<?php

// Does not use cookies for sessions since the only session exists between

// two requests where the URL of the second request is defined below.

ini_set('session.use_cookies', '0');

$compress = strpos($_SERVER['HTTP_ACCEPT_ENCODING'], 'gzip') !== false;

function mhtml($name, $data)

{

return "Content-Type: multipart/related; boundary=\"----\"\n".

"\n".

"------\n".

"Content-Location:$name\n".

"Content-Transfer-Encoding:base64\n".

"\n".

$data.

"=\n".

"------\n";

}

// Uses wire-compression for response

if ($compress)

{

ob_start();

ob_start("ob_gzhandler");

}

// Converts an uploaded file to a base64 MHTML response

// which is inserted via injected JavaScript on the client-side.

if ($_SERVER["REQUEST_METHOD"] == "POST")

{

$tmpfile = $_FILES["upfile"]["tmp_name"];

header("Content-Type: text/html");

echo "<html>\n";

echo "<head>\n";

echo "</head>\n";

echo "<body>\n";

echo "<script type=\"text/javascript\">\n";

// Shows an error message on the client-side if the file is larger than

// 32 KB, which is the maximum size foe data URIs in IE8.

if (filesize($tmpfile) > 32768)

{

echo "alert(\"File exceeds the maximum allowed size. File must be less than 32KB.\");\n";

}

else

{

$img = file_get_contents($tmpfile);

$data = base64_encode($img);

// Makes the name unique by adding a timestamp as a postfix

$name = $_FILES["upfile"]["name"]."-".mktime();

// Stores the file in the session which only exists between this and the

// next request. The subsequent request is handled in the else branch.

// Note that the request destroys the session and its contents, however,

// in IE the MHTML resource is only loaded once and kept in the browser.

if ($_POST["dataurl"] == "false")

{

// In theory, up to 4K in 300 cookies can be used to transfer the data

// directly in the GET request of the image to avoid a session state.

// This can be done by splitting the base64 data into 4K cookies in the

// insert method in the client and then forcing an image prefetch with

// the respective MHTML URL for the image. On the server-side all we

// we need to do is fetch the content location (get param) and data.

// In practice most servers have a header size limit of 8-16K.

session_start();

$url = "'mhtml:'+window.location.href+'?PHPSESSID=".session_id()."&img=$name!$name'";

$_SESSION["image"] = "<!--\n".mhtml($name, $data)."-->\n";

}

else

{

$url = "null";

}

echo "window.parent.insert(\"$name\", \"data:image/png,".$data."\", $url);\n";

}

// NOTE: Ignore "Failed to load resource" error in Chrome,

// see http://code.google.com/p/chromium/issues/detail?id=29180

echo "var iframe = window.parent.document.getElementById('embedimageframe');\n";

echo "iframe.parentNode.removeChild(iframe);";

echo "</script>\n";

echo "</body>\n";

echo "</html>\n";

}

// Fetches the given image and encodes it as a MHTM page.

// On the client-side the page is used as is and the

// base64 encoded data is extracted and put into an

// mxImageBundle for storage with the diagram.

else if (isset($_GET["url"]))

{

$url = $_GET["url"];

$img = file_get_contents($url);

// Enables caching of this response

header("Content-Type: text/plain");

header("Cache-Control: private");

header("Expires: Thu, 15 Apr 2030 20:00:00 GMT");

echo "<!--\n".mhtml("image", base64_encode($img))."-->\n";

}

// Returns the MHTML stored in the session.

else if (isset($_GET["PHPSESSID"]))

{

header("Content-Type: text/plain");

// Gets the image from the session and destroys the session (since we do

// not use session cookies there is no need to delete a cookie here).

session_start();

echo $_SESSION["image"];

session_destroy();

}

else

{

header("Content-Type: text/html");

$userAgent = strtoupper(getenv("HTTP_USER_AGENT"));

$dataUrl = strpos($userAgent, "MSIE 6") === false &&

strpos($userAgent, "MSIE 7") === false;

// In a real-world environment the following would be done for each entry

// of the image bundle in an XML file for a diagram.

$name = "myImage";

$data = "R0lGODlhEAAQAMIGAAAAAICAAICAgP//AOzp2O3r2////////yH+FUNyZWF0ZWQgd2l0aCBUaGUgR0lNUAAh+QQBCgAHACwAAAAAEAAQAAADTXi63AowynnAMDfjPUDlnAAJhmeBFxAEloliKltWmiYCQvfVr6lBPB1ggxN1hilaSSASFQpIV5HJBDyHpqK2ejVRm2AAgZCdmCGO9CIBADs";

$mhtml = ($dataUrl) ? "" : "\n".mhtml($name, $data);

$bundle = "bundle.putImage('myImage', 'data:image/png,$data=', 'mhtml:' + window.location.href + '!$name');";

// Replaces the placeholders in the template with the data from above.

// Note: In a production environment you should use a template engine.

$page = file_get_contents("embedimage.html");

$page = str_replace("%mhtml%", $mhtml, $page);

$page = str_replace("%dataUrl%", ($dataUrl) ? "true" : "false", $page);

$page = str_replace("%bundle%", $bundle, $page);

echo $page;

}

// Flushes the compression buffers

if ($compress)

{

ob_end_flush();

ob_end_flush();

}

?>