From 6a8214ebb93fa6f03ad2bf110c3d807c39702ae8 Mon Sep 17 00:00:00 2001
From: Wim De Clercq <declewi@gmail.com>
Date: Thu, 18 Jul 2024 10:21:13 +0200
Subject: [PATCH] Guarantee a session factory to be set.

Issue #891
---
 atramhasis/__init__.py | 77 ++++++++++++++++++++++++++++++++----------
 1 file changed, 60 insertions(+), 17 deletions(-)

diff --git a/atramhasis/__init__.py b/atramhasis/__init__.py
index 09026f24..920514b1 100644
--- a/atramhasis/__init__.py
+++ b/atramhasis/__init__.py
@@ -1,10 +1,16 @@
+import logging
 import os
 
 from pyramid.config import Configurator
+from pyramid.config import PHASE2_CONFIG
+from pyramid.interfaces import ISessionFactory
+from pyramid.session import SignedCookieSessionFactory
 from pyramid.settings import aslist
 
 from atramhasis.renderers import json_renderer_verbose
 
+LOG = logging.getLogger(__name__)
+
 
 DEFAULT_SETTINGS = {
     "cache.tree.backend": "dogpile.cache.memory",
@@ -29,30 +35,64 @@ def includeme(config):
         if key not in settings:
             settings[key] = value
 
-    config.include('pyramid_jinja2')
-    config.include('pyramid_tm')
-    config.add_static_view('static', 'static', cache_max_age=3600)
-    config.add_renderer('csv', 'atramhasis.renderers.CSVRenderer')
-    config.add_renderer('skosrenderer_verbose', json_renderer_verbose)
+    configure_session(config)
+    config.include("pyramid_jinja2")
+    config.include("pyramid_tm")
+    config.add_static_view("static", "static", cache_max_age=3600)
+    config.add_renderer("csv", "atramhasis.renderers.CSVRenderer")
+    config.add_renderer("skosrenderer_verbose", json_renderer_verbose)
     # Rewrite urls with trailing slash
-    config.include('pyramid_rewrite')
+    config.include("pyramid_rewrite")
     config.include("pyramid_openapi3")
-    config.include('atramhasis.routes')
-    config.include('pyramid_skosprovider')
-    config.include('atramhasis.cache')
-    config.scan('pyramid_skosprovider')
+    config.include("atramhasis.routes")
+    config.include("pyramid_skosprovider")
+    config.include("atramhasis.cache")
+    config.scan("pyramid_skosprovider")
 
-    config.add_translation_dirs('atramhasis:locale/')
+    config.add_translation_dirs("atramhasis:locale/")
 
     config.scan()
 
 
-def main(global_config, **settings):
-    """ This function returns a Pyramid WSGI application.
+def configure_session(config):
+    """
+    Configure pyramid's session factory.
+
+    People can configure their own session factory, but if no factory is registered
+    atramhasis will try configuring its own.
     """
-    settings['layout.focus_conceptschemes'] = aslist(settings['layout.focus_conceptschemes'], flatten=False)
 
-    dump_location = settings['atramhasis.dump_location']
+    def check_session_factory_set():
+        session_factory = config.registry.queryUtility(ISessionFactory)
+        if session_factory:
+            return
+
+        settings = config.registry.settings
+        if "atramhasis.session_factory.secret" not in settings:
+            msg = (
+                "No session factory is configured, and "
+                "atramhasis.session_factory.secret setting is missing."
+            )
+            raise ValueError(msg)
+
+        LOG.info("Using default SignedCookieSessionFactory.")
+        default_session_factory = SignedCookieSessionFactory(
+            settings["atramhasis.session_factory.secret"]
+        )
+        config.set_session_factory(default_session_factory)
+
+    config.action(
+        "check_session_factory_set", check_session_factory_set, order=PHASE2_CONFIG
+    )
+
+
+def main(global_config, **settings):
+    """This function returns a Pyramid WSGI application."""
+    settings["layout.focus_conceptschemes"] = aslist(
+        settings["layout.focus_conceptschemes"], flatten=False
+    )
+
+    dump_location = settings["atramhasis.dump_location"]
     if not os.path.exists(dump_location):
         os.makedirs(dump_location)
 
@@ -63,11 +103,14 @@ def main(global_config, **settings):
 
 def load_app(config, settings):
     from pyramid.session import SignedCookieSessionFactory
-    atramhasis_session_factory = SignedCookieSessionFactory(settings['atramhasis.session_factory.secret'])
+
+    atramhasis_session_factory = SignedCookieSessionFactory(
+        settings["atramhasis.session_factory.secret"]
+    )
     config.set_session_factory(atramhasis_session_factory)
 
     includeme(config)
 
-    config.include('atramhasis.data:db')
+    config.include("atramhasis.data:db")
 
     return config.make_wsgi_app()