What are Broken Links?

Broken links are links or URLs that are not reachable. They may be down or not functioning due to some server error

An URL will always have a status with 2xx which is valid. There are different HTTP status codes which are having different purposes. For an invalid request, HTTP status is 4xx and 5xx.

4xx class of status code is mainly for client side error, and 5xx class of status codes is mainly for the server response error.

We will most likely be unable to confirm if that link is working or not until we click and confirm it.

Why should you check Broken links?

You should always make sure that there are no broken links on the site because the user should not land into an error page.

The error happens if the rules are not updated correctly, or the requested resources are not existing at the server.

Manual checking of links is a tedious task, because each webpage may have a large number of links & manual process has to be repeated for all pages.

An Automation script using Selenium that will automate the process is a more apt solution.

How to check the Broken Links and images

For checking the broken links, you will need to do the following steps.

  1. Collect all the links in the web page based on <a> tag.
  2. Send HTTP request for the link and read HTTP response code.
  3. Find out whether the link is valid or broken based on HTTP response code.
  4. Repeat this for all the links captured.

Code to Find the Broken links on a webpage

Below is the web driver code which tests our use case:

package automationPractice;

import java.io.IOException;
import java.net.HttpURLConnection;
import java.net.MalformedURLException;
import java.net.URL;
import java.util.Iterator;
import java.util.List;

import org.openqa.selenium.By;
import org.openqa.selenium.WebDriver;
import org.openqa.selenium.WebElement;
import org.openqa.selenium.chrome.ChromeDriver;

public class BrokenLinks {
    
    private static WebDriver driver = null;

    public static void main(String[] args) {
        // TODO Auto-generated method stub
        
        String homePage = "http://www.zlti.com";
        String url = "";
        HttpURLConnection huc = null;
        int respCode = 200;
        
        driver = new ChromeDriver();
        
        driver.manage().window().maximize();
        
        driver.get(homePage);
        
        List<WebElement> links = driver.findElements(By.tagName("a"));
        
        Iterator<WebElement> it = links.iterator();
        
        while(it.hasNext()){
            
            url = it.next().getAttribute("href");
            
            System.out.println(url);
        
            if(url == null || url.isEmpty()){
System.out.println("URL is either not configured for anchor tag or it is empty");
                continue;
            }
            
            if(!url.startsWith(homePage)){
                System.out.println("URL belongs to another domain, skipping it.");
                continue;
            }
            
            try {
                huc = (HttpURLConnection)(new URL(url).openConnection());
                
                huc.setRequestMethod("HEAD");
                
                huc.connect();
                
                respCode = huc.getResponseCode();
                
                if(respCode >= 400){
                    System.out.println(url+" is a broken link");
                }
                else{
                    System.out.println(url+" is a valid link");
                }
                    
            } catch (MalformedURLException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            } catch (IOException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
        }
        
        driver.quit();

    }
}

Explaining the code

STEP 1: Import Packages

Import below package in addition to default packages:

import java.net.HttpURLConnection;

Using the methods in this package, we can send HTTP requests and capture HTTP response codes from the response.

STEP 2: Collect all links in web page

Identify all links in a webpage and store them in List.

List<WebElement> links = driver.findElements(By.tagName("a"));

Obtain Iterator to traverse through the List.

Iterator<WebElement> it = links.iterator();

Step 3: Identifying and Validating URL

In this part, we will check if URL belongs to Third party domain or whether URL is empty/null.

Get href of anchor tag and store it in url variable.

url = it.next().getAttribute("href");

Check if URL is null or Empty and skip the remaining steps if the condition is satisfied.

if(url == null || url.isEmpty()){
              System.out.println("URL is either not configured for anchor tag or it is empty");
              continue;
     }

Check whether URL belongs to a main domain or third party. Skip the remaining steps if it belongs to third party domain.

 if(!url.startsWith(homePage)){
           System.out.println("URL belongs to another domain, skipping it.");
           continue;
   }

Step 4: Send http request

HttpURLConnection class has methods to send HTTP request and capture HTTP response code. So, output of openConnection() method (URLConnection) is type casted to HttpURLConnection.

huc = (HttpURLConnection)(new URL(url).openConnection());

We can set Request type as "HEAD" instead of "GET". So that only headers are returned and not document body.

huc.setRequestMethod("HEAD");

On invoking connect() method, actual connection to url is established and the request is sent.

huc.connect();

Step 5: Validating Links

Using getResponseCode() method we can get response code for the request

respCode = huc.getResponseCode();

Based on response code we will try to check link status.

if(respCode >= 400){
        System.out.println(url+" is a broken link");
}
else{
        System.out.println(url+" is a valid link");
}

Thus, we can obtain all links from web page and print whether links are valid or broken.

Hope this tutorial helps you in checking Broken links using selenium.