Rewrite (Legacy Syntax)
This page describes the Rewrite syntax used before Loon 3.5.1 (978). It remains available for maintaining old configurations but will not receive new features.
Use the new Rewrite syntax for new configurations.
Rewrite can modify the URL, headers, and body before an HTTP request is sent or after a response is received. It can also return a redirect, reject response, or mock data immediately.
Rewrite applies only to HTTP traffic and HTTPS traffic decrypted through MitM. It runs before rule matching.
Match order
- Rewrite entries in the local configuration take priority over plugin entries.
- Entries in the same file are matched from top to bottom.
- Request-side and response-side entries can act on the same request.
- Since Loon 3.2.3 (749), entries on the same side using the same URL regular expression can run in sequence.
- The output of one entry becomes the input of the next, so later changes may override earlier ones.
URL replacement
^http://www\.google\.cn header http://www.google.com
Redirect
^http://example.com 302 https://example.com
^http://example.com 307 https://example.com
Reject
| Action | Response |
|---|---|
reject | Close the connection immediately |
reject-200 | 200 with an empty body |
reject-img | 200 with a 1×1 image |
reject-dict | 200 with {} |
reject-array | 200 with [] |
^http://example.com reject
^http://example.com reject-200
^http://example.com reject-img
^http://example.com reject-dict
^http://example.com reject-array
Request headers
^http://example.com header-add Connection keep-alive
^http://example.com header-del Cookie
^http://example.com header-replace User-Agent Unknown
^http://example.com header-replace-regex User-Agent regex replace-value
Since Loon 3.2.1 (730), one Rewrite entry can modify multiple headers:
^http://example.com header-add Connection keep-alive Proxy-Connection keep-alive
^http://example.com header-del Cookie Connection
^http://example.com header-replace User-Agent Unknown Content-Length 1999
^http://example.com header-replace-regex User-Agent regex replace-value Cookie UUID=123 UUID=456
Request body
Requires Build 729 or later.
^http://example.com request-body-replace-regex regex1 replace-value1 regex2 replace-value2
^http://example.com request-body-json-add data.apps[0] {"appName":"loon"} data.category tool
^http://example.com request-body-json-replace data.ad {}
^http://example.com request-body-json-del data.ad
^http://example.com request-body-json-jq 'del(.data.ad)'
JSON actions run only when the request body is valid JSON. Key paths use dot notation and [n] for array indexes, such as data.apps[0].appName.
request-body-json-jq uses a jq expression.
Mock request body
^http://example.com mock-request-body data-type=text data=""
^http://example.com mock-request-body data-type=json data-path=request_body.json
^http://example.com mock-request-body data-type=png data-path=request_body.raw mock-data-is-base64=true
Response headers
Requires Build 729 or later.
^http://example.com response-header-add Connection keep-alive
^http://example.com response-header-del Cookie
^http://example.com response-header-replace Cache-Control no-cache
^http://example.com response-header-replace-regex Content-Type regex replace-value
A single Rewrite entry can also modify multiple response headers.
Response body
Requires Build 729 or later.
^http://example.com response-body-replace-regex regex1 replace-value1 regex2 replace-value2
^http://example.com response-body-json-add data.apps[0] {"appName":"loon"} data.category tool
^http://example.com response-body-json-replace data.ad {}
^http://example.com response-body-json-del data.ad
^http://example.com response-body-json-jq 'del(.data.ad)'
JSON actions run only when the response body is valid JSON. Key paths follow the same rules as request bodies.
Mock response body
^http://example.com mock-response-body data-type=text data="" status-code=200
^http://example.com mock-response-body data-type=json data-path=response_body.json status-code=200
^http://example.com mock-response-body data-type=svg data-path=response_body.raw mock-data-is-base64=true status-code=200
Mock body options:
| Option | Description |
|---|---|
data-type | json, text, css, html, javascript, plain, png, gif, jpeg, tiff, svg, mp4, or form-data |
data | Body written directly in double quotes |
data-path | URL or a file in the iCloud/Mock directory |
mock-data-is-base64 | Whether the data is Base64 encoded |
status-code | Mock response status code; response only |
Use data-path for medium or large data.
The legacy syntax separates arguments by spaces. Use \x20 when a regular expression or replacement contains a space, or the configuration may fail to parse.