Fix resend integration headers (#219)

* fix: resend integration headers

content-type header wasn't being sent, so resend couldn't process the request. But the integration worked before. So I am suspecting that QStash used to set a default content header but it doesn't anymore. To fix the issue, I added a utility to properly merge the headers and added tests to make sure that we don't miss this behavior.

* fix: add method option to providers

src/client/api/base.ts

@@ -1,7 +1,9 @@
+import type { HTTPMethods } from "../types";
 import type { ApiKind, Owner, ProviderInfo } from "./types";
 
 export abstract class BaseProvider<TName extends ApiKind, TOwner = Owner> {
   public abstract readonly apiKind: TName;
+  public abstract readonly method: HTTPMethods;
 
   public readonly baseUrl: string;
   public token: string;

src/client/api/email.test.ts

@@ -9,6 +9,9 @@ describe("email", () => {
   const resendToken = nanoid();
   const client = new Client({ baseUrl: MOCK_QSTASH_SERVER_URL, token: qstashToken });
 
+  const header = "my-header";
+  const headerValue = "my-header-value";
+
   test("should use resend", async () => {
     await mockQStashServer({
       execute: async () => {
@@ -17,6 +20,9 @@ describe("email", () => {
             name: "email",
             provider: resend({ token: resendToken }),
           },
+          headers: {
+            [header]: headerValue,
+          },
           body: {
             from: "Acme <[email protected]>",
             to: ["[email protected]"],
@@ -42,6 +48,9 @@ describe("email", () => {
         headers: {
           authorization: `Bearer ${qstashToken}`,
           "upstash-forward-authorization": `Bearer ${resendToken}`,
+          "content-type": "application/json",
+          [`upstash-forward-${header}`]: headerValue,
+          "upstash-method": "POST",
         },
       },
     });
@@ -55,6 +64,70 @@ describe("email", () => {
             name: "email",
             provider: resend({ token: resendToken, batch: true }),
           },
+          headers: {
+            [header]: headerValue,
+          },
+          body: [
+            {
+              from: "Acme <[email protected]>",
+              to: ["[email protected]"],
+              subject: "hello world",
+              html: "<h1>it works!</h1>",
+            },
+            {
+              from: "Acme <[email protected]>",
+              to: ["[email protected]"],
+              subject: "world hello",
+              html: "<p>it works!</p>",
+            },
+          ],
+        });
+      },
+      responseFields: {
+        body: { messageId: "msgId" },
+        status: 200,
+      },
+      receivesRequest: {
+        method: "POST",
+        token: qstashToken,
+        url: "http://localhost:8080/v2/publish/https://api.resend.com/emails/batch",
+        body: [
+          {
+            from: "Acme <[email protected]>",
+            to: ["[email protected]"],
+            subject: "hello world",
+            html: "<h1>it works!</h1>",
+          },
+          {
+            from: "Acme <[email protected]>",
+            to: ["[email protected]"],
+            subject: "world hello",
+            html: "<p>it works!</p>",
+          },
+        ],
+        headers: {
+          authorization: `Bearer ${qstashToken}`,
+          "upstash-forward-authorization": `Bearer ${resendToken}`,
+          "content-type": "application/json",
+          [`upstash-forward-${header}`]: headerValue,
+          "upstash-method": "POST",
+        },
+      },
+    });
+  });
+
+  test("should be able to overwrite method", async () => {
+    await mockQStashServer({
+      execute: async () => {
+        await client.publishJSON({
+          api: {
+            name: "email",
+            provider: resend({ token: resendToken, batch: true }),
+          },
+          headers: {
+            [header]: headerValue,
+          },
+          method: "PUT",
           body: [
             {
               from: "Acme <[email protected]>",
@@ -96,6 +169,9 @@ describe("email", () => {
         headers: {
           authorization: `Bearer ${qstashToken}`,
           "upstash-forward-authorization": `Bearer ${resendToken}`,
+          "content-type": "application/json",
+          [`upstash-forward-${header}`]: headerValue,
+          "upstash-method": "PUT",
         },
       },
     });

src/client/api/email.ts

@@ -4,6 +4,7 @@ import type { EmailOwner, ProviderInfo } from "./types";
 export class EmailProvider extends BaseProvider<"email", EmailOwner> {
   public readonly apiKind = "email";
   public readonly batch: boolean;
+  public readonly method = "POST";
 
   constructor(baseUrl: string, token: string, owner: EmailOwner, batch: boolean) {
     super(baseUrl, token, owner);

src/client/api/llm.ts

@@ -5,6 +5,7 @@ import { updateWithAnalytics } from "./utils";
 export class LLMProvider<TOwner extends LLMOwner> extends BaseProvider<"llm", LLMOwner> {
   public readonly apiKind = "llm";
   public readonly organization?: string;
+  public readonly method = "POST";
 
   constructor(baseUrl: string, token: string, owner: TOwner, organization?: string) {
     super(baseUrl, token, owner);

src/client/api/types.ts

@@ -1,3 +1,4 @@
+import type { HTTPMethods } from "../types";
 import type { BaseProvider } from "./base";
 
 export type ProviderInfo = {
@@ -21,6 +22,10 @@ export type ProviderInfo = {
    * provider owner
    */
   owner: Owner;
+  /**
+   * method to use in the request
+   */
+  method: HTTPMethods;
 };
 
 export type ApiKind = "llm" | "email";

src/client/api/utils.ts

@@ -1,6 +1,7 @@
 import type { PublishRequest } from "../client";
 import type { LLMOptions, ProviderInfo, PublishEmailApi, PublishLLMApi } from "./types";
 import { upstash } from "./llm";
+import type { HeadersInit } from "../types";
 
