Add zaf_sdk user agent to headers for requests

- To assist with debugging the source of various requests it would be helpful
  to indicate whether requests have been touched by the zaf_sdk at any point
- This will help operationally for various things that need to be done to
  monitor things of an api related nature
- Knowing that a request has been touched by zaf_sdk helps to pinpoint the
  source + narrow down where things need fixing and/or patching
- It would be good to get the appId too but this is a good first port of call

lib/client.js

@@ -4,6 +4,7 @@ import { when, isObject, isString, debounce } from './utils'
 import IdleState from './utils/idleState'
 import Tracker from './tracker'
 import NativePromise from 'native-promise-only'
+import { addUserAgent } from './utils'
 
 const Promise = window.Promise || NativePromise
 
@@ -557,6 +558,8 @@ export default class Client {
         options = { url: options }
       }
 
+      options.headers = addUserAgent(options.headers)
+
       const doneEventKey = `${requestKey}.done`
       const failEventKey = `${requestKey}.fail`
 

lib/utils.js

@@ -1,6 +1,16 @@
 import NativePromise from 'native-promise-only'
+import pkgJson from '../package.json'
+
 const Promise = window.Promise || NativePromise
 
+export function addUserAgent(headers) {
+  const originalUserAgent = headers && headers['User-Agent'] ? headers['User-Agent'] : ''
+  return {
+    ...headers,
+    'User-Agent': originalUserAgent ? `${originalUserAgent} zendesk_app_framework_sdk/${pkgJson.version}` : `zendesk_app_framework_sdk/${pkgJson.version}`
+  }
+}
+
 export function isObject (obj) {
   return (obj !== null && typeof obj === 'object')
 }