Move tweens into a module

tildes/tildes/__init__.py

@@ -3,17 +3,13 @@
 
 """Configure and initialize the Pyramid app."""
 
-from time import time
-from typing import Any, Callable, Dict, Optional, Tuple
+from typing import Any, Dict, Optional, Tuple
 
 from marshmallow.exceptions import ValidationError
 from paste.deploy.config import PrefixMiddleware
-from prometheus_client import Histogram
 from pyramid.config import Configurator
 from pyramid.httpexceptions import HTTPTooManyRequests
-from pyramid.registry import Registry
 from pyramid.request import Request
-from pyramid.response import Response
 from redis import Redis
 import sentry_sdk
 from sentry_sdk.integrations.pyramid import PyramidIntegration
@@ -43,9 +39,9 @@ def main(global_config: Dict[str, str], **settings: str) -> PrefixMiddleware:
 
     config.scan("tildes.views")
 
-    config.add_tween("tildes.http_method_tween_factory")
-    config.add_tween("tildes.metrics_tween_factory")
-    config.add_tween("tildes.theme_cookie_tween_factory")
+    config.add_tween("tildes.tweens.http_method_tween_factory")
+    config.add_tween("tildes.tweens.metrics_tween_factory")
+    config.add_tween("tildes.tweens.theme_cookie_tween_factory")
 
     config.add_static_view("images", "/images")
 
@@ -86,90 +82,6 @@ def main(global_config: Dict[str, str], **settings: str) -> PrefixMiddleware:
     return prefixed_app
 
 
-def http_method_tween_factory(handler: Callable, registry: Registry) -> Callable:
-    # pylint: disable=unused-argument
-    """Return a tween function that can override the request's HTTP method."""
-
-    def method_override_tween(request: Request) -> Request:
-        """Override HTTP method with one specified in header."""
-        valid_overrides_by_method = {"POST": ["DELETE", "PATCH", "PUT"]}
-
-        original_method = request.method.upper()
-        valid_overrides = valid_overrides_by_method.get(original_method, [])
-        override = request.headers.get("X-HTTP-Method-Override", "").upper()
-
-        if override in valid_overrides:
-            request.method = override
-
-        return handler(request)
-
-    return method_override_tween
-
-
-def metrics_tween_factory(handler: Callable, registry: Registry) -> Callable:
-    # pylint: disable=unused-argument
-    """Return a tween function that gathers metrics for Prometheus."""
-
-    request_histogram = Histogram(
-        "tildes_pyramid_requests_seconds",
-        "Request processing times",
-        labelnames=["route", "status_code", "method", "logged_in"],
-    )
-
-    def metrics_tween(request: Request) -> Response:
-        """Gather metrics for each request."""
-        start_time = time()
-        response = handler(request)
-        duration = time() - start_time
-
-        # ignore requests for invalid addresses
-        if not request.matched_route:
-            return response
-
-        request_histogram.labels(
-            route=request.matched_route.name,
-            status_code=response.status_code,
-            method=request.method,
-            logged_in=str(bool(request.user)).lower(),
-        ).observe(duration)
-
-        return response
-
-    return metrics_tween
-
-
-def theme_cookie_tween_factory(handler: Callable, registry: Registry) -> Callable:
-    # pylint: disable=unused-argument
-    """Return a tween function that sets the theme cookie."""
-
-    def theme_cookie_tween(request: Request) -> Response:
-        """Set the theme cookie if needed (currently always, see comment below)."""
-        response = handler(request)
-
-        current_theme = request.cookies.get("theme", "")
-        if not current_theme and request.user:
-            current_theme = request.user.theme_default
-
-        # Currently, we want to always set the theme cookie. This is because we
-        # recently started setting the domain on this cookie (to be able to apply the
-        # user's theme to the Blog/Docs sites), and all older cookies won't have a
-        # domain set. This will basically let us convert the old no-domain cookies to
-        # new ones. After a decent amount of time (maybe sometime in April 2019), we
-        # can change this to only set the cookie when it's not already present and the
-        # user has a default theme set (so their default theme will work for Blog/Docs).
-        if current_theme:
-            response.set_cookie(
-                "theme",
-                current_theme,
-                max_age=315360000,
-                secure=True,
-                domain="." + request.domain,
-            )
-        return response
-
-    return theme_cookie_tween
-
-
 def get_redis_connection(request: Request) -> Redis:
     """Return a connection to the Redis server."""
     socket = request.registry.settings["redis.unix_socket_path"]

