Where To Precede The Tracking Url ?

Hi,

in practice you want to log the $url variable. Between line 202 and 246 the scripts initialize the variable, verifies if the url format is valid and finally it attemps to contact the server. Now you have to decide at which step you want to log, for example if you want separate logging for successful and failed requests do it after line 246, i.e. after this line:

$response = makeRequest($url);

and use the responseInfo index returned in the $response array to log the differences.

Bro,

Do me a favour.
Follow the following steps and give me your results:

1. Fire-up Xampp.
2. Create a folder "PROXY" in the "localhost". Then, create file: test.php
3. Add the following code into test.php:

https://github.com/joshdick/miniProxy/blob/master/miniProxy.php

1. Test the proxy script by navigating over to: C:\Xamp\htdocs\PROXY\test.php

What do you see ?
You see a page that looks like this:

Welcome to miniProxy!

miniProxy can be directly invoked like this: http://localhost:80/proxy/test.php?https://example.net

Or, you can simply enter a URL below:

1. Type the following url to proxify it:
   http://localhost:80/proxy/test.php?http://probloggerbook.com/

Now, hover your mouse over the "About the Book" but don't click it. What does the url get shown as ?
It gets shown as:
http://localhost:80/proxy/test.php?http://probloggerbook.com/about/

Note that the original url is:
http://probloggerbook.com/

But it gets shown to you by preceding: http://localhost:80/proxy/test.php?.

In other words, no matter what url you view via the proxy, it gets proxified by preceding "http://localhost:80/proxy/test.php?" onto the url. Like so:

http://localhost:80/proxy/test.php?http://probloggerbook.com/
http://localhost:80/proxy/test.php?http://ebay.com/

Those sites you are viewing do not host your http://localhost:80/proxy/test.php? links nor precede it but your proxy itself does it.
Now, as you can see the proxy is preceding "http://localhost:80/proxy/test.php?" in order to proxify your chosen url. But my idea is, instead of getting it to precede "http://localhost:80/proxy/test.php?", why don't we get it to precede "http://localhost:80/proxy/tracker.php?" instead. That way, our proxy tracker page script gets preceded and clicked in order for the tracker to log the user's clicked url (foreign domain) before forwarding the user to the proxified page http://localhost:80/proxy/test.php?somedomain.com.

Now, can you figure-out which part of the code to replace with what to get the script to start logging ?
I mean, which part in the script do we make changes so the script no longer precedes http://localhost:80/proxy/test.php?
but precedes instead:
http://localhost:80/proxy/tracker.php?
that redirects the user to:
http://localhost:80/proxy/test.php?somedomain.com

In short, the script should not directly forward the user to the proxified page (the page user wants to view) but forward him to the tracker page in the middle as a doorway page before redirecting to the final destination.

Anyone are welcome to make replies!

Those sites you are viewing do not host your http://localhost:80/proxy/test.php? links nor precede it but your proxy itself does it.
Now, as you can see the proxy is preceding "http://localhost:80/proxy/test.php?" in order to proxify your chosen url. But my idea is, instead of getting it to precede "http://localhost:80/proxy/test.php?", why don't we get it to precede "http://localhost:80/proxy/tracker.php?" instead.
Now, can you figure-out which part of the code to replace with what to get the script to start logging ?

Sorry, but tracker.php what should do? It's the same code of test.php? Then just rename the file. If it's different and you want to send people from script A (test.php) to script B (tracker.php), you just need a form whose action points to script B, but then what is the role of the proxy here? Once you are on the tracker script, the proxy won't work anymore as the execution is completed. If you want to mix the proxy with the tracker then rename test.php to tracker.php and include your tracking code inside this file.

I have already suggested where you can place the tracking code.

Also consider that you don't need a form to initialize the proxy script, just append a link to the file name with a ? and it will work fine. Anyway, see if you get other replies. Bye.

Bro,
Do me a favour.
Follow the following steps and give me your results

While regular contributors will help, this may be going above and beyond what you can expect. Keep your requests to small do-ables.

Cereal,

2 nights ago, I was thinking the same as you suggested now. To simply put the tracker code in the same file test.php that way both the proxy script and the tracker script are one.
I will try testing this now.

Thanks for confirming that it is possible. Another experienced programmer at another source was arguing that it's not possible and I just want to prove to him that it is possible.

