chrome.declarativeNetRequest

Description
The chrome.declarativeNetRequest API is used to block or modify network requests by specifying declarative rules. This lets extensions modify network requests without intercepting them and viewing their content, thus providing more privacy.
Permissions
declarativeNetRequest
declarativeNetRequestFeedback
host permissions
Note that declarativeNetRequestFeedback and host permissions should only be specified when necessary.
Availability
Since Chrome 84.

Manifest #

Extensions must declare the "declarativeNetRequest" permission in the extension manifest to use this API. The "declarativeNetRequestFeedback" permission is required to access functions and events which return information on declarative rules matched. Host permissions are required if the extension wants to redirect requests or modify headers. To specify static Rulesets, extensions must also declare the "declarative_net_request" manifest key, which should be a dictionary with a single key called "rule_resources". It should be a list containing dictionaries of type Ruleset, as shown below.

{
  "name": "My extension",
  ...

  "declarative_net_request" : {
    "rule_resources" : [{
      "id": "ruleset_1",
      "enabled": true,
      "path": "rules_1.json"
    }, {
      "id": "ruleset_2",
      "enabled": false,
      "path": "rules_2.json"
    }]
  },
  "permissions": [
    "declarativeNetRequest",
    "declarativeNetRequestFeedback",
    "*://example.com/*"
  ],
  ...
}

Rule Resources #

An extension can specify up to MAX_NUMBER_OF_STATIC_RULESETS rulesets as part of the "rule_resources" manifest key. An extension is allowed to enable at least GUARANTEED_MINIMUM_STATIC_RULES static rules. Additional static rule sets may or may not be enabled depending on the available global static rule limit.

Global Static Rule Limit #

In addition to the GUARANTEED_MINIMUM_STATIC_RULES static rules guaranteed for each extension, extensions can enable additional static rulesets depending on the available global static rule limit. This global limit is shared between all extensions and can be used by extensions on a first-come, first-served basis. Extensions shouldn't depend on the global limit having a specific value and should instead use the getAvailableStaticRuleCount API method to find the additional rule limit available to them.

Rules #

A single declarative Rule consists of four fields: id, priority, condition, and action. There are the following kinds of rules:

Rules that block a network request.
Rules that prevent a request from getting blocked by negating any matching blocked rules.
Rules that redirect a network request.
Rules that modify headers from a network request.

An example rule:

{
  "id" : 1,
  "priority": 1,
  "action" : { "type" : "block" },
  "condition" : {
    "urlFilter" : "abc",
    "domains" : ["foo.com"],
    "resourceTypes" : ["script"]
  }
}

The above rule will block all script requests originating from "foo.com" to any URL with "abc" as a substring.

The urlFilter field of a rule condition is used to specify the pattern which is matched against the request URL. Some examples of URL filters:

`urlFilter`	Matches	Does not match
`"abc"`	https://abcd.com https://example.com/abcd	http://ab.com
`"abc*d"`	https://abcd.com https://example.com/abcxyzd	http://abc.com
`"\|\|a.example.com"`	https://a.example.com/ https://b.a.example.com/xyz	http://example.com/
`"\|https*"`	https://example.com	http://example.com/ http://https.com
`"example*^123\|"`	https://example.com/123 http://abc.com/example?123	https://example.com/1234 https://abc.com/example0123

Dynamic and session-scoped rules #

An extension can add or remove rules dynamically using the updateDynamicRules and the updateSessionRules API methods.

Rules added using the updateDynamicRules API method are persisted across both sessions and extension updates.
Rules added using the updateSessionRules API method are not persisted across Chrome sessions. These rules are backed in memory by Chrome.
The number of dynamic and session-scoped rules that an an extension can add is bounded by the MAX_NUMBER_OF_DYNAMIC_AND_SESSION_RULES constant.

Updating enabled rulesets #

An extension can update the set of enabled static rulesets using the updateEnabledRulesets API method.

