Problem with strtotime in PHP

Today I found an interesting issue. Please try this following PHP code:
print strtotime("18/03/2012 06:08 am");
I didn't see any output. Then I looked at the documentation and found the following line:

Dates in the m/d/y or d-m-y formats are disambiguated by looking at the separator between the various components: if the separator is a slash (/), then the American m/d/y is assumed; whereas if the separator is a dash (-) or a dot (.), then the European d-m-y format is assumed.

So I had to replace "/" with "-" using str_replace and that worked!
print strtotime("18-03-2012 06:08 am");
Output:
1332029280

Phone Number Extractor in PHP

Here is a function to parse the content of a web page and extract phone / fax numbers (USA only). Regular expression is used to parse phone numbers.

 function extract_phone_numbers ($html_content)    
 {    
     $html_content = preg_replace("/[\s\+\-\(\)\.]/", "", $html_content);    
     $ara = array();    
     if (preg_match_all('/\D(\d{10})\D/', $html_content, $data)) {        
         $ara = array_unique($data[1]);        
     }    
     if (preg_match_all('/1(\d{10})\D/', $html_content, $data)) {        
         $ara = array_unique(array_merge($ara, $data[1]));    
     }    
     if (preg_match_all('/^(\d{10})$/', $html_content, $data)) {        
         $ara = array_unique(array_merge($ara, $data[1]));    
     }    
     return $ara;    
 }    

Email extractor in PHP using regex

Today, I am sharing my PHP code that extracts email address from html source of an URL. It uses regular expression to parse email address.

 function extract_email_addresses ($html_source)    
 {    
     $html_source = str_replace("(at)", "@", $html_source);    
     $html_source = str_replace("[at]", "@", $html_source);    
     $html_source = str_replace("(dot)", ".", $html_source);    
     $html_source = str_replace("[dot]", ".", $html_source);    
     $html_source = strtolower($html_source);    
     $ara = array();    
     if (preg_match_all('/([_a-z0-9-]+(\.[_a-z0-9-]+)*@[a-z0-9-]+(\.[a-z0-9-]+)*(\.[a-z]{2,3}))/', $html_source, $data)) {        
         $ara = array_unique($data[1]);    
     }    
     return $ara;    
 }    

Please share your thoughts to improve the function.

A simple crawler in Java

So far I have written crawlers in many languages (PHP, Perl, Python, C#). Recently I wrote another one in Java. This is a simple spider / crawler, that gets the html source and extracts all the URLs from that source and then checks the HTTP response of those URLs.

Steps:

1. Get the URL from user (as command line input).

2. Get the html source code of that URL (using the function getUrlContent(url)).

3. Get all the hyper-links from the html source code (using the function getHyperlinks(content)).

4. For each of the URLs extracted from html source, get the HTTP Response code (using the function getHTTPResponseCode(url)).

Here is the full code:

 import java.io.BufferedReader;    
 import java.io.IOException;    
 import java.io.InputStreamReader;    
 import java.io.FileWriter;    
 import java.io.BufferedWriter;    
 import java.net.HttpURLConnection;    
 import java.net.URL;    
 import java.net.SocketTimeoutException;    
 import java.net.UnknownHostException;    
 import java.util.ArrayList;    
 import java.util.regex.Matcher;    
 import java.util.regex.Pattern;    
 public class Checker {    
     public static void main(String args[]) throws Exception    
     {    
         String url = null;    
         if (args.length > 0) {    
             url = args[0];    
             System.out.println(url);    
         }    
         else {    
             System.out.println("Please enter the URL as a command line parameter.");    
             return;    
         }    
         String content = getUrlContent(url);    
         ArrayList<String> links = getHyperlinks(content);    
         FileWriter fstream = new FileWriter("out.txt");    
         BufferedWriter out = new BufferedWriter(fstream);    
         int status;    
         for (int i = 0; i < links.size(); i++) {    
             url = (String) links.get(i);    
             System.out.println(url);    
             status = getHTTPResponseCode(url);    
             if (status != 200) {    
                 if (status > 0) {    
                     out.write(url + ", HTTP Response Code: " + status + "\n");    
                 }    
                 else {    
                     out.write(url + ", Unknown Error\n");    
                 }    
             }                
         }    
         out.close();    
     }    
     private static ArrayList<String> getHyperlinks(String html)    
     {    
         ArrayList<String> links = new ArrayList<String>();    
         Pattern p = Pattern.compile("<a [^<>]*?href=\"(http.*?)\"");    
         Matcher m = p.matcher(html);    
         while(m.find()) {    
             links.add(m.group(1));    
         }    
         p = Pattern.compile("<a [^<>]*?href='(http.*?)'");    
         m = p.matcher(html);    
         while(m.find()) {    
             links.add(m.group(1));    
         }    
         return links;    
     }    
     private static String getUrlContent(String targetUrl) throws Exception    
     {    
         HttpURLConnection connection = null;    
         BufferedReader br = null;    
         StringBuilder sb = null;    
         String line = null;    
         String content = null;    
         URL target = null;    
         try {    
             target = new URL(targetUrl);    
             connection = (HttpURLConnection)target.openConnection();    
             connection.setRequestMethod("GET");    
             connection.setReadTimeout(30 * 1000); // timeout 30 seconds    
             connection.connect();    
             br = new BufferedReader(new InputStreamReader(connection.getInputStream()));    
             sb = new StringBuilder();    
             while ((line = br.readLine()) != null) {    
                 sb.append(line);    
             }    
             content = sb.toString();    
         } catch (SocketTimeoutException e) {    
             System.out.println("Timed Out!");                
         } catch (UnknownHostException e) {    
             System.out.println("Unknown Host");    
         } catch (Exception e) {    
             System.out.println("Unknown Error");    
         }    
         finally {    
             connection.disconnect();    
             br = null;    
             sb = null;    
             connection = null;    
         }    
         return content;    
     }    
     private static int getHTTPResponseCode(String targetUrl) throws Exception    
     {    
         HttpURLConnection connection = null;    
         int response;    
         URL target = null;    
         try {    
             target = new URL(targetUrl);    
             connection = (HttpURLConnection)target.openConnection();    
             connection.setRequestMethod("GET");    
             connection.setReadTimeout(10 * 1000); // timeout 10 seconds    
             connection.connect();    
             response = ((HttpURLConnection) connection).getResponseCode();    
         } catch (SocketTimeoutException e) {    
             response = -100;    
         } catch (UnknownHostException e) {    
             response = -101;    
         }catch (Exception e) {    
             response = -102;    
         }    
         finally {    
             connection.disconnect();    
             connection = null;    
         }    
         return response;    
     }    
 }