Thank you for your reply.

Cereal,

I didn't bother adding any tracking url with the "?" like you suggested at the end of your previous reply as I saw it is not needed.
To jog your memory, the test.php is the main one page web proxy script.
And, i wanted to log all the pages the user visits.
You stated that $url contains the user's current page's url. To verify this is correct, I echoed $url and it echoed the url of the page I was in. So that means, you are correct in stating the $url contains the current url the user is in. So far, so good.
You told me to add my tracker code after line 246.
I added the following lines after line 246. That code, dumps the $url into "browsings" column in "users" tbl in mysql db.
But for some reason, the $url is not getting dumped into mysql (hence, technically, the logging has failed). I get no errors, though. Instead, I get mssg that the $url has been successfully saved into the db. Strange! What do you think is wrong ?

[code]

//DUMP THE CURRENT PAGE'S URL INTO MYSQL DB.

$conn = mysqli_connect("localhost", "root", "", "DB NAME WENT HERE");

if (!$conn) {
// message to use in development to see errors
die("Database error : " . mysqli_error($conn));

// user friendly message
// die("Database error.");
exit();
}

// Dump $url into db
$sql = "INSERT INTO users(browsings) VALUES('$url')";
    if($sql)
    {
        echo "Logged $url to db a success!";
    }
    else    
    {
            echo "Logging $url to db failed!";
    }

[/code]

I, even tried taking out the single quotes from the VALUES in the INSERT command. Like so:

$sql = "INSERT INTO users(browsings) VALUES($url)";

But no luck.

Full Code:

