The module hooks early in the apache request processing.
If the module is configured in the Apache configuration the configured program will be run.
The program receives request information in environment variables.
The program then makes decisions about the request and writes what it wants to be done to stdout.
The module will read these commands from the program and modify the request accordingly.
First example of how a configuration might look like.
if(host("www.some.where")) {
if(path_match("/", "pcms/", RECSTART, "en/", "admin/", "showpic.php", RECSTOP, ENDOFLINE) ||
path_match("/", "pcms/", RECSTART, "favicon.ico", RECSTOP, ENDOFLINE)) {
proxy_host("www.some.where");
proxy_reverse("http://some.where.else/path/", "/");
proxy_reverse("https://some.where.else/path/", "/");
proxy_to("http://some.where.else/path/", recording[0]);
done();
}
}
And in Apache:
httpd.conf
----------
ReqFilter <prg> invoked for each request. Env contains request informaton.
ReqFilterError <prg> invoked if error. Env contains information about failed request.
ReqFilterLogLevel (DEBUG|INFO|WARN|ERR)
Output from your ReqFilter program:
-----------------------------------
DOCUMENT_URI=URI -- if URI begins with '/' rewrite local path. If not treat as proxy request to URI
Proxy-reverse-alias=real,fake -- URI translation of headers when proxying
Substitute=real,fake -- replace occurances of <real> with <fake> within the output document
Proxy-host=HOSTNAME -- hostname for proxyrequest
IN::Host=VHOST -- set incoming host header and switch vhost
DocumentRoot=PATH -- set document root for request
Filter=NNN -- add output filter named 'NNN' to request
Status=NNN -- return HTTP status NNN to client
Redirect=LOC -- redirect to URI 'LOC'
Filename=FN -- serve file 'FN'
Handler=HHH -- set handler to HHH
CGI=FN -- execute 'FN' as CGI
Export=NAME=VAL -- export variable to CGI
QUERY_STRING=S -- set HTTP query string to 'S'
PATH_INFO=PATH -- set PATH_INFO for CGI.
IN::NNN=VVV -- set incoming request header 'NNN' to 'VVV'
OUT::NNN=VVV -- set outgoing header 'NNN' to 'VVV'
ERR::NNN=VVV -- set outgoing error header 'NNN' to 'VVV' (If status is set to error).
Log=MSG -- Log message MSG to apache log
Environment variables set for invoked ReqFilter program
-------------------------------------------------------
IN::<header> -- One variable for each input header in request.
DOCUMENT_URI -- Document path requested
QUERY_STRING -- What comes after requestpath (after '?').
method -- GET, POST etc.
protocol -- 0.9, 1.0, 1.1
servername -- Name of the server according to apache
remote_ip -- Client IP address
local_ip -- Server IP address
status -- Status of the response. Only for ReqFilterError.
FILENAME -- Absolute path to file. Only for ReqFilterError.
PROXY_HOST -- Hostname for proxyrequest. Only for ReqFilterError.