From 2f7601361ba3378536167f2b1b1c5eae62b4a815 Mon Sep 17 00:00:00 2001
From: Daniel Young Lee <danielylee@google.com>
Date: Fri, 24 Jan 2025 14:51:35 -0800
Subject: [PATCH 1/3] Fix bug where sse response hangs if handler threw an
 error.

---
 spec/helper.ts                | 42 +++++++++++++++++++++++------------
 src/common/providers/https.ts |  3 ++-
 2 files changed, 30 insertions(+), 15 deletions(-)

diff --git a/spec/helper.ts b/spec/helper.ts
index 04829be38..9ce0c9f74 100644
--- a/spec/helper.ts
+++ b/spec/helper.ts
@@ -47,10 +47,11 @@ export function runHandler(
     // MockResponse mocks an express.Response.
     // This class lives here so it can reference resolve and reject.
     class MockResponse {
-      private sentBody = "";
+      private sentBody: string | undefined;
       private statusCode = 0;
       private headers: { [name: string]: string } = {};
       private callback: () => void;
+      private writeCalled = false;
 
       constructor() {
         request.on("close", () => this.end());
@@ -71,29 +72,42 @@ export function runHandler(
       }
 
       public send(sendBody: any) {
-        const toSend = typeof sendBody === "object" ? JSON.stringify(sendBody) : sendBody;
-        const body = this.sentBody ? this.sentBody + ((toSend as string) || "") : toSend;
-
-        resolve({
-          status: this.statusCode,
-          headers: this.headers,
-          body,
-        });
-        if (this.callback) {
-          this.callback();
+        if (this.writeCalled) {
+          throw Error("Cannot set headers after they are sent to the client")
         }
+
+        const toSend = typeof sendBody === "object" ? JSON.stringify(sendBody) : sendBody;
+        const body = typeof this.sentBody === 'undefined' ? toSend : this.sentBody + ((toSend as string) || "");
+        this.end(body);
       }
 
       public write(writeBody: any, cb?: () => void) {
-        this.sentBody += typeof writeBody === "object" ? JSON.stringify(writeBody) : writeBody;
+        this.writeCalled = true;
+
+        if (typeof this.sentBody === 'undefined') {
+          this.sentBody = writeBody;
+        } else {
+          this.sentBody += typeof writeBody === "object" ? JSON.stringify(writeBody) : writeBody;
+        }
         if (cb) {
           setImmediate(cb);
         }
         return true;
       }
 
-      public end() {
-        this.send(undefined);
+      public end(body?: unknown) {
+        if (body) {
+          this.write(body);
+        }
+        resolve({
+          status: this.statusCode,
+          headers: this.headers,
+          body: this.sentBody,
+        });
+
+        if (this.callback) {
+          this.callback();
+        }
       }
 
       public on(event: string, callback: () => void) {
diff --git a/src/common/providers/https.ts b/src/common/providers/https.ts
index c12278928..6ca37f69a 100644
--- a/src/common/providers/https.ts
+++ b/src/common/providers/https.ts
@@ -933,7 +933,8 @@ function wrapOnCallHandler<Req = any, Res = any, Stream = unknown>(
         const { status } = httpErr.httpErrorCode;
         const body = { error: httpErr.toJSON() };
         if (version === "gcfv2" && req.header("accept") === "text/event-stream") {
-          res.send(encodeSSE(body));
+          res.write(encodeSSE(body));
+          res.end();
         } else {
           res.status(status).send(body);
         }

From 7de0cc5669d50a2f48e3d43bac3ce8eb16f37bf6 Mon Sep 17 00:00:00 2001
From: Daniel Young Lee <danielylee@google.com>
Date: Sat, 25 Jan 2025 11:16:43 -0800
Subject: [PATCH 2/3] Add formatter.

---
 spec/helper.ts | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/spec/helper.ts b/spec/helper.ts
index 9ce0c9f74..d611e2e9a 100644
--- a/spec/helper.ts
+++ b/spec/helper.ts
@@ -73,18 +73,21 @@ export function runHandler(
 
       public send(sendBody: any) {
         if (this.writeCalled) {
-          throw Error("Cannot set headers after they are sent to the client")
+          throw Error("Cannot set headers after they are sent to the client");
         }
 
         const toSend = typeof sendBody === "object" ? JSON.stringify(sendBody) : sendBody;
-        const body = typeof this.sentBody === 'undefined' ? toSend : this.sentBody + ((toSend as string) || "");
+        const body =
+          typeof this.sentBody === "undefined"
+            ? toSend
+            : this.sentBody + ((toSend as string) || "");
         this.end(body);
       }
 
       public write(writeBody: any, cb?: () => void) {
         this.writeCalled = true;
 
-        if (typeof this.sentBody === 'undefined') {
+        if (typeof this.sentBody === "undefined") {
           this.sentBody = writeBody;
         } else {
           this.sentBody += typeof writeBody === "object" ? JSON.stringify(writeBody) : writeBody;

From e44fa6abe1ae36826310dbb4165b5597685be251 Mon Sep 17 00:00:00 2001
From: Daniel Young Lee <danielylee@google.com>
Date: Tue, 28 Jan 2025 07:43:35 -0800
Subject: [PATCH 3/3] Better typing.

---
 spec/helper.ts | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/spec/helper.ts b/spec/helper.ts
index d611e2e9a..bc1760f0e 100644
--- a/spec/helper.ts
+++ b/spec/helper.ts
@@ -80,7 +80,7 @@ export function runHandler(
         const body =
           typeof this.sentBody === "undefined"
             ? toSend
-            : this.sentBody + ((toSend as string) || "");
+            : this.sentBody + String(toSend || "");
         this.end(body);
       }