The number of rules across enabled static rulesets across all extensions must not exceed the global limit. Calling getAvailableStaticRuleCount is recommended to check the number of rules an extension can still enable before the global limit is reached.
The set of enabled static rulesets is persisted across sessions but not across extension updates. The rule_resources manifest key will determine the set of enabled static rulesets on initial extension install and on each subsequent extension update.

Implementation details #

Matching algorithm #

Before the request is sent, each extension is queried for an action to take. The following actions are considered at this stage:

Actions which block requests of type block
Actions which redirect requests of type redirect or upgradeScheme
Actions which allow requests of type allow or allowAllRequests

If more than one extension returns an action, the extension whose action type comes first in the list above gets priority. If more than one extension returns an action with the same priority (position in the list), the most recently installed extension gets priority.

When an extension is queried for how to handle a request, the highest priority matching rule is returned. If more than one matching rule has the highest priority, the tie is broken based on the action type, in the following order of decreasing precedence:

allow
allowAllRequests
block
upgradeScheme
redirect

If the request was not blocked or redirected, the matching modifyHeaders rules are evaluated with the most recently installed extensions getting priority. Within each extension, all modifyHeaders rules with a priority lower than matching allow or allowAllRequests rules are ignored.

If multiple modifyHeaders rules specify the same header, the resulting modification for the header is determined based on the priority of each rule and the operations specified.

If a rule has appended to a header, then lower priority rules can only append to that header. set and remove operations are not permitted.
If a rule has set a header, then lower priority rules cannot further modify the header, except for append rules from the same extension.
If a rule has removed a header, then lower priority rules cannot further modify the header.

Comparison with the webRequest API #

The declarativeNetRequest API allows for evaluating network requests in the browser itself. This makes it more performant than the webRequest API, where each network request is evaluated in JavaScript in the extension process.
Because the requests are not intercepted by the extension process, declarativeNetRequest removes the need for extensions to have a background page; resulting in less memory consumption.
Unlike the webRequest API, blocking requests using the declarativeNetRequest API requires no host permissions.
The declarativeNetRequest API provides better privacy to users because extensions can't actually read the network requests made on the user's behalf.
Unlike the webRequest API, any images or iframes blocked using the declarativeNetRequest API are automatically collapsed in the DOM.
While deciding whether a request is to be blocked or redirected, the declarativeNetRequest API is given priority over the webRequest API because it allows for synchronous interception. Similarly, any headers removed through declarativeNetRequest API are not made visible to web request extensions.
The webRequest API is more flexible as compared to the declarativeNetRequest API because it allows extensions to evaluate a request programmatically.

Example #

manifest.json

{
  "name": "declarativeNetRequest extension",
  "version": "1",
  "declarative_net_request": {
    "rule_resources": [{
      "id": "ruleset_1",
      "enabled": true,
      "path": "rules.json"
    }]
  },
  "permissions": [
    "*://*.google.com/*",
    "*://*.abcd.com/*",
    "*://*.example.com/*",
    "http://*.xyz.com/*",
    "*://*.headers.com/*",
    "declarativeNetRequest"
  ],
  "manifest_version": 2
}

