Fix page-break on table rows

The dompdf library messes up the document layout, when page breaks reach over
several sites and will eventually even crash completely. Add a function to
split up tables in different chunks to fix this issue.

refs #4356

library/Icinga/File/Pdf.php

@@ -3,6 +3,8 @@
 namespace Icinga\File;
 
 use \DOMPDF;
+use \DOMDocument;
+use \DOMXPath;
 
 require_once 'vendor/dompdf/dompdf_config.inc.php';
 
@@ -10,6 +12,20 @@ spl_autoload_register("DOMPDF_autoload");
 
 class Pdf extends DOMPDF
 {
+    /**
+     * The amount of table rows that fit on one page before a page-break is inserted.
+     *
+     * @var int
+     */
+    public $rowsPerPage = 10;
+
+    /**
+     * If occuring tables should be split up into smaller tables to avoid errors in the document layout.
+     *
+     * @var bool
+     */
+    public $paginateTable = true;
+
     public function __construct() {
         $this->set_paper(DOMPDF_DEFAULT_PAPER_SIZE, "portrait");
         parent::__construct();
@@ -28,10 +44,86 @@ class Pdf extends DOMPDF
                . $body
             . '</body>'
           . '</html>';
+        if ($this->paginateTable === true) {
+            $html = $this->paginateHtmlTables($html);
+        }
         $this->load_html($html);
         $this->render();
     }
 
+    /**
+     * Split up tables into multiple elements that each contain $rowsPerPage of all original rows
+     *
+     * NOTE: This is a workaround to fix the buggy page-break on table-rows in dompdf.
+     *
+     * @param  string   A html-string.
+     *
+     * @return string   The html string with the paginated rows.
+     */
+    private function paginateHtmlTables($html)
+    {
+        $doc = new DOMDocument();
+        @$doc->loadHTML($html);
+        $xpath = new DOMXPath($doc);
+
+        $tables =  $xpath->query('.//table');
+        foreach ($tables as $table) {
+            $containerType  = null;
+            $rows           = $xpath->query('.//tr', $table);
+            $rowCnt         = $rows->length;
+            $tableCnt       = (Integer)ceil($rowCnt / $this->rowsPerPage);
+            if ($rowCnt <= $this->rowsPerPage) {
+                continue;
+            }
+            // remove all rows from the original parent
+            foreach ($rows as $row) {
+                if (!isset($containerType)) {
+                    $containerType = $row->parentNode->nodeName;
+                }
+                $row->parentNode->removeChild($row);
+            }
+
+            // clone table for each additional page and fetch the row containers
+            $containers = array();
+            $pages = array();
+
+            // insert page-break
+            $div = $doc->createElement('div');
+            $div->setAttribute('style', 'page-break-before: always;');
+            $table->parentNode->insertBefore($div, $table);
+
+            for ($i = 0; $i < $tableCnt; $i++) {
+                // clone table
+                $currentPage = $table->cloneNode(true);
+                $pages[$i] = $currentPage;
+                $table->parentNode->insertBefore($currentPage, $table);
+
+                // insert page-break
+                if ($i < $tableCnt - 1) {
+                    $div = $doc->createElement('div');
+                    $div->setAttribute('style', 'page-break-before: always;');
+                    $table->parentNode->insertBefore($div, $table);
+                }
+
+                // fetch row container
+                $container = $xpath->query('.//' . $containerType, $currentPage)->item(0);
+                $containers[$i] = $container;
+            }
+
+            $i = 0;
+            foreach ($rows as $row) {
+                $p = (Integer)floor($i / $this->rowsPerPage);
+                $containers[$p]->appendChild($row);
+                //echo "Inserting row $i into container $p <br />";
+                $i++;
+            }
+
+            // remove original table
+            $table->parentNode->removeChild($table);
+        }
+        return $doc->saveHTML();
+    }
+
     /**
      * Prepare the given css for rendering with DOMPDF, by removing or hiding all incompatible
      * styles
@@ -45,14 +137,20 @@ class Pdf extends DOMPDF
         $css = preg_replace('/\*:\s*before\s*,\s*/', '', $css);
         $css = preg_replace('/\*\s*:\s*after\s*\{[^\}]*\}/', '', $css);
 
+
         // TODO: Move into own .css file that is loaded when requesting a pdf
-        return $css . "\n"
+        return $css  . "\n"
+          . '*, html { font-size: 100%; } ' . "\n"
+
           . 'form { display: none; }' . "\n"
 
+          // Insert page breaks
+          . 'div.pdf-page { page-break-before: always; } ' . "\n"
+
           // Don't show any link outline
           . 'a { outline: 0; }' . "\n"
 
