location

This directive allows different configurations depending on the URI. It can be configured using both literal strings and regular expressions. To use regular expressions, you must use a prefix:

1. "~" for case sensitive matching
2. "~*" for case insensitive matching
3. there is no syntax for NOT matching a regular expression. Instead, match the target regular expression and assign an empty block, then uselocation / to match anything else.

The order in which location directives are checked is as follows:

1. Directives with the "=" prefix that match the query exactly (literal string). If found, searching stops.
2. All remaining directives with conventional strings. If this match used the "^~" prefix, searching stops.
3. Regular expressions, in the order they are defined in the configuration file.
4. If #3 yielded a match, that result is used. Otherwise, the match from #2 is used.

Details below.

To determine which location directive matches a particular query, the literal strings are checked first. Literal strings match the beginning portion of the query - the most specific match will be used. Afterwards, regular expressions are checked in the order defined in the configuration file. The first regular expression to match the query will stop the search. If no regular expression matches are found, the result from the literal string search is used.

For case-insensitive operating systems, like Mac OS X or Windows with Cygwin, literal string matching is done in a case insensitive way (0.7.7). However, comparison is limited to single-byte locale's only.

Regular expression may contain captures (0.7.40), which can then be used in other directives.

It is possible to disable regular expression checks after literal string matching by using "^~" prefix. If the most specific match literal location has this prefix: regular expressions aren't checked.

The "=" prefix forces an exact (literal) match between the request URI and the location parameter. When matched, the search stops immediately. A useful application is that if the request "/" occurs frequently, it's better to use "location = /", as that will speed up the processing of this request a bit, since the search will stop after the first comparison.

It is important to know that nginx does the comparison against decoded URIs. For example, if you wish to match "/images/%20/test", then you must use "/images/ /test" to determine the location.

Example:

location  = / {
  # matches the query / only.
  [ configuration A ] 
}
location  / {
  # matches any query, since all queries begin with /, but regular
  # expressions and any longer conventional blocks will be
  # matched first.
  [ configuration B ] 
}
location /documents/ {
  # matches any query beginning with /documents/ and continues searching,
  # so regular expressions will be checked. This will be matched only if
  # regular expressions don't find a match.
  [ configuration C ] 
}
location ^~ /images/ {
  # matches any query beginning with /images/ and halts searching,
  # so regular expressions will not be checked.
  [ configuration D ] 
}
location ~* \.(gif|jpg|jpeg)$ {
  # matches any request ending in gif, jpg, or jpeg. However, all
  # requests to the /images/ directory will be handled by
  # Configuration D.   
  [ configuration E ] 
}

Example requests:

• / -> configuration A
• /index.html -> configuration B
• /documents/document.html -> configuration C
• /images/1.gif -> configuration D
• /documents/1.jpg -> configuration E

Note that you could define these 5 configurations in any order and the results would remain the same.

The prefix "@" specifies a named location. Such locations are not used during normal processing of requests, they are intended only to process internally redirected requests (see error_page, try_files).

官方文件是這麼寫的:

第一步:先查詢,看是否有完全匹配的

第二步:查詢^~開頭匹配的

第三步:通過正則表示式查詢第一個匹配的

第四步:查詢 ...