How to Send an HTTPS Request through a Proxy in Java?

Question

How to send an HTTPS request through a proxy in Java?

// Example of sending an HTTPS request through a proxy in Java
import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.net.HttpURLConnection;
import java.net.Proxy;
import java.net.InetSocketAddress;
import java.net.URL;

public class HttpsProxyExample {
    public static void main(String[] args) throws Exception {
        // Define the proxy information
        String proxyHost = "your.proxy.host";
        int proxyPort = 8080;

        // Create a Proxy object
        Proxy proxy = new Proxy(Proxy.Type.HTTP, new InetSocketAddress(proxyHost, proxyPort));

        // Open a URL connection through the proxy
        URL url = new URL("https://api.example.com/data");
        HttpURLConnection connection = (HttpURLConnection) url.openConnection(proxy);
        connection.setRequestMethod("GET");

        // Read the response
        BufferedReader in = new BufferedReader(new InputStreamReader(connection.getInputStream()));
        String inputLine;
        StringBuffer response = new StringBuffer();
        while ((inputLine = in.readLine()) != null) {
            response.append(inputLine);
        }
        in.close();

        // Print the response
        System.out.println("Response: " + response.toString());
    }
}

Answer

Sending HTTPS requests through a proxy in Java can be done by configuring the connection to utilize the proxy settings. This is particularly useful in environments where direct Internet access is restricted, and all traffic must go through a specified proxy server.

// See the code snippet provided in the question for implementation.

Causes

Need to access external resources while adhering to network security protocols.
Application requirement to debug HTTP requests through a proxy.
Specific use cases where monitoring or logging traffic is necessary.

Solutions

Define the proxy host and port before establishing the connection.
Utilize the `HttpURLConnection` class, specifying the proxy instance when opening a connection.
Handle potential authentication if the proxy requires it.

Common Mistakes

Mistake: Not specifying the proxy type correctly, leading to connection errors.

Solution: Ensure that the `Proxy.Type.HTTP` or `Proxy.Type.SOCKS` is used based on the proxy type.

Mistake: Ignoring SSL certificates when using HTTPS through a proxy.

Solution: Use a `TrustManager` to accept or validate certificates correctly when needed.

Helpers

Java HTTPS request proxy
Send HTTPS request through proxy Java
Java proxy connection example
HttpURLConnection proxy Java