tildes/tildes/tweens.py

@@ -0,0 +1,96 @@
+# Copyright (c) 2019 Tildes contributors <code@tildes.net>
+# SPDX-License-Identifier: AGPL-3.0-or-later
+
+"""Contains Pyramid "tweens", used to insert additional logic into request-handling."""
+
+from time import time
+from typing import Callable
+
+from prometheus_client import Histogram
+from pyramid.registry import Registry
+from pyramid.request import Request
+from pyramid.response import Response
+
+
+def http_method_tween_factory(handler: Callable, registry: Registry) -> Callable:
+    # pylint: disable=unused-argument
+    """Return a tween function that can override the request's HTTP method."""
+
+    def method_override_tween(request: Request) -> Response:
+        """Override HTTP method with one specified in header."""
+        valid_overrides_by_method = {"POST": ["DELETE", "PATCH", "PUT"]}
+
+        original_method = request.method.upper()
+        valid_overrides = valid_overrides_by_method.get(original_method, [])
+        override = request.headers.get("X-HTTP-Method-Override", "").upper()
+
+        if override in valid_overrides:
+            request.method = override
+
+        return handler(request)
+
+    return method_override_tween
+
+
+def metrics_tween_factory(handler: Callable, registry: Registry) -> Callable:
+    # pylint: disable=unused-argument
+    """Return a tween function that gathers metrics for Prometheus."""
+
+    request_histogram = Histogram(
+        "tildes_pyramid_requests_seconds",
+        "Request processing times",
+        labelnames=["route", "status_code", "method", "logged_in"],
+    )
+
+    def metrics_tween(request: Request) -> Response:
+        """Gather metrics for each request."""
+        start_time = time()
+        response = handler(request)
+        duration = time() - start_time
+
+        # ignore requests for invalid addresses
+        if not request.matched_route:
+            return response
+
+        request_histogram.labels(
+            route=request.matched_route.name,
+            status_code=response.status_code,
+            method=request.method,
+            logged_in=str(bool(request.user)).lower(),
+        ).observe(duration)
+
+        return response
+
+    return metrics_tween
+
+
+def theme_cookie_tween_factory(handler: Callable, registry: Registry) -> Callable:
+    # pylint: disable=unused-argument
+    """Return a tween function that sets the theme cookie."""
+
+    def theme_cookie_tween(request: Request) -> Response:
+        """Set the theme cookie if needed (currently always, see comment below)."""
+        response = handler(request)
+
+        current_theme = request.cookies.get("theme", "")
+        if not current_theme and request.user:
+            current_theme = request.user.theme_default
+
+        # Currently, we want to always set the theme cookie. This is because we
+        # recently started setting the domain on this cookie (to be able to apply the
+        # user's theme to the Blog/Docs sites), and all older cookies won't have a
+        # domain set. This will basically let us convert the old no-domain cookies to
+        # new ones. After a decent amount of time (maybe sometime in April 2019), we
+        # can change this to only set the cookie when it's not already present and the
+        # user has a default theme set (so their default theme will work for Blog/Docs).
+        if current_theme:
+            response.set_cookie(
+                "theme",
+                current_theme,
+                max_age=315360000,
+                secure=True,
+                domain="." + request.domain,
+            )
+        return response
+
+    return theme_cookie_tween