December 2019
Intermediate to advanced
598 pages
12h 21m
English
Content preview from ASP.NET Core 3 and React
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Adding CORS to our backend
We are going to try our real-time API now and discover a problem with it because the frontend is hosted in a different origin from the backend. Let's carry out the following steps to expose this problem and then correct it:
- Run the backend project by pressing F5 in Visual Studio.
- Run the frontend project by entering npm start in the Terminal in Visual Studio Code.
- When the frontend app runs, press F12 to open the browser DevTools and select the Console panel.
- Click on a question to open the question page. This is where the SignalR connection should be started and the client can subscribe to the question. We get an error, though:
The request to start the SignalR connection has been blocked by a CORS policy.
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O’Reilly covers everything we've got, with content to help us build a world-class technology community, upgrade the capabilities and competencies of our teams, and improve overall team performance as well as their engagement.Julian F.
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