From 0599c38922f49e70d898f84c91d3cc07e56bdda6 Mon Sep 17 00:00:00 2001
From: Stanley Cheung <stanleycheung@google.com>
Date: Fri, 7 Aug 2020 15:36:30 -0700
Subject: [PATCH] Roll forward of #853

---
 .../web/streambodyclientreadablestream.js     | 109 +++++++++++++++---
 1 file changed, 94 insertions(+), 15 deletions(-)

diff --git a/javascript/net/grpc/web/streambodyclientreadablestream.js b/javascript/net/grpc/web/streambodyclientreadablestream.js
index 578a132..b98406c 100644
--- a/javascript/net/grpc/web/streambodyclientreadablestream.js
+++ b/javascript/net/grpc/web/streambodyclientreadablestream.js
@@ -33,9 +33,13 @@ goog.module.declareLegacyNamespace();
 
 const ClientReadableStream = goog.require('grpc.web.ClientReadableStream');
 const ErrorCode = goog.require('goog.net.ErrorCode');
+const EventType = goog.require('goog.net.EventType');
+const GoogleRpcStatus = goog.require('proto.google.rpc.Status');
+const GrpcWebError = goog.requireType('grpc.web.Error');
 const NodeReadableStream = goog.require('goog.net.streams.NodeReadableStream');
 const StatusCode = goog.require('grpc.web.StatusCode');
 const XhrIo = goog.require('goog.net.XhrIo');
+const events = goog.require('goog.events');
 const {GenericTransportInterface} = goog.require('grpc.web.GenericTransportInterface');
 const {Status} = goog.require('grpc.web.Status');
 
@@ -111,7 +115,83 @@ class StreamBodyClientReadableStream {
      */
     this.rpcStatusParseFn_ = null;
 
-    this.setStreamCallback_();
+    if (this.xhrNodeReadableStream_) {
+      this.setStreamCallback_();
+    }
+  }
+
+
+  /**
+   * Set up the callback functions for unary calls.
+   * @param {function(?GrpcWebError, ?)} callback
+   */
+  setUnaryCallback(callback) {
+    this.onDataCallbacks_.push((response) => callback(null, response));
+    this.onErrorCallbacks_.push((error) => callback(error, null));
+
+    events.listen(/** @type {!XhrIo}*/ (this.xhr_), EventType.COMPLETE, (e) => {
+      if (this.xhr_.isSuccess()) {
+        // If the response is serialized as Base64 (for example if the
+        // X-Goog-Encode-Response-If-Executable header is in effect), decode it
+        // before passing it to the deserializer.
+        var responseText = this.xhr_.getResponseText();
+        if (this.xhr_.headers.get('X-Goog-Encode-Response-If-Executable') ==
+                'base64' &&
+            this.xhr_.getResponseHeader(XhrIo.CONTENT_TYPE_HEADER) ===
+                'text/plain') {
+          if (!atob) {
+            throw new Error('Cannot decode Base64 response');
+          }
+          responseText = atob(responseText);
+        }
+
+        var response = this.grpcResponseDeserializeFn_(responseText);
+        var grpcStatus = StatusCode.fromHttpStatus(this.xhr_.getStatus());
+        if (grpcStatus == StatusCode.OK) {
+          this.sendDataCallbacks_(response);
+        } else {
+          callback(
+              /** @type {!GrpcWebError} */ ({
+                code: grpcStatus,
+              }),
+              response);
+        }
+      } else {
+        var rawResponse = this.xhr_.getResponseText();
+        var code;
+        var message;
+        var metadata = {};
+        if (rawResponse) {
+          try {
+            var status = GoogleRpcStatus.deserialize(rawResponse);
+            code = status.getCode();
+            message = status.getMessage();
+            if (status.getDetailsList().length) {
+              metadata['grpc-web-status-details-bin'] = rawResponse;
+            }
+          } catch (e) {
+            // 404s may be accompanied by a GoogleRpcStatus. If they are not,
+            // the generic message will fail to deserialize because it is not a
+            // status.
+            if (this.xhr_.getStatus() == 404) {
+              code = StatusCode.NOT_FOUND;
+              message = 'Not Found: ' + this.xhr_.getLastUri();
+            } else {
+              code = StatusCode.UNAVAILABLE;
+              message = 'Unable to parse RpcStatus: ' + e;
+            }
+          }
+        } else {
+          code = StatusCode.UNAVAILABLE;
+          message = ErrorCode.getDebugMessage(this.xhr_.getLastErrorCode());
+        }
+        this.sendErrorCallbacks_({
+          code: code,
+          message: message,
+          metadata: metadata,
+        });
+      }
+    });
   }
 
   /**
@@ -119,24 +199,23 @@ class StreamBodyClientReadableStream {
    */
   setStreamCallback_() {
     // Add the callback to the underlying stream
-    var self = this;
-    this.xhrNodeReadableStream_.on('data', function(data) {
+    this.xhrNodeReadableStream_.on('data', (data) => {
       if ('1' in data) {
-        var response = self.grpcResponseDeserializeFn_(data['1']);
-        self.sendDataCallbacks_(response);
+        var response = this.grpcResponseDeserializeFn_(data['1']);
+        this.sendDataCallbacks_(response);
       }
       if ('2' in data) {
-        var status = self.rpcStatusParseFn_(data['2']);
-        self.sendStatusCallbacks_(status);
+        var status = this.rpcStatusParseFn_(data['2']);
+        this.sendStatusCallbacks_(status);
       }
     });
-    this.xhrNodeReadableStream_.on('end', function() {
-      self.sendEndCallbacks_();
+    this.xhrNodeReadableStream_.on('end', () => {
+      this.sendEndCallbacks_();
     });
-    this.xhrNodeReadableStream_.on('error', function() {
-      if (self.onErrorCallbacks_.length == 0) return;
-      var lastErrorCode = self.xhr_.getLastErrorCode();
-      if (lastErrorCode === ErrorCode.NO_ERROR && !self.xhr_.isSuccess()) {
+    this.xhrNodeReadableStream_.on('error', () => {
+      if (this.onErrorCallbacks_.length == 0) return;
+      var lastErrorCode = this.xhr_.getLastErrorCode();
+      if (lastErrorCode === ErrorCode.NO_ERROR && !this.xhr_.isSuccess()) {
         // The lastErrorCode on the XHR isn't useful in this case, but the XHR
         // status is. Full details about the failure should be available in the
         // status handler.
@@ -155,13 +234,13 @@ class StreamBodyClientReadableStream {
           grpcStatusCode = StatusCode.DEADLINE_EXCEEDED;
           break;
         case ErrorCode.HTTP_ERROR:
-          grpcStatusCode = StatusCode.fromHttpStatus(self.xhr_.getStatus());
+          grpcStatusCode = StatusCode.fromHttpStatus(this.xhr_.getStatus());
           break;
         default:
           grpcStatusCode = StatusCode.UNAVAILABLE;
       }
 
-      self.sendErrorCallbacks_({
+      this.sendErrorCallbacks_({
         code: grpcStatusCode,
         // TODO(armiller): get the message from the response?
         // GoogleRpcStatus.deserialize(rawResponse).getMessage()?