rules.json

[
  {
    "id": 1,
    "priority": 1,
    "action": { "type": "block" },
    "condition": {"urlFilter": "google.com", "resourceTypes": ["main_frame"] }
  },
  {
    "id": 2,
    "priority": 1,
    "action": { "type": "allow" },
    "condition": { "urlFilter": "google.com/123", "resourceTypes": ["main_frame"] }
  },
  {
    "id": 3,
    "priority": 2,
    "action": { "type": "block" },
    "condition": { "urlFilter": "google.com/12345", "resourceTypes": ["main_frame"] }
  },
  {
    "id": 4,
    "priority": 1,
    "action": { "type": "redirect", "redirect": { "url": "https://example.com" } },
    "condition": { "urlFilter": "google.com", "resourceTypes": ["main_frame"] }
  },
  {
    "id": 5,
    "priority": 1,
    "action": { "type": "redirect", "redirect": { "extensionPath": "/a.jpg" } },
    "condition": { "urlFilter": "abcd.com", "resourceTypes": ["main_frame"] }
  },
  {
    "id": 6,
    "priority": 1,
    "action": {
      "type": "redirect",
      "redirect": {
        "transform": { "scheme": "https", "host": "new.example.com" }
      }
    },
    "condition": { "urlFilter": "||example.com", "resourceTypes": ["main_frame"] }
  },
  {
    "id": 7,
    "priority": 1,
    "action": {
      "type": "redirect",
      "redirect": {
        "regexSubstitution": "https://\\1.xyz.com/"
      }
    },
    "condition": {
      "regexFilter": "^http://www\\.(abc|def)\\.xyz\\.com/",
      "resourceTypes": [
        "main_frame"
      ]
    }
  },
  {
    "id" : 8,
    "priority": 2,
    "action" : {
      "type" : "allowAllRequests"
    },
    "condition" : {
      "urlFilter" : "||b.com/path",
      "resourceTypes" : ["sub_frame"]
    }
  },
  {
    "id" : 9,
    "priority": 1,
    "action" : {
      "type" : "block"
    },
    "condition" : {
      "urlFilter" : "script.js",
      "resourceTypes" : ["script"]
    }
  },
  {
    "id": 10,
    "priority": 2,
    "action": {
      "type": "modifyHeaders",
      "responseHeaders": [
        { "header": "h1", "operation": "remove" },
        { "header": "h2", "operation": "set", "value": "v2" },
        { "header": "h3", "operation": "append", "value": "v3" }
      ]
    },
    "condition": { "urlFilter": "headers.com/123", "resourceTypes": ["main_frame"] }
  },
  {
    "id": 11,
    "priority": 1,
    "action": {
      "type": "modifyHeaders",
      "responseHeaders": [
        { "header": "h1", "operation": "set", "value": "v4" },
        { "header": "h2", "operation": "append", "value": "v5" },
        { "header": "h3", "operation": "append", "value": "v6" }
      ]
    },
    "condition": { "urlFilter": "headers.com/12345", "resourceTypes": ["main_frame"] }
  },
]

Consider a navigation to "http://google.com". Rules with id (1) and (4) match. The request will be blocked because blocking rules have higher priority than redirect rules when the "priority" is the same.
Consider a navigation to "http://google.com/1234". Rules with id (1), (2), and (4) match. Because the request has a matching allow rule and no higher priority rules, the request is not blocked nor redirected and continues to "http://google.com/1234".
Consider a navigation to "http://google.com/12345" Rules with id (1), (2), (3), and (4) match. The request will be blocked because rule (3) has the highest priority, overriding all other matching rules.
Consider a navigation to "http://abcd.com". The rule with id (5) matches. Since rule (5) specifies an extension path, the request is redirected to "chrome-extension://<extension-id>/a.jpg".
Consider a navigation to "http://example.com/path". The rule with id (6) matches. Since rule (6) specifies a url transform, the request is redirected to "https://new.example.com/path".
Consider a navigation to "http://www.abc.xyz.com/path". The rule with id (7) matches. The request will be redirected to "https://abc.xyz.com/path".
Consider the following request hierarchy:
- https://a.com/path (main-frame request)
  - https://b.com/path (sub-frame request, matches rule with id (8))
    - https://c.com/path (sub-frame request, matches rule with id (8))
      - https://c.com/script.js (script request, matches rules with ids (8, 9) but (8) has higher priority)
    - https://b.com/script.js (script request, matches rules with ids (8, 9) but (8) has higher priority)
  - https://d.com/path (sub-frame request)
    - https://d.com/script.js (script request, matches rule with ids (9))All requests in green will be allow-listed due to rule with id (8) and not be evaluated by the extensions' ruleset. Requests in red will be blocked due to rule with id (9).
Consider a navigation to "http://headers.com/12345" with response headers { "h1": "initial_1", "h2": "initial_2" }. Rules with id (10) and (11) match. The request will have its response headers modified to { "h2": "v2", "h2": "v5", "h3": "v3", "h3": "v6" }. Header h1 was removed by (10), h2 was set by (10) then appended by (11), and h3 was appended by (10) and (11).

