Opened 7 years ago
Last modified 5 years ago
#1285 new defect
map regexp positional captures interfere with location regexp positional captures
| Reported by: | Owned by: | ||
|---|---|---|---|
| Priority: | minor | Milestone: | |
| Component: | documentation | Version: | 1.10.x |
| Keywords: | map location | Cc: | |
| uname -a: | Linux srv 3.10.0-327.36.3.el7.x86_64 #1 SMP Mon Oct 24 16:09:20 UTC 2016 x86_64 x86_64 x86_64 GNU/Linux | ||
| nginx -V: |
nginx version: nginx/1.10.3
built by gcc 4.8.5 20150623 (Red Hat 4.8.5-4) (GCC) built with OpenSSL 1.1.0c 10 Nov 2016 TLS SNI support enabled configure arguments: --prefix=/etc/nginx --sbin-path=/usr/sbin/nginx --modules-path=/usr/lib64/nginx/modules --conf-path=/etc/nginx/nginx.conf --error-log-path=/var/log/nginx/error.log --http-log-path=/var/log/nginx/access.log --pid-path=/var/run/nginx.pid --lock-path=/var/run/nginx.lock --http-client-body-temp-path=/var/cache/nginx/client_temp --http-proxy-temp-path=/var/cache/nginx/proxy_temp --http-fastcgi-temp-path=/var/cache/nginx/fastcgi_temp --http-uwsgi-temp-path=/var/cache/nginx/uwsgi_temp --http-scgi-temp-path=/var/cache/nginx/scgi_temp --user=nginx --group=nginx --with-file-aio --with-threads --with-ipv6 --with-http_addition_module --with-http_auth_request_module --with-http_dav_module --with-http_flv_module --with-http_gunzip_module --with-http_gzip_static_module --with-http_mp4_module --with-http_random_index_module --with-http_realip_module --with-http_secure_link_module --with-http_slice_module --with-http_ssl_module --with-http_stub_status_module --with-http_sub_module --with-http_v2_module --with-stream --with-stream_ssl_module --add-module=/opt/nginx-sla --with-cc-opt='-O2 -g -pipe -Wall -Wp,-D_FORTIFY_SOURCE=2 -fexceptions -fstack-protector-strong --param=ssp-buffer-size=4 -grecord-gcc-switches -m64 -mtune=generic -I /opt/openssl110/include' --with-ld-opt='-L /opt/openssl110/lib' |
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Description
I have map configuration like this:
map $uri $rewrite_scheme {
default "http";
~*test "https";
}
And location configuration like this:
location ~ /proxy_host/(host1|host2)/(.*)$ {
proxy_pass $rewrite_scheme://$1/$2$is_args$args;
}
Before I have added map configuration location was working as expected, but after adding map all positional captures inside location became empty. Probably it is due to map initialization on variable call (which occurs after location).
If it is by design, then it would be nice to document this behavior as it is too hard to investigate.
As a solution named captures could be used like this:
location ~ /proxy_host/(?<rewrite_host>host1|host2)/(?<rewrite_path>.*)$ {
proxy_pass $rewrite_scheme://$rewrite_host/$rewrite_path$is_args$args;
}
Positional captures as available via
$1..$9variables are from the last executed regular expression. Asmapin your configuration contains a regular expression, it is executed during the map value lookup, and captures refer to the result of this regular expression execution. That's more or less why positional captures are not generally recommended for use, especially inlocationandserver_namedirectives: they are easily overwritten by any regular expression, and there are lots of cases when a different regular expression can be executed, including non-intuitive ones. Improving the documentation to make this more clear might make sense.(See also #564, which discusses similar problems with positional captures in
rewritewhen used withmapwith regular expressions. This one is a bit different though, and$1..$9variables in rewrite replacement string probably should be changed to always refer captures from rewrite's own regular expression.)