token not being sent in pre-flight request Ionic2 - django

Question

I am working on an app in Ionic 2 using DRF as API service. For authentication purpose I am using JWT. I am sending auth token with each request as Authorization: jwt [token]. In Postman, API is working fine.
Now when I am testing it in browser it is not working and I figured out that it is probably not working because the JWT auth token is not being sent in the OPTIONS request as a pre-flight. So how do I tackle this problem.

Answer 1

In the Ionic latest versions if you are using ionic serve commnad then you must have to use Proxies to prevent Preflight and CORS Issues,
First add API path and URL in ionic.config.json file like
{
"name": "APP-NAME",
"app_id": "",
"proxies": [
{
"path": "/api",
"proxyUrl": "http://example.com/api"
}
]
}
Now, while calling your API from http use the /api URL instead of the http://example.com/api like,
....
this.http.post('/api', data, {headers:headers}).map(res=>res.json()).subscribe(data=>{
console.log(data)
}, err=>{
console.log("Error!:", err.json());
});
....
After making the above changes you must rerun command ionic serve.
Still, if you are getting issues then refer Handling CORS Issues In Ionic and https://ionicframework.com/docs/cli/configuring.html

Answer 2

In CORS preflight OPTIONS response Cross-Origin-Allow-Headers should match that of the request.
Cross-Origin-Allow-Headers: Authorization

Answer 3

Actually the problem was that the OPTIONS api was not readable without the Authorization token so we added the readonly Auth level for the OPTIONS and GET api.