Summary

Types
ExtensionActionOptions
IsRegexSupportedResult
MatchedRule
MatchedRuleInfo
MatchedRuleInfoDebug
MatchedRulesFilter
ModifyHeaderInfo
QueryKeyValue
QueryTransform
Redirect
RegexOptions
RequestDetails
Rule
RuleAction
RuleCondition
RulesMatchedDetails
Ruleset
TabActionCountUpdate
URLTransform
UpdateRuleOptions
UpdateRulesetOptions
DomainType
HeaderOperation
RequestMethod
ResourceType
RuleActionType
UnsupportedRegexReason
Properties
DYNAMIC_RULESET_ID
GETMATCHEDRULES_QUOTA_INTERVAL
GUARANTEED_MINIMUM_STATIC_RULES
MAX_GETMATCHEDRULES_CALLS_PER_INTERVAL
MAX_NUMBER_OF_DYNAMIC_AND_SESSION_RULES
MAX_NUMBER_OF_REGEX_RULES
MAX_NUMBER_OF_STATIC_RULESETS
SESSION_RULESET_ID
Methods
getAvailableStaticRuleCount
declarativeNetRequest.getAvailableStaticRuleCount(callback: function)
getDynamicRules
declarativeNetRequest.getDynamicRules(callback: function)
getEnabledRulesets
declarativeNetRequest.getEnabledRulesets(callback: function)
getMatchedRules
declarativeNetRequest.getMatchedRules(filter?: MatchedRulesFilter, callback: function)
getSessionRules
declarativeNetRequest.getSessionRules(callback: function)
isRegexSupported
declarativeNetRequest.isRegexSupported(regexOptions: RegexOptions, callback: function)
setExtensionActionOptions
declarativeNetRequest.setExtensionActionOptions(options: ExtensionActionOptions, callback: function)
updateDynamicRules
declarativeNetRequest.updateDynamicRules(options: UpdateRuleOptions, callback: function)
updateEnabledRulesets
declarativeNetRequest.updateEnabledRulesets(options: UpdateRulesetOptions, callback: function)
updateSessionRules
declarativeNetRequest.updateSessionRules(options: UpdateRuleOptions, callback: function)
Events
onRuleMatchedDebug

Types

ExtensionActionOptions

Since Chrome 88.

Properties

displayActionCountAsBadgeText
boolean optional
Whether to automatically display the action count for a page as the extension's badge text. This preference is persisted across sessions.
tabUpdate
TabActionCountUpdate optional
Since Chrome 89.
Details of how the tab's action count should be adjusted.

IsRegexSupportedResult

Since Chrome 87.

Properties

isSupported
boolean
reason
UnsupportedRegexReason optional
Specifies the reason why the regular expression is not supported. Only provided if isSupported is false.

MatchedRule

Properties

ruleId
number
A matching rule's ID.
rulesetId
string
ID of the Ruleset this rule belongs to. For a rule originating from the set of dynamic rules, this will be equal to DYNAMIC_RULESET_ID.

MatchedRuleInfo

Properties

rule
MatchedRule
tabId
number
The tabId of the tab from which the request originated if the tab is still active. Else -1.
timeStamp
number
The time the rule was matched. Timestamps will correspond to the Javascript convention for times, i.e. number of milliseconds since the epoch.

MatchedRuleInfoDebug

Properties

request
RequestDetails
Details about the request for which the rule was matched.
rule
MatchedRule

MatchedRulesFilter

Properties

minTimeStamp
number optional
If specified, only matches rules after the given timestamp.
tabId
number optional
If specified, only matches rules for the given tab. Matches rules not associated with any active tab if set to -1.

ModifyHeaderInfo

Since Chrome 86.

Properties

header
string
The name of the header to be modified.
operation
HeaderOperation
The operation to be performed on a header.
value
string optional
The new value for the header. Must be specified for append and set operations.

QueryKeyValue

Properties

key
string
value
string

QueryTransform

Properties

addOrReplaceParams
QueryKeyValue[] optional
The list of query key-value pairs to be added or replaced.
removeParams
string[] optional
The list of query keys to be removed.