 <?php
/*
miniProxy - A simple PHP web proxy. <https://github.com/joshdick/miniProxy>
Written and maintained by Joshua Dick <http://joshdick.net>.
miniProxy is licensed under the GNU GPL v3 <http://www.gnu.org/licenses/gpl.html>.
*/
/****************************** START CONFIGURATION ******************************/
//To allow proxying any URL, set $whitelistPatterns to an empty array (the default).
//To only allow proxying of specific URLs (whitelist), add corresponding regular expressions
//to the $whitelistPatterns array. Enter the most specific patterns possible, to prevent possible abuse.
//You can optionally use the "getHostnamePattern()" helper function to build a regular expression that
//matches all URLs for a given hostname.
$whitelistPatterns = array(
  //Usage example: To support any URL at example.net, including sub-domains, uncomment the
  //line below (which is equivalent to [ @^https?://([a-z0-9-]+\.)*example\.net@i ]):
  //getHostnamePattern("example.net")
);
//To enable CORS (cross-origin resource sharing) for proxied sites, set $forceCORS to true.
$forceCORS = false;
//URL that will be used as an example in the instructional text on the miniProxy landing page,
//and that will be proxied when pressing the 'Proxy It!' button on the landing page
//if the URL form is left blank.
$exampleURL = 'https://example.net';
/****************************** END CONFIGURATION ******************************/
ob_start("ob_gzhandler");
if (version_compare(PHP_VERSION, "5.4.7", "<")) {
    die("miniProxy requires PHP version 5.4.7 or later.");
}
if (!function_exists("curl_init")) die("miniProxy requires PHP's cURL extension. Please install/enable it on your server and try again.");
//Helper function for use inside $whitelistPatterns.
//Returns a regex that matches all HTTP[S] URLs for a given hostname.
function getHostnamePattern($hostname) {
  $escapedHostname = str_replace(".", "\.", $hostname);
  return "@^https?://([a-z0-9-]+\.)*" . $escapedHostname . "@i";
}
//Helper function used to removes/unset keys from an associative array using case insensitive matching
function removeKeys(&$assoc, $keys2remove) {
  $keys = array_keys($assoc);
  $map = array();
  foreach ($keys as $key) {
     $map[strtolower($key)] = $key;
  }
  foreach ($keys2remove as $key) {
    $key = strtolower($key);
    if (isset($map[$key])) {
       unset($assoc[$map[$key]]);
    }
  }
}
if (!function_exists("getallheaders")) {
  //Adapted from http://www.php.net/manual/en/function.getallheaders.php#99814
  function getallheaders() {
    $result = array();
    foreach($_SERVER as $key => $value) {
      if (substr($key, 0, 5) == "HTTP_") {
        $key = str_replace(" ", "-", ucwords(strtolower(str_replace("_", " ", substr($key, 5)))));
        $result[$key] = $value;
      }
    }
    return $result;
  }
}
$usingDefaultPort =  (!isset($_SERVER["HTTPS"]) && $_SERVER["SERVER_PORT"] === 80) || (isset($_SERVER["HTTPS"]) && $_SERVER["SERVER_PORT"] === 443);
$prefixPort = $usingDefaultPort ? "" : ":" . $_SERVER["SERVER_PORT"];
//Use HTTP_HOST to support client-configured DNS (instead of SERVER_NAME), but remove the port if one is present
$prefixHost = $_SERVER["HTTP_HOST"];
$prefixHost = strpos($prefixHost, ":") ? implode(":", explode(":", $_SERVER["HTTP_HOST"], -1)) : $prefixHost;
define("PROXY_PREFIX", "http" . (isset($_SERVER["HTTPS"]) ? "s" : "") . "://" . $prefixHost . $prefixPort . $_SERVER["SCRIPT_NAME"] . "?");
//Makes an HTTP request via cURL, using request data that was passed directly to this script.
function makeRequest($url) {
  //Tell cURL to make the request using the brower's user-agent if there is one, or a fallback user-agent otherwise.
  $user_agent = $_SERVER["HTTP_USER_AGENT"];
  if (empty($user_agent)) {
    $user_agent = "Mozilla/5.0 (compatible; miniProxy)";
  }
  $ch = curl_init();
  curl_setopt($ch, CURLOPT_USERAGENT, $user_agent);
  //Get ready to proxy the browser's request headers...
  $browserRequestHeaders = getallheaders();
  //...but let cURL set some headers on its own.
  removeKeys($browserRequestHeaders, array(
    "Host",
    "Content-Length",
