print.php / wkhtmltopdf: wrapper to offer HTML to PDF conversion.

Index.rst: Update Administratormanual how to install and use print.php.
print.php: wrapper for wkhtmltopdf.

extension/Documentation/AdministratorManual/Index.rst

@@ -14,6 +14,9 @@ Administrator Manual
 Preparation
 -----------
 
+Report & Form
+^^^^^^^^^^^^^
+
 The QFQ extension needs in PHP 5.x the PHP MySQL native driver. The following functions are used and are only available with the
 native driver (see also: http://dev.mysql.com/downloads/connector/php-mysqlnd/):
 
@@ -34,6 +37,34 @@ Preparation steps for Ubuntu 16.04::
 
 	sudo apt install php7.0-intl
 
+Print page via wkhtmltopdf
+^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+Different browser prints the same page in different variations. To prevent this, QFQ implements a small PHP wrapper `print.php`
+which uses http://wkhtmltopdf.org/ (webkit based) to convert HTML to PDF. The converter is not included in QFQ and has
+to be manually installed.
+
+Hint: The Ubuntu package `wkhtmltopdf` needs a running Xserver - this does not work on a headless webserver. Best is to
+install the QT version from the named website above.
+
+In config.qfq.ini specify the:
+* installed `wkhtmltopdf` binary,
+* the site base URL.
+
+Provide a `print this page`-link (replace {current pageId})::
+
+	<a href="typo3conf/ext/qfq/qfq/api/print.php?id={current pageId}">Print this page</a>
+
+Any parameter specified after `print.php` will be delivered to `wkhtmltopdf` as part of the URL.
+
+Typoscript code to implement a print link on every page::
+
+	10 = TEXT
+	10 {
+		wrap = <a href="typo3conf/ext/qfq/qfq/api/print.php?id=|&type=2"><span class="glyphicon glyphicon-print" aria-hidden="true"></span> Printview</a>
+		data = page:uid
+	}
+
 Setup
 -----
 
@@ -162,7 +193,10 @@ config.qfq.ini
 +-----------------------------+-----------------------------------------+----------------------------------------------------------------------------+
 | FORM_BUTTON_ON_CHANGE_CLASS | FORM_BUTTON_ON_CHANGE_CLASS=alert-info btn-info | Color for save button after modification                           |
 +-----------------------------+-----------------------------------------+----------------------------------------------------------------------------+
-
+| BASE_URL_PRINT              | BASE_URL_PRINT=http://example.com       | URL where wkhtmltopdf will fetch the HTML (no parameter, those comes later)|
++-----------------------------+-----------------------------------------+----------------------------------------------------------------------------+
+| WKHTMLTOPDF                 | WKHTMLTOPDF=/usr/bin/wkhtmltopdf        | Binary where to find wkhtmltopdf                                           |
++-----------------------------+-----------------------------------------+----------------------------------------------------------------------------+
 
 
 Example: *typo3conf/config.qfq.ini*
@@ -190,6 +224,8 @@ Example: *typo3conf/config.qfq.ini*
 	;FORM_BS_LABEL_COLUMNS = 3
 	;FORM_BS_INPUT_COLUMNS = 6
 	;FORM_BS_NOTE_COLUMNS = 3
+	BASE_URL_PRINT=http://example.com
+	WKHTMLTOPDF=/usr/bin/wkhtmltopdf
 
 Documentation
 -------------

extension/config.qfq.example.ini

@@ -41,3 +41,7 @@ DATE_FORMAT = yyyy-mm-dd
 ;FORM_BS_LABEL_COLUMNS = 3
 ;FORM_BS_INPUT_COLUMNS = 6
 ;FORM_BS_NOTE_COLUMNS = 3
+
+; Configure URL where `wkhtmltopdf` fetches pages and produces PDFs
+BASE_URL_PRINT = http://example.com/
+WKHTMLTOPDF = /opt/wkhtmltox/bin/wkhtmltopdf