Redirect

Properties

extensionPath
string optional
Path relative to the extension directory. Should start with '/'.
regexSubstitution
string optional
Substitution pattern for rules which specify a regexFilter. The first match of regexFilter within the url will be replaced with this pattern. Within regexSubstitution, backslash-escaped digits (\1 to \9) can be used to insert the corresponding capture groups. \0 refers to the entire matching text.
transform
URLTransform optional
Url transformations to perform.
url
string optional
The redirect url. Redirects to JavaScript urls are not allowed.

RegexOptions

Since Chrome 87.

Properties

isCaseSensitive
boolean optional
Whether the regex specified is case sensitive. Default is true.
regex
string
The regular expresson to check.
requireCapturing
boolean optional
Whether the regex specified requires capturing. Capturing is only required for redirect rules which specify a regexSubstition action. The default is false.

RequestDetails

Properties

frameId
number
The value 0 indicates that the request happens in the main frame; a positive value indicates the ID of a subframe in which the request happens. If the document of a (sub-)frame is loaded (type is main_frame or sub_frame), frameId indicates the ID of this frame, not the ID of the outer frame. Frame IDs are unique within a tab.
initiator
string optional
The origin where the request was initiated. This does not change through redirects. If this is an opaque origin, the string 'null' will be used.
method
string
Standard HTTP method.
parentFrameId
number
ID of frame that wraps the frame which sent the request. Set to -1 if no parent frame exists.
requestId
string
The ID of the request. Request IDs are unique within a browser session.
tabId
number
The ID of the tab in which the request takes place. Set to -1 if the request isn't related to a tab.
type
ResourceType
The resource type of the request.
url
string
The URL of the request.

Rule

Properties

action
RuleAction
The action to take if this rule is matched.
condition
RuleCondition
The condition under which this rule is triggered.
id
number
An id which uniquely identifies a rule. Mandatory and should be >= 1.
priority
number optional
Rule priority. Defaults to 1. When specified, should be >= 1.

RuleAction

Properties

redirect
Redirect optional
Describes how the redirect should be performed. Only valid for redirect rules.
requestHeaders
ModifyHeaderInfo[] optional
Since Chrome 86.
The request headers to modify for the request. Only valid if RuleActionType is "modifyHeaders".
responseHeaders
ModifyHeaderInfo[] optional
Since Chrome 86.
The response headers to modify for the request. Only valid if RuleActionType is "modifyHeaders".
type
RuleActionType
The type of action to perform.

RuleCondition

Properties

domainType
DomainType optional
Specifies whether the network request is first-party or third-party to the domain from which it originated. If omitted, all requests are accepted.
domains
string[] optional
The rule will only match network requests originating from the list of domains. If the list is omitted, the rule is applied to requests from all domains. An empty list is not allowed.
Notes:
- Sub-domains like "a.example.com" are also allowed.
- The entries must consist of only ascii characters.
- Use punycode encoding for internationalized domains.
- This matches against the request initiator and not the request url.
excludedDomains
string[] optional
The rule will not match network requests originating from the list of excludedDomains. If the list is empty or omitted, no domains are excluded. This takes precedence over domains.
Notes:
- Sub-domains like "a.example.com" are also allowed.
- The entries must consist of only ascii characters.
- Use punycode encoding for internationalized domains.
- This matches against the request initiator and not the request url.
excludedRequestMethods
RequestMethod[] optional
List of request methods which the rule won't match. Only one of requestMethods and excludedRequestMethods should be specified. If neither of them is specified, all request methods are matched.
excludedResourceTypes
ResourceType[] optional
List of resource types which the rule won't match. Only one of resourceTypes and excludedResourceTypes should be specified. If neither of them is specified, all resource types except "main_frame" are blocked.
isUrlFilterCaseSensitive
boolean optional
Whether the urlFilter or regexFilter (whichever is specified) is case sensitive. Default is true.
regexFilter
string optional
Regular expression to match against the network request url. This follows the RE2 syntax.
Note: Only one of urlFilter or regexFilter can be specified.
Note: The regexFilter must be composed of only ASCII characters. This is matched against a url where the host is encoded in the punycode format (in case of internationalized domains) and any other non-ascii characters are url encoded in utf-8.
requestMethods
RequestMethod[] optional
List of HTTP request methods which the rule can match. An empty list is not allowed. Note: Non HTTP requests are considered to have the "get" request method.
resourceTypes
ResourceType[] optional
List of resource types which the rule can match. An empty list is not allowed.
Note: this must be specified for allowAllRequests rules and may only include the sub_frame and main_frame resource types.
urlFilter
string optional
The pattern which is matched against the network request url. Supported constructs:
'*' : Wildcard: Matches any number of characters.
'|' : Left/right anchor: If used at either end of the pattern, specifies the beginning/end of the url respectively.
'||' : Domain name anchor: If used at the beginning of the pattern, specifies the start of a (sub-)domain of the URL.
'^' : Separator character: This matches anything except a letter, a digit or one of the following: _ - . %. This can also match the end of the URL.
Therefore urlFilter is composed of the following parts: (optional Left/Domain name anchor) + pattern + (optional Right anchor).
If omitted, all urls are matched. An empty string is not allowed.
A pattern beginning with || is not allowed. Use instead.
Note: Only one of urlFilter or regexFilter can be specified.
Note: The urlFilter must be composed of only ASCII characters. This is matched against a url where the host is encoded in the punycode format (in case of internationalized domains) and any other non-ascii characters are url encoded in utf-8. For example, when the request url is http://abc.рф?q=ф, the urlFilter will be matched against the url http://abc.xn--p1ai/?q=%D1%84.

