Add error handling to a few error conditions

javascript/net/grpc/web/grpcwebclientbase.js

@@ -300,7 +300,14 @@ class GrpcWebClientBase {
 
     stream.on('end', function() {
       if (!errorEmitted) {
-        callback(null, responseReceived);
+        if (responseReceived == null) {
+          callback({
+            code: StatusCode.UNKNOWN,
+            message: 'Incomplete response',
+          });
+        } else {
+          callback(null, responseReceived);
+        }
       }
       if (useUnaryResponse) {
         callback(null, null);  // trigger unaryResponse

javascript/net/grpc/web/grpcwebclientreadablestream.js

@@ -158,16 +158,33 @@ class GrpcWebClientReadableStream {
         });
         return;
       }
-      var messages = self.parser_.parse(byteSource);
+      var messages = null;
+      try {
+        messages = self.parser_.parse(byteSource);
+      } catch (err) {
+        self.handleError_({
+          code: StatusCode.UNKNOWN,
+          message: 'Error in parsing response body',
+          metadata: {},
+        });
+      }
       if (messages) {
         var FrameType = GrpcWebStreamParser.FrameType;
         for (var i = 0; i < messages.length; i++) {
           if (FrameType.DATA in messages[i]) {
             var data = messages[i][FrameType.DATA];
             if (data) {
-              var response = self.responseDeserializeFn_(data);
-              if (response) {
-                self.sendDataCallbacks_(response);
+              try {
+                var response = self.responseDeserializeFn_(data);
+                if (response) {
+                  self.sendDataCallbacks_(response);
+                }
+              } catch (err) {
+                self.handleError_({
+                  code: StatusCode.UNKNOWN,
+                  message: 'Error in response deserializer function.',
+                  metadata: {},
+                });
               }
             }
           }

packages/grpc-web/test/generated_code_test.js

@@ -328,6 +328,97 @@ describe('grpc-web generated code (commonjs+grpcwebtext)', function() {
     });
   });
 
+  it('should error out on incomplete response', function(done) {
+    execSync(genCodeCmd);
+    const {EchoServiceClient} = require(genCodePath);
+    const {EchoRequest} = require(protoGenCodePath);
+    var echoService = new EchoServiceClient('MyHostname', null, null);
+    var request = new EchoRequest();
+    MockXMLHttpRequest.onSend = function(xhr) {
+      xhr.respond(200, {'Content-Type': 'application/grpc-web-text'},
+                  // An incomplete response. The frame length indicates
+                  // 26 bytes, but the rest of the frame only contains
+                  // 18 bytes.
+                  'AAAAABoKCwgBEgdGaWN0aW9uCgsIAhI');
+    };
+    var call = echoService.echo(
+      request, {}, function(err, response) {
+        if (response) {
+          assert.fail('should not receive response');
+        }
+        assert.equal(2, err.code);
+        assert.equal(true, err.message.toLowerCase().includes(
+          'incomplete response'));
+        done();
+    });
+    call.on('data', (response) => {
+      assert.fail('should not receive response this way');
+    });
+    call.on('error', (error) => {
+      assert.fail('should not receive error this way');
+    });
+  });
+
+  it('should error out on invalid proto response', function(done) {
+    execSync(genCodeCmd);
+    const {EchoServiceClient} = require(genCodePath);
+    const {EchoRequest} = require(protoGenCodePath);
+    var echoService = new EchoServiceClient('MyHostname', null, null);
+    var request = new EchoRequest();
+    MockXMLHttpRequest.onSend = function(xhr) {
+      xhr.respond(200, {'Content-Type': 'application/grpc-web-text'},
+                  // A valid grpc-web frame, but contains an invalid
+                  // protobuf payload.
+                  'AAAAAAUKCgoKCg==');
+    };
+    var call = echoService.echo(
+      request, {}, function(err, response) {
+        if (response) {
+          assert.fail('should not receive response');
+        }
+        assert.equal(2, err.code);
+        assert.equal(true, err.message.toLowerCase().includes('deserialize'));
+        assert.equal(true, err.message.toLowerCase().includes('error'));
+        done();
+    });
+    call.on('data', (response) => {
+      assert.fail('should not receive response this way');
+    });
+    call.on('error', (error) => {
+      assert.fail('should not receive error this way');
+    });
+  });
+
+  it('should error out on invalid response body', function(done) {
+    execSync(genCodeCmd);
+    const {EchoServiceClient} = require(genCodePath);
+    const {EchoRequest} = require(protoGenCodePath);
+    var echoService = new EchoServiceClient('MyHostname', null, null);
+    var request = new EchoRequest();
+    MockXMLHttpRequest.onSend = function(xhr) {
+      xhr.respond(200, {'Content-Type': 'application/grpc-web-text'},
+                  // An invalid response body. Should trip up in the
+                  // stream parser.
+                  'ZZZZZ');
+    };
+    var call = echoService.echo(
+      request, {}, function(err, response) {
+        if (response) {
+          assert.fail('should not receive response');
+        }
+        assert.equal(2, err.code);
+        assert.equal(true, err.message.toLowerCase().includes(
+          'error in parsing response body'));
+        done();
+    });
+    call.on('data', (response) => {
+      assert.fail('should not receive response this way');
+    });
+    call.on('error', (error) => {
+      assert.fail('should not receive error this way');
+    });
+  });
+
   it('should not receive response on non-ok status', function(done) {
     done = multiDone(done, 2);
     execSync(genCodeCmd);