    "Accept-Encoding" //Throw away the browser's Accept-Encoding header if any and let cURL make the request using gzip if possible.
  ));
  curl_setopt($ch, CURLOPT_ENCODING, "");
  //Transform the associative array from getallheaders() into an
  //indexed array of header strings to be passed to cURL.
  $curlRequestHeaders = array();
  foreach ($browserRequestHeaders as $name => $value) {
    $curlRequestHeaders[] = $name . ": " . $value;
  }
  curl_setopt($ch, CURLOPT_HTTPHEADER, $curlRequestHeaders);
  //Proxy any received GET/POST/PUT data.
  switch ($_SERVER["REQUEST_METHOD"]) {
    case "POST":
      curl_setopt($ch, CURLOPT_POST, true);
      //For some reason, $HTTP_RAW_POST_DATA isn't working as documented at
      //http://php.net/manual/en/reserved.variables.httprawpostdata.php
      //but the php://input method works. This is likely to be flaky
      //across different server environments.
      //More info here: http://stackoverflow.com/questions/8899239/http-raw-post-data-not-being-populated-after-upgrade-to-php-5-3
      //If the miniProxyFormAction field appears in the POST data, remove it so the destination server doesn't receive it.
      $postData = Array();
      parse_str(file_get_contents("php://input"), $postData);
      if (isset($postData["miniProxyFormAction"])) {
        unset($postData["miniProxyFormAction"]);
      }
      curl_setopt($ch, CURLOPT_POSTFIELDS, http_build_query($postData));
    break;
    case "PUT":
      curl_setopt($ch, CURLOPT_PUT, true);
      curl_setopt($ch, CURLOPT_INFILE, fopen("php://input", "r"));
    break;
  }
  //Other cURL options.
  curl_setopt($ch, CURLOPT_HEADER, true);
  curl_setopt($ch, CURLOPT_FOLLOWLOCATION, true);
  curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
  //Set the request URL.
  curl_setopt($ch, CURLOPT_URL, $url);
  //Make the request.
  $response = curl_exec($ch);
  $responseInfo = curl_getinfo($ch);
  $headerSize = curl_getinfo($ch, CURLINFO_HEADER_SIZE);
  curl_close($ch);
  //Setting CURLOPT_HEADER to true above forces the response headers and body
  //to be output together--separate them.
  $responseHeaders = substr($response, 0, $headerSize);
  $responseBody = substr($response, $headerSize);
  return array("headers" => $responseHeaders, "body" => $responseBody, "responseInfo" => $responseInfo);
}
//Converts relative URLs to absolute ones, given a base URL.
//Modified version of code found at http://nashruddin.com/PHP_Script_for_Converting_Relative_to_Absolute_URL
function rel2abs($rel, $base) {
  if (empty($rel)) $rel = ".";
  if (parse_url($rel, PHP_URL_SCHEME) != "" || strpos($rel, "//") === 0) return $rel; //Return if already an absolute URL
  if ($rel[0] == "#" || $rel[0] == "?") return $base.$rel; //Queries and anchors
  extract(parse_url($base)); //Parse base URL and convert to local variables: $scheme, $host, $path
  $path = isset($path) ? preg_replace("#/[^/]*$#", "", $path) : "/"; //Remove non-directory element from path
  if ($rel[0] == "/") $path = ""; //Destroy path if relative url points to root
  $port = isset($port) && $port != 80 ? ":" . $port : "";
  $auth = "";
  if (isset($user)) {
    $auth = $user;
    if (isset($pass)) {
      $auth .= ":" . $pass;
    }
    $auth .= "@";
  }
  $abs = "$auth$host$port$path/$rel"; //Dirty absolute URL
  for ($n = 1; $n > 0; $abs = preg_replace(array("#(/\.?/)#", "#/(?!\.\.)[^/]+/\.\./#"), "/", $abs, -1, $n)) {} //Replace '//' or '/./' or '/foo/../' with '/'
  return $scheme . "://" . $abs; //Absolute URL is ready.
}
//Proxify contents of url() references in blocks of CSS text.
function proxifyCSS($css, $baseURL) {
  // Add a "url()" wrapper to any CSS @import rules that only specify a URL without the wrapper,
  // so that they're proxified when searching for "url()" wrappers below.
  $sourceLines = explode("\n", $css);
  $normalizedLines = [];
  foreach ($sourceLines as $line) {
    if (preg_match("/@import\s+url/i", $line)) {
      $normalizedLines[] = $line;
    } else {
      $normalizedLines[] = preg_replace_callback(
        "/(@import\s+)([^;\s]+)([\s;])/i",
        function($matches) use ($baseURL) {
          return $matches[1] . "url(" . $matches[2] . ")" . $matches[3];