RulesMatchedDetails

Properties

rulesMatchedInfo
MatchedRuleInfo[]
Rules matching the given filter.

Ruleset

Properties

enabled
boolean
Whether the ruleset is enabled by default.
id
string
A non-empty string uniquely identifying the ruleset. IDs beginning with '_' are reserved for internal use.
path
string
The path of the JSON ruleset relative to the extension directory.

TabActionCountUpdate

Since Chrome 89.

Properties

increment
number
The amount to increment the tab's action count by. Negative values will decrement the count.
tabId
number
The tab for which to update the action count.

URLTransform

Properties

fragment
string optional
The new fragment for the request. Should be either empty, in which case the existing fragment is cleared; or should begin with '#'.
host
string optional
The new host for the request.
password
string optional
The new password for the request.
path
string optional
The new path for the request. If empty, the existing path is cleared.
port
string optional
The new port for the request. If empty, the existing port is cleared.
query
string optional
The new query for the request. Should be either empty, in which case the existing query is cleared; or should begin with '?'.
queryTransform
QueryTransform optional
Add, remove or replace query key-value pairs.
scheme
string optional
The new scheme for the request. Allowed values are "http", "https", "ftp" and "chrome-extension".
username
string optional
The new username for the request.

UpdateRuleOptions

Since Chrome 87.

Properties

addRules
Rule[] optional
Rules to add.
removeRuleIds
number[] optional
IDs of the rules to remove. Any invalid IDs will be ignored.

UpdateRulesetOptions

Since Chrome 87.

Properties

disableRulesetIds
string[] optional
The set of ids corresponding to a static Ruleset that should be disabled.
enableRulesetIds
string[] optional
The set of ids corresponding to a static Ruleset that should be enabled.

DomainType

This describes whether the request is first or third party to the frame in which it originated. A request is said to be first party if it has the same domain (eTLD+1) as the frame in which the request originated.

Enum

"firstParty", or "thirdParty"

HeaderOperation

Since Chrome 86.

This describes the possible operations for a "modifyHeaders" rule.

Enum

"append", "set", or "remove"

RequestMethod

This describes the HTTP request method of a network request.

Enum

"delete", "get", "head", "options", "patch", "post", or "put"

ResourceType

This describes the resource type of the network request.

Enum

"main_frame", "sub_frame", "stylesheet", "script", "image", "font", "object", "xmlhttprequest", "ping", "csp_report", "media", "websocket", or "other"

RuleActionType

Describes the kind of action to take if a given RuleCondition matches.

