File Properties

Some algorithms will want to take a file/directory path as input. This could be accomplished by using a string property. A FileProperty has the advantage that if given just a filename then it will search the current list of data directories for that file rather than having to hard code paths in scripts.

A file property is declared as:

def PyInit(self):
    self.declareProperty(FileProperty(name="InputFile",defaultValue="",
                                      action=FileAction.Load,
                                      extensions = ["txt"]))

The extensions argument is optional. The action argument is one of the following FileAction:

• FileAction.Load - The string is treated as a file that will be loaded during the algorithm. By default the property is not valid. The file is searched for on the paths specified by the data search directories.

• FileAction.OptionalLoad - As above, except a blank string is valid.

• FileAction.Save - The string is treated as a file that will be saved by the algorithm. If only a file name is given then a full path is produced by prefixing the name by the current default save directory.

• FileAction.OptionalSave - As above, except a blank string is valid.

• FileAction.Directory - The value of the string is treated as if it is a directory and must exist for the property to be valid.

• FileAction.OptionalDirectory - As above, except a blank string is valid.