feat: accept userAgent property in purgeCache method (#553)

src/lib/purge_cache.test.ts

@@ -123,3 +123,41 @@ test('Ignores purgeCache if in local dev with no token or site', async () => {
 
   expect(response).toBeUndefined()
 })
+
+test('Accepts a custom user-agent', async () => {
+  if (!hasFetchAPI) {
+    console.warn('Skipping test requires the fetch API')
+
+    return
+  }
+
+  const userAgent = 'Netlify'
+  const mockSiteID = '123456789'
+  const mockToken = '1q2w3e4r5t6y7u8i9o0p'
+
+  process.env.NETLIFY_PURGE_API_TOKEN = mockToken
+  process.env.SITE_ID = mockSiteID
+
+  const mockAPI = new MockFetch().post({
+    body: (payload: string) => {
+      const data = JSON.parse(payload)
+
+      expect(data.site_id).toBe(mockSiteID)
+    },
+    headers: { Authorization: `Bearer ${mockToken}`, 'user-agent': userAgent },
+    method: 'post',
+    response: new Response(null, { status: 202 }),
+    url: `https://api.netlify.com/api/v1/purge`,
+  })
+
+  const myFunction = async () => {
+    await purgeCache({ userAgent })
+  }
+
+  globalThis.fetch = mockAPI.fetcher
+
+  const response = await invokeLambda(myFunction)
+
+  expect(response).toBeUndefined()
+  expect(mockAPI.fulfilled).toBeTruthy()
+})

src/lib/purge_cache.ts

@@ -5,6 +5,7 @@ interface BasePurgeCacheOptions {
   deployAlias?: string
   tags?: string[]
   token?: string
+  userAgent?: string
 }
 
 interface PurgeCacheOptionsWithSiteID extends BasePurgeCacheOptions {
@@ -73,13 +74,19 @@ export const purgeCache = async (options: PurgeCacheOptions = {}) => {
     )
   }
 
+  const headers: Record<string, string> = {
+    'Content-Type': 'application/json; charset=utf8',
+    Authorization: `Bearer ${token}`,
+  }
+
+  if (options.userAgent) {
+    headers['user-agent'] = options.userAgent
+  }
+
   const apiURL = options.apiURL || 'https://api.netlify.com'
   const response = await fetch(`${apiURL}/api/v1/purge`, {
     method: 'POST',
-    headers: {
-      'Content-Type': 'application/json; charset=utf8',
-      Authorization: `Bearer ${token}`,
-    },
+    headers,
     body: JSON.stringify(payload),
   })