Enum

"block", "redirect", "allow", "upgradeScheme", "modifyHeaders", or "allowAllRequests"

UnsupportedRegexReason

Since Chrome 87.

Describes the reason why a given regular expression isn't supported.

Enum

"syntaxError", or "memoryLimitExceeded"

Properties

DYNAMIC_RULESET_ID

Ruleset ID for the dynamic rules added by the extension.

Value

string "_dynamic"

GETMATCHEDRULES_QUOTA_INTERVAL

Time interval within which MAX_GETMATCHEDRULES_CALLS_PER_INTERVAL getMatchedRules calls can be made, specified in minutes. Additional calls will fail immediately and set runtime.lastError. Note: getMatchedRules calls associated with a user gesture are exempt from the quota.

Value

number 10

GUARANTEED_MINIMUM_STATIC_RULES

Since Chrome 89.

The minimum number of static rules guaranteed to an extension across its enabled static rulesets. Any rules above this limit will count towards the global rule limit.

Value

number 30000

MAX_GETMATCHEDRULES_CALLS_PER_INTERVAL

The number of times getMatchedRules can be called within a period of GETMATCHEDRULES_QUOTA_INTERVAL.

Value

number 20

MAX_NUMBER_OF_DYNAMIC_AND_SESSION_RULES

Since Chrome 90.

The maximum number of combined dynamic and session scoped rules an extension can add.

Value

number 5000

MAX_NUMBER_OF_REGEX_RULES

The maximum number of regular expression rules that an extension can add. This limit is evaluated separately for the set of dynamic rules and those specified in the rule resources file.

Value

number 1000

MAX_NUMBER_OF_STATIC_RULESETS

The maximum number of static Rulesets an extension can specify as part of the "rule_resources" manifest key.

Value

number 10

SESSION_RULESET_ID

Since Chrome 90.

Ruleset ID for the session-scoped rules added by the extension.

Value

string "_session"

Methods

getAvailableStaticRuleCount

declarativeNetRequest.getAvailableStaticRuleCount(callback: function)

Since Chrome 89.

Returns the number of static rules an extension can enable before the global static rule limit is reached.

Parameters

callback
function
The callback parameter should be a function that looks like this:
(count: number) => {...}
- count
  number

getDynamicRules

declarativeNetRequest.getDynamicRules(callback: function)

Returns the current set of dynamic rules for the extension.

Parameters

callback
function
Called with the set of dynamic rules. An error might be raised in case of transient internal errors.
The callback parameter should be a function that looks like this:
(rules: Rule[]) => {...}
- rules
  Rule[]

getEnabledRulesets

declarativeNetRequest.getEnabledRulesets(callback: function)

Returns the ids for the current set of enabled static rulesets.

Parameters

callback
function
Called with a list of ids, where each id corresponds to an enabled static Ruleset.
The callback parameter should be a function that looks like this:
(rulesetIds: string[]) => {...}
- rulesetIds
  string[]

getMatchedRules

declarativeNetRequest.getMatchedRules(filter?: MatchedRulesFilter, callback: function)

Returns all rules matched for the extension. Callers can optionally filter the list of matched rules by specifying a filter. This method is only available to extensions with the declarativeNetRequestFeedback permission or having the activeTab permission granted for the tabId specified in filter. Note: Rules not associated with an active document that were matched more than five minutes ago will not be returned.

Parameters

filter
MatchedRulesFilter optional
An object to filter the list of matched rules.
callback
function
Called once the list of matched rules has been fetched. In case of an error, runtime.lastError will be set and no rules will be returned. This can happen for multiple reasons, such as insufficient permissions, or exceeding the quota.
The callback parameter should be a function that looks like this:
(details: RulesMatchedDetails) => {...}
- details
  RulesMatchedDetails

getSessionRules

declarativeNetRequest.getSessionRules(callback: function)

Since Chrome 90.

Returns the current set of session scoped rules for the extension.

Parameters

callback
function
Called with the set of session scoped rules.
The callback parameter should be a function that looks like this:
(rules: Rule[]) => {...}
- rules
  Rule[]

isRegexSupported

declarativeNetRequest.isRegexSupported(regexOptions: RegexOptions, callback: function)

Since Chrome 87.

