feat: rest header injection (#3122)

* feat: made some progress on a function which can be overridden to allow users to inject custom headers into a rest request

* made the changes suggested in PR. Renamed inject headers to createBaseHeaders, which adds the user agent into the headers.

packages/rest/src/manager.ts

@@ -98,10 +98,17 @@ export function createRestManager(options: CreateRestManagerOptions): RestManage
 
     routes: createRoutes(),
 
+    createBaseHeaders() {
+      return {
+        'user-agent': `DiscordBot (https://github.com/discordeno/discordeno, v${version})`,
+      }
+    },
+
     checkRateLimits(url, headers) {
       const authHeader = headers?.authorization ?? ''
 
       const ratelimited = rest.rateLimitedPaths.get(`${authHeader}${url}`)
+
       const global = rest.rateLimitedPaths.get('global')
       const now = Date.now()
 
@@ -161,9 +168,7 @@ export function createRestManager(options: CreateRestManagerOptions): RestManage
     },
 
     createRequestBody(method, options) {
-      const headers: Record<string, string> = {
-        'user-agent': `DiscordBot (https://github.com/discordeno/discordeno, v${version})`,
-      }
+      const headers = this.createBaseHeaders()
 
       if (options?.unauthorized !== true) headers.authorization = `Bot ${rest.token}`
 

packages/rest/src/types.ts

@@ -176,6 +176,8 @@ export interface RestManager {
   invalidBucket: InvalidRequestBucket
   /** The routes that are available for this manager. */
   routes: RestRoutes
+  /** Allows the user to inject custom headers that will be sent with every request. */
+  createBaseHeaders: () => Record<string, string>
   /** Whether or not the rest manager should keep objects in raw snake case from discord. */
   preferSnakeCase: (enabled: boolean) => RestManager
   /** Check the rate limits for a url or a bucket. */