[sc-9487] add setApiRequestInterceptor

Author: haoAddsearch

README.md

@@ -413,6 +413,17 @@ client.setThrottleTime(500);
 client.setApiHostname('api.addsearch.com');
 ```
 
+#### Set API request interceptor
+`configurationObject` contains 2 keys: <string>`url` and <object>`headers`. Modify the `configurationObject` before it is sent.
+```js
+function callback(configurationObject) {
+  configurationObject.headers['X-Api-Key'] = 'YOUR API KEY';
+  return configurationObject;
+}
+client.setApiRequestInterceptor(callback);
+```
+
+
 ## Indexing API
 With the Indexing API, you can fetch, create, update, and delete single documents or
 batches of documents.

src/api.js

@@ -0,0 +1,22 @@
+'use strict';
+
+const axios = require('axios').default;
+const apiInstance = axios.create();
+
+const setRequestInterceptor = (callback) => {
+  apiInstance.interceptors.request.use( (config) => {
+    const updatedConfig = callback({
+      url: config.url,
+      headers: config.headers
+    });
+    config = {...config, ...updatedConfig};
+    return config;
+  }, function (error) {
+    return Promise.reject(error);
+  });
+};
+
+module.exports = {
+  apiInstance,
+  setRequestInterceptor
+};

src/apifetch.js

@@ -1,7 +1,7 @@
 'use strict';
 
 require('es6-promise').polyfill();
-const axios = require('axios').default;
+const apiInstance = require('./api').apiInstance;
 
 /**
  * Fetch search results of search suggestions from the Addsearch API
@@ -174,7 +174,7 @@ var executeApiFetch = function(apiHostname, sitekey, type, settings, cb, fuzzyRe
     'https://' + apiHostname + '/v1/' + apiPath + '/' + sitekey + '?configurationKey=' + recommendOptions.configurationKey + qs :
     'https://' + apiHostname + '/v1/' + apiPath + '/' + sitekey + '?term=' + kw + qs;
 
-  axios.get(api)
+  apiInstance.get(api)
     .then(function(response) {
       var json = response.data;
       // Search again with fuzzy=true if no hits

src/index.js

@@ -7,6 +7,7 @@ var Settings = require('./settings');
 var util = require('./util');
 var throttle = require('./throttle');
 var cookie = require('./cookie');
+var setRequestInterceptor = require('./api').setRequestInterceptor;
 
 var API_HOSTNAME = 'api.addsearch.com';
 var USER_TOKEN_COOKIE_NAME = 'addsearchUserToken';
@@ -269,6 +270,17 @@ var client = function(sitekey, privatekey) {
     isAddSearchCookieConsented = !!isEnabled;
   };
 
+  /*
+   * API interceptor
+   */
+  this.setApiRequestInterceptor = function(callback) {
+    if (typeof callback === 'function') {
+      setRequestInterceptor(callback);
+    } else {
+      window.console.error('API interceptor must be a function');
+    }
+  };
+
 
   // Deprecated
   this.searchResultClicked = function(documentId, position) {