 /**
  * copies and updates the request by removing the api field and adding url & headers.
@@ -37,29 +38,63 @@ export const getProviderInfo = (
     route: finalProvider.getRoute(),
     appendHeaders: finalProvider.getHeaders(parameters),
     owner: finalProvider.owner,
+    method: finalProvider.method,
   };
 
   return finalProvider.onFinish(providerInfo, parameters);
 };
 
+/**
+ * joins two header sets. If the same header exists in both headers and record,
+ * one in headers is used.
+ *
+ * The reason why we added this method is because the following doesn't work:
+ *
+ * ```ts
+ * const joined = {
+ *   ...headers,
+ *   ...record
+ * }
+ * ```
+ *
+ * `headers.toJSON` could have worked, but it exists in bun, and not necessarily in
+ * other runtimes.
+ *
+ * @param headers Headers object
+ * @param record record
+ * @returns joined header
+ */
+const safeJoinHeaders = (headers: Headers, record: Record<string, string>) => {
+  const joinedHeaders = new Headers(record);
+  for (const [header, value] of headers.entries()) {
+    joinedHeaders.set(header, value);
+  }
+  return joinedHeaders as HeadersInit;
+};
+
 /**
  * copies and updates the request by removing the api field and adding url & headers.
  *
- * if there is no api field, simply returns.
+ * if there is no api field, simply returns after overwriting headers with the passed headers.
  *
  * @param request request with api field
+ * @param headers processed headers. Previously, these headers were assigned to the request
+ *   when the headers were calculated. But PublishRequest.request type (HeadersInit) is broader
+ *   than headers (Headers). PublishRequest.request is harder to work with, so we set them here.
  * @param upstashToken used if provider is upstash and token is not set
  * @returns updated request
  */
 export const processApi = (
   request: PublishRequest<unknown>,
+  headers: Headers,
   upstashToken: string
 ): PublishRequest<unknown> => {
   if (!request.api) {
+    request.headers = headers;
     return request;
   }
 
-  const { url, appendHeaders, owner } = getProviderInfo(request.api, upstashToken);
+  const { url, appendHeaders, owner, method } = getProviderInfo(request.api, upstashToken);
 
   if (request.api.name === "llm") {
     const callback = request.callback;
@@ -69,23 +104,17 @@ export const processApi = (
 
     return {
       ...request,
-      // @ts-expect-error undici header conflict
-      headers: new Headers({
-        ...request.headers,
-        ...appendHeaders,
-      }),
+      method: request.method ?? method,
+      headers: safeJoinHeaders(headers, appendHeaders),
       ...(owner === "upstash" && !request.api.analytics
         ? { api: { name: "llm" }, url: undefined, callback }
         : { url, api: undefined }),
     };
   } else {
     return {
       ...request,
-      // @ts-expect-error undici header conflict
-      headers: new Headers({
-        ...request.headers,
-        ...appendHeaders,
-      }),
+      method: request.method ?? method,
+      headers: safeJoinHeaders(headers, appendHeaders),
       url,
       api: undefined,
     };

src/client/client.ts

@@ -378,11 +378,10 @@ export class Client {
     //@ts-expect-error caused by undici and bunjs type overlap
     const headers = prefixHeaders(new Headers(request.headers));
     headers.set("Content-Type", "application/json");
-    request.headers = headers;
 
     //@ts-expect-error hacky way to get bearer token
     const upstashToken = String(this.http.authorization).split("Bearer ")[1];
-    const nonApiRequest = processApi(request, upstashToken);
+    const nonApiRequest = processApi(request, headers, upstashToken);
 
     // @ts-expect-error it's just internal
     const response = await this.publish<TRequest>({
@@ -436,12 +435,12 @@ export class Client {
       if ("body" in message) {
         message.body = JSON.stringify(message.body) as unknown as TBody;
       }
-      //@ts-expect-error caused by undici and bunjs type overlap
-      message.headers = new Headers(message.headers);
 
       //@ts-expect-error hacky way to get bearer token
       const upstashToken = String(this.http.authorization).split("Bearer ")[1];
-      const nonApiMessage = processApi(message, upstashToken);
+
+      //@ts-expect-error caused by undici and bunjs type overlap
+      const nonApiMessage = processApi(message, new Headers(message.headers), upstashToken);
 
       (nonApiMessage.headers as Headers).set("Content-Type", "application/json");
 

src/client/queue.ts

@@ -134,11 +134,10 @@ export class Queue {
     //@ts-expect-error caused by undici and bunjs type overlap
     const headers = prefixHeaders(new Headers(request.headers));
     headers.set("Content-Type", "application/json");
-    request.headers = headers;
 
     //@ts-expect-error hacky way to get bearer token
     const upstashToken = String(this.http.authorization).split("Bearer ")[1];
-    const nonApiRequest = processApi(request, upstashToken);
+    const nonApiRequest = processApi(request, headers, upstashToken);
 
     const response = await this.enqueue({
       ...nonApiRequest,