build(debug): add django-debug-toolbar to debug dependencies

configure urls.py and settings.py to allow the toolbar to show
when DEBUG = True

app/public/cantusdata/settings.py

@@ -33,7 +33,7 @@
 
 # Application definition
 
-INSTALLED_APPS = (
+INSTALLED_APPS = [
     # Template apps
     "django.contrib.admin",
     "django.contrib.auth",
@@ -46,20 +46,23 @@
     "rest_framework",
     "rest_framework.authtoken",
     "cantusdata.CantusdataConfig",
-)
+]
 
 if DEBUG:
-    INSTALLED_APPS += ("django_extensions",)
+    INSTALLED_APPS.extend(["django_extensions", "debug_toolbar"])
 
-MIDDLEWARE = (
+MIDDLEWARE = [
     "django.middleware.security.SecurityMiddleware",  # Migration: + django 3.1
     "django.contrib.sessions.middleware.SessionMiddleware",
     "django.middleware.common.CommonMiddleware",
     "django.middleware.csrf.CsrfViewMiddleware",
     "django.contrib.auth.middleware.AuthenticationMiddleware",
     "django.contrib.messages.middleware.MessageMiddleware",
     "django.middleware.clickjacking.XFrameOptionsMiddleware",
-)
+]
+
+if DEBUG:
+    MIDDLEWARE.insert(0, "debug_toolbar.middleware.DebugToolbarMiddleware")
 
 ROOT_URLCONF = "cantusdata.urls"
 
@@ -179,3 +182,9 @@
 CELERY_RESULT_EXTENDED = True
 CELERY_APP = "cantusdata"
 CELERY_TASK_TRACK_STARTED = True
+
+DEBUG_TOOLBAR_CONFIG = {
+    "SHOW_TOOLBAR_CALLBACK": lambda request: (
+        False if request.headers.get("x-requested-with") == "XMLHttpRequest" else True
+    ),
+}

app/public/cantusdata/urls.py

@@ -1,5 +1,6 @@
 # from django.conf.urls import patterns, include, url
 from django.contrib import admin
+from django.conf import settings
 from django.urls import path
 from rest_framework.urlpatterns import format_suffix_patterns
 from cantusdata.views.browse import browse_view
@@ -110,5 +111,9 @@
 # Disambiguates json/html/browsable-api urls
 urlpatterns = format_suffix_patterns(urlpatterns)
 
+if settings.DEBUG:
+    from debug_toolbar.toolbar import debug_toolbar_urls  # type: ignore
+
+    urlpatterns += debug_toolbar_urls()
 
 admin.site.site_header = "Cantus Ultimus Admin"