确定 哪个location 指令匹配一个特定指令，常规字符串第一个测试。常规字符串匹配请求的开始部分并且区分大小写，最明确的匹配将会被使用（查看下文明白 nginx 怎么确定它）。然后正则表达式按照配置文件里的顺序测试。找到第一个比配的正则表达式将停止搜索。如果没有找到匹配的正则表达式，使用常规字符串的结果。
There are two ways to modify this behavior. The first is to use the prefix “=”, which matches an exact query only. If the query matches, then searching stops and the request is handled immediately. For example, if the request “/” occurs frequently, then using “location = /” will expedite the processing of this request.
有两个方法修改这个行为。第一个方法是使用 “=”前缀，将只执行严格匹配。如果这个查询匹配，那么将停止搜索并立即处理这个请求。例子：如果经常发生”/”请求，那么使用 “location = /” 将加速处理这个请求。
The second is to use the prefix ^~. This prefix is used with a conventional string and tells nginx to not check regular expressions if the path provided is a match. For instance, “location ^~ /images/” would halt searching if the query begins with /images/ - all regular expression directives would not be checked.
第二个是使用 ^~ 前缀。如果把这个前缀用于一个常规字符串那么告诉nginx 如果路径匹配那么不测试正则表达式。
Furthermore it is important to know that NGINX does the comparison not URL encoded, so if you have a URL like “/images/%20/test” then use “/images/ /test” to determine the location.
而且它重要在于 NGINX 做比较没有 URL 编码，所以如果你有一个 URL 链接'/images/%20/test' , 那么使用 “images/ /test” 限定location。
To summarize, the order in which directives are checked is as follows:
总结，指令按下列顺序被接受:
1. Directives with the = prefix that match the query exactly. If found, searching stops.
1. = 前缀的指令严格匹配这个查询。如果找到，停止搜索。
2. All remaining directives with conventional strings, longest match first. If this match used the ^~ prefix, searching stops.
2. 剩下的常规字符串，长的在前。如果这个匹配使用 ^~ 前缀，搜索停止。
3. Regular expressions, in order of definition in the configuration file.
3. 正则表达式，按配置文件里的顺序。
4. If #3 yielded a match, that result is used. Else the match from #2 is used.
4. 如果第三步产生匹配，则使用这个结果。否则使用第二步的匹配结果。
Example:
例子：
location = / {
# matches the query / only.
# 只匹配 / 查询。
[ configuration A ]
}
location / {
# matches any query, since all queries begin with /, but regular
# expressions and any longer conventional blocks will be
