ngx_http_core_module

1. alias
```
context: location
```

Defines a replacement for the specified location. For example, with the following configuration
location /i/ {
    alias /data/w3/images/;
}

on request of “/i/top.gif”, the file /data/w3/images/top.gif will be sent.
The path value can contain variables, except $document_root and $realpath_root.
If alias is used inside a location defined with a regular expression then such regular expression should contain captures and alias should refer to these captures (0.7.40), for example:

location ~ ^/users/(.+\.(?:gif|jpe?g|png))$ {
    alias /data/w3/images/$1;
}
When location matches the last part of the directive’s value:

location /images/ {
    alias /data/w3/images/;
}
it is better to use the root directive instead:

location /images/ {
    root /data/w3;
}

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

正则匹配~* (不区分大小写)
正则匹配~ (区分大小写)
最大路径匹配 = 和 ^~
如果查找到^~就不再继续匹配