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.\" ========================================================================
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.IX Title "HTTP::Proxy::BodyFilter::htmlparser 3pm"
.TH HTTP::Proxy::BodyFilter::htmlparser 3pm "2022-12-04" "perl v5.36.0" "User Contributed Perl Documentation"
.\" For nroff, turn off justification.  Always turn off hyphenation; it makes
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.SH "NAME"
HTTP::Proxy::BodyFilter::htmlparser \- Filter using HTML::Parser
.SH "SYNOPSIS"
.IX Header "SYNOPSIS"
.Vb 1
\&    use HTTP::Proxy::BodyFilter::htmlparser;
\&
\&    # $parser is a HTML::Parser object
\&    $proxy\->push_filter(
\&        mime     => \*(Aqtext/html\*(Aq,
\&        response => HTTP::Proxy::BodyFilter::htmlparser\->new( $parser );
\&    );
.Ve
.SH "DESCRIPTION"
.IX Header "DESCRIPTION"
The HTTP::Proxy::BodyFilter::htmlparser lets you create a
filter based on the HTML::Parser object of your choice.
.PP
This filter takes a HTML::Parser object as an argument to its constructor.
The filter is either read-only or read-write. A read-only filter will
not allow you to change the data on the fly. If you request a read-write
filter, you'll have to rewrite the response-body completely.
.PP
With a read-write filter, you \fBmust\fR recreate the whole body data. This
is mainly due to the fact that the HTML::Parser has its own buffering
system, and that there is no easy way to correlate the data that triggered
the HTML::Parser event and its original position in the chunk sent by the
origin server. See below for details.
.PP
Note that a simple filter that modify the \s-1HTML\s0 text (not the tags) can
be created more easily with HTTP::Proxy::BodyFilter::htmltext.
.SS "Creating a HTML::Parser that rewrites pages"
.IX Subsection "Creating a HTML::Parser that rewrites pages"
A read-write filter is declared by passing \f(CW\*(C`rw => 1\*(C'\fR to the constructor:
.PP
.Vb 1
\&     HTTP::Proxy::BodyFilter::htmlparser\->new( $parser, rw => 1 );
.Ve
.PP
To be able to modify the body of a message, a filter created with
HTTP::Proxy::BodyFilter::htmlparser must rewrite it completely. The
HTML::Parser object can update a special attribute named \f(CW\*(C`output\*(C'\fR.
To do so, the HTML::Parser handler will have to request the \f(CW\*(C`self\*(C'\fR
attribute (that is to say, require access to the parser itself) and
update its \f(CW\*(C`output\*(C'\fR key.
.PP
The following attributes are added to the HTML::Parser object by this filter:
.IP "output" 4
.IX Item "output"
A string that will hold the data sent back by the proxy.
.Sp
This string will be used as a replacement for the body data only
if the filter is read-write, that is to say, if it was initialised with
\&\f(CW\*(C`rw => 1\*(C'\fR.
.Sp
Data should always be \fBappended\fR to \f(CW\*(C`$parser\->{output}\*(C'\fR.
.IP "message" 4
.IX Item "message"
A reference to the HTTP::Message that triggered the filter.
.IP "protocol" 4
.IX Item "protocol"
A reference to the HTTP::Protocol object.
.SH "METHODS"
.IX Header "METHODS"
This filter defines three methods, called automatically:
.IP "\fBfilter()\fR" 4
.IX Item "filter()"
The \f(CW\*(C`filter()\*(C'\fR method handles all the interactions with the HTML::Parser
object.
.IP "\fBinit()\fR" 4
.IX Item "init()"
Initialise the filter with the HTML::Parser object passed to the constructor.
.IP "\fBwill_modify()\fR" 4
.IX Item "will_modify()"
This method returns a boolean value that indicates to the system
if it will modify the data passing through. The value is actually
the value of the \f(CW\*(C`rw\*(C'\fR parameter passed to the constructor.
.SH "SEE ALSO"
.IX Header "SEE ALSO"
HTTP::Proxy, HTTP::Proxy::Bodyfilter,
HTTP::Proxy::BodyFilter::htmltext.
.SH "AUTHOR"
.IX Header "AUTHOR"
Philippe \*(L"BooK\*(R" Bruhat, <book@cpan.org>.
.SH "COPYRIGHT"
.IX Header "COPYRIGHT"
Copyright 2003\-2015, Philippe Bruhat.
.SH "LICENSE"
.IX Header "LICENSE"
This module is free software; you can redistribute it or modify it under
the same terms as Perl itself.