Badge Baker Offline Feature - Refs #7978

main/badge/issued.php

@@ -6,6 +6,7 @@
  * @package chamilo.badge
  */
 require_once '../inc/global.inc.php';
+require_once '../inc/lib/baker.lib.php';
 
 $userId = isset($_GET['user']) ? intval($_GET['user']) : 0;
 $skillId = isset($_GET['skill']) ? intval($_GET['skill']) : 0;
@@ -101,11 +102,46 @@ if ($allowExport) {
 
     $htmlHeadXtra[] = '<script src="' . $backpack . 'issuer.js"></script>';
 }
+$objSkill = new Skill();
+$skills = $objSkill->get($skillId);
+$unbakedBadge = api_get_path(SYS_UPLOAD_PATH) . "badges/".$skills['icon'];
+
+$unbakedBadge = file_get_contents($unbakedBadge);
+$badgeInfoError = false;
+$personalBadge = "";
+$png = new PNGImageBaker($unbakedBadge);
+
+if ($png->checkChunks("tEXt", "openbadges")) {
+    $bakedInfo = $png->addChunk("tEXt", "openbadges", $assertionUrl);
+    $bakedBadge = UserManager::getUserPathById($userId, "system");
+    $bakedBadge = $bakedBadge.'badges';
+    if (!file_exists($bakedBadge)) {
+        mkdir($bakedBadge, api_get_permissions_for_new_directories(), true);
+    }
+    $skillRelUserId = $userSkills[0]->getId();
+    if (!file_exists($bakedBadge . "/badge_" . $skillRelUserId)) {
+        file_put_contents($bakedBadge . "/badge_" . $skillRelUserId . ".png", $bakedInfo);
+    }
+    
+    //Process to validate a baked badge
+    $badgeContent = file_get_contents($bakedBadge . "/badge_" . $skillRelUserId . ".png");
+    $verifyBakedBadge = $png->extractBadgeInfo($badgeContent);
+    if (!is_array($verifyBakedBadge)) {
+        $badgeInfoError = true;
+    }
+
+    if (!$badgeInfoError) {
+        $personalBadge = UserManager::getUserPathById($userId, "web");
+        $personalBadge = $personalBadge."badges/badge_" . $skillRelUserId . ".png";  
+    }
+}
 
 $template = new Template('');
 $template->assign('skill_info', $skillInfo);
 $template->assign('user_info', $userInfo);
 $template->assign('allow_export', $allowExport);
+$template->assign('badge_error', $badgeInfoError);
+$template->assign('personal_badge', $personalBadge);
 
 if ($allowExport) {
     $template->assign('assertions', $badgeAssertions);

