Hi Ari, Aristedes Maniatis wrote: > In the manual [1] there is an example for using reqrep with syntax > like this: > > # replace "/static/" with "/" at the beginning of any request path. > reqrep ^([^\ :]*)\ /static/(.*) \1\ /\2 > > [...] > > Firstly, is there no better/cleaner way to rewrite the path than this > messy regex which seems to process all the http headers rather than > just the request line that contains the path?
With a modern HAProxy (i.e. anything >= 1.6), you can just use http-request set-path %[path,regsub(^/static,/)] Generally, you should always use the http-request rules instead of the (older) reg* rules since the http-request rules are much more powerful, cleaner and have the advantage of always being evaluated in the defined order which the reg* rules are not. Old guides like the one you linked to in [2] were written before the http-request rules got as powerful as they are today. The guide was written for HAProxy 1.4 which is quite outdated now. > Secondly, why was this particular regex used in the example? If I'm > reading this correctly, quoting the string would simplify it to: > > reqrep '^([^ :]*) /static/(.*)' '\1 /\2' String quoting was only introduced in HAProxy 1.6. Before that (and during the time reqrep was the only way to manipulate HTTP requests), you always had to escape spaces with a backslash. > But is this even clearer and safer: > > reqrep '^([A-Z]+) /static(/.*)' '\1 \2' > > or narrow this down (where appropriate to the type of request) to > > reqrep '^(GET|POST) /static(/.*)' '\1 \2' > > Perhaps the example would be clearer like this (even though this is > slower and not needed here, it is clearly demonstrating the point): > > reqrep '^(GET|POST) /static(/.*) (HTTP/.+)' '\1 \2 \3' These are all valid variations for the common case. Still, users might decide to also send lower-case HTTP verbs or other variations. The syntax from the guides is the most generic one. Still, you should probably just get rid of any regrep rules and just use http-request. Cheers, Holger [2] https://fromanegg.com/post/2014/12/05/how-to-rewrite-and-redirect-with-haproxy/
