Scrape web page contents

Question

I am developing a project, for which I want to scrape the contents of a website in the background and get some limited content from that scraped website. For example, in my page I have "userid" and "password" fields, by using those I will access my mail and scrape my inbox contents and display it in my page.

I done the above by using javascript alone. But when I click the sign in button the URL of my page (http://localhost/web/Login.html) is changed to the URL (http://mail.in.com/mails/inbox.php?nomail=....) which I am scraped. But I scrap the details without changing my url.

Solution 1

Definitely go with PHP Simple HTML DOM Parser. It's fast, easy and super flexible. It basically sticks an entire HTML page in an object then you can access any element from that object.

Like the example of the official site, to get all links on the main Google page:

// Create DOM from URL or file
$html = file_get_html('http://www.google.com/');

// Find all images 
foreach($html->find('img') as $element) 
       echo $element->src . '<br>';

// Find all links 
foreach($html->find('a') as $element) 
       echo $element->href . '<br>';

Solution 2

The HTTP Request

First, you make an HTTP request to get the content of the page. There are several ways to do that.

fopen

The most basic way to send an HTTP request, is to use fopen. A main advantage is that you can set how many characters are read at a time, which can be useful when reading very large files. It's not the easiest thing to do correctly, though, and it's not recommended to do this unless you're reading very large files and fear running into memory issues.

$fp = fopen("http://www.4wtech.com/csp/web/Employee/Login.csp", "rb");
if (FALSE === $fp) {
    exit("Failed to open stream to URL");
}

$result = '';

while (!feof($fp)) {
    $result .= fread($fp, 8192);
}
fclose($fp);
echo $result;

file_get_contents

The easiest way, is just using file_get_contents. If does more or less the same as fopen, but you have less options to choose from. A main advantage here is that it requires but one line of code.

$result = file_get_contents('http://www.4wtech.com/csp/web/Employee/Login.csp');
echo $result;

sockets

If you need more control of what headers are sent to the server, you can use sockets, in combination with fopen.

$fp = fsockopen("www.4wtech.com/csp/web/Employee/Login.csp", 80, $errno, $errstr, 30);
if (!$fp) {
    $result = "$errstr ($errno)<br />\n";
} else {
    $result = '';
    $out = "GET / HTTP/1.1\r\n";
    $out .= "Host: www.4wtech.com/csp/web/Employee/Login.csp\r\n";
    $out .= "Connection: Close\r\n\r\n";
    fwrite($fp, $out);
    while (!feof($fp)) {
        $result .= fgets($fp, 128);
    }
    fclose($fp);
}
echo $result;

streams

Alternatively, you can also use streams. Streams are similar to sockets and can be used in combination with both fopen and file_get_contents.

$opts = array(
  'http'=>array(
    'method'=>"GET",
    'header'=>"Accept-language: en\r\n" .
              "Cookie: foo=bar\r\n"
  )
);

$context = stream_context_create($opts);

$result = file_get_contents('http://www.4wtech.com/csp/web/Employee/Login.csp', false, $context);
echo result;

cURL

If your server supports cURL (it usually does), it is recommended to use cURL. A key advantage of using cURL, is that it relies on a popular C library commonly used in other programming languages. It also provides a convenient way for creating request headers, and auto-parses response headers, with a simple interface in case of errors.

$defaults = array( 
    CURLOPT_URL, "http://www.4wtech.com/csp/web/Employee/Login.csp"
    CURLOPT_HEADER=> 0
);

$ch = curl_init(); 
curl_setopt_array($ch, ($options + $defaults)); 
if( ! $result = curl_exec($ch)) { 
    trigger_error(curl_error($ch)); 
} 
curl_close($ch); 
echo $result; 

Libraries

Alternatively, you can use one of many PHP libraries. I wouldn't recommend using a library, though, as it's likely to be overkill. In most cases, you're better off writing your own HTTP class using cURL under the hood.

---

The HTML parsing

PHP has a convenient way to load any HTML into a DOMDocument.

$pagecontent = file_get_contents('http://www.4wtech.com/csp/web/Employee/Login.csp');
$doc = new DOMDocument();
$doc->loadHTML($pagecontent);
echo $doc->saveHTML();

Unfortunately, PHP support for HTML5 is limited. If you run into errors trying to parse your page content, consider using a third party library. For that, I can recommend Masterminds/html5-php. Parsing an HTML file with this library is very similar to parsing an HTML file with DOMDocument.

use Masterminds\HTML5;

$pagecontent = file_get_contents('http://www.4wtech.com/csp/web/Employee/Login.csp');
$html5 = new HTML5();
$dom = $html5->loadHTML($html);
echo $html5->saveHTML($dom);

Alternatively, you can use eg. my library PHPPowertools/DOM-Query. It uses customized version of Masterminds/html5-php under the hood parsing an HTML5 string into a DomDocument and symfony/DomCrawler for conversion of CSS selectors to XPath selectors. It always uses the same DomDocument, even when passing one object to another, to ensure decent performance.

namespace PowerTools;

// Get file content
$pagecontent = file_get_contents( 'http://www.4wtech.com/csp/web/Employee/Login.csp' );

// Define your DOMCrawler based on file string
$H = new DOM_Query( $pagecontent );

// Define your DOMCrawler based on an existing DOM_Query instance
$H = new DOM_Query( $H->select('body') );

// Passing a string (CSS selector)
$s = $H->select( 'div.foo' );

// Passing an element object (DOM Element)
$s = $H->select( $documentBody );

// Passing a DOM Query object
$s = $H->select( $H->select('p + p') );

// Select the body tag
$body = $H->select('body');

// Combine different classes as one selector to get all site blocks
$siteblocks = $body->select('.site-header, .masthead, .site-body, .site-footer');

// Nest your methods just like you would with jQuery
$siteblocks->select('button')->add('span')->addClass('icon icon-printer');

// Use a lambda function to set the text of all site blocks
$siteblocks->text(function( $i, $val) {
    return $i . " - " . $val->attr('class');
});

// Append the following HTML to all site blocks
$siteblocks->append('<div class="site-center"></div>');

// Use a descendant selector to select the site's footer
$sitefooter = $body->select('.site-footer > .site-center');

// Set some attributes for the site's footer
$sitefooter->attr(array('id' => 'aweeesome', 'data-val' => 'see'));

// Use a lambda function to set the attributes of all site blocks
$siteblocks->attr('data-val', function( $i, $val) {
    return $i . " - " . $val->attr('class') . " - photo by Kelly Clark";
});

// Select the parent of the site's footer
$sitefooterparent = $sitefooter->parent();

// Remove the class of all i-tags within the site's footer's parent
$sitefooterparent->select('i')->removeAttr('class');

// Wrap the site's footer within two nex selectors
$sitefooter->wrap('<section><div class="footer-wrapper"></div></section>');