        },
        $line);
    }
  }
  $normalizedCSS = implode("\n", $normalizedLines);
  return preg_replace_callback(
    "/url\((.*?)\)/i",
    function($matches) use ($baseURL) {
        $url = $matches[1];
        //Remove any surrounding single or double quotes from the URL so it can be passed to rel2abs - the quotes are optional in CSS
        //Assume that if there is a leading quote then there should be a trailing quote, so just use trim() to remove them
        if (strpos($url, "'") === 0) {
          $url = trim($url, "'");
        }
        if (strpos($url, "\"") === 0) {
          $url = trim($url, "\"");
        }
        if (stripos($url, "data:") === 0) return "url(" . $url . ")"; //The URL isn't an HTTP URL but is actual binary data. Don't proxify it.
        return "url(" . PROXY_PREFIX . rel2abs($url, $baseURL) . ")";
    },
    $normalizedCSS);
}
//Proxify "srcset" attributes (normally associated with <img> tags.)
function proxifySrcset($srcset, $baseURL) {
  $sources = array_map("trim", explode(",", $srcset)); //Split all contents by comma and trim each value
  $proxifiedSources = array_map(function($source) use ($baseURL) {
    $components = array_map("trim", str_split($source, strrpos($source, " "))); //Split by last space and trim
    $components[0] = PROXY_PREFIX . rel2abs(ltrim($components[0], "/"), $baseURL); //First component of the split source string should be an image URL; proxify it
    return implode($components, " "); //Recombine the components into a single source
  }, $sources);
  $proxifiedSrcset = implode(", ", $proxifiedSources); //Recombine the sources into a single "srcset"
  return $proxifiedSrcset;
}
//Extract and sanitize the requested URL, handling cases where forms have been rewritten to point to the proxy.
if (isset($_POST["miniProxyFormAction"])) {
  $url = $_POST["miniProxyFormAction"];
  unset($_POST["miniProxyFormAction"]);
} else {
  $queryParams = Array();
  parse_str($_SERVER["QUERY_STRING"], $queryParams);
  //If the miniProxyFormAction field appears in the query string, make $url start with its value, and rebuild the the query string without it.
  if (isset($queryParams["miniProxyFormAction"])) {
    $formAction = $queryParams["miniProxyFormAction"];
    unset($queryParams["miniProxyFormAction"]);
    $url = $formAction . "?" . http_build_query($queryParams);
  } else {
    $url = substr($_SERVER["REQUEST_URI"], strlen($_SERVER["SCRIPT_NAME"]) + 1);
  }
}
if (empty($url)) {
    die("<html><head><title>miniProxy</title></head><body><h1>Welcome to miniProxy!</h1>miniProxy can be directly invoked like this: <a href=\"" . PROXY_PREFIX . $exampleURL . "\">" . PROXY_PREFIX . $exampleURL . "</a><br /><br />Or, you can simply enter a URL below:<br /><br /><form onsubmit=\"if (document.getElementById('site').value) { window.location.href='" . PROXY_PREFIX . "' + document.getElementById('site').value; return false; } else { window.location.href='" . PROXY_PREFIX . $exampleURL . "'; return false; } \"><input id=\"site\" type=\"text\" size=\"50\" /><input type=\"submit\" value=\"Proxy It!\" /></form></body></html>");
} else if (strpos($url, ":/") !== strpos($url, "://")) {
    //Work around the fact that some web servers (e.g. IIS 8.5) change double slashes appearing in the URL to a single slash.
    //See https://github.com/joshdick/miniProxy/pull/14
    $pos = strpos($url, ":/");
    $url = substr_replace($url, "://", $pos, strlen(":/"));
}
$scheme = parse_url($url, PHP_URL_SCHEME);
if (empty($scheme)) {
  //Assume that any supplied URLs starting with // are HTTP URLs.
  if (strpos($url, "//") === 0) {
    $url = "http:" . $url;
  }
} else if (!preg_match("/^https?$/i", $scheme)) {
    die('Error: Detected a "' . $scheme . '" URL. miniProxy exclusively supports http[s] URLs.');
}
//Validate the requested URL against the whitelist.
$urlIsValid = count($whitelistPatterns) === 0;
foreach ($whitelistPatterns as $pattern) {
  if (preg_match($pattern, $url)) {
    $urlIsValid = true;
    break;
  }
}
if (!$urlIsValid) {
  die("Error: The requested URL was disallowed by the server administrator.");
}
$response = makeRequest($url);

