feat: Allow custom headers (#3660)

* custom headers and fix response shape

---------

Co-authored-by: Leo Romanovsky <[email protected]>

Author: typotter

packages/flagging/.gitignore

@@ -0,0 +1 @@
+.env

packages/flagging/src/openfeature/provider.spec.ts

@@ -15,8 +15,9 @@ describe('DatadogProvider', () => {
       addAction: jasmine.createSpy('addAction'),
     }
     provider = new DatadogProvider({
-      applicationId: 'xxx',
       clientToken: 'xxx',
+      applicationId: 'xxx',
+      env: 'test',
       site: 'http://localhost:8000',
       rum: {
         sdk: mockDatadogRum,

packages/flagging/src/openfeature/provider.ts

@@ -1,9 +1,9 @@
 import type {
-  Provider,
   EvaluationContext,
   JsonValue,
   Logger,
   Paradigm,
+  Provider,
   ProviderMetadata,
   ResolutionDetails,
   HookContext,
@@ -20,14 +20,20 @@ import type { DDRum } from './rumIntegration'
 
 export type DatadogProviderOptions = {
   /**
-   * The RUM application ID.
+   * The application key for Datadog. Required for initializing the Datadog Flagging client.
    */
   applicationId: string
+
   /**
-   * The client token for Datadog. Required for authenticating your application with Datadog.
+   * The client token for Datadog. Required for initializing the Datadog Flagging client.
    */
   clientToken: string
 
+  /**
+   * The application environment.
+   */
+  env: string
+
   /**
    * The site to use for the Datadog API.
    */
@@ -52,6 +58,15 @@ export type DatadogProviderOptions = {
      */
     ddExposureLogging?: boolean
   }
+  /**
+   * Custom headers to add to the request to the Datadog API.
+   */
+  customHeaders?: Record<string, string>
+
+  /**
+   * Whether to overwrite the default request headers.
+   */
+  overwriteRequestHeaders?: boolean
 }
 
 // We need to use a class here to properly implement the OpenFeature Provider interface
@@ -164,18 +179,45 @@ export class DatadogProvider implements Provider {
 async function fetchConfiguration(options: DatadogProviderOptions, context: EvaluationContext): Promise<Configuration> {
   const baseUrl = options.site || 'https://dd.datad0g.com'
 
-  const parameters = [`application_id=${options.applicationId}`, `client_token=${options.clientToken}`]
+  // Stringify all context values
+  const stringifiedContext: Record<string, string> = {}
+  for (const [key, value] of Object.entries(context)) {
+    stringifiedContext[key] = typeof value === 'string' ? value : JSON.stringify(value)
+  }
 
-  const response = await fetch(`${baseUrl}/api/unstable/precompute-assignments?${parameters.join('&')}`, {
+  const response = await fetch(`${baseUrl}/api/unstable/precompute-assignments`, {
     method: 'POST',
     headers: {
-      'Content-Type': 'application/json',
-      'DD-API-KEY': options.clientToken,
+      'Content-Type': 'application/vnd.api+json',
+      ...(!options.overwriteRequestHeaders
+        ? {
+            'dd-client-token': options.clientToken,
+            'dd-application-id': options.applicationId,
+          }
+        : {}),
+      ...options.customHeaders,
     },
     body: JSON.stringify({
-      context,
+      data: {
+        type: 'precompute-assignments-request',
+        attributes: {
+          env: {
+            name: options.env,
+          },
+          subject: {
+            targeting_key: context.targetingKey || '',
+            targeting_attributes: stringifiedContext,
+          },
+        },
+      },
     }),
   })
   const precomputed = await response.json()
-  return { precomputed }
+  return {
+    precomputed: {
+      response: precomputed,
+      context,
+      fetchedAt: dateNow(),
+    },
+  }
 }