fix(middleware-eventstream): lowercase headers more consistently

packages/credential-provider-http/src/fromHttp/fromHttp.spec.ts

@@ -25,7 +25,7 @@ const mockHandle = jest.fn().mockResolvedValue({
   response: new HttpResponse({
     statusCode: 200,
     headers: {
-      "Content-Type": "application/json",
+      "content-type": "application/json",
     },
     body: Readable.from([""]),
   }),

packages/credential-provider-http/src/fromHttp/requestHelpers.spec.ts

@@ -17,7 +17,7 @@ describe(getCredentials.name, () => {
     const response = new HttpResponse({
       statusCode: 200,
       headers: {
-        "Content-Type": "application/json",
+        "content-type": "application/json",
       },
       body: Readable.from(JSON.stringify(data)),
     });
@@ -34,7 +34,7 @@ describe(getCredentials.name, () => {
     const response = new HttpResponse({
       statusCode: 400,
       headers: {
-        "Content-Type": "application/json",
+        "content-type": "application/json",
       },
       body: Readable.from(
         JSON.stringify({
@@ -57,7 +57,7 @@ describe(getCredentials.name, () => {
     const response = new HttpResponse({
       statusCode: 500,
       headers: {
-        "Content-Type": "json",
+        "content-type": "json",
       },
       body: Readable.from(JSON.stringify({})),
     });

packages/middleware-eventstream/src/eventStreamHeaderMiddleware.ts

@@ -5,7 +5,7 @@ export const eventStreamHeaderMiddleware: BuildMiddleware<any, any> = (next) =>
   if (!HttpRequest.isInstance(request)) return next(args);
   request.headers = {
     ...request.headers,
-    "Content-Type": "application/vnd.amazon.eventstream",
+    "content-type": "application/vnd.amazon.eventstream",
     "x-amz-content-sha256": "STREAMING-AWS4-HMAC-SHA256-EVENTS",
   };
   return next({

packages/middleware-eventstream/src/middleware-eventstream.integ.spec.ts

@@ -20,7 +20,7 @@ describe("middleware-eventstream", () => {
 
       requireRequestsFrom(client).toMatch({
         headers: {
-          "Content-Type": "application/vnd.amazon.eventstream",
+          "content-type": "application/vnd.amazon.eventstream",
           "x-amz-content-sha256": "STREAMING-AWS4-HMAC-SHA256-EVENTS",
         },
       });
@@ -51,7 +51,7 @@ describe("middleware-eventstream", () => {
 
       requireRequestsFrom(client).toMatch({
         headers: {
-          "Content-Type": "application/vnd.amazon.eventstream",
+          "content-type": "application/vnd.amazon.eventstream",
           "x-amz-content-sha256": "STREAMING-AWS4-HMAC-SHA256-EVENTS",
         },
       });
@@ -83,7 +83,7 @@ describe("middleware-eventstream", () => {
 
       requireRequestsFrom(client).toMatch({
         headers: {
-          "Content-Type": "application/vnd.amazon.eventstream",
+          "content-type": "application/vnd.amazon.eventstream",
           "x-amz-content-sha256": "STREAMING-AWS4-HMAC-SHA256-EVENTS",
         },
       });

packages/middleware-sdk-transcribe-streaming/src/middleware-sdk-transcribe-streaming.integ.spec.ts

@@ -12,7 +12,7 @@ describe("middleware-sdk-transcribe-streaming", () => {
 
       requireRequestsFrom(client).toMatch({
         headers: {
-          "Content-Type": /undefined/,
+          "content-type": /undefined/,
           host: "transcribestreaming.us-west-2.amazonaws.com:8443",
         },
         query: {

packages/middleware-websocket/src/middleware-websocket-endpoint.spec.ts

@@ -51,7 +51,6 @@ describe(websocketEndpointMiddleware.name, () => {
       expect(HttpRequest.isInstance(args.request)).toBeTruthy();
       const processed = args.request as HttpRequest;
       expect(processed.headers["content-type"]).toBeUndefined();
-      expect(processed.headers["Content-Type"]).toBeUndefined();
       expect(processed.headers["x-amz-content-sha256"]).toBeUndefined();
       expect(processed.headers["X-Amz-Content-Sha256"]).toBeUndefined();
       done();

packages/middleware-websocket/src/middleware-websocket-endpoint.ts

@@ -37,7 +37,7 @@ export const websocketEndpointMiddleware =
       // 'Content-Type' and 'x-amz-content-sha256' headers are normally set for
       // event stream, but WebSocket doesn't require it.
       // See: 'eventStreamHeaderMiddleware' in @aws-sdk/middleware-eventstream
-      delete headers["Content-Type"];
+      delete headers["content-type"];
       delete headers["x-amz-content-sha256"];
 
       for (const name of Object.keys(headers)) {

packages/middleware-websocket/src/middleware-websocket.integ.spec.ts

@@ -21,7 +21,7 @@ describe("middleware-websocket", () => {
         path: "/start-face-liveness-session-websocket",
         headers: {
           host: "streaming-rekognition.us-west-2.amazonaws.com",
-          "Content-Type": /^undefined$/,
+          "content-type": /^undefined$/,
           "x-amz-content-sha256": /^undefined$/,
           "user-agent": /^aws-sdk-js/,
         },

packages/s3-request-presigner/src/presigner.spec.ts

@@ -71,7 +71,7 @@ describe("s3 presigner", () => {
       ...minimalRequest,
       headers: {
         ...minimalRequest.headers,
-        "Content-Type": "application/octet-stream",
+        "content-type": "application/octet-stream",
       },
     };
     const signed = await signer.presign(requestWithContentTypeHeader, presigningOptions);