grass.app.data — GRASS Python Library documentation

# Source code for grass.app.data

    """Provides functions for the main GRASS GIS executable

    (C) 2020 by Vaclav Petras and the GRASS Development Team

    This program is free software under the GNU General Public
    License (>=v2). Read the file COPYING that comes with GRASS
    for details.

    .. sectionauthor:: Vaclav Petras <wenzeslaus gmail com>
    .. sectionauthor:: Linda Kladivova <l.kladivova seznam cz>

    This is not a stable part of the API. Use at your own risk.
    """

    import os
    import tempfile
    import getpass
    import sys
    from shutil import copytree, ignore_patterns
    import grass.grassdb.config as cfg

    from grass.grassdb.checks import is_location_valid

    def get_possible_database_path():
        """Looks for directory 'grassdata' (case-insensitive) in standard
        locations to detect existing GRASS Database.

        Returns the path as a string or None if nothing was found.
        """
        home = os.path.expanduser("~")

        # try some common directories for grassdata
        candidates = [
            home,
            os.path.join(home, "Documents"),
        ]

        # find possible database path
        for candidate in candidates:
            if os.path.exists(candidate):
                for subdir in next(os.walk(candidate))[1]:
                    if "grassdata" in subdir.lower():
                        return os.path.join(candidate, subdir)
        return None

    def create_database_directory():
        """Creates the standard GRASS GIS directory.
        Creates database directory named grassdata in the standard location
        according to the platform.

        Returns the new path as a string or None if nothing was found or created.
        """
        home = os.path.expanduser("~")

        # Determine the standard path according to the platform
        if sys.platform == "win32":
            path = os.path.join(home, "Documents", "grassdata")
        else:
            path = os.path.join(home, "grassdata")

        # Create "grassdata" directory
        try:
            os.mkdir(path)
            return path
        except OSError:
            pass

        # Create a temporary "grassdata" directory if GRASS is running
        # in some special environment and the standard directories
        # cannot be created which might be the case in some "try out GRASS"
        # use cases.
        path = os.path.join(tempfile.gettempdir(), "grassdata_{}".format(getpass.getuser()))

        # The created tmp is not cleaned by GRASS, so we are relying on
        # the system to do it at some point. The positive outcome is that
        # another GRASS instance will find the data created by the first
        # one which is desired in the "try out GRASS" use case we are
        # aiming towards."
        if os.path.exists(path):
            return path
        try:
            os.mkdir(path)
            return path
        except OSError:
            pass

        return None

    def _get_startup_location_in_distribution():
        """Check for startup location directory in distribution.

        Returns startup location if found or None if nothing was found.
        """
        gisbase = os.getenv("GISBASE")
        startup_location = os.path.join(gisbase, "demolocation")

        # Find out if startup location exists
        if os.path.exists(startup_location):
            return startup_location
        return None

    def _copy_startup_location(startup_location, location_in_grassdb):
        """Copy the simple startup_location with some data to GRASS database.

        Returns True if successfully copied or False
        when an error was encountered.
        """
        # Copy source startup location into GRASS database
        try:
            copytree(
                startup_location,
                location_in_grassdb,
                ignore=ignore_patterns("*.tmpl", "Makefile*"),
            )
            return True
        except OSError:
            pass
        return False

    def create_startup_location_in_grassdb(grassdatabase, startup_location_name):
        """Create a new startup location in the given GRASS database.

        Returns True if a new startup location successfully created
        in the given GRASS database.
        Returns False if there is no location to copy in the installation
        or copying failed.
        """
        # Find out if startup location exists
        startup_location = _get_startup_location_in_distribution()
        if not startup_location:
            return False

        # Copy the simple startup_location with some data to GRASS database
        location_in_grassdb = os.path.join(grassdatabase, startup_location_name)
        if _copy_startup_location(startup_location, location_in_grassdb):
            return True
        return False

    def ensure_default_data_hierarchy():
        """Ensure that default gisdbase, location and mapset exist.
        Creates database directory based on the default path determined
        according to OS if needed. Creates location if needed.

        Returns the db, loc, mapset, mapset_path"""

        gisdbase = get_possible_database_path()
        location = cfg.default_location
        mapset = cfg.permanent_mapset

        # If nothing found, try to create GRASS directory
        if not gisdbase:
            gisdbase = create_database_directory()

        if not is_location_valid(gisdbase, location):
            # If not valid, copy startup loc
            create_startup_location_in_grassdb(gisdbase, location)

        mapset_path = os.path.join(gisdbase, location, mapset)

        return gisdbase, location, mapset, mapset_path

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