CORS在Cordova中重定向

Question

I have a Cordova/Phonegap application trying to get some files with AJAX. I get the following error:

XMLHttpRequest cannot load https://docs.google.com/uc?export=open&id=.... Redirect from 'https://docs.google.com/uc?export=open&id=...' to 'https://doc-xx-xx-docs.googleusercontent.com/docs/...?e=open' has been blocked by CORS policy: No 'Access-Control-Allow-Origin' header is present on the requested resource. Origin 'null' is therefore not allowed access.

I tried adding the following to config.xml

<access origin="*" />
<allow-navigation href="*" />
<allow-navigation href="http://*/*" />
<allow-navigation href="https://*/*" />

and also added to index.html

<meta http-equiv="Content-Security-Policy" content="default-src 'self' data: gap: 'unsafe-eval' 'unsafe-inline' http: https:">

I'm accessing the application in the browser using cordova serve.

I still get the same error. Any idea?

Answer 1

Assuming you don't​ have control over the endpoint you may well need to setup your own API to do this.

For example if you create an endpoint in php you could include the line:

 header('Access-Control-Allow-Origin: *');

Then your end point can forward the request to the Google endpoint which will pass the response to your API and that can pass your app the response.

I believe the Google endpoint will accept a request from other servers but not if the origin is null.

In effect you need to make sure your request is coming from a http:// and not a file:// URL.