diff options
| author | root <root@rbsd.ankarstrom.se> | 2021-04-29 00:02:41 +0000 |
|---|---|---|
| committer | root <root@rbsd.ankarstrom.se> | 2021-04-29 00:11:29 +0000 |
| commit | 96e026c1815f123e5a60ee106cb802fc841faa6c (patch) | |
| tree | 5f410a9d50a757e21b104afc2d22a8a22551b60d /lib | |
| parent | 6cac80b5c80e89ac46e8a8fc928aa98de183a47f (diff) | |
| download | Apache-Inject-master.tar.gz | |
Apparently, an Apache filter can be invoked more than once for a
single request, depending on the size of the contents [1].
Luckily, though, a filter can save state in the ctx field [1,2].
The solution isn't perfect, as it can't handle arbitrary long heads,
but they're very unlikely.
[1] https://httpd.apache.org/docs/2.4/developer/output-filters.html#invocation
[2] https://perl.apache.org/docs/2.0/user/handlers/filters.html#Introducing_Filters
Diffstat (limited to 'lib')
| -rw-r--r-- | lib/Apache/Inject.pm | 16 | ||||
| -rw-r--r-- | lib/Apache/Inject/Filter.pm | 32 |
2 files changed, 39 insertions, 9 deletions
diff --git a/lib/Apache/Inject.pm b/lib/Apache/Inject.pm index 1d6f49b..68e003e 100644 --- a/lib/Apache/Inject.pm +++ b/lib/Apache/Inject.pm @@ -182,6 +182,10 @@ intelligently and forwards their combined contents. =head1 CAVEATS +=over + +=item * + Apache::Inject::Filter uses a regular expression to determine the proper location of the injected header. It supports all valid HTML. However, it does not parse embedded CSS and JavaScript, which means @@ -204,10 +208,22 @@ This specific type of document, however, is I<incredibly> unlikely. In this case, an ad-hoc solution is simpler, more efficient and more maintainable than a general one. +=item * + +Because of how Apache filters work, Inject may fail to find the end +of the E<lt>headE<gt> if the E<lt>headE<gt> is very long (in my +experience over 7000 characters). If this happens, it will decline +the request, and the contents will be served as though Inject had +not been enabled. + +=item * + On FreeBSD, you may need to enable the accf_http kernel module in order for the tests to work. Note that Apache::Inject works fine without the module; it is only the tests that require it. +=back + =head1 DIAGNOSTICS Apache::Inject and Apache::Inject::Filter log all errors and diff --git a/lib/Apache/Inject/Filter.pm b/lib/Apache/Inject/Filter.pm index f87cdc1..67511e2 100644 --- a/lib/Apache/Inject/Filter.pm +++ b/lib/Apache/Inject/Filter.pm @@ -49,15 +49,29 @@ sub handler : FilterRequestHandler { return DECLINED; } - my ($buf, $content); - $content .= $buf while $f->read($buf); - return DECLINED if not $content =~ /$doc/; - - $f->print($+{head}) if $+{head}; - inject($f, "InjectHead"); - $f->print($+{body}) if $+{body}; - inject($f, "InjectFoot"); - $f->print($+{rest}) if $+{rest}; + # First pass + if (not $f->ctx) { + my ($buf, $content); + $content .= $buf while $f->read($buf); + if (not $content =~ /$doc/) { + $f->r->warn('Inject: Cannot find <body> (<head> too long?)'); + return DECLINED; + } + + $f->print($+{head}) if $+{head}; + inject($f, "InjectHead"); + $f->print($+{body}) if $+{body}; + inject($f, "InjectFoot"); + $f->print($+{rest}) if $+{rest}; + + $f->ctx(1); + } + + # Any subsequent pass + else { + my $buf; + $f->print($buf) while $f->read($buf); + } return OK; } |