Apache flags, sorted by frequency of use (more common at the top)

R

• Perform an HTTP redirect
• Default is a temporary 302 redirect
• Always use with an L
• e.g., [L,R=301]

L

• Break if the rule matches, i.e. don't process subsequent rules
• e.g., [L]

F

• If matches, send 403 fobidden header
• e.g., [F]
• Note that this rule always sends an L as well, stopping the evaluation

G

• If matches, send 410 gone header, indicating a resource isn't available anymore
• e.g., [G]

S

• Skip rules below from running, specify number of lines to skip
• Can be used as a technique for control structures, the first line acts as an if statement
• e.g., [S=2]

T

• Force a mime type
• e.g., [T=image/gif]

E

• Set environment variable
• e.g., [E=STAGING:1]
• Note that all environment variables are prefixed with REDIRECT_ and should be accessed as such

CO

• Inject a cookie if a rule matches
• e.g., [CO=key:value:.foo.com:1440:/]
  • This sets a cookie 24 hour cookie

Query parameters

• [QSA] Append params from request to target
• [QSD] Discard params
• [QSL] Use the last ? in the URL string as the delimeter, instead of the default, using the first (match from right)

H

• Set a handler, overriding what's set right now
• e.g., [H=application/x-httpd-php]

B

• Escape special characters
• Specify them like [B=#?;]

BNP

• To be used with B
• Converts spaces to %20 when escaped with B
• e.g., [B,BNP]

C

• Chain rules
• Only move on to the next rule if this rule passes
• i.e., if the rule does not evaluate to true, break out of sequence
• e.g., [C]

DPI

• Discard PathInfo object
• i.e., If redirect matches don't pass metadata
• e.g., [DPI]
• Note that this removes this data from the set of redirect rules being processed

N

• Loop the rule while it matches, optionally set a maximum iteration limit
• e.g., [N=5]
• Note this can cause an indefinite loop, or at least one that errors out after the default 32000 iterations

NC

• No case, rule is case insensitive
• e.g., [NC]

NE

• No escape, don't convert special characters to hex
• e.g., [NE]

NS

• No subrequests, don't match if this URL contains subrequests, which aren't used often, except in some CGI configurations
• e.g., [NS]

PT

• Pass through treats the path as a URI, allowing it to be processed by other rules or modules
• e.g., [PT]

P

• Use mod_proxy for this request
• e.g., [P]
• Note: Avoid using this flag