NGINX: Server & Location Block

2017-10-17 · 2 min read

NGINX determines a server and location block to use each time a client request is made.

A server block defines a virtual server used to handle requests based on the domain name, port, and IP address. listen and server_name directives are used by NGINX to determine that server block by matching the IP address and the port of the request.

A location block is defined within a server block. It is used to define how to handle requests for different resources and URIs within the context of the parent server block.

A listen directive can be set to a pair of IP address and port, to only an IP address (with the default port 80), to only a port (with every interface i.e. for that port) and finally to a path to a Unix socket. Any server block that does not include a listen directive is given the listen parameters of (or if being run by a non-root user).

If there are multiple server blocks matching listen, NGINX evaluates the server_name directive by checking the request's Host header.

location optional_modifier location_match {

If there's no modifier, a location is interpreted as a prefix match. It will be matched against the beginning of the request URI. = request's URI must match exactly the location match. ~ the location is interpreted as a case-sensitive regular expression match. ~* the location is interpreted as a case-insensitive regular expression match.

The return directive defines a new (rewritten) URL. It is simpler and recommend instead of rewrite whenever possible.

return (301 | 302 | 303 | 307) url;

If the code is omitted, 302 is used by default.

return url;

If there's a need to test for more complicated distinctions between URLs, capture elements in the original URL that don’t have corresponding NGINX variables, or change or add elements in the path? You can use the rewrite directive in such cases.

If you need capture elements in the original URL that don’t have corresponding NGINX variables, or change elements in the path, use the rewrite directive. The rewrite directive may not halt request processing by NGINX. return directive always halts the processing, thus it is more efficient.

The last flag indicates to skip any subsequent rewrite directives in the current server or location block and it starts a search for a new location that matches the rewritten URL.