proxy-server

README

Proxy Server

This repository contains a simple Go code for a reverse proxy server. The proxy server can be used to forward requests to one or more backend servers.

Usage

To run the proxy server, simply execute the following command:

" go run main.go "

The proxy server will start listening on port 8080 by default. You can access the proxy server at the following URL:

" http://localhost:8080 "

Configuration

The proxy server can be configured using the following environment variables:

• BACKEND_HOST: The URL of the backend server to proxy.
• DIRECTOR: The name of a custom director function to use.

Custom Director Functions

A custom director function is a function that is responsible for choosing which backend server to forward a request to. To use a custom director function, you need to set the DIRECTOR environment variable to the name of the function.

Here is an example of a custom director function that proxies requests to two backend servers in a round-robin fashion:

" func roundRobinDirector(req *http.Request) { // Get the list of backend servers. backendServers := []string{ "http://localhost:8081", "http://localhost:8082", }

// Choose a backend server in a round-robin fashion.
nextBackend := backendServers[len(backendServers)-1]
backendServers = append([]string{nextBackend}, backendServers[:len(backendServers)-1]...)

// Set the target URL of the reverse proxy.
req.URL.Host = nextBackend

} "

To use this director function, you would set the DIRECTOR environment variable to roundRobinDirector.

Modifying Requests and Responses

The proxy server can also be used to modify requests and responses before they are forwarded to the backend server. To do this, you can use the ModifyRequest() and ModifyResponse() functions on the reverse proxy object.

For example, you could use the ModifyRequest() function to add a custom header to all requests:

" reverseProxy := httputil.NewSingleHostReverseProxy(nil) reverseProxy.Director = roundRobinDirector reverseProxy.ModifyRequest = func(req *http.Request) { req.Header.Set("X-Custom-Header", "my-value") } "

Now, all requests made to the proxy server will have the X-Custom-Header header set to my-value.

You can also use the ModifyResponse() function to modify the response before it is sent to the client. For example, you could use it to remove a sensitive header from the response:

" reverseProxy := httputil.NewSingleHostReverseProxy(nil) reverseProxy.Director = roundRobinDirector reverseProxy.ModifyResponse = func(res *http.Response) { res.Header.Del("X-Sensitive-Header") } "

Now, all responses sent by the proxy server will have the X-Sensitive-Header header removed.

Conclusion

The proxy server is a powerful tool that can be used to improve the performance, reliability, and security of your applications.