uploads: Add LOCAL_AVATARS_DIR / LOCAL_FILES_DIR computed settings.

This avoids strewing "avatars" and "files" constants throughout.

zproject/computed_settings.py

@@ -40,6 +40,7 @@ from .configured_settings import (
     EXTRA_INSTALLED_APPS,
     GOOGLE_OAUTH2_CLIENT_ID,
     IS_DEV_DROPLET,
+    LOCAL_UPLOADS_DIR,
     MEMCACHED_LOCATION,
     MEMCACHED_USERNAME,
     RATE_LIMITING_RULES,
@@ -539,6 +540,9 @@ if PRODUCTION or IS_DEV_DROPLET or os.getenv("EXTERNAL_HOST") is not None:
 else:
     STATIC_URL = "http://localhost:9991/static/"
 
+LOCAL_AVATARS_DIR = os.path.join(LOCAL_UPLOADS_DIR, "avatars") if LOCAL_UPLOADS_DIR else None
+LOCAL_FILES_DIR = os.path.join(LOCAL_UPLOADS_DIR, "files") if LOCAL_UPLOADS_DIR else None
+
 # ZulipStorage is a modified version of ManifestStaticFilesStorage,
 # and, like that class, it inserts a file hash into filenames
 # to prevent the browser from using stale files from cache.

zproject/default_settings.py

@@ -141,6 +141,8 @@ S3_REGION: Optional[str] = None
 S3_ENDPOINT_URL: Optional[str] = None
 S3_SKIP_PROXY = True
 LOCAL_UPLOADS_DIR: Optional[str] = None
+LOCAL_AVATARS_DIR: Optional[str] = None
+LOCAL_FILES_DIR: Optional[str] = None
 MAX_FILE_UPLOAD_SIZE = 25
 
 # Jitsi Meet video call integration; set to None to disable integration.

zproject/dev_urls.py

@@ -125,10 +125,10 @@ i18n_urls = [
 urls += i18n_urls
 
 # On a production instance, these files would be served by nginx.
-if settings.LOCAL_UPLOADS_DIR is not None:
+if settings.LOCAL_AVATARS_DIR is not None:
     avatars_url = path(
         "user_avatars/<path:path>",
         serve,
-        {"document_root": os.path.join(settings.LOCAL_UPLOADS_DIR, "avatars")},
+        {"document_root": os.path.join(settings.LOCAL_AVATARS_DIR)},
     )
     urls += [avatars_url]