    //DUMP THE CURRENT PAGE'S URL INTO MYSQL DB.

    $conn = mysqli_connect("localhost", "root", "", "DB NAME WENT HERE");

    if (!$conn) {
    // message to use in development to see errors
    die("Database error : " . mysqli_error($conn));

    // user friendly message
    // die("Database error.");
    exit();
    }

    // Dump $url into db
    $sql = "INSERT INTO users(browsings) VALUES('$url')";
        if($sql)
        {
            echo "Logged $url to db a success!";
        }
        else    
        {
                echo "Logging $url to db failed!";
        }

$rawResponseHeaders = $response["headers"];
$responseBody = $response["body"];
$responseInfo = $response["responseInfo"];
echo "$responseInfo";
//If CURLOPT_FOLLOWLOCATION landed the proxy at a diferent URL than
//what was requested, explicitly redirect the proxy there.
$responseURL = $responseInfo["url"];
if ($responseURL !== $url) {
  header("Location: " . PROXY_PREFIX . $responseURL, true);
  exit(0);
}
//A regex that indicates which server response headers should be stripped out of the proxified response.
$header_blacklist_pattern = "/^Content-Length|^Transfer-Encoding|^Content-Encoding.*gzip/i";
//cURL can make multiple requests internally (for example, if CURLOPT_FOLLOWLOCATION is enabled), and reports
//headers for every request it makes. Only proxy the last set of received response headers,
//corresponding to the final request made by cURL for any given call to makeRequest().
$responseHeaderBlocks = array_filter(explode("\r\n\r\n", $rawResponseHeaders));
$lastHeaderBlock = end($responseHeaderBlocks);
$headerLines = explode("\r\n", $lastHeaderBlock);
foreach ($headerLines as $header) {
  $header = trim($header);
  if (!preg_match($header_blacklist_pattern, $header)) {
    header($header, false);
  }
}
//Prevent robots from indexing proxified pages
header("X-Robots-Tag: noindex, nofollow", true);
if ($forceCORS) {
  //This logic is based on code found at: http://stackoverflow.com/a/9866124/278810
  //CORS headers sent below may conflict with CORS headers from the original response,
  //so these headers are sent after the original response headers to ensure their values
  //are the ones that actually end up getting sent to the browser.
  //Explicit [ $replace = true ] is used for these headers even though this is PHP's default behavior.
  //Allow access from any origin.
  header("Access-Control-Allow-Origin: *", true);
  header("Access-Control-Allow-Credentials: true", true);
  //Handle CORS headers received during OPTIONS requests.
  if ($_SERVER["REQUEST_METHOD"] == "OPTIONS") {
    if (isset($_SERVER["HTTP_ACCESS_CONTROL_REQUEST_METHOD"])) {
      header("Access-Control-Allow-Methods: GET, POST, OPTIONS", true);
    }
    if (isset($_SERVER["HTTP_ACCESS_CONTROL_REQUEST_HEADERS"])) {
      header("Access-Control-Allow-Headers: {$_SERVER['HTTP_ACCESS_CONTROL_REQUEST_HEADERS']}", true);
    }
    //No further action is needed for OPTIONS requests.
    exit(0);
  }
}
$contentType = "";
if (isset($responseInfo["content_type"])) $contentType = $responseInfo["content_type"];
//This is presumably a web page, so attempt to proxify the DOM.
if (stripos($contentType, "text/html") !== false) {
  //Attempt to normalize character encoding.
  $detectedEncoding = mb_detect_encoding($responseBody, "UTF-8, ISO-8859-1");
  if ($detectedEncoding) {
    $responseBody = mb_convert_encoding($responseBody, "HTML-ENTITIES", $detectedEncoding);
  }
  //Parse the DOM.
  $doc = new DomDocument();
  @$doc->loadHTML($responseBody);
  $xpath = new DOMXPath($doc);
  //Rewrite forms so that their actions point back to the proxy.
  foreach($xpath->query("//form") as $form) {
    $method = $form->getAttribute("method");
    $action = $form->getAttribute("action");
    //If the form doesn't have an action, the action is the page itself.
    //Otherwise, change an existing action to an absolute version.
    $action = empty($action) ? $url : rel2abs($action, $url);
    //Rewrite the form action to point back at the proxy.
    $form->setAttribute("action", rtrim(PROXY_PREFIX, "?"));
    //Add a hidden form field that the proxy can later use to retreive the original form action.
    $actionInput = $doc->createDocumentFragment();
    $actionInput->appendXML('<input type="hidden" name="miniProxyFormAction" value="' . htmlspecialchars($action) . '" />');
    $form->appendChild($actionInput);
  }
  //Proxify <meta> tags with an 'http-equiv="refresh"' attribute.
  foreach ($xpath->query("//meta[@http-equiv]") as $element) {
    if (strcasecmp($element->getAttribute("http-equiv"), "refresh") === 0) {
      $content = $element->getAttribute("content");
      if (!empty($content)) {
        $splitContent = preg_split("/=/", $content);
        if (isset($splitContent[1])) {
          $element->setAttribute("content", $splitContent[0] . "=" . PROXY_PREFIX . rel2abs($splitContent[1], $url));
        }
      }
    }
  }
  //Profixy <style> tags.
  foreach($xpath->query("//style") as $style) {
    $style->nodeValue = proxifyCSS($style->nodeValue, $url);
  }
  //Proxify tags with a "style" attribute.
  foreach ($xpath->query("//*[@style]") as $element) {
