Actually I tried to find out how to escape ExtFilterDefine commands correctly. I defined ExtFilterDefine sed-replace cmd="/bin/sed s/verdana/arial/g" as an example (the actual problem was that cmd="/bin/sed 's/verdana/arial/g'" doesn't work). This external filter works okay with Set/AddOutputFilter. To debug the command I added ExtFilterOptions DebugLevel=9 to the corresponding <Directory> context. But then the ExtFilter stops working and gives me [error] couldn't find definition of filter 'sed-replace' in my error_log and a related error is given back to UA. Nothing else has been changed after adding the ExtFilterOptions directive.
I wasn't able to reproduce the lost filter definition when using this configuration: <Directory /photo> DirectoryIndex index.cgi Options Indexes ExecCGI AddHandler cgi-script .cgi SetOutputFilter sed-replace ExtFilterOptions DebugLevel=9 </Directory> ExtFilterDefine sed-replace cmd="/bin/sed 's/photos/picurs/g'" (I didn't see any output at the client because sed got confused by the single quotes. When I remove the single quotes it works fine.) Can you spot something about my testcase which is inconsistent with your description, or can you perhaps supply a set of minimal changes to the default httpd-std.conf which would expose the problem? Thanks so much! (Certainly I need to update the doc to describe quoting issues like this!!)
I did it the other way 'round and tried to reproduce your situation :) It does work if the ExtFilterDefine and the ExtFilterOptions statement are located _within the same VH_. In my configuration ExtFilterDefine is located in the main config (so I can reuse it otherwhere) and ExtFilterOptions + SetOutputFilter in a directory context within a VH. Contrarily the ExtFilter works fine in this situation if ExtFilterOptions is not set. So the bahaviour is inconsistent and I think one should have the possibility to split Define and Options for ExtFilter just like I did. Apart from that - wouldn't it be nice to have a separate logfile for ExtFilters just like with CGIs oder URL rewriting? I dunno if it's a enough for a formal feature request.
Thanks for the update... I was able to reproduce and am working on a change to mod_ext_filter so that filter definitions can be used across multiple servers/vhosts. (I'm ignoring your feature request for the moment :) ) Thanks again!
mod_ext_filter has been changed to find filter definitions in the main server in case they weren't defined in the vhost... the patch as committed is below, and will be in the next release of Apache: http://cvs.apache.org/viewcvs.cgi/httpd- 2.0/modules/experimental/mod_ext_filter.c.diff?r1=1.29&r2=1.30 I tweaked the documentation to try to clarify how parameters to the external program are specified. In addition, I added a new example which you might recognize. If you really want to have stderr from the filter written to a file, please write another PR for the feature request. I don't personally plan on doing anything about that unless it is clear that there is a widespread desire for it. (Other folks may be interested however.) Note that the LogStderr option (on the ExtFilterOptions directive) can be used to capture the external filter's stderr in the Apache error log. Thanks again for your report!