-          // Fix badge positioning  TODO: Badge should be at the right border
+          // Fix badge positioning
           . 'span.badge { float: right; max-width: 5px; }'
 
           // prevent table rows from growing too big on page breaks
@@ -60,6 +158,7 @@ class Pdf extends DOMPDF
 
           // Hide buttons
           . '*.button { display: none; }' . "\n"
+          . '*.btn-group { display: none; }' . "\n"
           . 'button > i { display: none; }' . "\n"
 
           // Hide navigation

library/Icinga/Web/Controller/ActionController.php

@@ -241,21 +241,40 @@ class ActionController extends Zend_Controller_Action
             }
         }
         if ($this->_request->getParam('format') === 'pdf' && $this->_request->getControllerName() !== 'static') {
-            $html = $this->view->render(
+            $this->sendAsPdf();
-                $this->_request->getControllerName() . '/' . $this->_request->getActionName() . '.phtml'
-            );
-            $this->sendAsPdf($html);
             die();
         }
     }
 
-    protected function sendAsPdf($body)
+    protected function sendAsPdf()
     {
+        $body = $this->view->render(
+            $this->_request->getControllerName() . '/' . $this->_request->getActionName() . '.phtml'
+        );
         if (!headers_sent()) {
             $css = $this->view->getHelper('action')->action('stylesheet', 'static', 'application');
             $pdf = new PDF();
+
+            if ($this->_request->getControllerName() === 'list') {
+                switch ($this->_request->getActionName()) {
+                    case 'notifications':
+                        $pdf->rowsPerPage = 8;
+                        break;
+                    case 'comments':
+                        $pdf->rowsPerPage = 8;
+                        break;
+                    default:
+                        $pdf->rowsPerPage = 12;
+                        break;
+                }
+            } else {
+                $pdf->paginateTable = false;
+            }
+
             $pdf->renderPage($body, $css);
-            $pdf->stream($this->_request->getControllerName() . '-' . $this->_request->getActionName() . '.pdf');
+            $pdf->stream(
+                $this->_request->getControllerName() . '-' . $this->_request->getActionName() . '-' . time() . '.pdf'
+            );
         } else {
             Logger::error('Could not send pdf-response, content already written to output.');
             die();

library/vendor/dompdf/dompdf_config.inc.php

@@ -4,7 +4,7 @@
  * @link    http://www.dompdf.com/
  * @author  Benj Carson <benjcarson@digitaljunkies.ca>
  * @author  Helmut Tischer <htischer@weihenstephan.org>
- * @author  Fabien Ménager <fabien.menager@gmail.com>
+ * @author  Fabien M<EFBFBD>nager <fabien.menager@gmail.com>
  * @license http://www.gnu.org/copyleft/lesser.html GNU Lesser General Public License
  * @version $Id: dompdf_config.inc.php 468 2012-02-05 10:51:40Z fabien.menager $
  */
@@ -199,7 +199,7 @@ def("DOMPDF_DEFAULT_MEDIA_TYPE", "screen");
  *
  * @see CPDF_Adapter::PAPER_SIZES for valid sizes
  */
-def("DOMPDF_DEFAULT_PAPER_SIZE", "letter");
+def("DOMPDF_DEFAULT_PAPER_SIZE", "a4");
 
 /**
  * The default font family
@@ -285,7 +285,7 @@ def("DOMPDF_ENABLE_JAVASCRIPT", true);
  *
  * @var bool
  */
-def("DOMPDF_ENABLE_REMOTE", false);
+def("DOMPDF_ENABLE_REMOTE", true);
 
 /**
  * The debug output log
@@ -304,7 +304,7 @@ def("DOMPDF_FONT_HEIGHT_RATIO", 1.1);
  * Allows people to disabled CSS float support
  * @var bool
  */
-def("DOMPDF_ENABLE_CSS_FLOAT", false);
+def("DOMPDF_ENABLE_CSS_FLOAT", true);
 
 /**
  * Prepend the DOMPDF autoload function the spl_autoload stack
@@ -378,7 +378,7 @@ def('DEBUGCSS', false);
  * Visible in the PDF itself.
  */
 def('DEBUG_LAYOUT', false);
-def('DEBUG_LAYOUT_LINES', true);
+def('DEBUG_LAYOUT_LINES', false);
-def('DEBUG_LAYOUT_BLOCKS', true);
+def('DEBUG_LAYOUT_BLOCKS', false);
-def('DEBUG_LAYOUT_INLINE', true);
+def('DEBUG_LAYOUT_INLINE', false);
-def('DEBUG_LAYOUT_PADDINGBOX', true);
+def('DEBUG_LAYOUT_PADDINGBOX', false);