Intercept the network Intercept the network requests initiated by Web components

Setting Up Network Interceptors for Web Components in HarmonyOS Next

Setting Up Network Interceptors

To set up a network interceptor for a specific Web component or ServiceWorker, you can use the ArkWeb_SchemeHandler. This handler is triggered when the Web kernel issues a request for the specified scheme. The network interceptor must be set up after the Web component has been initialized.

Callbacks

• ArkWeb_OnRequestStart: Triggered when a request starts.
• ArkWeb_OnRequestStop: Triggered when a request ends.

Example: Intercepting the First Request

To intercept the first request made by a Web component, you can initialize the Web component using initializeWebEngine and then set up the interceptor.

// Create an ArkWeb_SchemeHandler object.
ArkWeb_SchemeHandler *schemeHandler;
OH_ArkWeb_CreateSchemeHandler(&schemeHandler);

// Set the ArkWeb_OnRequestStart and ArkWeb_OnRequestStop callbacks for the ArkWeb_SchemeHandler.
OH_ArkWebSchemeHandler_SetOnRequestStart(schemeHandler, OnURLRequestStart);
OH_ArkWebSchemeHandler_SetOnRequestStop(schemeHandler, OnURLRequestStop);

// Intercept requests with the "https" scheme from the Web component with webTag "scheme-handler".
OH_ArkWeb_SetSchemeHandler("https", "scheme-handler", schemeHandler);
OH_ArkWebServiceWorker_SetSchemeHandler("https", schemeHandler);

Intercepting Non-Built-in Schemes

You can also intercept requests for non-built-in schemes.

// Create an ArkWeb_SchemeHandler object.
ArkWeb_SchemeHandler *schemeHandler;
OH_ArkWeb_CreateSchemeHandler(&schemeHandler);

// Set the ArkWeb_OnRequestStart and ArkWeb_OnRequestStop callbacks for the ArkWeb_SchemeHandler.
OH_ArkWebSchemeHandler_SetOnRequestStart(schemeHandler, OnURLRequestStart);
OH_ArkWebSchemeHandler_SetOnRequestStop(schemeHandler, OnURLRequestStop);

// Intercept requests with the "custom" scheme from the Web component with webTag "scheme-handler".
OH_ArkWeb_SetSchemeHandler("custom", "scheme-handler", schemeHandler);
OH_ArkWebServiceWorker_SetSchemeHandler("custom", schemeHandler);

Registering Custom Schemes

To intercept requests for custom schemes, you must register the custom scheme with the Web kernel before initializing the Web component. Registration after initialization will fail.

// Register the "custom" scheme with the Web component, specifying that it follows standard scheme rules and allows cross-origin requests.
OH_ArkWeb_RegisterCustomSchemes("custom", ARKWEB_SCHEME_OPTION_STANDARD | ARKWEB_SCHEME_OPTION_CORS_ENABLED);

// Register the "custom-local" scheme with the Web component, specifying that it follows the same rules as the "file" scheme.
OH_ArkWeb_RegisterCustomSchemes("custom-local", ARKWEB_SCHEME_OPTION_LOCAL);

// Register the "custom-csp-bypassing" scheme with the Web component, specifying that it follows standard scheme rules and allows bypassing CSP checks.
OH_ArkWeb_RegisterCustomSchemes("custom-csp-bypassing", ARKWEB_SCHEME_OPTION_CSP_BYPASSING | ARKWEB_SCHEME_OPTION_STANDARD);

// Register the "custom-isolated" scheme with the Web component, specifying that requests for this scheme must be initiated from a webpage loaded with the same scheme.
OH_ArkWeb_RegisterCustomSchemes("custom-isolated", ARKWEB_SCHEME_OPTION_DISPLAY_ISOLATED);

Since scheme registration must occur before Web component initialization, and network interceptors must be set up after initialization, it is recommended to call the C++ interface to register schemes in the onCreate method of EntryAbility.

Example: Initializing and Setting Up the Interceptor

export default class EntryAbility extends UIAbility {
    onCreate(want: Want, launchParam: AbilityConstant.LaunchParam): void {
        // Register the custom schemes.
        testNapi.registerCustomSchemes();
        // Initialize the Web component engine, which initializes the Browser process and creates the BrowserContext.
        webview.WebviewController.initializeWebEngine();
        // Create and set up the ArkWeb_SchemeHandler.
        testNapi.setSchemeHandler();
    }
    ...
};

Retrieving Intercepted Request Information

Use the OH_ArkWebResourceRequest_* interfaces to retrieve information about the intercepted request. You can obtain the URL, method, referrer, headers, and resource type.

char* url;
OH_ArkWebResourceRequest_GetUrl(resourceRequest_, &url);
OH_ArkWeb_ReleaseString(url);

char* method;
OH_ArkWebResourceRequest_GetMethod(resourceRequest_, &method);
OH_ArkWeb_ReleaseString(method);

int32_t resourceType = OH_ArkWebResourceRequest_GetResourceType(resourceRequest_);

char* frameUrl;
OH_ArkWebResourceRequest_GetFrameUrl(resourceRequest_, &frameUrl);
OH_ArkWeb_ReleaseString(frameUrl);
...

Handling PUT/POST Request Upload Data

You can retrieve upload data for PUT/POST requests. The data types supported include BYTES, FILE, BLOB, and CHUNKED.

// Retrieve the upload data for the intercepted request.
OH_ArkWebResourceRequest_GetHttpBodyStream(resourceRequest(), &stream_);
// Set the read callback for uploading data.
OH_ArkWebHttpBodyStream_SetReadCallback(stream_, ReadCallback);
// Initialize the ArkWeb_HttpBodyStream; other OH_ArkWebHttpBodyStream* functions must be called after initialization.
OH_ArkWebHttpBodyStream_Init(stream_, InitCallback);

Providing a Custom Response Body for Intercepted Requests

The network interceptor for Web components supports providing a custom response body for intercepted requests in a streaming manner on the worker thread. You can also end the intercepted request with a specific network error code (arkweb_net_error_list.h).

// Create a response for the intercepted request.
ArkWeb_Response *response;
OH_ArkWeb_CreateResponse(&response);

// Set the HTTP status code to 200.
OH_ArkWebResponse_SetStatus(response, 200);
// Set the charset of the response body.
OH_ArkWebResponse_SetCharset(response, "UTF-8");
// Set the size of the response body.
OH_ArkWebResponse_SetHeaderByName(response, "content-length", "1024", false);
// Pass the created response header to the Web component.
OH_ArkWebResourceHandler_DidReceiveResponse(resourceHandler, response);

// This function can be called multiple times to pass data to the Web component in chunks.
OH_ArkWebResourceHandler_DidReceiveData(resourceHandler, buffer, bufLen);

// Indicate the end of the response body. If you want the request to fail, you can call OH_ArkWebResourceHandler_DidFailWithError(resourceHandler_, errorCode);
// to pass an error code to the Web component and end the request.
OH_ArkWebResourceHandler_DidFinish(resourceHandler);