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package Koha::Middleware::SetEnv; |
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# Copyright 2016 ByWater Solutions and the Koha Dev Team |
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# |
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# This file is part of Koha. |
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# |
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# Koha is free software; you can redistribute it and/or modify it |
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# under the terms of the GNU General Public License as published by |
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# the Free Software Foundation; either version 3 of the License, or |
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# (at your option) any later version. |
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# |
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# Koha is distributed in the hope that it will be useful, but |
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# WITHOUT ANY WARRANTY; without even the implied warranty of |
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# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
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# GNU General Public License for more details. |
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# |
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# You should have received a copy of the GNU General Public License |
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# along with Koha; if not, see <http://www.gnu.org/licenses>. |
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use Modern::Perl; |
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use parent qw(Plack::Middleware); |
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use Plack::Request; |
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=head1 NAME |
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Koha::Middleware::SetEnv - Plack middleware to allow SetEnv through proxied headers |
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=head1 SYNOPSIS |
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builder { |
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... |
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enable "Koha::Middleware::SetEnv"; |
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... |
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} |
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SetEnv MEMCACHED_NAMESPACE "localhost:11211" |
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RequestHeader add X-Koha-SetEnv "MEMCACHED_NAMESPACE localhost:11211" |
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=head1 DESCRIPTION |
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This module adds a Plack middleware to convert C<X-Koha-SetEnv> request headers to actual |
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environment variables. |
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This is needed because Plackified Koha is currently connected to Apache via an HTTP proxy, and |
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C<SetEnv>s are not passed through. Koha uses SetEnvs to pass memcached settings and per-virtualhost |
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styles, search limits and syspref overrides. |
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=head1 CAVEATS |
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Due to how HTTP headers are combined, if you want to set a value with an embedded comma, it must be |
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escaped: |
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SetEnv OVERRIDE_SYSPREF_LibraryName "The Best, Truly the Best, Koha Library" |
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RequestHeader add X-Koha-SetEnv "OVERRIDE_SYSPREF_LibraryName The Best\, Truly the Best\, Koha Library" |
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=head1 NOTES |
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This system was designed to use a single header for reasons of security. We have no way of knowing |
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whether a given request header was set by Apache or the original client, so we have to clear any |
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relevant headers before Apache starts adding them. This is only really practical for a single header |
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name. |
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=cut |
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my $allowed_setenvs = qr/^( |
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MEMCACHED_SERVERS | |
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MEMCACHED_NAMESPACE | |
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OVERRIDE_SYSPREF_(\w+) | |
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OVERRIDE_SYSPREF_NAMES | |
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OPAC_CSS_OVERRIDE | |
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OPAC_SEARCH_LIMIT | |
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OPAC_LIMIT_OVERRIDE |
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)\ /x; |
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sub call { |
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my ( $self, $env ) = @_; |
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my $req = Plack::Request->new($env); |
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# First, we split the result only on unescaped commas. |
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my @setenv_headers = split /(?<!\\),\s*/, $req->header('X-Koha-SetEnv') || ''; |
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# Then, these need to be mapped to key-value pairs, and commas removed. |
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my %setenvs = map { |
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# The syntax of this is a bit awkward because you can't use return inside a map (it |
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# returns from the enclosing function). |
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if (!/$allowed_setenvs/) { |
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warn "Forbidden/incorrect X-Koha-SetEnv: $_"; |
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(); |
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} else { |
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my ( $key, $value ) = /(\w+) (.*)/; |
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$value =~ s/\\,/,/g; |
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( $key, $value ); |
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} |
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} @setenv_headers; |
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# Finally, everything is shoved into the $env. |
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$env = { |
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%$env, |
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%setenvs |
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}; |
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# We also add the MEMCACHED_ settings to the actual environment, to make sure any early |
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# initialization of Koha::Cache correctly sets up a memcached connection. |
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foreach my $special_var ( qw( MEMCACHED_SERVERS MEMCACHED_NAMESPACE ) ) { |
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$ENV{$special_var} = $setenvs{$special_var} if defined $setenvs{$special_var}; |
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} |
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return $self->app->($env); |
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} |
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=head1 AUTHOR |
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Jesse Weaver, E<lt>jweaver@bywatersolutions.comE<gt> |
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=cut |
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1; |