serializers: add record link factory

* Closes inveniosoftware#172

{{cookiecutter.project_shortname}}/tests/api/test_api_simple_flow.py

@@ -24,4 +24,8 @@ def test_simple_flow(client):
 
     # retrieve record
     res = client.get('https://localhost:5000/records/1')
+
+    # Check if the files link is present
+    assert res.json['links']['files'].endswith('{0}/files') == \
+        'https://localhost:5000/records/1/files'
     assert res.status_code == 200

{{cookiecutter.project_shortname}}/{{cookiecutter.package_name}}/records/config.py

@@ -26,16 +26,13 @@ def _(x):
         search_index='records',
         search_type=None,
         record_serializers={
-            'application/json': ('{{ cookiecutter.package_name }}.records.serializers'
-                                 ':json_v1_response'),
+            'application/json': ('{{ cookiecutter.package_name }}.records.serializers:json_v1_response'),
         },
         search_serializers={
-            'application/json': ('{{ cookiecutter.package_name }}.records.serializers'
-                                 ':json_v1_search'),
+            'application/json': ('{{ cookiecutter.package_name }}.records.serializers:json_v1_search'),
         },
         record_loaders={
-            'application/json': ('{{ cookiecutter.package_name }}.records.loaders'
-                                 ':json_v1'),
+            'application/json': ('{{ cookiecutter.package_name }}.records.loaders:json_v1'),
         },
         list_route='/records/',
         item_route='/records/<pid(recid,'
@@ -48,7 +45,9 @@ def _(x):
         read_permission_factory_imp=check_elasticsearch,
         update_permission_factory_imp=allow_all,
         delete_permission_factory_imp=allow_all,
-        list_permission_factory_imp=allow_all
+        list_permission_factory_imp=allow_all,
+        links_factory_imp='{{ cookiecutter.package_name }}.'
+                          'records.links.record_links:record_links_factory',
     ),
 }
 """REST API for {{cookiecutter.project_shortname}}."""

{{cookiecutter.project_shortname}}/{{cookiecutter.package_name}}/records/ext.py

@@ -35,7 +35,8 @@ def init_config(self, app):
             elif k == 'PIDSTORE_RECID_FIELD':
                 app.config['PIDSTORE_RECID_FIELD'] = getattr(config, k)
             elif k == 'FILES_REST_PERMISSION_FACTORY':
-                app.config['FILES_REST_PERMISSION_FACTORY'] = getattr(config, k)
+                app.config['FILES_REST_PERMISSION_FACTORY'] = \
+                    getattr(config, k)
             else:
                 for n in ['RECORDS_REST_ENDPOINTS', 'RECORDS_UI_ENDPOINTS',
                           'RECORDS_REST_FACETS', 'RECORDS_REST_SORT_OPTIONS',

{{cookiecutter.project_shortname}}/{{cookiecutter.package_name}}/records/links/__init__.py

@@ -0,0 +1,10 @@
+# -*- coding: utf-8 -*-
+#
+# Copyright (C) 2019 CERN.
+#
+# My site is free software; you can redistribute it and/or modify it under
+# the terms of the MIT License; see LICENSE file for more details.
+
+"""Module for defining link factories"""
+
+from __future__ import absolute_import, print_function

{{cookiecutter.project_shortname}}/{{cookiecutter.package_name}}/records/links/record_links.py

@@ -0,0 +1,33 @@
+# -*- coding: utf-8 -*-
+#
+# Copyright (C) 2019 CERN.
+#
+# My site is free software; you can redistribute it and/or modify it under
+# the terms of the MIT License; see LICENSE file for more details.
+
+from __future__ import absolute_import, print_function
+
+from flask import url_for, g
+
+from invenio_records_rest.proxies import current_records_rest
+
+
+def record_links_factory(pid, record=None, **kwargs):
+    """Factory for record links generation.
+
+    :param pid: A Persistent Identifier instance.
+    :returns: Dictionary containing a list of useful links for the record.
+    """
+    # Load pid in the global context for the url construction
+    g.pid = pid.pid_value
+    record_endpoint = '.{0}_item'.format(
+        current_records_rest.default_endpoint_prefixes[pid.pid_type])
+    links = dict(
+        self=url_for(record_endpoint, pid_value=pid.pid_value, _external=True),
+        files=url_for(
+                'invenio_records_files.bucket_api',
+                pid_value=pid.pid_value,
+                _external=True
+            )
+    )
+    return links