Nginx核心模块之location匹配规则浅析

location 规则

匹配规则

先匹配前缀字符串，然后记住最长匹配。
再匹配正则，如果正则的location中有匹配上的则返回第一个匹配上的正则，否则返回上一步中记住的最长前缀匹配。

当前缀字符串使用 =, ^~ 修饰的时候且匹配成功时直接返回结果，不进行正则匹配。

修饰符

匹配前缀字符串

= 表示精确匹配。只有请求的url路径与后面的字符串完全相等时，才会命中。
^~ 表示如果该符号后面的字符是最佳匹配，采用该规则，不再进行后续的查找。

注：当前缀字符串匹配规则前有修饰符修饰时，如果匹配成功不进行正则匹配。

匹配正则

~ 表示该规则是使用正则定义的，区分大小写。
~* 表示该规则是使用正则定义的，不区分大小写。

原文

Syntax: location [ = | ~ | ~* | ^~ ] uri { ... }                
        location @name { ... }             
Default:	—               
Context:	server, location

Sets configuration depending on a request URI.

The matching is performed against a normalized URI, after decoding the text encoded in the “%XX” form, resolving references to relative path components “.” and “..”, and possible compression of two or more adjacent slashes into a single slash.

A location can either be defined by a prefix string, or by a regular expression. Regular expressions are specified with the preceding “*” modifier (for case-insensitive matching), or the “” modifier (for case-sensitive matching). To find location matching a given request, nginx first checks locations defined using the prefix strings (prefix locations). Among them, the location with the longest matching prefix is selected and remembered. Then regular expressions are checked, in the order of their appearance in the configuration file. The search of regular expressions terminates on the first match, and the corresponding configuration is used. If no match with a regular expression is found then the configuration of the prefix location remembered earlier is used.

location blocks can be nested, with some exceptions mentioned below.

For case-insensitive operating systems such as macOS and Cygwin, matching with prefix strings ignores a case (0.7.7). However, comparison is limited to one-byte locales.

Regular expressions can contain captures (0.7.40) that can later be used in other directives.

If the longest matching prefix location has the “^~” modifier then regular expressions are not checked.

Also, using the “=” modifier it is possible to define an exact match of URI and location. If an exact match is found, the search terminates. For example, if a “/” request happens frequently, defining “location = /” will speed up the processing of these requests, as search terminates right after the first comparison. Such a location cannot obviously contain nested locations.

Let’s illustrate the above by an example:

location = / {
    [ configuration A ]
}

location / {
    [ configuration B ]
}

location /documents/ {
    [ configuration C ]
}

location ^~ /images/ {
    [ configuration D ]
}

location ~* \.(gif|jpg|jpeg)$ {
    [ configuration E ]
}

The “/” request will match configuration A, the “/index.html” request will match configuration B, the “/documents/document.html” request will match configuration C, the “/images/1.gif” request will match configuration D, and the “/documents/1.jpg” request will match configuration E.

The “@” prefix defines a named location. Such a location is not used for a regular request processing, but instead used for request redirection. They cannot be nested, and cannot contain nested locations.

If a location is defined by a prefix string that ends with the slash character, and requests are processed by one of proxy_pass, fastcgi_pass, uwsgi_pass, scgi_pass, memcached_pass, or grpc_pass, then the special processing is performed. In response to a request with URI equal to this string, but without the trailing slash, a permanent redirect with the code 301 will be returned to the requested URI with the slash appended. If this is not desired, an exact match of the URI and location could be defined like this:

location /user/ {
    proxy_pass http://user.example.com;
}

location = /user {
    proxy_pass http://login.example.com;
}

引用

ngx_http_core_module_location