Source code for invenio_pidstore.ext

# -*- coding: utf-8 -*-
#
# This file is part of Invenio.
# Copyright (C) 2015, 2016 CERN.
#
# Invenio is free software; you can redistribute it
# and/or modify it under the terms of the GNU General Public License as
# published by the Free Software Foundation; either version 2 of the
# License, or (at your option) any later version.
#
# Invenio is distributed in the hope that it will be
# useful, but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
# General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with Invenio; if not, write to the
# Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston,
# MA 02111-1307, USA.
#
# In applying this license, CERN does not
# waive the privileges and immunities granted to it by virtue of its status
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"""Invenio module that stores and registers persistent identifiers."""

from __future__ import absolute_import, print_function

import pkg_resources

from .cli import pid as cmd
from .errors import PIDDoesNotExistError
from .models import PersistentIdentifier, logger


def pid_exists(value, pidtype=None):
    """Check if a persistent identifier exists.

    :param value: The PID value.
    :param pidtype: The pid value (Default: None).
    :returns: `True` if the PID exists.
    """
    try:
        PersistentIdentifier.get(pidtype, value)
        return True
    except PIDDoesNotExistError:
        return False


class _PIDStoreState(object):
    """Persistent identifier store state."""

    def __init__(self, app, minters_entry_point_group=None,
                 fetchers_entry_point_group=None):
        """Initialize state."""
        self.app = app
        self.minters = {}
        self.fetchers = {}
        if minters_entry_point_group:
            self.load_minters_entry_point_group(minters_entry_point_group)
        if fetchers_entry_point_group:
            self.load_fetchers_entry_point_group(fetchers_entry_point_group)

    def register_minter(self, name, minter):
        """Register a minter.

        :param name: Minter name.
        :param minter: The new minter.
        """
        assert name not in self.minters
        self.minters[name] = minter

    def register_fetcher(self, name, fetcher):
        """Register a fetcher.

        :param name: Fetcher name.
        :param fetcher: The new fetcher.
        """
        assert name not in self.fetchers
        self.fetchers[name] = fetcher

    def load_minters_entry_point_group(self, entry_point_group):
        """Load minters from an entry point group.

        :param entry_point_group: The entrypoint group.
        """
        for ep in pkg_resources.iter_entry_points(group=entry_point_group):
            self.register_minter(ep.name, ep.load())

    def load_fetchers_entry_point_group(self, entry_point_group):
        """Load fetchers from an entry point group.

        :param entry_point_group: The entrypoint group.
        """
        for ep in pkg_resources.iter_entry_points(group=entry_point_group):
            self.register_fetcher(ep.name, ep.load())


class InvenioPIDStore(object):
    """Invenio-PIDStore extension."""

    def __init__(self, app=None,
                 minters_entry_point_group='invenio_pidstore.minters',
                 fetchers_entry_point_group='invenio_pidstore.fetchers'):
        """Extension initialization.

        :param minters_entry_point_group: The entrypoint for minters.
            (Default: `invenio_pidstore.minters`).
        :param fetchers_entry_point_group: The entrypoint for fetchers.
            (Default: `invenio_pidstore.fetchers`).
        """
        if app:
            self._state = self.init_app(
                app, minters_entry_point_group=minters_entry_point_group,
                fetchers_entry_point_group=fetchers_entry_point_group
            )

    def init_app(self, app, minters_entry_point_group=None,
                 fetchers_entry_point_group=None):
        """Flask application initialization.

        Initialize:

        * The CLI commands.

        * Initialize the logger (Default: `app.debug`).

        * Initialize the default admin object link endpoint.
            (Default: `{"rec": "recordmetadata.details_view"}` if
            `invenio-records` is installed, otherwise `{}`).

        * Register the `pid_exists` template filter.

        * Initialize extension state.

        :param app: The Flask application
        :param minters_entry_point_group: The minters entrtypoint group
            (Default: None).
        :param fetchers_entry_point_group: The fetchers entrtypoint group
            (Default: None).
            :returns: PIDStore state application.
        """
        # Initialize CLI
        app.cli.add_command(cmd)

        # Initialize logger
        app.config.setdefault('PIDSTORE_APP_LOGGER_HANDLERS', app.debug)
        if app.config['PIDSTORE_APP_LOGGER_HANDLERS']:
            for handler in app.logger.handlers:
                logger.addHandler(handler)

        # Initialize admin object link endpoints.
        try:
            pkg_resources.get_distribution('invenio-records')
            app.config.setdefault('PIDSTORE_OBJECT_ENDPOINTS', dict(
                rec='recordmetadata.details_view',
            ))
        except pkg_resources.DistributionNotFound:
            app.config.setdefault('PIDSTORE_OBJECT_ENDPOINTS', {})

        # Register template filter
        app.jinja_env.filters['pid_exists'] = pid_exists

        # Initialize extension state.
        state = _PIDStoreState(
            app=app,
            minters_entry_point_group=minters_entry_point_group,
            fetchers_entry_point_group=fetchers_entry_point_group,
        )
        app.extensions['invenio-pidstore'] = state
        return state

    def __getattr__(self, name):
        """Proxy to state object."""
        return getattr(self._state, name, None)