Implement modifyRequestHeaders for Hangouts and document (#137)

Co-Authored-By: Mahadevan Sreenivasan <mahadevan_sv@yahoo.com>

1 files changed, 28 insertions, 0 deletions

diff --git a/docs/backend_api.md b/docs/backend_api.md
index 512912b..dc3bfaa 100644
--- a/docs/backend_api.md
+++ b/docs/backend_api.md
@@ -5,6 +5,7 @@ Provides a set of helper functions to integrate the recipe into [Ferdi](https://
 ## Ferdi Backend Class Methods
 * [validateUrl](#user-content-validateurl)
 * [overrideUserAgent](#user-content-overrideuseragent)
+* [modifyRequestHeaders](#user-content-modifyrequestheaders)
 
 ## Events
 * [webview events](#user-content-events)
@@ -72,6 +73,32 @@ module.exports = Ferdi => class Example extends Ferdi {
 };
 ```
 
+### modifyRequestHeaders()
+Modify headers of HTTP requests sent from a recipe's webview
+Any standard HTTP header can be added to the requests. 
+
+#### Returns
+`Array` containing objects, each of which should have two properties.
+- `headers` - Object containing the header params and their values in key-value format
+- `requestFilters` - Array of URL patterns used to filter requests for which the headers need to be added. 
+Valid URL patterns can be referred from [here](https://www.electronjs.org/docs/api/web-request#webrequestonbeforerequestfilter-listener)
+
+#### Usage
+
+```js
+// Hangouts Chat integration
+module.exports = Ferdi => class HangoutsChat extends Ferdi {
+    modifyRequestHeaders() {
+      return [{
+        // Adding an origin header for all http requests from this recipe
+        headers: { 'origin': 'https://chat.google.com' },
+        requestFilters: {
+          urls: ['*://*/*']
+        }
+      }]
+    }
+};
+```
 
 ### Events
 Ferdi recipes can hook into the [electron webview events](https://electron.atom.io/docs/api/webview-tag/#dom-events) to trigger custom functions.
@@ -95,3 +122,4 @@ module.exports = Ferdi => class Tweetdeck extends Ferdi {
   }
 };
 ```
+