    $element->setAttribute("style", proxifyCSS($element->getAttribute("style"), $url));
  }
  //Proxify "srcset" attributes in <img> tags.
  foreach ($xpath->query("//img[@srcset]") as $element) {
    $element->setAttribute("srcset", proxifySrcset($element->getAttribute("srcset"), $url));
  }
  //Proxify any of these attributes appearing in any tag.
  $proxifyAttributes = array("href", "src");
  foreach($proxifyAttributes as $attrName) {
    foreach($xpath->query("//*[@" . $attrName . "]") as $element) { //For every element with the given attribute...
      $attrContent = $element->getAttribute($attrName);
      if ($attrName == "href" && preg_match("/^(about|javascript|magnet|mailto):/i", $attrContent)) continue;
      $attrContent = rel2abs($attrContent, $url);
      $attrContent = PROXY_PREFIX . $attrContent;
      $element->setAttribute($attrName, $attrContent);
    }
  }
  //Attempt to force AJAX requests to be made through the proxy by
  //wrapping window.XMLHttpRequest.prototype.open in order to make
  //all request URLs absolute and point back to the proxy.
  //The rel2abs() JavaScript function serves the same purpose as the server-side one in this file,
  //but is used in the browser to ensure all AJAX request URLs are absolute and not relative.
  //Uses code from these sources:
  //http://stackoverflow.com/questions/7775767/javascript-overriding-xmlhttprequest-open
  //https://gist.github.com/1088850
  //TODO: This is obviously only useful for browsers that use XMLHttpRequest but
  //it's better than nothing.
  $head = $xpath->query("//head")->item(0);
  $body = $xpath->query("//body")->item(0);
  $prependElem = $head != NULL ? $head : $body;
  //Only bother trying to apply this hack if the DOM has a <head> or <body> element;
  //insert some JavaScript at the top of whichever is available first.
  //Protects against cases where the server sends a Content-Type of "text/html" when
  //what's coming back is most likely not actually HTML.
  //TODO: Do this check before attempting to do any sort of DOM parsing?
  if ($prependElem != NULL) {
    $scriptElem = $doc->createElement("script",
      '(function() {
        if (window.XMLHttpRequest) {
          function parseURI(url) {
            var m = String(url).replace(/^\s+|\s+$/g, "").match(/^([^:\/?#]+:)?(\/\/(?:[^:@]*(?::[^:@]*)?@)?(([^:\/?#]*)(?::(\d*))?))?([^?#]*)(\?[^#]*)?(#[\s\S]*)?/);
            // authority = "//" + user + ":" + pass "@" + hostname + ":" port
            return (m ? {
              href : m[0] || "",
              protocol : m[1] || "",
              authority: m[2] || "",
              host : m[3] || "",
              hostname : m[4] || "",
              port : m[5] || "",
              pathname : m[6] || "",
              search : m[7] || "",
              hash : m[8] || ""
            } : null);
          }
          function rel2abs(base, href) { // RFC 3986
            function removeDotSegments(input) {
              var output = [];
              input.replace(/^(\.\.?(\/|$))+/, "")
                .replace(/\/(\.(\/|$))+/g, "/")
                .replace(/\/\.\.$/, "/../")
                .replace(/\/?[^\/]*/g, function (p) {
                  if (p === "/..") {
                    output.pop();
                  } else {
                    output.push(p);
                  }
                });
              return output.join("").replace(/^\//, input.charAt(0) === "/" ? "/" : "");
            }
            href = parseURI(href || "");
            base = parseURI(base || "");
            return !href || !base ? null : (href.protocol || base.protocol) +
            (href.protocol || href.authority ? href.authority : base.authority) +
            removeDotSegments(href.protocol || href.authority || href.pathname.charAt(0) === "/" ? href.pathname : (href.pathname ? ((base.authority && !base.pathname ? "/" : "") + base.pathname.slice(0, base.pathname.lastIndexOf("/") + 1) + href.pathname) : base.pathname)) +
            (href.protocol || href.authority || href.pathname ? href.search : (href.search || base.search)) +
            href.hash;
          }
          var proxied = window.XMLHttpRequest.prototype.open;
          window.XMLHttpRequest.prototype.open = function() {
              if (arguments[1] !== null && arguments[1] !== undefined) {
                var url = arguments[1];
                url = rel2abs("' . $url . '", url);
                url = "' . PROXY_PREFIX . '" + url;
                arguments[1] = url;
              }
              return proxied.apply(this, [].slice.call(arguments));
          };
        }
      })();'
    );
    $scriptElem->setAttribute("type", "text/javascript");
    $prependElem->insertBefore($scriptElem, $prependElem->firstChild);
  }
  echo "<!-- Proxified page constructed by miniProxy -->\n" . $doc->saveHTML();
} else if (stripos($contentType, "text/css") !== false) { //This is CSS, so proxify url() references.
  echo proxifyCSS($responseBody, $url);
} else { //This isn't a web page or CSS, so serve unmodified through the proxy with the correct headers (images, JavaScript, etc.)
  header("Content-Length: " . strlen($responseBody), true);
  echo $responseBody;
}

