Add `fetchOptions` for the RemoteStorage. Closes #1885

src/storage_manager/config/config.js

@@ -55,5 +55,13 @@ module.exports = {
   // false: 'x-www-form-urlencoded'
   contentTypeJson: true,
 
-  credentials: 'include'
+  credentials: 'include',
+
+  // Pass custom options to fetch API (remote storage)
+  // You can pass a simple object: { someOption: 'someValue' }
+  // or a function wich returns and object to add:
+  // currentOpts => {
+  //  return currentOpts.method === 'post' ?  { method: 'patch' } : {};
+  // }
+  fetchOptions: ''
 };

src/storage_manager/model/RemoteStorage.js

@@ -1,5 +1,5 @@
 import fetch from 'utils/fetch';
-import { isUndefined } from 'underscore';
+import { isUndefined, isFunction } from 'underscore';
 
 module.exports = require('backbone').Model.extend({
   fetch,
@@ -11,7 +11,8 @@ module.exports = require('backbone').Model.extend({
     beforeSend() {},
     onComplete() {},
     contentTypeJson: false,
-    credentials: 'include'
+    credentials: 'include',
+    fetchOptions: ''
   },
 
   /**
@@ -123,8 +124,16 @@ module.exports = require('backbone').Model.extend({
       fetchOptions.body = body;
     }
 
+    const fetchOpts = this.get('fetchOptions') || {};
+    const addOpts = isFunction(fetchOpts)
+      ? fetchOpts(fetchOptions)
+      : fetchOptions;
+
     this.onStart();
-    this.fetch(url, fetchOptions)
+    this.fetch(url, {
+      ...fetchOptions,
+      ...(addOpts || {})
+    })
       .then(res =>
         ((res.status / 200) | 0) == 1
           ? res.text()

test/specs/storage_manager/model/Models.js

@@ -141,6 +141,23 @@ module.exports = {
           credentials: false
         });
       });
+
+      test('Load data with custom fetch options as function', () => {
+        const customOpts = { customOpt: 'customValue' };
+        obj = new RemoteStorage({
+          ...storageOptions,
+          fetchOptions: () => {
+            return customOpts;
+          }
+        });
+        sinon
+          .stub(obj, 'fetch')
+          .returns(Promise.resolve(mockResponse({ data: 1 })));
+        obj.load(['item1', 'item2']);
+        const callResult = obj.fetch;
+        expect(callResult.called).toEqual(true);
+        expect(callResult.firstCall.args[1]).toMatchObject(customOpts);
+      });
     });
   }
 };