extension/qfq/api/print.php

+<?php
+/**
+ * Created by PhpStorm.
+ * User: ep
+ * Date: 12/23/15
+ * Time: 6:17 PM
+ */
+
+
+namespace qfq;
+
+use qfq;
+
+require_once(__DIR__ . '/../qfq/store/Config.php');
+require_once(__DIR__ . '/../qfq/Constants.php');
+require_once(__DIR__ . '/../qfq/helper/KeyValueStringParser.php');
+
+const PAGEID = 'id';
+const PARAM_GET = 'paramGet';
+const URL_PRINT = 'urlPrint';
+
+/**
+ * Create a temporary file.
+ *
+ * @return string
+ */
+function createEmptyFile() {
+    return tempnam(sys_get_temp_dir(), "webkitPrintPdf");
+}
+
+/**
+ * Set HTML Header to initiate PDF download.
+ *
+ * @param $filename
+ */
+function setHeader($filename) {
+
+    header("Content-Disposition: inline; filename=\"$filename\"");
+    header("Content-Type: application/pdf");
+    header("Content-Transfer-Encoding: binary");
+}
+
+/**
+ * Read QFQ config. Only SYSTEM_BASE_URL_PRINT and SYSTEM_WKHTMLTOPDF will be used.
+ * Check and get all clean _GET Parameter. Build a URL based on SYSTEM_BASE_URL_PRINT and the delivered URL params.
+ *
+ * @return array
+ * @throws UserFormException
+ * @throws \exception
+ */
+function init() {
+    $cfg = new Config();
+
+    $config = $cfg->readConfig('');
+    $param = readCleanGetParam();
+
+    if (!isset($config[SYSTEM_BASE_URL_PRINT]) || $config[SYSTEM_BASE_URL_PRINT] == '') {
+        throw new \exception(CONFIG_INI . ' - Missing ' . SYSTEM_BASE_URL_PRINT);
+    }
+
+    if (!isset($config[SYSTEM_WKHTMLTOPDF]) || $config[SYSTEM_WKHTMLTOPDF] == '') {
+        throw new \exception(CONFIG_INI . ' - Missing ' . SYSTEM_WKHTMLTOPDF);
+    }
+
+    if (!is_executable($config[SYSTEM_WKHTMLTOPDF])) {
+        throw new \exception(CONFIG_INI . ' - ' . SYSTEM_WKHTMLTOPDF . '=' . $config[SYSTEM_WKHTMLTOPDF] . ' - not found or not executable.');
+    }
+
+    if (!isset($param[PAGEID]) || $param[PAGEID] == '') {
+        throw new \exception("Missing GET Parameter '" . PAGEID . "'.");
+    }
+
+    $setup = array();
+    $setup[URL_PRINT] = $config[SYSTEM_BASE_URL_PRINT] . '/?' . KeyValueStringParser::unparse($param, '=', '&');
+    $setup[PAGEID] = $param[PAGEID];
+    $setup[SYSTEM_WKHTMLTOPDF] = $config[SYSTEM_WKHTMLTOPDF];
+
+    return $setup;
+}
+
+;
+
+/**
+ * Return an array with GET params who are clean - they do not violate $pattern.
+ *
+ * @return array
+ */
+function readCleanGetParam() {
+
+    $param = array();
+    $pattern = '^[\-_\.,;:\/a-zA-Z0-9]*$'; // ':alnum:' does not work here in FF
+
+    foreach ($_GET as $key => $value) {
+        if (preg_match("/$pattern/", $value) === 1) {
+            $param[$key] = $value;
+        }
+    }
+
+    return $param;
+}
+
+/**
+ * @param array $setup
+ * @throws \exception
+ */
+function page2pdf($setup) {
+
+    $rc = 0;
+    $file = createEmptyFile();
+
+    $cmd = $setup[SYSTEM_WKHTMLTOPDF] . " '" . $setup[URL_PRINT] . "' " . $file . " > $file.log 2>&1";
+
+    $line = system($cmd, $rc);
+
+    if ($rc == 0) {
+        setHeader('print.' . $setup[PAGEID] . '.pdf');
+        @readfile($file);
+        @unlink($file);
+        @unlink($file . '.log');
+        exit; // Do an extremely hard exit here to make sure there are no more additional bytes sent (makes the delivered PDF unusable).
+    } else {
+        throw new \exception("Error [RC=$rc] $line: $cmd");
+    }
+}
+
+
+/**
+ * Main
+ */
+try {
+    $setup = init();
+
+    page2pdf($setup);
+
+} catch (\Exception $e) {
+    echo "Exception: " . $e->getMessage();
+}

extension/qfq/qfq/Constants.php

@@ -322,6 +322,9 @@ const SYSTEM_FORM_BS_NOTE_COLUMNS = 'FORM_BS_NOTE_COLUMNS';
 
 const SYSTEM_FORM_BUTTON_ON_CHANGE_CLASS = 'FORM_BUTTON_ON_CHANGE_CLASS';
 
+const SYSTEM_BASE_URL_PRINT = 'BASE_URL_PRINT';
+const SYSTEM_WKHTMLTOPDF = 'WKHTMLTOPDF';
+
 // computed automatically during runtime
 const SYSTEM_PATH_EXT = 'EXT_PATH';
 const SYSTEM_SITE_PATH = 'SITE_PATH';