Capital omega is used to do unbreakable dashes and
.\" therefore won't be available.  \*(C` and \*(C' expand to `' in nroff,
.\" nothing in troff, for use with C<>.
.tr \(*W-
.ds C+ C\v'-.1v'\h'-1p'\s-2+\h'-1p'+\s0\v'.1v'\h'-1p'
.ie n \{\
.    ds -- \(*W-
.    ds PI pi
.    if (\n(.H=4u)&(1m=24u) .ds -- \(*W\h'-12u'\(*W\h'-12u'-\" diablo 10 pitch
.    if (\n(.H=4u)&(1m=20u) .ds -- \(*W\h'-12u'\(*W\h'-8u'-\"  diablo 12 pitch
.    ds L" ""
.    ds R" ""
.    ds C` ""
.    ds C' ""
'br\}
.el\{\
.    ds -- \|\(em\|
.    ds PI \(*p
.    ds L" ``
.    ds R" ''
'br\}
.\"
.\" Escape single quotes in literal strings from groff's Unicode transform.
.ie \n(.g .ds Aq \(aq
.el       .ds Aq '
.\"
.\" If the F register is turned on, we'll generate index entries on stderr for
.\" titles (.TH), headers (.SH), subsections (.SS), items (.Ip), and index
.\" entries marked with X<> in POD.  Of course, you'll have to process the
.\" output yourself in some meaningful fashion.
.ie \nF \{\
.    de IX
.    tm Index:\\$1\t\\n%\t"\\$2"
..
.    nr % 0
.    rr F
.\}
.el \{\
.    de IX
..
.\}
.\"
.\" Accent mark definitions (@(#)ms.acc 1.5 88/02/08 SMI; from UCB 4.2).
.\" Fear.  Run.  Save yourself.  No user-serviceable parts.
.    \" fudge factors for nroff and troff
.if n \{\
.    ds #H 0
.    ds #V .8m
.    ds #F .3m
.    ds #[ \f1
.    ds #] \fP
.\}
.if t \{\
.    ds #H ((1u-(\\\\n(.fu%2u))*.13m)
.    ds #V .6m
.    ds #F 0
.    ds #[ \&
.    ds #] \&
.\}
.    \" simple accents for nroff and troff
.if n \{\
.    ds ' \&
.    ds ` \&
.    ds ^ \&
.    ds , \&
.    ds ~ ~
.    ds /
.\}
.if t \{\
.    ds ' \\k:\h'-(\\n(.wu*8/10-\*(#H)'\'\h"|\\n:u"
.    ds ` \\k:\h'-(\\n(.wu*8/10-\*(#H)'\`\h'|\\n:u'
.    ds ^ \\k:\h'-(\\n(.wu*10/11-\*(#H)'^\h'|\\n:u'
.    ds , \\k:\h'-(\\n(.wu*8/10)',\h'|\\n:u'
.    ds ~ \\k:\h'-(\\n(.wu-\*(#H-.1m)'~\h'|\\n:u'
.    ds / \\k:\h'-(\\n(.wu*8/10-\*(#H)'\z\(sl\h'|\\n:u'
.\}
.    \" troff and (daisy-wheel) nroff accents
.ds : \\k:\h'-(\\n(.wu*8/10-\*(#H+.1m+\*(#F)'\v'-\*(#V'\z.\h'.2m+\*(#F'.\h'|\\n:u'\v'\*(#V'
.ds 8 \h'\*(#H'\(*b\h'-\*(#H'
.ds o \\k:\h'-(\\n(.wu+\w'\(de'u-\*(#H)/2u'\v'-.3n'\*(#[\z\(de\v'.3n'\h'|\\n:u'\*(#]
.ds d- \h'\*(#H'\(pd\h'-\w'~'u'\v'-.25m'\f2\(hy\fP\v'.25m'\h'-\*(#H'
.ds D- D\\k:\h'-\w'D'u'\v'-.11m'\z\(hy\v'.11m'\h'|\\n:u'
.ds th \*(#[\v'.3m'\s+1I\s-1\v'-.3m'\h'-(\w'I'u*2/3)'\s-1o\s+1\*(#]
.ds Th \*(#[\s+2I\s-2\h'-\w'I'u*3/5'\v'-.3m'o\v'.3m'\*(#]
.ds ae a\h'-(\w'a'u*4/10)'e
.ds Ae A\h'-(\w'A'u*4/10)'E
.    \" corrections for vroff
.if v .ds ~ \\k:\h'-(\\n(.wu*9/10-\*(#H)'\s-2\u~\d\s+2\h'|\\n:u'
.if v .ds ^ \\k:\h'-(\\n(.wu*10/11-\*(#H)'\v'-.4m'^\v'.4m'\h'|\\n:u'
