Work on #464.

src/fetchermanipulators/OaipmhIslandoraByMimetype.php

@@ -0,0 +1,127 @@
+<?php
+
+namespace mik\fetchermanipulators;
+
+use League\CLImate\CLImate;
+
+/**
+ * Fetcher manipulator that filters records based on the MIME type of the first
+ * datastream file listed in the ['FILE_GETTER']['datastream_ids'] configuration
+ * setting.
+ */
+
+class OaipmhIslandoraByMimetype extends FetcherManipulator
+{
+    /**
+     * Create a new OaipmhIslandoraObjByMimetype fetchermanipulator Instance
+     *
+     * @param array $settings
+     *   All of the settings from the .ini file.
+     *
+     * @param array $manipulator_settings
+     *   An array of all of the settings for the current manipulator,
+     *   with the manipulator class name in the first position and
+     *   the list of allowed MiME types, separated by commas,
+     *   as the second member.
+     */
+    public function __construct($settings, $manipulator_settings)
+    {
+        $this->settings = $settings;
+        // $manipulator_settings[0] contains the the classname of this class.
+        $params = explode('|', $manipulator_settings[1]);
+        $this->dsid = $params[0];
+        $this->allowed_mimetypes = explode(',', $params[1]);
+        // To get the value of $onWindows.
+        parent::__construct();
+
+        $this->oai_endpoint = $settings['FETCHER']['oai_endpoint'];
+        $this->datastreamIds = $settings['FILE_GETTER']['datastream_ids'];
+    }
+
+    /**
+     * Performs an HTTP HEAD request to get the file's Content-Type header.
+     * If the values is in the allowed list, keep the record.
+     *
+     * @param array $all_records
+     *   All of the records from the fetcher.
+     * @return array $filtered_records
+     *   An array of records that pass the test(s) defined in this function.
+     */
+    public function manipulate($records)
+    {
+        $numRecs = count($records);
+        echo "Filtering $numRecs records through the OaipmhIslandoraObjByMimetype fetcher manipulator.\n";
+        // Instantiate the progress bar.
+        if (!$this->onWindows) {
+            $climate = new \League\CLImate\CLImate;
+            $progress = $climate->progress()->total($numRecs);
+        }
+
+        $record_num = 0;
+        $filtered_records = array();
+        foreach ($records as $record) {
+            $mimetype = $this->getMimeType($record->key);
+
+            if (in_array($mimetype, $this->allowed_mimetypes)) {
+                $filtered_records[] = $record;
+            }
+            $record_num++;
+            if ($this->onWindows) {
+                print '.';
+            } else {
+                $progress->current($record_num);
+            }
+        }
+        if ($this->onWindows) {
+            print "\n";
+        }
+        return $filtered_records;
+    }
+
+    /**
+     * Get the URL for the datastream (OBJ, PDF, image, etc.).
+     *
+     * @param string $record_key
+     *
+     * @return string
+     *    The content of the Content-Type header.
+     */
+
+    public function getMimeType($record_key)
+    {
+        // Get the OAI record from the temp directory.
+        $raw_metadata_path = $this->settings['FETCHER']['temp_directory'] . DIRECTORY_SEPARATOR . $record_key . '.metadata';
+        $dom = new \DOMDocument;
+        $xml = file_get_contents($raw_metadata_path);
+        $dom->loadXML($xml);
+
+        // There will only be one oai:identifer element. Islandora's OAI identifiers look like
+        // oai:digital.lib.sfu.ca:foo_112, 'foo_123' being the object's PID.
+        $identifier = $dom->getElementsByTagNameNS('http://www.openarchives.org/OAI/2.0/', 'identifier')->item(0);
+        $raw_pid = preg_replace('#.*:#', '', trim($identifier->nodeValue));
+        $pid = preg_replace('/_/', ':', $raw_pid);
+
+        // Get bits that make up the Islandora instances host plus port. Assumes that the OAI-PMH
+        // endpoint is on the same host as the datastream files.
+        $islandora_url_info = parse_url($this->oai_endpoint);
+        if (isset($islandora_url_info['port'])) {
+            $port = ':' . $islandora_url_info['port'];
+        } else {
+            $port = '';
+        }
+        $islandora_host = $islandora_url_info['scheme'] . '://' . $islandora_url_info['host'] . $port;
+
+        // Assemble the URL of each datastream listed in the config and return on the first one
+        // that is available. We loop through DSIDs because not all Islandora content models
+        // require an OBJ datastream, e.g., PDF, video and audio content models.
+        foreach ($this->datastreamIds as $dsid) {
+            $ds_url = $islandora_host . '/islandora/object/' . $pid . '/datastream/' . $dsid . '/download';
+            // HEAD is more efficient than the default GET.
+            stream_context_set_default(array('http' => array('method' => 'HEAD')));
+            $headers = get_headers($ds_url, 1);
+            if ($dsid == $this->dsid && $headers[0] == 'HTTP/1.1 200 OK' && isset($headers['Content-Type'])) {
+                return $headers['Content-Type'];
+            } 
+        }
+    }
+}