# CORS (Cross-Origin Resource Sharing) { #cors-cross-origin-resource-sharing }

<a href="https://developer.mozilla.org/en-US/docs/Web/HTTP/CORS" class="external-link" target="_blank">CORS or "Cross-Origin Resource Sharing"</a> refers to the situations when a frontend running in a browser has JavaScript code that communicates with a backend, and the backend is in a different "origin" than the frontend.

## Origin { #origin }

But if you have custom headers that you want a client in a browser to be able to see, you need to add them to your CORS configurations ([CORS (Cross-Origin Resource Sharing)](cors.md){.internal-link target=_blank}) using the parameter `expose_headers` documented in <a href="https://www.starlette.io/middleware/#corsmiddleware" class="external-link" target="_blank">Starlette's CORS docs</a>.

	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		if origin := w.Header().Get("Access-Control-Allow-Origin"); origin == "null" {
			// This is a workaround change to ensure that "Origin: null"
			// incoming request to a response back as "*" instead of "null"
			w.Header().Set("Access-Control-Allow-Origin", "*")
		}
		if globalDNSConfig == nil || !globalBucketFederation ||

      id: cherrypick
      run: |
          git config --global user.name "TensorFlow Release Automation"
          git config --global user.email "******@****.***"
          git fetch origin master
          git cherry-pick ${{ github.event.inputs.git_commit }}
          echo "SHORTSHA=$(git log -1 ${{ github.event.inputs.git_commit }} --format="%h")" >> "$GITHUB_OUTPUT"

        final String clusterName = UUID.randomUUID().toString();
        runner.onBuild((number, settingsBuilder) -> {
            settingsBuilder.put("http.cors.enabled", true);
            settingsBuilder.put("http.cors.allow-origin", "*");
            settingsBuilder.put("discovery.type", "single-node");
        }).build(newConfigs().clusterName(clusterName).numOfNode(1));

        // wait for yellow status
        runner.ensureYellow();

P/Headers" class="external-link" target="_blank">using the 'X-' prefix</a>.

But if you have custom headers that you want a client in a browser to be able to see, you need to add them to your CORS configurations (read more in [CORS (Cross-Origin Resource Sharing)](../tutorial/cors.md){.internal-link target=_blank}), using the parameter `expose_headers` documented in <a href="https://www.starlette.io/middleware/#corsmiddleware" class="external-link" target="_blank">Starlette's CORS docs</a>....

3. **Follow** the coding standards: `mvn formatter:format`
4. **Add** comprehensive tests for new functionality
5. **Commit** your changes: `git commit -m 'Add amazing feature'`
6. **Push** to the branch: `git push origin feature/amazing-feature`
7. **Submit** a Pull Request with detailed description

### Code Standards
- Follow the project's Eclipse formatter configuration

1. **Fork** the repository
2. **Create** a feature branch (`git checkout -b feature/amazing-feature`)
3. **Commit** your changes (`git commit -m 'Add amazing feature'`)
4. **Push** to the branch (`git push origin feature/amazing-feature`)
5. **Open** a Pull Request

### Development Setup

```bash
# Clone the repository
git clone https://github.com/codelibs/fess-crawler.git
cd fess-crawler

4. Add tests for new functionality
5. Ensure all tests pass: `mvn test`
6. Check license headers: `mvn license:format`
7. Commit changes: `git commit -m 'Add amazing feature'`
8. Push to branch: `git push origin feature/amazing-feature`
9. Open a Pull Request

### Code Style

- Use Eclipse formatter configuration (`src/config/eclipse/formatter/java.xml`)
- Follow existing naming conventions

      }
    }
  }

  internal class CallReference(
    referent: RealCall,
    /**
     * Captures the stack trace at the time the Call is executed or enqueued. This is helpful for
     * identifying the origin of connection leaks.
     */
    val callStackTrace: Any?,
  ) : WeakReference<RealCall>(referent)