mca blog

i was able to clean up my httpd.ini (i use ISAPI_Rewrite) file this morning. the result is that i now have a single RegEx filter for incoming requests instead of four - very nice!. this was done to help me sort out some representation support issues. it was a benefit that i was able to reduce the expressions. i was able to turn this:

# special call to the templates folder
RewriteRule (.*)/xcs/templates/(.*) $1/xcs/templates/$2.xcs [L,I]
# handle naked directory call
RewriteRule  (.*)/xcs/(.*)([.?/]) $1/xcs/$2$3.xcs [L,I]
# has query args after the slash
RewriteRule  (.*)/xcs/(.*)(\?.*) $1/xcs/$2.xcs$3$4 [L,I]
# missing backslash (assume trailing item is id)
RewriteRule  (.*)/xcs/([^.?]+[^.?/]) $1/xcs/$2$3.xcs$4 [L,I]

into this:

# updated rule (2007-11-24)
RewriteRule (.*)/xcs/([^.?]*)(?:\.xcs)?(\?.*)? $1/xcs/$2.xcs$3 [L,I]

here's the expanded regex including comments for clarity:

@"
(           # Match the regular expression below and capture its match into backreference number 1
   .           # Match any single character that is not a line break character
      *           # Between zero and unlimited times, as many times as possible, giving back as needed (greedy)
)
/xcs/       # Match the characters “/xcs/” literally
(           # Match the regular expression below and capture its match into backreference number 2
   [^.?]       # Match a single character NOT present in the list “.?”
      *           # Between zero and unlimited times, as many times as possible, giving back as needed (greedy)
)
(?:         # Match the regular expression below
   \.          # Match the character “.” literally
   xcs         # Match the characters “xcs” literally
)?          # Between zero and one times, as many times as possible, giving back as needed (greedy)
(           # Match the regular expression below and capture its match into backreference number 3
   \?          # Match the character “?” literally
   .           # Match any single character that is not a line break character
      *           # Between zero and unlimited times, as many times as possible, giving back as needed (greedy)
)?          # Between zero and one times, as many times as possible, giving back as needed (greedy)
"