attachaspropertystorage: allow using content_type for attachment and

fix bug

src/jio.storage/attachaspropertystorage.js

 /*jslint nomen: true*/
-/*global RSVP, FileReader*/
-// JIO AttachAsProperty Storage Description :
-// {
+/*global RSVP, FileReader, Blob*/
+//JIO AttachAsProperty Storage Description :
+//description = {
 //  type: "attachasproperty",
 //  map: {
-//           attach_id: 'property_ud',
-//           attach1_id: 'property1_ud',
+//    attach_id: {
+//      // name of property containing body of attachment
+//      body_name: 'property_id',
+//      // name of property containing content_type of attachment
+//      content_type_name: 'content_type'
 //    },
-//   sub_storage: {
-//     }
+//    attach1_id: {
+//      body_name: 'property1_id',
+//      content_type_name: 'content_type'
 //    }
+//  },
+//  sub_storage: {}
+//};
 
 (function (jIO, RSVP) {
   "use strict";
@@ -36,21 +43,24 @@
       sub_storage = this._sub_storage;
     return this._sub_storage.get.apply(this._sub_storage, arguments)
       .push(function (result) {
-        var property_name,
-          arg_list = [],
+        var arg_list = [],
           attach_name;
         for (attach_name in map) {
           if (map.hasOwnProperty(attach_name)) {
-            property_name = map[attach_name] || attach_name;
             arg_list.push(attach_name);
           }
         }
         return RSVP.all(arg_list.map(function (attach_name) {
+          var body_name = map[attach_name].body_name || attach_name,
+            content_type_name = map[attach_name].content_type_name;
           return sub_storage.getAttachment(key, attach_name)
             .push(function (value) {
+              if (content_type_name) {
+                result[content_type_name] = value.type;
+              }
               return jIO.util.readBlobAsText(value)
                 .then(function (r) {
-                  result[property_name] = r.target.result;
+                  result[body_name] = r.target.result;
                 });
             })
             .push(undefined, function (error) {
@@ -67,23 +77,38 @@
   AttachAsProperty.prototype.put = function (key, value_to_save) {
     var attach_name,
       args_list = [],
-      property_name,
+      body_name,
+      content_type_name,
+      content_type,
       value,
       sub_storage = this._sub_storage;
     for (attach_name in this.map) {
       if (this.map.hasOwnProperty(attach_name)) {
-        property_name = this.map[attach_name] || attach_name;
-        value = value_to_save[property_name];
+        body_name = this.map[attach_name].body_name || attach_name;
+        value = value_to_save[body_name];
         if (value !== undefined) {
-          delete value_to_save[property_name];
-          args_list.push([attach_name, value]);
+          content_type_name = this.map[attach_name].content_type_name;
+          if (content_type_name) {
+            content_type = value_to_save[content_type_name];
+          } else {
+            content_type = null;
+          }
+          delete value_to_save[body_name];
+          args_list.push([attach_name, value, content_type]);
         }
       }
     }
     return sub_storage.put.apply(sub_storage, arguments)
       .push(function () {
         return RSVP.all(args_list.map(function (a) {
-          return sub_storage.putAttachment(key, a[0], a[1]);
+          var content_type = a[2],
+            body;
+          if (content_type) {
+            body = new Blob([a[1]], {type: content_type});
+          } else {
+            body = a[1];
+          }
+          return sub_storage.putAttachment(key, a[0], body);
         }));
       });
   };