Source code for invenio_previewer.views

# -*- coding: utf-8 -*-
#
# This file is part of Invenio.
# Copyright (C) 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
# as an Intergovernmental Organization or submit itself to any jurisdiction.

"""View method for Invenio-Records-UI for previewing files."""

from __future__ import absolute_import, print_function

from flask import Blueprint, abort, current_app, request

from .api import PreviewFile
from .extensions import default
from .proxies import current_previewer

blueprint = Blueprint(
    'invenio_previewer',
    __name__,
    template_folder='templates',
    static_folder='static',
)
"""Blueprint used to register template and static folders."""


def preview(pid, record, template=None, **kwargs):
    """Preview file for given record.

    Plug this method into your ``RECORDS_UI_ENDPOINTS`` configuration:

    .. code-block:: python

        RECORDS_UI_ENDPOINTS = dict(
            recid=dict(
                # ...
                route='/records/<pid_value/preview/<path:filename>',
                view_imp='invenio_previewer.views.preview',
                record_class='invenio_records_files.api:Record',
            )
        )
    """
    # Get file from record
    fileobj = current_previewer.record_file_factory(
        pid, record, request.view_args.get(
            'filename', request.args.get('filename', type=str))
    )
    if not fileobj:
        abort(404)

    # Try to see if specific previewer is requested?
    try:
        file_previewer = fileobj['previewer']
    except KeyError:
        file_previewer = None

    # Find a suitable previewer
    fileobj = PreviewFile(pid, record, fileobj)
    for plugin in current_previewer.iter_previewers(
            previewers=[file_previewer] if file_previewer else None):
        if plugin.can_preview(fileobj):
            try:
                return plugin.preview(fileobj)
            except Exception:
                current_app.logger.warning(
                    ('Preview failed for {key}, in {pid_type}:{pid_value}'
                     .format(key=fileobj.file.key,
                             pid_type=fileobj.pid.pid_type,
                             pid_value=fileobj.pid.pid_value)),
                    exc_info=True)
    return default.preview(fileobj)


@blueprint.app_template_test('previewable')
def is_previewable(extension):
    """Test if a file can be previewed checking its extension."""
    return extension in current_previewer.previewable_extensions