Solved: Blocked by CORS when fetching 'firebase' for web n... - Page 2

mobileappdev · 05-22-2023 05:21 AM

We have developed a PWA using javascript and have followed the docs to setup web push notifications using firebase.

Is there something in our firebase console that needs to be enabled or setup to allow CORS.

The error is similar to this:

"Access to fetch at 'https://firebase.googleapis.com/v1alpha/projects/-/apps*****' from origin 'http://localhost:4746' has been blocked by CORS policy: Response to preflight request doesn't pass access control check: No 'Access-Control-Allow-Origin' header is present on the requested resource. If an opaque response serves your needs, set the request's mode to 'no-cors' to fetch the resource with CORS disabled."

The app uses javascript and has installed the firebase SDK.

it pulls the firebase .js files from gstatic using version 9.22.0.

Any advice is appreciated.

mobileappdev

I found the solution, and the finger points back at me.

I had added a package for BlazorApplicationInsights which required setup code in index.html.

Inside that setup code, CORS was being required on all calls.:

...

cfg: {

connectionString: "InstrumentationKey=****",

enableCorsCorrelation: true,

enableRequestHeaderTracking: true,

enableResponseHeaderTracking: true

}

});</script>

Removing this fixed my issue with CORS.

Thank you

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Blocked by CORS when fetching 'firebase' for web notifications