[Beginner] Programming Challenge: 4

[JupiterV2]

It works, it does what is asked of it. It doesn't handle poor user input all that well though.

#!/bin/sh

target_site="http://laroza.freehostia.com/home/index.php"
temp_file=/tmp/www.$$

trap 'rm -f $temp_file' EXIT

if [ "$1" != "" ]; then 
    target_site=$1
fi

echo "Attempting to acquire file: $target_site"
wget -q $target_site -O $temp_file

if [ $? ]; then
    echo "Failed to aquire file: $target_site"
    exit 1
fi

title="$(grep '<title>' $temp_file | sed 's/<\.title>//' | sed 's/<\/title>//')"

file_ext=${target_site##*.}
cp -f $temp_file "$title.$file_ext"

exit 0 

[RobOrr]

Here's my code. Larger than it strictly needs to be, but mostly due to my exception handling and user interface.

#!/usr/bin/python
#Filename: challenge4.py
#Author: Robert Orr

import sys
import urllib2

print '\nWelcome to the WebPage Download Program.\nIf you wish to exit, \
please type exit at the prompt.'
print '--------------------------------------------------------'
url = raw_input('Please enter the URL you wish to download source code from:\n')

if url == 'exit':
    print 'Thankyou for using this program.'
    sys.exit()

#open the url file if it is a valid url
try:    
    webpage = urllib2.urlopen(url)
except urllib2.URLError:
    print 'Please enter a working URL next time.'
    sys.exit()
except ValueError:
    print 'Incorrect format. Please enter a URL next time.'
    sys.exit()

#create the local file and transfer the data over.
localpage = file('index.xhtml', 'w')
transferdata = webpage.read()
localpage.write(transferdata)

webpage.close()
localpage.close()

print '\nThankyou for using this program.'
print '%s is now stored in index.xhtml.' % url 

[texaswriter]

Most basic, in C#, requires a valid html address including http:// ...

This does virtually no validation, but it works if valid html addresses are entered, 100%. This I compile in Monodevelop, I don't think anything special is required to compile.

using System;
using System.Net;

class MainClass
{
    public static void Main (string[] args)
    {
        WebClient client = new WebClient();
        int i = 0;
        string filebase = "wgetted - ";
        string filename;
        
        foreach(string arg in args)
        {
            Console.WriteLine("{0}", arg);
            client.DownloadFile(arg, filebase+i.ToString());
            i++;
        }
        
    }
} 

[xSaintFunkyx]

Way too late. Just wanted the comments if anyone had any...

import java.net.*;
import java.io.*;
import javax.swing.*;

public class URLWriter {
    public static void main(String[] args) throws Exception {
           
        String inputUrl = JOptionPane.showInputDialog("Please enter the url you wish to read: ");
        URL url = new URL(inputUrl);
        URLConnection uC = url.openConnection();
        BufferedReader in = new BufferedReader(
                                new InputStreamReader(
                                uC.getInputStream()));
        String inputLine;

        PrintWriter outFile = new PrintWriter("HTMLFILE.txt");    
          
        System.out.println("Writing to file...");
        while ((inputLine = in.readLine()) != null) 
        {
            outFile.println(inputLine);
        }
        System.out.println("\nDone.");
        in.close();
        outFile.close();
    }
}

Vers. 1.1

import java.net.*;
import java.io.*;
import javax.swing.*;

public class URLWriter {
    public static void main(String[] args) throws Exception {
           
          boolean valid = false;          
          while (!(valid))
          {      
              try
              {    
                   String inputUrl = JOptionPane.showInputDialog("Please enter the url you wish to read: ");
                   URL url = new URL(inputUrl);
                   URLConnection yc = url.openConnection();
                   valid = true; // if connection is succesful    
                   BufferedReader in = new BufferedReader(
                                        new InputStreamReader(
                                        yc.getInputStream()));        
                   String inputLine;
                   PrintWriter outFile = new PrintWriter("HTMLFILE.txt");    
                  
                   System.out.println("Writing to file...");
                   while ((inputLine = in.readLine()) != null) 
                   {
                       outFile.println(inputLine);
                   }
                   System.out.println("\nDone.");
                   in.close();
                   outFile.close();            
                  
              }
              catch(MalformedURLException e)
              {
                  JOptionPane.showMessageDialog(null, "Please enter a valid url in the format - http://theurladdresshere/");

