added conveninece method to wrap datastream writing

api/fedora_item.inc

@@ -164,6 +164,30 @@ class Fedora_Item {
     return $returnvalue;
   }
 
+  
+  /**
+   * Wrapper to add new or modify existing datastream 
+   * @global url $base_url
+   * @param url $external_url
+   * @param string $dsid
+   * @param string $label
+   * @param string $mime_type
+   * @param string $controlGroup
+   * @param boolean $force
+   * @param string $logMessage
+   * @param boolean $quiet 
+   */
+  function add_or_modify_by_reference($external_url, $dsid, $label, $mime_type, $controlGroup = 'M', $force = FALSE, $logMessage = 'Modified by Islandora API', $quiet=FALSE) {
+    global $base_url;
+    if (array_key_exists($dsid, $this->datastreams)) {
+      $this->modify_datastream_by_reference($external_url, $dsid, $label, $mime_type, $force, $logMessage, $quiet);
+    }
+    else {
+      $file_location = str_replace("$base_url/", '', $external_url);
+      $this->add_datastream_from_file($file_location, $dsid, $label, $mime_type, $controlGroup = 'M', $logMessage = NULL);
+    }
+  }
+
   /**
    * Add a relationship string to this object's RELS-EXT.
    * does not support rels-int yet.
@@ -583,7 +607,6 @@ class Fedora_Item {
     return $relationships;
   }
 
-
   function get_models() {
     $relationships = array();
     try {