contentType: Reply back proper contentTypes based on the file extension.

Currently the server would set 'application/octet-stream' for all
objects, set this value based on the file extension transparently.

This is useful in case of minio browser to facilitate displaying
proper icons for the different mime data types.

web-handlers.go

@@ -95,10 +95,18 @@ func (web *WebAPI) ListObjects(r *http.Request, args *ListObjectsArgs, reply *[]
 		if object.Err != nil {
 			return object.Err
 		}
+		// TODO - This can get slower for large directories, we can
+		// perhaps extend the ListObjects XML to reply back
+		// ContentType as well.
+		objectInfo, e := web.Client.StatObject(args.BucketName, object.Key)
+		if e != nil {
+			return e
+		}
 		*reply = append(*reply, ObjectInfo{
-			Key:          object.Key,
-			LastModified: object.LastModified,
-			Size:         object.Size,
+			Key:          objectInfo.Key,
+			LastModified: objectInfo.LastModified,
+			Size:         objectInfo.Size,
+			ContentType:  objectInfo.ContentType,
 		})
 	}
 	return nil