Checks if the given regular expression will be supported as a regexFilter rule condition.

Parameters

regexOptions
RegexOptions
The regular expression to check.
callback
function
Called with details consisting of whether the regular expression is supported and the reason if not.
The callback parameter should be a function that looks like this:
(result: IsRegexSupportedResult) => {...}
- result
  IsRegexSupportedResult

setExtensionActionOptions

declarativeNetRequest.setExtensionActionOptions(options: ExtensionActionOptions, callback: function)

Since Chrome 88.

Configures if the action count for tabs should be displayed as the extension action's badge text and provides a way for that action count to be incremented.

Parameters

options
ExtensionActionOptions
callback
function
Since Chrome 89.
The callback parameter should be a function that looks like this:
() => {...}

updateDynamicRules

declarativeNetRequest.updateDynamicRules(options: UpdateRuleOptions, callback: function)

Modifies the current set of dynamic rules for the extension. The rules with IDs listed in options.removeRuleIds are first removed, and then the rules given in options.addRules are added. Notes:

This update happens as a single atomic operation: either all specified rules are added and removed, or an error is returned.
These rules are persisted across browser sessions and across extension updates.
Static rules specified as part of the extension package can not be removed using this function.
MAX_NUMBER_OF_DYNAMIC_AND_SESSION_RULES is the maximum number of combined dynamic and session rules an extension can add.

Parameters

options
UpdateRuleOptions
Since Chrome 87.
callback
function
Called once the update is complete or has failed. In case of an error, runtime.lastError will be set and no change will be made to the rule set. This can happen for multiple reasons, such as invalid rule format, duplicate rule ID, rule count limit exceeded, internal errors, and others.
The callback parameter should be a function that looks like this:
() => {...}

updateEnabledRulesets

declarativeNetRequest.updateEnabledRulesets(options: UpdateRulesetOptions, callback: function)

Updates the set of enabled static rulesets for the extension. The rulesets with IDs listed in options.disableRulesetIds are first removed, and then the rulesets listed in options.enableRulesetIds are added.
Note that the set of enabled static rulesets is persisted across sessions but not across extension updates, i.e. the rule_resources manifest key will determine the set of enabled static rulesets on each extension update.

Parameters

options
UpdateRulesetOptions
Since Chrome 87.
callback
function
Called once the update is complete. In case of an error, runtime.lastError will be set and no change will be made to set of enabled rulesets. This can happen for multiple reasons, such as invalid ruleset IDs, rule count limit exceeded, or internal errors.
The callback parameter should be a function that looks like this:
() => {...}

updateSessionRules

declarativeNetRequest.updateSessionRules(options: UpdateRuleOptions, callback: function)

Since Chrome 90.

Modifies the current set of session scoped rules for the extension. The rules with IDs listed in options.removeRuleIds are first removed, and then the rules given in options.addRules are added. Notes:

This update happens as a single atomic operation: either all specified rules are added and removed, or an error is returned.
These rules are not persisted across sessions and are backed in memory.
MAX_NUMBER_OF_DYNAMIC_AND_SESSION_RULES is the maximum number of combined dynamic and session rules an extension can add.

Parameters

options
UpdateRuleOptions
callback
function
Called once the update is complete or has failed. In case of an error, runtime.lastError will be set and no change will be made to the rule set. This can happen for multiple reasons, such as invalid rule format, duplicate rule ID, rule count limit exceeded, and others.
The callback parameter should be a function that looks like this:
() => {...}

Events

onRuleMatchedDebug

declarativeNetRequest.onRuleMatchedDebug.addListener(listener: function)

Fired when a rule is matched with a request. Only available for unpacked extensions with the declarativeNetRequestFeedback permission as this is intended to be used for debugging purposes only.

Event

listener
function
The listener parameter should be a function that looks like this:
(info: MatchedRuleInfoDebug) => {...}
- info
  MatchedRuleInfoDebug
  Since Chrome 85.
  The rule that has been matched along with information about the associated request.