Support for XMP metadata in JPEG and TIFF files (#3)

CHANGELOG.md

@@ -1,6 +1,8 @@
 # Changelog
 
 ## [Unreleased]
+### Added
+- Support for XMP metadata in JPEG and TIFF files
 
 ## 0.4.0 – 2017-08-15
 ### Added

appinfo/info.xml

@@ -8,7 +8,7 @@
 
 See the [README](https://github.com/gino0631/nextcloud-metadata/blob/master/README.md) for the supported file types and limitations.]]>
     </description>
-    <version>0.4.0</version>
+    <version>0.5.0</version>
     <licence>agpl</licence>
     <author>gino0631</author>
     <category>files</category>

lib/Controller/XmpMetadata.php

@@ -0,0 +1,130 @@
+<?php
+namespace OCA\Metadata\Controller;
+
+class XmpMetadata {
+    const EL_MWG_RS_REGIONS = 'mwg-rs:Regions';
+    const EL_MWG_RS_NAME = 'mwg-rs:Name';
+    const EL_MWG_RS_TYPE = 'mwg-rs:Type';
+    const EL_DC_TITLE = 'dc:title';
+    const EL_DC_DESCRIPTION = 'dc:description';
+    const EL_RDF_DESCRIPTION = 'rdf:Description';
+    const EL_RDF_LI = 'rdf:li';
+
+    private $parser;
+    private $text;
+    private $data = array();
+    private $context = array();
+    private $rsName = null;
+    private $rsType = null;
+
+    public function __construct($xml) {
+        $this->parser = xml_parser_create('UTF-8');
+        xml_parser_set_option($this->parser, XML_OPTION_CASE_FOLDING, 0);
+        xml_parser_set_option($this->parser, XML_OPTION_SKIP_WHITE, 0);
+        xml_set_element_handler($this->parser, array($this, 'startElement'), array($this, 'endElement'));
+        xml_set_character_data_handler($this->parser, array($this, 'charData'));
+
+        xml_parse($this->parser, $xml, true);
+    }
+
+    public function __destruct() {
+        if (is_resource($this->parser)) {
+            xml_parser_free($this->parser);
+        }
+    }
+
+    public function getArray() {
+        return $this->data;
+    }
+
+    public function startElement($parser, $name, array $attributes) {
+        $this->text = null;
+
+        switch ($name) {
+            // Elements to remember
+            case self::EL_MWG_RS_REGIONS:
+            case self::EL_DC_TITLE:
+            case self::EL_DC_DESCRIPTION:
+                $this->contextPush($name);
+                break;
+
+            case self::EL_RDF_DESCRIPTION:
+                switch ($this->contextPeek()) {
+                    case self::EL_MWG_RS_REGIONS:
+                        if (array_key_exists(self::EL_MWG_RS_NAME, $attributes)) {
+                            $this->rsName = $attributes[self::EL_MWG_RS_NAME];
+                        }
+                        if (array_key_exists(self::EL_MWG_RS_TYPE, $attributes)) {
+                            $this->rsType = $attributes[self::EL_MWG_RS_TYPE];
+                        }
+                        break;
+                }
+                break;
+        }
+    }
+
+    public function endElement($parser, $name) {
+        if ($this->contextPeek() === $name) {
+            $this->contextPop();
+        }
+
+        switch ($name) {
+            case self::EL_MWG_RS_NAME:
+                $this->rsName = $this->text;
+                break;
+
+            case self::EL_MWG_RS_TYPE:
+                $this->rsType = $this->text;
+                break;
+
+            case self::EL_RDF_LI:
+                switch ($this->contextPeek()) {     // memorized in startElement()
+                    case self::EL_MWG_RS_REGIONS:
+                        if (($this->rsType === 'Face') && !empty($this->rsName)) {
+                            $this->addVal('people', $this->rsName);
+                        }
+                        $this->rsName = null;
+                        $this->rsType = null;
+                        break;
+
+                    case self::EL_DC_TITLE:
+                        if (!empty($this->text)) {
+                            $this->addVal('title', $this->text);
+                        }
+                        break;
+
+                    case self::EL_DC_DESCRIPTION:
+                        if (!empty($this->text)) {
+                            $this->addVal('description', $this->text);
+                        }
+                        break;
+                }
+                break;
+        }
+    }
+
+    public function charData($parser, $data) {
+        $this->text = $data;
+    }
+
+    protected function addVal($key, $value) {
+        if (!array_key_exists($key, $this->data)) {
+            $this->data[$key] = array($value);
+
+        } else {
+            $this->data[$key][] = $value;
+        }
+    }
+
+    protected function contextPush($var) {
+        array_push($this->context, $var);
+    }
+
+    protected function contextPop() {
+        return array_pop($this->context);
+    }
+
+    protected function contextPeek() {
+        return empty($this->context) ? null : array_values(array_slice($this->context, -1))[0];
+    }
+}