fix: Patch downstream responses for unknown upstream protocol (#353)

lib/jsonwp-proxy/protocol-converter.js

@@ -2,6 +2,7 @@ import _ from 'lodash';
 import { logger, util } from 'appium-support';
 import { duplicateKeys } from '../basedriver/helpers';
 import { PROTOCOLS, MJSONWP_ELEMENT_KEY, W3C_ELEMENT_KEY } from '../protocol/protocol';
+import { errors } from '../protocol/errors';
 
 const log = logger.getLogger('Protocol Converter');
 
@@ -187,6 +188,18 @@ class ProtocolConverter {
       : await this.proxyFunc(url, method, body);
   }
 
+  async proxyGetStatus (url, method, body) {
+    const [res, resBodyObj] = await this.proxyFunc(url, method, body);
+    if (!_.isPlainObject(resBodyObj)) {
+      return [res, resBodyObj];
+    }
+    const patchedBody = _.clone(resBodyObj);
+    if (!_.has(resBodyObj, 'status')) {
+      resBodyObj.status = res.statusCode === 200 ? 0 : errors.UnknownError.code();
+    }
+    return [res, patchedBody];
+  }
+
   /**
    * Handle "crossing" endpoints for the case
    * when upstream and downstream drivers operate different protocols
@@ -199,6 +212,11 @@ class ProtocolConverter {
    */
   async convertAndProxy (commandName, url, method, body) {
     if (!this.downstreamProtocol) {
+      if (commandName === 'getStatus') {
+        // Patch getStatus call for GENERIC protocol
+        // to preserve the backward compatibility
+        return await this.proxyGetStatus(url, method, body);
+      }
       // There is no point to convert anything if we do not know
       // for which protocol the conversion should be done
       return await this.proxyFunc(url, method, body);

lib/jsonwp-proxy/proxy.js

@@ -118,28 +118,6 @@ class JWProxy {
     return proxyBase + remainingUrl;
   }
 
-  syncDownstreamProtocol (resBodyObj, isSessionCreationRequest) {
-    if (!this.downstreamProtocol) {
-      this.downstreamProtocol = this.getProtocolFromResBody(resBodyObj);
-      log.debug(`Determined the downstream protocol as '${this.downstreamProtocol}'`);
-    } else if (isSessionCreationRequest) {
-      // It might be that we proxy API calls to the downstream driver
-      // without creating a session first
-      // and it responds using the default proto,
-      // but then after createSession request is sent the internal proto is changed
-      // to the other one based on the actually provided caps
-      const previousValue = this.downstreamProtocol;
-      this.downstreamProtocol = this.getProtocolFromResBody(resBodyObj);
-      if (previousValue && previousValue !== this.downstreamProtocol) {
-        log.debug(`Updated the downstream protocol to '${this.downstreamProtocol}' ` +
-          `as per session creation request`);
-      } else {
-        log.debug(`Determined the downstream protocol as '${this.downstreamProtocol}' ` +
-          `per session creation request`);
-      }
-    }
-  }
-
   async proxy (url, method, body = null) {
     method = method.toUpperCase();
     const newUrl = this.getUrlForProxy(url);
@@ -201,12 +179,14 @@ class JWProxy {
       log.debug(`Got response with status ${res.statusCode}: ${truncateBody(res.body)}`);
       isResponseLogged = true;
       const isSessionCreationRequest = /\/session$/.test(url) && method === 'POST';
-      if (isSessionCreationRequest && res.statusCode === 200) {
-        this.sessionId = resBodyObj.sessionId || (resBodyObj.value || {}).sessionId;
+      if (isSessionCreationRequest) {
+        if (res.statusCode === 200) {
+          this.sessionId = resBodyObj.sessionId || (resBodyObj.value || {}).sessionId;
+        }
+        this.downstreamProtocol = this.getProtocolFromResBody(resBodyObj);
+        log.info(`Determined the downstream protocol as '${this.downstreamProtocol}'`);
       }
-      this.syncDownstreamProtocol(resBodyObj, isSessionCreationRequest);
-      if (res.statusCode < 400 && this.downstreamProtocol === MJSONWP &&
-        _.has(resBodyObj, 'status') && parseInt(resBodyObj.status, 10) !== 0) {
+      if (res.statusCode < 400 && _.has(resBodyObj, 'status') && parseInt(resBodyObj.status, 10) !== 0) {
         // Some servers, like chromedriver may return response code 200 for non-zero JSONWP statuses
         throwProxyError(resBodyObj);
       }