GCDWebServer make Cross-Origin Resource Sharing (WKWebView as example)

GCDWebServer+CORS.m

      GCDWebServer *_webServer = [[GCDWebServer alloc] init];

      [_webServer addDefaultHandlerForMethod:@"GET"
                                requestClass:[GCDWebServerRequest class]
                                processBlock:^GCDWebServerResponse *(GCDWebServerRequest* request) {

            GCDWebServerDataResponse *response = [GCDWebServerDataResponse responseWithHTML:@"true"];
            [response setValue:@"*" forAdditionalHeader:@"Access-Control-Allow-Origin"];
            [response setValue:@"X-Requested-With, Content-Type" forAdditionalHeader:@"Access-Control-Allow-Headers"];
            [response setValue:@"GET, POST, OPTIONS" forAdditionalHeader:@"Access-Control-Allow-Methods"];
            response.statusCode = 200;
            return response;
        }];

    [_webServer addDefaultHandlerForMethod:@"OPTIONS"
    requestClass:[GCDWebServerRequest class]
    processBlock:^GCDWebServerResponse *(GCDWebServerRequest* request) {

        GCDWebServerDataResponse *response = [GCDWebServerDataResponse responseWithHTML:@"true"];
        [response setValue:@"*" forAdditionalHeader:@"Access-Control-Allow-Origin"];
        [response setValue:@"X-Requested-With, Content-Type" forAdditionalHeader:@"Access-Control-Allow-Headers"];
        [response setValue:@"GET, POST, OPTIONS" forAdditionalHeader:@"Access-Control-Allow-Methods"];
        response.statusCode = 200;
        return response;
    }];

      [_webServer startWithPort:59999 bonjourName:nil];