I have a requirement to send a response header by filtering the request header string in apache. To filter the string, a regular expression can be used.
The echo command is working fine to send the response header from the request header.
Reference URL to use echo command https://httpd.apache.org/docs/current/mod/mod_headers.html#page-header
Ex.
Header echo ^group
Now we have a requirement to filter the groups with regular expression.
Ex.
Header echo ^group <filter group with regular expression>
Regex needs to be used is: /(?<=,)[^,]*MYROLE[^,] (?=,)/gm
example of group string: "AV=en:CN=(A) MYROLE - Application, AV=en:CN=(A) DATA - Application";
I tried given below syntax but it's not working
Header echo group "%{HTTP:group}i m#/(?<=,)[^,]*MYROLE[^,] (?=,)/#"
Expected Request and Response Dump.
Request
HTTP/1.1 200 OK
Cache-Control: private
group: OU=Groups Azure Virtual Desktop,OU=PROD,DC=prod,DC=test,DC=be:CN=(A) MYROLE - BO - TC BO Admin,OU=Groups XYZ Application Entitlements,OU=PROD,DC=prod,DC=test,DC=be:CN=(A) MYROLE - BO - ABO,OU=Groups XYZ Application Entitlements,OU=PROD,DC=prod,DC=test,DC=be:CN=(A) MYROLE - BO - TBO,OU=Groups XYZ Application Entitlements,OU=PROD,DC=prod,DC=test,DC=be:CN=(A) MYROLE - BO - B and C,OU=Groups XYZ Application Entitlements,OU=PROD,DC=prod,DC=test,DC=be:CN=(C) Adobe Fullstack Engineers
Expected Response
HTTP/1.1 200 OK
Cache-Control: private
group: DC=be:CN=(A) MYROLE - BO - TC BO Admin,DC=be:CN=(A) MYROLE - BO - ABO,DC=be:CN=(A) MYROLE - BO - TBO,CN=(A) MYROLE - BO - B and C
Please suggest how to use regular expression to filter the string(group) and send it back as as comma separated groups as response header.
CodePudding user response：
This was a challenge, I must admit first.
After digging through the official docs for more than an hour, I have come up to this solution. Please read my inline comments to understand the solution:
# copy header named group from request to response
Header echo "^group$"
# use regex to remove all comma separated substrings
# as long as those substrings don't contain string MYROLE
Header edit* group "(?:^|,)(?![^,]*?MYROLE)[^,] " ""
# remove first comma if it exists
Header edit group "^," ""
On my local Apache I tested it with command line curl and here are the results:
curl -H 'group: OU=Groups Azure Virtual Desktop,OU=PROD,DC=prod,DC=test,DC=be:CN=(A) MYROLE - BO - TC BO Admin,OU=Groups XYZ Application Entitlements,OU=PROD,DC=prod,DC=test,DC=be:CN=(A) MYROLE - BO - ABO,OU=Groups XYZ Application Entitlements,OU=PROD,DC=prod,DC=test,DC=be:CN=(A) MYROLE - BO - TBO,OU=Groups XYZ Application Entitlements,OU=PROD,DC=prod,DC=test,DC=be:CN=(A) MYROLE - BO - B and C,OU=Groups XYZ Application Entitlements,OU=PROD,DC=prod,DC=test,DC=be:CN=(C) Adobe Fullstack Engineers' -H 'mygroup: foobar' -IL 'http://localhost/'
HTTP/1.1 200 OK
Date: Wed, 15 Jun 2022 19:15:19 GMT
Server: Apache/2.4.53 (Unix) OpenSSL/1.1.1o PHP/8.1.6
X-Powered-By: PHP/8.1.6
group: DC=be:CN=(A) MYROLE - BO - TC BO Admin,DC=be:CN=(A) MYROLE - BO - ABO,DC=be:CN=(A) MYROLE - BO - TBO,DC=be:CN=(A) MYROLE - BO - B and C
Content-Type: text/html; charset=UTF-8