Docker and Vite running Getting problem loading page because of CORS error.

Docker and Vite running Getting problem loading page because of CORS error.

CORS (Cross-Origin Resource Sharing) is a security feature implemented by web browsers that restricts loading of resources from a different domain, protocol, or port than the one that served the web page. When you're trying to run Docker and Vite together, you might encounter a CORS error due to the way these technologies handle network requests.

To resolve the CORS error when running Docker and Vite, follow these steps:

1. Understand the problem: The CORS error occurs when Vite tries to make a request to an API or a resource that is not on the same origin as the Vite development server. Docker, on the other hand, isolates the application from the host system, which can cause issues with CORS.

2. Configure Docker to allow CORS: To allow CORS in Docker, you need to modify the Dockerfile or the docker-compose.yml file to expose the necessary headers. Here's an example of how to modify the Dockerfile:

FROM node:14

WORKDIR /app

COPY package*.json ./
RUN npm install

COPY . .

EXPOSE 3000

RUN echo "CORS headers" >> Dockerfile.cors
RUN echo "Header Access-Control-Allow-Origin: *\n" >> Dockerfile.cors
RUN echo "Header Access-Control-Allow-Methods: GET, POST, PUT, DELETE, OPTIONS\n" >> Dockerfile.cors
RUN echo "Header Access-Control-Allow-Headers: Content-Type, Authorization\n" >> Dockerfile.cors
RUN echo "Header Access-Control-Allow-Credentials: true\n" >> Dockerfile.cors

COPY Dockerfile.cors /etc/nginx/conf.d/default.conf

CMD ["nginx", "-g", "daemon off;"]

In this example, we're using Nginx as a reverse proxy and adding CORS headers to the Nginx configuration file. If you're using a different web server, you might need to modify the configuration accordingly.

3. Configure Vite to bypass CORS: Vite has a built-in feature to bypass CORS checks during development. To enable it, you need to add the following flag when starting the Vite server:

vite --base=http://localhost:3000 --server.middlewareMode=full --server.strictMode=false

Here, we're setting the base URL to the Docker container's exposed port and disabling the strict CORS mode.

4. Test the solution: After making these changes, start the Docker container and the Vite server. Open your web browser and navigate to the application's URL. If the CORS error is resolved, you're good to go.

5. Consider production deployment: In production, you should not disable CORS checks entirely. Instead, you should configure your API or the web server to allow the necessary origins. This can be done by adding the appropriate CORS headers to the API response or the web server configuration.

By following these steps, you should be able to resolve the CORS error when running Docker and Vite together.