C# Program: Download content from multiple URLs with exception handling

C# Sharp Exception Handling: Exercise-13 with Solution

Write a C# program that reads a list of URLs from the user and downloads the content of each URL. Handle the exception if any URL is inaccessible.

Sample Solution:

C# Sharp Code:

using System;
using System.Net;

class Program {
  static void Main() {
    // Prompt the user to input URLs, one URL per line, and press Enter to complete
    Console.WriteLine("Input the URLs (one URL per line, press Enter to complete):");

    try {
      while (true) {
        // Read the URL entered by the user
        string url = Console.ReadLine();

        // Check if the entered URL is null, empty, or contains only whitespace
        if (string.IsNullOrWhiteSpace(url)) {
          // Break out of the loop if the entered URL is empty or whitespace
          break;
        }

        // Call the method to download content from the specified URL
        DownloadContent(url);
      }
    } catch (WebException ex) {
      // Catch block for handling WebException when accessing URLs
      Console.WriteLine("Error accessing URL: " + ex.Message);
    } catch (Exception ex) {
      // Catch block for handling other types of exceptions
      Console.WriteLine("An error occurred: " + ex.Message);
    }
  }

  // Method to download content from a specified URL and display it
  static void DownloadContent(string url) {
    // Create a new instance of WebClient to download content
    WebClient webClient = new WebClient();

    // Download the content from the provided URL
    string content = webClient.DownloadString(url);

    // Display the content of the downloaded URL
    Console.WriteLine("Content of URL '" + url + "':");
    Console.WriteLine(content);
    Console.WriteLine();
  }
}

Sample Output:

Input the URLs (one URL per line, press Enter to complete):
https://jsonplaceholder.typicode.com/posts/1
Content of URL 'https://jsonplaceholder.typicode.com/posts/1':
{
  "userId": 1,
  "id": 1,
  "title": "sunt aut facere repellat provident occaecati excepturi optio reprehenderit",
  "body": "quia et suscipit\nsuscipit recusandae consequuntur expedita et cum\nreprehenderit molestiae ut ut quas totam\nnostrum rerum est autem sunt rem eveniet architecto"
}

https://jsonplaceholder.typicode.com/posts/3
Content of URL 'https://jsonplaceholder.typicode.com/posts/3':
{
  "userId": 1,
  "id": 3,
  "title": "ea molestias quasi exercitationem repellat qui ipsa sit aut",
  "body": "et iusto sed quo iure\nvoluptatem occaecati omnis eligendi aut ad\nvoluptatem doloribus vel accusantium quis pariatur\nmolestiae porro eius odio et labore et velit aut"
}

 
Input the URLs (one URL per line, press Enter to complete):
https://jsonplaceholder.typicode.com/posts/4
Content of URL 'https://jsonplaceholder.typicode.com/posts/4':
{
  "userId": 1,
  "id": 4,
  "title": "eum et est occaecati",
  "body": "ullam et saepe reiciendis voluptatem adipisci\nsit amet autem assumenda provident rerum culpa\nquis hic commodi nesciunt rem tenetur doloremque ipsam iure\nquis sunt voluptatem rerum illo velit"
}

https://jsonplaceholder.typicode.com/posts/101
Error accessing URL: The remote server returned an error: (404) Not Found.

Explanation:

In the above exercise,

• The "Main()" method prompts the user to input URLs, one URL per line. The program reads URLs until the user presses Enter without entering any URL.
• Inside the Main method, the URLs are passed to the DownloadContent method for downloading and displaying the content.
• The DownloadContent method uses the WebClient class to download the given URL content using the DownloadString method.
• If any exception occurs during the download, such as a WebException indicating an inaccessible URL, it is caught in the catch block in the "Main()" method. An appropriate error message is displayed.
• Any other exceptions are caught by the generic catch block in the Main method, and a general error message is displayed.
• The downloaded content is displayed using Console.WriteLine.

Flowchart:

C# Sharp Code Editor:

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