index.md

---

title: declarativeNetRequest.onRuleMatchedDebug
slug: Mozilla/Add-ons/WebExtensions/API/declarativeNetRequest/onRuleMatchedDebug
tags:
  - API
  - Add-ons
  - Extensions
  - Reference
  - WebExtensions
  - Event
  - declarativeNetRequest
  - onRuleMatchedDebug
browser-compat: webextensions.api.declarativeNetRequest.onRuleMatchedDebug

---

{{AddonSidebar()}}

Fired when a rule is matched with a request. Only available extensions with the "declarativeNetRequestFeedback" permission, as this is intended for debugging purposes only. See Testing for details on how testing is enabled in each browser.

Syntax

browser.declarativeNetRequest.onRuleMatchedDebug.addListener(listener)
browser.declarativeNetRequest.onRuleMatchedDebug.removeListener(listener)
browser.declarativeNetRequest.onRuleMatchedDebug.hasListener(listener)

Events have three functions:

• addListener(listener)

  • : Adds a listener to this event.

• removeListener(listener)

  • : Stop listening to this event. The listener argument is the listener to remove.

• hasListener(listener)

  • : Check whether listener is registered for this event. Returns true if it is listening, false otherwise.

addListener syntax

Parameters

• callback

  • : Function that is called when this event occurs. The function is passed these arguments:

    • request

      • : An object containing information about the request the rule matched.

        • documentId {{optional_inline}}

          • : A string. The unique identifier for the frame's document, if this request is for a frame.

        • documentLifecycle {{optional_inline}}

          • : A string. The lifecycle of the frame's document, if this request is for a frame. Possible values are: "prerender", "active", "cached", or "pending_deletion".

        • frameId

          • : A number. The value 0 indicates that the request happens in the main frame. A positive value indicates the ID of a subframe where the request happens. If the document of a (sub-)frame is loaded (type is main_frame or sub_frame), frameId indicates this frame's ID, not the outer frame's ID. Frame IDs are unique within a tab.

        • frameType {{optional_inline}}

          • : A string. The type of the frame, if this request is for a frame. Possible values are: "outermost_frame", "fenced_frame", or "sub_frame".

        • initiator {{optional_inline}}

          • : A string. The origin where the request was initiated. This does not change through redirects. The string 'null' is used if this is an opaque origin.

        • method

          • : A string. A standard HTTP method.

        • parentDocumentId {{optional_inline}}

          • : A string. The unique identifier for the frame's parent document, if this request is for a frame and has a parent.

        • parentFrameId

          • : A number. The ID of the frame that wraps the frame which sent the request. Set to -1 if there is no parent frame.

        • requestId

          • : A string. The ID of the request. Request IDs are unique within a browser session.

        • tabId

          • : A number. The ID of the tab in which the request takes place. Set to -1 if the request is not related to a tab.

        • type

          • : {{WebExtAPIRef("declarativeNetRequest.ResourceType", "ResourceType")}}. The resource type of the request.

        • url

          • : A string. The URL of the request.

    • rule

      • : {{WebExtAPIRef("declarativeNetRequest.MatchedRule", "MatchedRule")}}. Details of a matched rule.

{{WebExtExamples}}

Browser compatibility

{{Compat}}