From 741bb99ebcc163003de7a1310910d667fc9ce405 Mon Sep 17 00:00:00 2001
From: AllanZhengYP <zheallan@amazon.com>
Date: Fri, 8 Jan 2021 11:50:25 -0800
Subject: [PATCH] fix(s3-request-presigner): not to throw when get signed urls
 concurrently (#1884)

---
 .../src/getSignedUrl.spec.ts                  | 12 +++++++++++
 .../s3-request-presigner/src/getSignedUrl.ts  | 21 +++++++++++++------
 2 files changed, 27 insertions(+), 6 deletions(-)

diff --git a/packages/s3-request-presigner/src/getSignedUrl.spec.ts b/packages/s3-request-presigner/src/getSignedUrl.spec.ts
index 3b5aafcf4804..c0090e91d4df 100644
--- a/packages/s3-request-presigner/src/getSignedUrl.spec.ts
+++ b/packages/s3-request-presigner/src/getSignedUrl.spec.ts
@@ -99,4 +99,16 @@ describe("getSignedUrl", () => {
     expect(mockPresign).toBeCalled();
     expect(mockPresign.mock.calls[0][1]).toMatchObject(options);
   });
+
+  it("should not throw if it's called concurrently", async () => {
+    const mockPresigned = "a presigned url";
+    mockPresign.mockReturnValue(mockPresigned);
+    const client = new S3Client(clientParams);
+    const command = new GetObjectCommand({
+      Bucket: "Bucket",
+      Key: "Key",
+    });
+    const commands = [command, command];
+    return expect(Promise.all(commands.map((command) => getSignedUrl(client, command)))).resolves.toBeInstanceOf(Array);
+  });
 });
diff --git a/packages/s3-request-presigner/src/getSignedUrl.ts b/packages/s3-request-presigner/src/getSignedUrl.ts
index 3d3c22305df0..a67a9665f352 100644
--- a/packages/s3-request-presigner/src/getSignedUrl.ts
+++ b/packages/s3-request-presigner/src/getSignedUrl.ts
@@ -40,11 +40,20 @@ export const getSignedUrl = async <
       },
     } as any;
   };
-  client.middlewareStack.addRelativeTo(presignInterceptMiddleware, {
-    name: "presignInterceptMiddleware",
-    relation: "before",
-    toMiddleware: "awsAuthMiddleware",
-  });
+  const middlewareName = "presignInterceptMiddleware";
+  try {
+    client.middlewareStack.addRelativeTo(presignInterceptMiddleware, {
+      name: middlewareName,
+      relation: "before",
+      toMiddleware: "awsAuthMiddleware",
+    });
+  } catch (e) {
+    if (e.message!.includes(`Duplicated middleware name '${middlewareName}'`)) {
+      // Swallow if the interceptor is already added. See https://github.com/aws/aws-sdk-js-v3/issues/1857
+    } else {
+      throw e;
+    }
+  }
 
   let presigned: HttpRequest;
   try {
@@ -52,7 +61,7 @@ export const getSignedUrl = async <
     //@ts-ignore the output is faked, so it's not actually OutputType
     presigned = output.presigned;
   } finally {
-    client.middlewareStack.remove("presignInterceptMiddleware");
+    client.middlewareStack.remove(middlewareName);
   }
 
   return formatUrl(presigned);