aerokube#1063 Add Selenium-like websocket endpoint for CDP proxy

docs/cli-flags.adoc

@@ -37,6 +37,8 @@ The following flags are supported by `selenoid` command:
     New session attempts retry count (default 1)
 -save-all-logs
     Whether to save all logs without considering capabilities
+-callback-urlstring
+    Selenoid callback url
 -service-startup-timeout duration
     Service startup timeout in time.Duration format (default 30s)
 -session-attempt-timeout duration

docs/devtools.adoc

@@ -7,7 +7,7 @@
 . We recommend to use the most recent Chrome version possible.
 ====
 
-Selenoid is proxying Chrome Developer Tools API to browser container.  For every running Selenium session to access the API just use the following URL:
+Selenoid is proxying Chrome Developer Tools API to browser container. For every running Selenium session to access the API just use the following URL:
 
 ```
 <ws or http>://selenoid.example.com:4444/devtools/<session-id>/<method>
@@ -31,6 +31,13 @@ For example an URL to connect to current page websocket would be:
 ws://selenoid.example.com:4444/devtools/<session-id>/page
 ```
 
+.Accessing Developer Tools API with Selenium 4
+
+Selenium 4 and above has functionality allowing to access Chrome DevTools features. This works just out of the box.
+This feature needs full Selenoid server URL in order to work properly.
+To enable this feature, set the Selenoid `-callback-url` flag to the correct Selenoid address, such as `-callback-url="https://selenoid.example.com/"`.
+This can also be set through the `callbackUrl` capability.
+
 .Accessing Developer Tools API with Webdriver.io and Puppeteer
 [source,javascript]
 ----

docs/special-capabilities.adoc

@@ -256,6 +256,15 @@ s3KeyPattern: "$quota/$fileType$fileExtension"
 
 The same key placeholders are supported. Please refer to <<Uploading Files To S3>> section for more details.
 
+=== CDP Url: callbackUrl
+
+This capability allows to set Selenoid server URL to enable Selenium 4 CDP access.
+
+.Type: string
+----
+callbackUrl: "https://selenoid.example.com/"
+----
+
 === Specifying Capabilities via Protocol Extensions
 
 Some Selenium clients allow passing only a limited number of capabilities specified in https://w3c.github.io/webdriver/webdriver-spec.html[WebDriver specification]. For such cases Selenoid supports reading capabilities using https://w3c.github.io/webdriver/webdriver-spec.html#protocol-extensions[WebDriver protocol extensions] feature. The following two examples deliver the same result. Usually capabilities are passed like this:

main.go

@@ -55,6 +55,7 @@ var (
 	videoRecorderImage       string
 	logOutputDir             string
 	saveAllLogs              bool
+	callbackUrl              string
 	ggrHost                  *ggr.Host
 	conf                     *config.Config
 	queue                    *protect.Queue
@@ -92,6 +93,7 @@ func init() {
 	flag.BoolVar(&disablePrivileged, "disable-privileged", false, "Whether to disable privileged container mode")
 	flag.StringVar(&videoOutputDir, "video-output-dir", "video", "Directory to save recorded video to")
 	flag.StringVar(&videoRecorderImage, "video-recorder-image", "selenoid/video-recorder:latest-release", "Image to use as video recorder")
+	flag.StringVar(&callbackUrl, "callback-url", "", "Selenoid callback url")
 	flag.StringVar(&logOutputDir, "log-output-dir", "", "Directory to save session log to")
 	flag.BoolVar(&saveAllLogs, "save-all-logs", false, "Whether to save all logs without considering capabilities")
 	flag.DurationVar(&gracefulPeriod, "graceful-period", 300*time.Second, "graceful shutdown period in time.Duration format, e.g. 300s or 500ms")

selenoid.go

@@ -180,6 +180,9 @@ func create(w http.ResponseWriter, r *http.Request) {
 		if logOutputDir != "" && (saveAllLogs || caps.Log) {
 			caps.LogName = getTemporaryFileName(logOutputDir, logFileExtension)
 		}
+		if caps.CallbackUrl == "" {
+			caps.CallbackUrl = callbackUrl
+		}
 		starter, ok = manager.Find(caps, requestId)
 		if ok {
 			break
@@ -281,12 +284,23 @@ func create(w http.ResponseWriter, r *http.Request) {
 			w.WriteHeader(resp.StatusCode)
 		}
 	} else {
-		tee := io.TeeReader(resp.Body, w)
 		w.WriteHeader(resp.StatusCode)
-		json.NewDecoder(tee).Decode(&s)
+		respBody, _ := io.ReadAll(resp.Body)
+		json.Unmarshal(respBody, &s)
 		if s.ID == "" {
 			s.ID = s.Value.ID
 		}
+		if caps.CallbackUrl != "" && s.ID != "" {
+			respBody, err = addCdpCapabilities(respBody, caps.CallbackUrl, s.ID)
+			if err != nil {
+				log.Printf("[%d] [SESSION_FAILED] [%s] [%s]", requestId, u.String(), resp.Status)
+				jsonerror.SessionNotCreated(err).Encode(w)
+				queue.Drop()
+				cancel()
+				return
+			}
+		}
+		w.Write(respBody)
 	}
 	if s.ID == "" {
 		log.Printf("[%d] [SESSION_FAILED] [%s] [%s]", requestId, u.String(), resp.Status)
@@ -393,6 +407,41 @@ func removeSelenoidOptions(input []byte) []byte {
 	return ret
 }
 
+func addCdpCapabilities(input []byte, baseUrl string, sessionId string) ([]byte, error) {
+	var body map[string]interface{}
+	if err := json.Unmarshal(input, &body); err != nil {
+		return nil, err
+	}
+
+	value, ok := body["value"].(map[string]interface{})
+	if !ok {
+		return nil, fmt.Errorf("expected key 'value' of type 'map', but got %T", body["value"])
+	}
+
+	caps, ok := value["capabilities"].(map[string]interface{})
+	if !ok {
+		return nil, fmt.Errorf("expected key 'capabilities' of type 'map', but got %T", value["capabilities"])
+	}
+
+	caps["se:cdpEnable"] = true
+	cdpUrl, err := url.JoinPath(baseUrl, "devtools", sessionId)
+	if err != nil {
+		return nil, fmt.Errorf("cannot construct devtools url: %v", err)
+	}
+	caps["se:cdp"] = cdpUrl
+
+	var version interface{}
+	if v, ok := caps["browserVersion"]; ok {
+		version = v
+	} else {
+		version = caps["version"]
+	}
+	caps["se:cdpVersion"] = version
+
+	result, _ := json.Marshal(body)
+	return result, nil
+}
+
 func preprocessSessionId(sid string) string {
 	if ggrHost != nil {
 		return ggrHost.Sum() + sid

session/session.go

@@ -38,6 +38,7 @@ type Caps struct {
 	Labels                map[string]string `json:"labels,omitempty"`
 	SessionTimeout        string            `json:"sessionTimeout,omitempty"`
 	S3KeyPattern          string            `json:"s3KeyPattern,omitempty"`
+	CallbackUrl           string            `json:"callbackUrl,omitempty"`
 	ExtensionCapabilities *Caps             `json:"selenoid:options,omitempty"`
 }