main/inc/lib/baker.lib.php

@@ -0,0 +1,165 @@
+<?php
+
+/**
+ * Php library to Bake the PNG Images
+ * 
+ */
+class PNGImageBaker
+{
+    private $_contents;
+    private $_size;
+    private $_chunks;
+    
+    /**
+     * Prepares file for handling metadata.
+     * Verifies that this file is a valid PNG file.
+     * Unpacks file chunks and reads them into an array.
+     *
+     * @param string $contents File content as a string
+     */
+    public function __construct($contents) {
+        $this->_contents = $contents;
+        $png_signature = pack("C8", 137, 80, 78, 71, 13, 10, 26, 10);
+        // Read 8 bytes of PNG header and verify.
+        $header = substr($this->_contents, 0, 8);
+        if ($header != $png_signature) {
+            echo 'This is not a valid PNG image';
+        }
+        $this->_size = strlen($this->_contents);
+        $this->_chunks = array();
+        // Skip 8 bytes of IHDR image header.
+        $position = 8;
+        do {
+            $chunk = @unpack('Nsize/a4type', substr($this->_contents, $position, 8));
+            $this->_chunks[$chunk['type']][] = substr($this->_contents, $position + 8, $chunk['size']);
+            // Skip 12 bytes chunk overhead.
+            $position += $chunk['size'] + 12;
+        } while ($position < $this->_size);
+    }
+  
+    /**
+     * Checks if a key already exists in the chunk of said type.
+     * We need to avoid writing same keyword into file chunks.
+     *
+     * @param string $type Chunk type, like iTXt, tEXt, etc.
+     * @param string $check Keyword that needs to be checked.
+     *
+     * @return boolean (true|false) True if file is safe to write this keyword, false otherwise.
+     */
+    public function checkChunks($type, $check) {
+        if (array_key_exists($type, $this->_chunks)) {
+            foreach (array_keys($this->_chunks[$type]) as $typekey) {
+                list($key, $data) = explode("\0", $this->_chunks[$type][$typekey]);
+                if (strcmp($key, $check) == 0) {
+                    echo 'Key "' . $check . '" already exists in "' . $type . '" chunk.';
+                    return false;
+                }
+            }
+        }
+        return true;
+    }
+    
+    /**
+     * Add a chunk by type with given key and text
+     *
+     * @param string $chunkType Chunk type, like iTXt, tEXt, etc.
+     * @param string $key Keyword that needs to be added.
+     * @param string $value Currently an assertion URL that is added to an image metadata.
+     *
+     * @return string $result File content with a new chunk as a string.
+     */
+    public function addChunk($chunkType, $key, $value) {
+        
+        $chunkData = $key . "\0" . $value;
+        $crc = pack("N", crc32($chunkType . $chunkData));
+        $len = pack("N", strlen($chunkData));
+        
+        $newChunk = $len . $chunkType . $chunkData . $crc;
+        $result = substr($this->_contents, 0, $this->_size - 12)
+                . $newChunk
+                . substr($this->_contents, $this->_size - 12, 12);
+        return $result;
+    }
+    
+    /**
+     * removes a chunk by type with given key and text
+     *
+     * @param string $chunkType Chunk type, like iTXt, tEXt, etc.
+     * @param string $key Keyword that needs to be deleted.
+     * @param string $png the png image.
+     *
+     * @return string $result New File content.
+     */
+    public function removeChunks($chunkType, $key, $png) {
+        // Read the magic bytes and verify
+        $retval = substr($png,0,8);
+        $ipos = 8;
+        if ($retval != "\x89PNG\x0d\x0a\x1a\x0a")
+            throw new Exception('Is not a valid PNG image');
+        // Loop through the chunks. Byte 0-3 is length, Byte 4-7 is type
+        $chunkHeader = substr($png,$ipos,8);
+        $ipos = $ipos + 8;
+        while ($chunkHeader) {
+            // Extract length and type from binary data
+            $chunk = @unpack('Nsize/a4type', $chunkHeader);
+            $skip = false;
+            if ( $chunk['type'] == $chunkType ) {
+                $data = substr($png,$ipos,$chunk['size']);
+                $sections = explode("\0", $data);
+                print_r($sections);
+                if ( $sections[0] == $key ) $skip = true;
+            }
+            // Extract the data and the CRC
+            $data = substr($png,$ipos,$chunk['size']+4);
+            $ipos = $ipos + $chunk['size'] + 4;
+            // Add in the header, data, and CRC
+            if ( ! $skip ) $retval = $retval . $chunkHeader . $data;
+            // Read next chunk header
+            $chunkHeader = substr($png,$ipos,8);
+            $ipos = $ipos + 8;
+        }
+        return $retval;
+    }
+
+    /**
+     * Extracts the baked PNG info by the Key
+     * 
+     * @param string $png the png image
+     * @param string $key Keyword that needs to be searched.
+     * 
+     * @return mixed - If there is an error - boolean false is returned
+     * If there is PNG information that matches the key an array is returned
+     * 
+     */
+    public function extractBadgeInfo($png, $key='openbadges') {
+        // Read the magic bytes and verify
+        $retval = substr($png,0,8);
+        $ipos = 8;
+        if ($retval != "\x89PNG\x0d\x0a\x1a\x0a") {
+            return false;
+        }
+
+        // Loop through the chunks. Byte 0-3 is length, Byte 4-7 is type
+        $chunkHeader = substr($png,$ipos,8);
+        $ipos = $ipos + 8;
+        while ($chunkHeader) {
+            // Extract length and type from binary data
+            $chunk = @unpack('Nsize/a4type', $chunkHeader);
+            $skip = false;
+            if ($chunk['type'] == 'tEXt') {
+                $data = substr($png,$ipos,$chunk['size']);
+                $sections = explode("\0", $data);
+                if ($sections[0] == $key) {
+                   return $sections;
+                }
+            }
+            // Extract the data and the CRC
+            $data = substr($png,$ipos,$chunk['size']+4);
+            $ipos = $ipos + $chunk['size'] + 4;
+
+            // Read next chunk header
+            $chunkHeader = substr($png,$ipos,8);
+            $ipos = $ipos + 8;
+        }
+    }
+}

main/template/default/skill/issued.tpl

@@ -20,6 +20,15 @@
                     {% endfor %}
                 </div>
             </div>
+        {% if badge_error %}
+            <div class="alert alert-danger"> {{ 'BakedBadgeProblem'|get_lang }}</div>
+        {% else %}
+            <p class="text-center">
+                <a href="{{ personal_badge }}" class="btn btn-primary" target="_new" download="badge">
+                    <em class="fa fa-download fa-fw"></em> {{ 'DownloadBadge'|get_lang }}
+                </a>
+            </p>
+        {% endif %}
         {% if allow_export %}
             <p class="text-center">
                 <a href="#" class="btn btn-success" id="badge-export-button">