Merge branch '546-pdf-generation-doesn-t-use-context-processors' into 'master'

Resolve "PDF generation doesn't use context processors"

Closes #546

See merge request !811

CHANGELOG.rst

@@ -18,6 +18,7 @@ Fixed
 ~~~~~
 
 * View for assigning permissions didn't work with some global permissions.
+* PDFs generated in background didn't contain logo or site title.
 
 `2.2.1_ – 2021-12-02
 --------------------

aleksis/core/settings.py

@@ -196,6 +196,14 @@ TEMPLATES = [
     },
 ]
 
+# Attention: The following context processors must accept None
+# as first argument (in addition to a HttpRequest object)
+PDF_CONTEXT_PROCESSORS = [
+    "django.template.context_processors.i18n",
+    "django.template.context_processors.tz",
+    "aleksis.core.util.core_helpers.custom_information_processor",
+]
+
 WSGI_APPLICATION = "aleksis.core.wsgi.application"
 
 # Database

aleksis/core/util/core_helpers.py

@@ -3,7 +3,7 @@ from datetime import datetime, timedelta
 from importlib import import_module, metadata
 from itertools import groupby
 from operator import itemgetter
-from typing import Any, Callable, Optional, Sequence, Union
+from typing import Any, Callable, Dict, Optional, Sequence, Union
 from warnings import warn
 
 from django.conf import settings
@@ -14,6 +14,7 @@ from django.http import HttpRequest
 from django.shortcuts import get_object_or_404
 from django.utils import timezone
 from django.utils.functional import lazy
+from django.utils.module_loading import import_string
 
 from cache_memoize import cache_memoize
 
@@ -198,7 +199,7 @@ def has_person(obj: Union[HttpRequest, Model]) -> bool:
         return True
 
 
-def custom_information_processor(request: HttpRequest) -> dict:
+def custom_information_processor(request: Union[HttpRequest, None]) -> dict:
     """Provide custom information in all templates."""
     from ..models import CustomMenu
 
@@ -316,3 +317,12 @@ def get_allowed_object_ids(request: HttpRequest, models: list) -> list:
         ]
 
     return allowed_object_ids
+
+
+def process_custom_context_processors(context_processors: list) -> Dict[str, Any]:
+    """Process custom context processors."""
+    context = {}
+    processors = tuple(import_string(path) for path in context_processors)
+    for processor in processors:
+        context.update(processor(None))
+    return context

aleksis/core/util/pdf.py

 import os
 import subprocess  # noqa
 from tempfile import TemporaryDirectory
-from typing import Optional, Tuple
+from typing import Optional, Tuple, Union
 from urllib.parse import urljoin
 
 from django.conf import settings
@@ -22,6 +22,7 @@ from celery_progress.backend import ProgressRecorder
 from aleksis.core.celery import app
 from aleksis.core.models import PDFFile
 from aleksis.core.util.celery_progress import recorded_task, render_progress_page
+from aleksis.core.util.core_helpers import process_custom_context_processors
 
 
 @recorded_task
@@ -71,7 +72,12 @@ def generate_pdf_from_template(
     template_name: str, context: Optional[dict] = None, request: Optional[HttpRequest] = None
 ) -> Tuple[PDFFile, AsyncResult]:
     """Start a PDF generation task and return the matching file object and Celery result."""
-    html_template = render_to_string(template_name, context, request)
+    if not request:
+        processed_context = process_custom_context_processors(settings.PDF_CONTEXT_PROCESSORS)
+        processed_context.update(context)
+    else:
+        processed_context = context
+    html_template = render_to_string(template_name, processed_context, request)
 
     file_object = PDFFile.objects.create(html_file=ContentFile(html_template, name="source.html"))
 
@@ -87,7 +93,9 @@ def generate_pdf_from_template(
     return file_object, result
 
 
-def render_pdf(request: HttpRequest, template_name: str, context: dict = None) -> HttpResponse:
+def render_pdf(
+    request: Union[HttpRequest, None], template_name: str, context: dict = None
+) -> HttpResponse:
     """Start PDF generation and show progress page.
 
     The progress page will redirect to the PDF after completion.