2.7 Reading and caching remote files

ArtiSynth applications often require the use of large data files to specify items such as FEM mesh geometry, surface mesh geometry, or medical imaging data. The size of these files may make it inconvenient to store them in any version control system that is used to store the application source code. As an alternative, ArtiSynth provides a file manager utility that allows such files to be stored on a separate server, and then downloaded on-demand and cached locally. To use this, one starts by creating an instance of a FileManager, using the constructor

where downloadPath is a path to the local directory where the downloaded file should be placed, and remoteSourceName is a URI indicating the remote server location of the files. After the file manager has been created, it can be used to fetch remote files and cache them locally, using various get methods:

Both of these look for the file destName specified relative to the local directory, and return a File handle for it if it is present. Otherwise, they attempt to download the file from the remote source location, place it in the local directory, and return a File handle for it. The location of the remote file is given relative to the remote source URI by destName for the first method and sourceName for the second.

A simple example of using a file manager within a RootModel build() method is given by the following fragment:

Here, a file manager is created that uses a local directory "geometry", located relative to the RootModel source directory (see Section 2.6), and looks for missing files relative to the URI

  http://myserver.org/artisynth/data/geometry

The get() method is then used to obtain the file "tibia.obj" from the local directory. If it is not already present, it is downloaded from the remote location.

The FileManager contains other features and functionality, and one should consult its API documentation for more information.