(Java) HTTP Redirect Handling

Examine HTTP redirects.

Chilkat Java Downloads Java Libs for Windows, MacOS, Linux, Alpine Linux Java Libs for Android

import com.chilkatsoft.*;

public class ChilkatExample {

  static {
    try {
        System.loadLibrary("chilkat");
    } catch (UnsatisfiedLinkError e) {
      System.err.println("Native code library failed to load.\n" + e);
      System.exit(1);
    }
  }

  public static void main(String argv[])
  {
    // This example assumes the Chilkat API to have been previously unlocked.
    // See Global Unlock Sample for sample code.

    CkHttp http = new CkHttp();

    String url;
    String html;
    int status;

    // Please note: The URL used in this example was a valid redirect many years ago,
    // but the site does not exist any longer..
    url = "http://www.planyourweddingonline.co.za/";

    // The FollowRedirects property controls whether redirects
    // are automatically followed.  The default behavior is to
    // automatically follow redirects.

    // Explicitly set FollowRedirects so that redirects are automatically taken:
    http.put_FollowRedirects(true);

    // Send the HTTP GET and return the content in a string.
    html = http.quickGetStr(url);
    if (http.get_LastMethodSuccess() != true) {
        System.out.println(http.lastErrorText());
        }

    // On success, LastErrorText will provide information about
    // what happened during the call.
    System.out.println("--------------- LastErrorText ------------------");
    System.out.println(http.lastErrorText());
    System.out.println("------------------------------------------------");

    // In this case, we see something like this:
    // ChilkatLog:
    //   QuickGetHtml:
    //     DllDate: Jul 27 2007
    //     url: http://www.planyourweddingonline.co.za/
    //     httpServer: www.planyourweddingonline.co.za
    //     port: 80
    //     StatusCode: 302
    //     StatusText: Found
    //     Reading chunked response
    //     redirectUrl: main/main/home/index.php
    //     url: http://www.planyourweddingonline.co.za/main/main/home/index.php
    //     StatusCode: 302
    //     StatusText: Found
    //     Reading chunked response
    //     redirectUrl: /main/main/home/index.php?SMC=1
    //     url: http://www.planyourweddingonline.co.za/main/main/home/index.php?SMC=1
    //     StatusCode: 200
    //     StatusText: OK
    //     CompressedSize: 7434
    //     UncompressedSize: 40999

    // Was the GET redirected?
    if (http.get_WasRedirected() == true) {
        System.out.println("Chilkat HTTP followed the redirect.");

        // Display the final redirect URL:
        System.out.println("Final URL:");
        System.out.println(http.finalRedirectUrl());

        // Note the HTML returned is from the final redirect URL.

        }
    else {
        System.out.println("Not redirected.");
        }

    status = http.get_LastStatus();
    if (status == 200) {
        System.out.println("status = 200, OK!");
        }
    else {
        System.out.println("HTTP Response status = " + status);

        // Display the complete response header.
        System.out.println(http.lastResponseHeader());
        }

    // Now try it without following redirects:
    System.out.println("-------- Now trying without following redirects....");
    http.put_FollowRedirects(false);

    // Send the HTTP GET and return the content in a string.
    html = http.quickGetStr(url);
    if (http.get_LastMethodSuccess() != true) {
        // the HTML string can NULL if a 302 redirect response is received.
        System.out.println("HTML string returned NULL...");
        }

    // On success, LastErrorText will provide information about
    // what happened during the call.
    System.out.println("--------------- LastErrorText ------------------");
    System.out.println(http.lastErrorText());
    System.out.println("------------------------------------------------");

    // In this case, we see something like this:
    // ChilkatLog:
    //   QuickGetHtml:
    //     DllDate: Jul 27 2007
    //     url: http://www.planyourweddingonline.co.za/
    //     StatusCode: 302
    //     StatusText: Found
    //     Reading chunked response
    //     redirectUrl: main/main/home/index.php

    // Was this a redirect?  Even if FollowRedirects is false,
    // WasRedirected will be true (non-zero) if the response
    // indicated a redirect.
    if (http.get_WasRedirected() == true) {
        System.out.println("This was a redirect response");

        // When redirects are not followed, FinalRedirectUrl
        // contains the redirect URL that would've been taken...
        // Display the redirect URL, which was not taken...
        System.out.println("Redirect URL:");
        System.out.println(http.finalRedirectUrl());

        }
    else {
        System.out.println("Not redirected.");
        }

    status = http.get_LastStatus();
    if (status == 200) {
        System.out.println("status = 200, OK!");
        }
    else {
        System.out.println("HTTP Response status = " + status);

        // Display the complete response header.
        System.out.println(http.lastResponseHeader());
        }
  }
}