I, even tried taking out the single quotes from the VALUES in the INSERT command. Like so:
$sql = "INSERT INTO users(browsings) VALUES($url)";

Single quotes are necessary as $url is a string, so:

$sql = "INSERT INTO users(browsings) VALUES('$url')";

$sql is a string too, it has not been submitted to mysqli_query() yet, so, instead of:

if($sql)

do:

if(TRUE === $conn->query($sql))

Cereal,

Thanks.
That is excellent. It is working now. But one problem which I'll mention later.
I am actually learning procedural style and mysqli at the moment as most beginenr tutorials are based on them. later, will get into oop and pdo.
All my other scripts (mysqli and procedural) worked like this:

if($sql)

So, why didn't it tonight ?
Why it only worked with oop style ?
if(TRUE === $conn->query($sql))
Is it because most part of the script is oop ?

Anyway, even though the proxified url is getting logged (dumped into mysql db), it is not actually dumping just the url I am visiting but more. Infact, it's logging other links on my visited page.
Run the script yourself on Xampp on your end and see for yourself.

When I navigate to ebay.com, the following are getting logged into db:

https://ir.ebaystatic.com/pictures/aw/home/feed/sprite_201505141202_opt.png
https://ir.ebaystatic.com/pictures/aw/home/feed/sprite_201505141202_opt.png
https://ir.ebaystatic.com/pictures/aw/pics/s.gif
https://ir.ebaystatic.com/pictures/aw/pics/cmp/ds3/sprds3_18.png
http://rover.ebay.com/roversync/?site=0&stg=1&mpt=1494881501430
http://www.ebay.com/

Look at the final url. That is the one I was visiting and so this got logged. That is good. But why did it log the others ? The img links and one link twice ? Is it because the browser called those links to load the images (even though I did not click them) ?
If you were in my position, how would you code it so the img or video links (that are residing on the visited page) do not get logged but only the url of the page that you visit by clicking it's link or by directly typing the url on your browser ?
From my example, only the following should get logged since I was only on that page:
http://www.ebay.com/

All my other scripts (mysqli and procedural) worked like this:
if($sql)
So, why didn't it tonight ?
Why it only worked with oop style ?
if(TRUE === $conn->query($sql))
Is it because most part of the script is oop ?

No, it happens because $sql is a string, you could either do:

$conn->query($sql);

Or procedural:

$sql = mysqli_query($conn, "INSERT QUERY HERE");

With the procedural then your IF statement would work fine:

if($sql)

as the result of the query is assigned to the $sql variable. In my example I just skipped the assignement to a new variable an ran the query directly in the statement. It's the same.

it is not actually dumping just the url I am visiting but more. Infact, it's logging other links on my visited page.
Is it because the browser called those links to load the images (even though I did not click them) ?

Yes, the proxy is rewriting all the urls, so the browser is going to request them through the proxy script, it's the same list that you get through the Network tab of the Developer Tools.

and one link twice ?

It happens because there is a redirect with status code 301 or 302, then it reloads the page with status code 200, so the script log its boths.

If you were in my position, how would you code it so the img or video links (that are residing on the visited page) do not get logged but only the url of the page that you visit by clicking it's link or by directly typing the url on your browser ?

The less intrusive approach is to append the tracking code after the IF statement at line 323:

//This is presumably a web page, so attempt to proxify the DOM.
if (stripos($contentType, "text/html") !== false) {

But this can be tricked if there are frames or if the server is sending the wrong content-type header for a resource. You have to experiment and decide where to log and how to filter.

Cereal,

Thanks for the reply. I missed this as I haven't been in the forum lately.
Anyway. So, you suggest I experiment and see which one is suitable. But from your own experience, which one you reckon is most suitable ?
I might aswell go with what you deem is best rather than rely on my judgment which could backfire somewhere along the line on other occassions when I'm not aware of it.