              }
          }
          
     }
}

[CuracaoThe]

Written in Ruby:

require 'open-uri'

module PageScrape

  def self.start_scraping(url="http://www.tomayko.com/")
    # Either open an url from command line argument 
    # or, if no argument provided, open a default url.
    page = open(ARGV[0] || url)

    # Default filename.
    filename = "index"

    # Parse webpage to find a title. If no title
    # provided, then use default filename.
    page.readlines.each do |line|
      filename = $1 if line.match(/<title>(.*)<\/title>/)
    end

    page.rewind
    File.open("#{filename}.xhtml", "w+") do |f|
      f.puts page.readlines.join
    end
  end
  
end

PageScrape.start_scraping 

[CoyleTrydan]

I know I'm a little late to the party here, but I'm working on learning Python, and hope to be able to contribute some in the future. This seems like a great way to start towards that goal. Sorry if I'm necro-ing something that I'm not supposed to. I'm not sure if I should do these all sequentially, or jump up to some of the later challenges.

Here is my Challenge 4. I like to separate things out into functions, but I'm not sure if doing so like I have is good form. I'd love feedback on that. I also tried to get exception handling in there, and it seems to work, but it just doesn't feel quite right...

Thanks for any feedback! Not sure if anyone will even see this...

from __future__ import print_function
import urllib2

def getWeb(url):
    try:    
        site = urllib2.urlopen(url)
        source = site.read()
        return(source)
    except urllib2.URLError:
        print("The page was unable to be accessed.")
        
def writeFile(source):
    try:    
        file = open("index.xhtml", "w")
        file.write(source)
        file.close()
    except IOError:
        print("The file was not able to be saved.")

def selectSite():
        url = raw_input("Please enter a URL:")
        return(url)
        
def main():
    url = selectSite()
    
    while True:    
        try:    
            source = getWeb(url)
            writeFile(source)
            print("The page was successfully saved.")
            break
        except ValueError:
            print("That is not a valid URL.")
            url = selectSite()

main() 

[r-senior]

I like to separate things out into functions, but I'm not sure if doing so like I have is good form. I'd love feedback on that. I also tried to get exception handling in there, and it seems to work, but it just doesn't feel quite right...

I found both your programs easy to read and understand largely because of the way you have separated them into individual functions that each have a clear purpose. You could work on the names (functions and variables) a little bit to make the code that calls them read even more clearly but the structure is good IMO.

You might want to look more closely at your error handling of the file in this submission, in particular whether you need a finally block and whether your error message is accurate. Or consider the 'with' statement.

In your other submission, I found your checkGuess function and while loop a bit cumbersome. Also, checking for an out of range input would be better handled with simple loops and conditionals rather than assert and exceptions IMO.

Icing on the cake would be some docstrings and perhaps choose to follow the PEP8 Python style guide more rigorously. Tools like pylint are very useful for advising you about code quality in that respect.

[shadyWilliams]

Hi all,

First things first, first post here on Ubuntu forums!

Second, I know I am way too late to enter the contest, but I am using these beginner exercises to learn C#. Here is what I came up with:


C# (C-Sharp)

using System;using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Net;


namespace ProgramChallenge4
{
    class ProgramChallenge4
    {
        static void Main(string[] args)
        {
            bool keepRunning = true;
            string url = "";
            while (keepRunning)
            {
                url = SelectSite();
                UpdateURL(ref url);
                try
                {
                    DownloadSite(ref url);
                    keepRunning = false;
                }
                catch (Exception)
                {
                    Console.WriteLine("You've entered an invalid URL =/");
                }
            }
            Console.WriteLine(url + " downloaded and saved!");
            Console.ReadLine();
        }


        public static string SelectSite()
        {
            Console.WriteLine("Please enter a valid URL: ");
            string url = Console.ReadLine();
            return url;
        }


        public static string UpdateURL(ref string url)
        {
            url = url.Trim();
            if (url.IndexOf("http://", 0) != 0)
                url = "http://" + url;
            return url;
        }


        public static string DownloadSite(ref string url)
        {
                WebClient wc = new WebClient();
                wc.DownloadFile(url, @"C:\Users\Will\Desktop\Programming Material\Challenges\Program Challenge 4\index.html");
                return url;
        }


    }
}