.    \" for low resolution devices (crt and lpr)
.if \n(.H>23 .if \n(.V>19 \
\{\
.    ds : e
.    ds 8 ss
.    ds o a
.    ds d- d\h'-1'\(ga
.    ds D- D\h'-1'\(hy
.    ds th \o'bp'
.    ds Th \o'LP'
.    ds ae ae
.    ds Ae AE
.\}
.rm #[ #] #H #V #F C
.\" ========================================================================
.\"
.IX Title "Plack::Middleware::Conditional 3pm"
.TH Plack::Middleware::Conditional 3pm "2012-04-14" "perl v5.14.2" "User Contributed Perl Documentation"
.\" For nroff, turn off justification.  Always turn off hyphenation; it makes
.\" way too many mistakes in technical documents.
.if n .ad l
.nh
.SH "NAME"
Plack::Middleware::Conditional \- Conditional wrapper for Plack middleware
.SH "SYNOPSIS"
.IX Header "SYNOPSIS"
.Vb 1
\&  use Plack::Builder;
\&
\&  builder {
\&      enable_if { $_[0]\->{REMOTE_ADDR} eq \*(Aq127.0.0.1\*(Aq } \*(AqStackTrace\*(Aq, force => 1;
\&      $app;
\&  };
\&
\&  # or using the OO interface:
\&  $app = Plack::Middleware::Conditional\->wrap(
\&      $app,
\&      condition  => sub { $_[0]\->{REMOTE_ADDR} eq \*(Aq127.0.0.1\*(Aq },
\&      builder => sub { Plack::Middleware::StackTrace\->wrap($_[0], force => 1) },
\&  );
.Ve
.SH "DESCRIPTION"
.IX Header "DESCRIPTION"
Plack::Middleware::Conditional is a piece of meta-middleware, to run a
specific middleware component under runtime conditions. The goal of
this middleware is to avoid baking runtime configuration options in
individual middleware components, and rather share them as another
middleware component.
.SH "EXAMPLES"
.IX Header "EXAMPLES"
Note that some of the middleware component names are just made up for
the explanation and might not exist.
.PP
.Vb 2
\&  # Minify JavaScript if the browser is Firefox
\&  enable_if { $_[0]\->{HTTP_USER_AGENT} =~ /Firefox/ } \*(AqJavaScriptMinifier\*(Aq;
\&
\&  # Enable Stacktrace when being accessed from the local network
\&  enable_if { $_[0]\->{REMOTE_ADDR} =~ /^10\e.0\e.1\e.*/ } \*(AqStackTrace\*(Aq;
\&
\&  # Work with other conditional setter middleware:
\&  # Transcode Jpeg on the fly for mobile clients
\&  builder {
\&      enable \*(AqMobileDetector\*(Aq;
\&      enable_if { $_[0]\->{\*(Aqplack.mobile_detected\*(Aq} }
\&        \*(AqTranscodeJpeg\*(Aq, max_size => 30_000;
\&      $app;
\&  };
.Ve
.PP
Note that in the last example \fIMobileDetector\fR should come first
because the conditional check runs in \fIpre-run\fR conditions, which is
from outer to inner: that is, from the top to the bottom in the
Builder \s-1DSL\s0 code.
.SH "AUTHOR"
.IX Header "AUTHOR"
Tatsuhiko Miyagawa
.PP
Steve Cook
.SH "SEE ALSO"
.IX Header "SEE ALSO"
Plack::Builder