config_rewrite.md

Configure Rewrite

This chapter describes how to configure HTTP rewrite. This function modifies the received HTTP request and forwards it to the backend service.

Enable Rewrite

In conf/bfe.conf, enable the module

Modules = mod_write

Configuration

The configuration is located in the directory conf/mod_rewrite/, contains two files:

$ ls
mod_rewrite.conf	rewrite.data

mod_rewrite.conf is the basic configuration file of the module, pointing to the rewrite rule file. mod_rewrite.conf usually does not need to be modified.

$ cat mod_rewrite.conf 
[basic]
DataPath = mod_rewrite/rewrite.data

rewrite.data contains rewrite rules and can be loaded dynamically. The sample configuration file in the installation package is as follows:

$ cat rewrite.data 
{
    "Version": "1",
    "Config": {
        "example_product": [
            {
                "Cond": "req_path_prefix_in(\"/rewrite\", false)",
                "Actions": [
                    {
                        "Cmd": "PATH_PREFIX_ADD",
                        "Params": [
                            "/bfe/"
                        ]
                    }
                ],
                "Last": true
            }
        ]
    }
}

The above configuration adds a rule for product example_product: for the request that meets the condition identified by "Cond", execute the actions identified by "Actions" (including the action name identified by "Cmd" and the corresponding parameter). If "Last" is true, stop the execution of subsequent actions, otherwise continue to match the next rule.

Finally, the rule will modify the request whose path starts with "/rewrite" and add the path prefix "/bfe/" to it, that is, change the path from "/rewrite" to "/bfe/rewrite".

Actions

The "Cmd" in "Actions" indicates the specific rewrite action.

HOST_SET

Set the Host in the request header. The parameter is the value to be set.

Example:

{
    "Cmd": "HOST_SET", 
    "Params": ["www.example.com"]
}

Result:

Original value	http://abc.example.com
After rewrite	http://www.example.com

HOST_SET_FROM_PATH_PREFIX

Set the first section in Path to the value of Host and remove it from Path. For example, if the Path is "/x.example.com/xxxx", set the Host to "x.example.com", and the PATH to "/xxxx".

Example:

{
    "cmd": "HOST_SET_FROM_PATH_PREFIX", 
    "params": []
}

Result:

Original value	http://www.example.com/test.example.com/xxxx
After rewrite	http://test.example.com/xxxx

HOST_SUFFIX_REPLACE

Replace the specific suffix in the domain name. The two parameters are the suffix string to be replaced and the new string.

Example:

{
    "cmd": "HOST_SUFFIX_REPLACE", 
    "params": ["net", "com"]
}

Result:

Original value	http://www.example.net
After rewrite	http://www.example.com

PATH_SET

Set the Path to the specified value and the parameter to the new value of Path .

Example:

{
    "cmd": "PATH_SET", 
    "params": ["/index"]
}

Result:

Original value	http://www.example.com/current
After rewrite	http://www.example.com/index

PATH_PREFIX_ADD

Add a prefix for Path. The parameter is the prefix to add.

Example:

{
    "cmd": "PATH_PREFIX_ADD", 
    "params": ["/index"]
}

Result:

Original value	http://www.example.com/current
After rewrite	http://www.example.com/index/current

PATH_PREFIX_TRIM

Delete the Path prefix. The parameter is the prefix to delete.

Example:

{
    "cmd": "PATH_PREFIX_TRIM", 
    "params": ["/service"]
}

Result:

Original value	http://www.example.com/service/index.html
After rewrite	http://www.example.com/index.html

QUERY_ADD

Add Query. The parameter specifies the key and value of the query to be added.

Example:

{
    "cmd": "QUERY_ADD", 
    "params": ["name", "alice"]
}

Result:

Original value	http://www.example.com/
After rewrite	http://www.example.com/?name=alice

QUERY_RENAME

Rename the query. The parameter specifies the original name and new name of the key.

Example:

{
    "cmd": "QUERY_ADD", 
    "params": ["name", "user"]
}

Result:

Original value	http://www.example.com/?name=alice
After rewrite	http://www.example.com/?user=alice

QUERY_DEL

Delete the specified Query. The parameter specifies the name of the key.

Example:

{
    "cmd": "QUERY_ADD", 
    "params": ["name"]
}

Result:

Original value	http://www.example.com/?name=alice
After rewrite	http://www.example.com/

QUERY_DEL_ALL_EXCEPT

Delete all other keys except the specified key in Query.

Example:

{
    "cmd": "QUERY_DEL_ALL_EXCEPT", 
    "params": ["name"]
}

Result:

Original value	http://www.example.com/?name=alice?key1=value2&key2=value2
After rewrite	http://www.example.com/?name=alice

links

Previous: Chap22 Configure HTTPS Service
Next: Chap24 Configure Redirect