DevTools protocol interception, blocking & modification of requests

third_party/WebKit/Source/core/inspector/browser_protocol.json

 {
     "version": { "major": "1", "minor": "2" },
     "domains": [{
         "domain": "Inspector",
         "experimental": true,
         "types": [],
         "commands": [
             {
                 "name": "enable",
                 "description": "Enables inspector domain notifications."
@@ skipping 935 matching lines @@
                 "id": "LoaderId",
                 "type": "string",
                 "description": "Unique loader identifier."
             },
             {
                 "id": "RequestId",
                 "type": "string",
                 "description": "Unique request identifier."
             },
             {
+                "id": "InterceptId",
+                "type": "string",
+                "description": "Unique intercepted request identifier."
+            },
+            {
+                "id": "ErrorReason",
+                "type": "string",
+                "enum": ["Failed", "Aborted", "TimedOut", "AccessDenied", "ConnectionClosed", "ConnectionReset", "ConnectionRefused", "ConnectionAborted", "ConnectionFailed", "NameNotResolved", "InternetDisconnected", "AddressUnreachable"],
+                "description": "Network level fetch failure reason."
+            },
+            {
                 "id": "Timestamp",
                 "type": "number",
                 "description": "Number of seconds since epoch."
             },
             {
                 "id": "Headers",
                 "type": "object",
                 "description": "Request / response headers as keys / values of JSON object."
             },
             {
@@ skipping 370 matching lines @@
             {
                 "name": "getCertificate",
                 "description": "Returns the DER-encoded certificate.",
                 "parameters": [
                     { "name": "origin", "type": "string", "description": "Origin to get certificate for." }
                 ],
                 "returns": [
                     { "name": "tableNames", "type": "array", "items": { "type": "string" } }
                 ],
                 "experimental": true
+            },
+            {
+                "name": "enableFetchInterception",
+                "parameters": [
+                    { "name": "enabled", "type": "boolean", "description": "Whether or not HTTP requests should be intercepted and Network.interceptedRequest events sent." }

[Sami, 2017/03/22 17:00:46]

Did we decide if this can be disabled after being enabled? Or is it that the
outstanding requests still need to be allowed/blocked/etc?

+                ],
+                "experimental": true
+            },
+            {
+                "name": "allowRequest",
+                "description": "Response to Network.interceptedRequest which allows the request to proceed unchanged.",
+                "parameters": [
+                    { "name": "id", "$ref": "InterceptId" }
+                ],
+                "experimental": true
+            },
+            {
+                "name": "blockRequest",
+                "description": "Response to Network.interceptedRequest which causes the request to fail.",
+                "parameters": [
+                    { "name": "id", "$ref": "InterceptId" },
+                    { "name": "errorReason", "$ref": "ErrorReason" }
+                ],
+                "experimental": true
+            },
+            {
+                "name": "modifyRequest",
+                "description": "Response to Network.interceptedRequest which modifies any or all fetch parameters before allowing the request to proceed.",
+                "parameters": [
+                    { "name": "id", "$ref": "InterceptId" },
+                    { "name": "url", "type": "string", "optional": true },
+                    { "name": "method", "type": "string", "optional": true },
+                    { "name": "postData", "type": "string", "optional": true },
+                    { "name": "headers", "$ref": "Headers", "optional": true }
+                ],
+                "experimental": true
+            },
+            {
+                "name": "mockResponse",
+                "description": "Response to Network.interceptedRequest which makes the request complete with the provided mock response.",
+                "parameters": [
+                    { "name": "id", "$ref": "InterceptId" },
+                    { "name": "rawResponse", "type": "string" }

[Sami, 2017/03/22 17:00:46]

Might be worth mentioning that this should contain the full HTTP response
including the status line and headers.

+                ],
+                "experimental": true
             }
         ],
         "events": [
             {
                 "name": "resourceChangedPriority",
                 "description": "Fired when resource loading priority is changed",
                 "parameters": [
                     { "name": "requestId", "$ref": "RequestId", "description": "Request identifier." },
                     { "name": "newPriority", "$ref": "ResourcePriority", "description": "New priority" },
                     { "name": "timestamp", "$ref": "Timestamp", "description": "Timestamp." }
@@ skipping 25 matching lines @@
             },
             {
                 "name": "responseReceived",
                 "description": "Fired when HTTP response is available.",
                 "parameters": [
                     { "name": "requestId", "$ref": "RequestId", "description": "Request identifier." },
                     { "name": "frameId", "$ref": "Page.FrameId", "description": "Frame identifier.", "experimental": true },
                     { "name": "loaderId", "$ref": "LoaderId", "description": "Loader identifier." },
                     { "name": "timestamp", "$ref": "Timestamp", "description": "Timestamp." },
                     { "name": "type", "$ref": "Page.ResourceType", "description": "Resource type." },
-                    { "name": "response", "$ref": "Response", "description": "Response data." }
+                    { "name": "response", "$ref": "Response", "description": "Response data." },
+                    { "name": "interceptId", "$ref": "InterceptId", "optional": true, "experimental": true }
                 ]
             },
             {
                 "name": "dataReceived",
                 "description": "Fired when data chunk was received over the network.",
                 "parameters": [
                     { "name": "requestId", "$ref": "RequestId", "description": "Request identifier." },
                     { "name": "timestamp", "$ref": "Timestamp", "description": "Timestamp." },
                     { "name": "dataLength", "type": "integer", "description": "Data chunk length." },
                     { "name": "encodedDataLength", "type": "integer", "description": "Actual bytes received (might be less than dataLength for compressed encodings)." }
@@ skipping 94 matching lines @@
                 "name": "eventSourceMessageReceived",
                 "description": "Fired when EventSource message is received.",
                 "parameters": [
                     { "name": "requestId", "$ref": "RequestId", "description": "Request identifier." },
                     { "name": "timestamp", "$ref": "Timestamp", "description": "Timestamp." },
                     { "name": "eventName", "type": "string", "description": "Message type." },
                     { "name": "eventId", "type": "string", "description": "Message identifier." },
                     { "name": "data", "type": "string", "description": "Message content." }
                 ],
                 "experimental": true
+            },
+            {
+                "name": "interceptedRequest",
+                "description": "Details of an intercepted HTTP request, which must be either allowed, blocked, modified or mocked.",
+                "parameters": [
+                    { "name": "id", "$ref": "InterceptId", "description": "Description unless part of a redirect chain, this id will be unique." },
+                    { "name": "request", "$ref": "Request" }
+                ],
+                "experimental": true 
+            },
+            {
+                "name": "interceptedRedirect",
+                "description": "Details of an intercepted HTTP redirect, which must be either allowed, blocked, modified or mocked.",
+                "parameters": [
+                    { "name": "id", "$ref": "InterceptId" },
+                    { "name": "responseHeaders", "$ref": "Headers", "description": "HTTP response headers." },
+                    { "name": "responseStatusCode", "type": "integer", "description": "HTTP response code."},
+                    { "name": "redirectUrl", "type": "string" }
+                ],
+                "experimental": true 
             }
         ]
     },
     {
         "domain": "Database",
         "experimental": true,
         "types": [
             {
                 "id": "DatabaseId",
                 "type": "string",
@@ skipping 3030 matching lines @@
                 "name": "accepted",
                 "description": "Informs that port was successfully bound and got a specified connection id.",
                 "parameters": [
                     {"name": "port", "type": "integer", "description": "Port number that was successfully bound." },
                     {"name": "connectionId", "type": "string", "description": "Connection id to be used." }
                 ]
             }
         ]
     }]
 }