From 64d44192cc0615980f4f5307b0631c83db4176e7 Mon Sep 17 00:00:00 2001
From: Adam Hopkins <adam@amhopkins.com>
Date: Thu, 17 Feb 2022 12:10:18 +0200
Subject: [PATCH] Add alt-svc header touchup

---
 sanic/http/http1.py               |  6 ++++++
 sanic/touchup/schemes/__init__.py |  1 +
 sanic/touchup/schemes/base.py     | 26 ++++++++++++++++++++++----
 sanic/touchup/schemes/ode.py      | 22 ++++++----------------
 sanic/touchup/service.py          |  6 ++----
 5 files changed, 37 insertions(+), 24 deletions(-)

diff --git a/sanic/http/http1.py b/sanic/http/http1.py
index 96232fb5..111357cb 100644
--- a/sanic/http/http1.py
+++ b/sanic/http/http1.py
@@ -333,6 +333,12 @@ class Http(metaclass=TouchUpMeta):
             self.response_func = self.head_response_ignored
 
         headers["connection"] = "keep-alive" if self.keep_alive else "close"
+
+        # This header may be removed or modified by the AltSvcCheck Touchup
+        # service. At server start, we either remove this header from ever
+        # being assigned, or we change the value as required.
+        headers["alt-svc"] = ""
+
         ret = format_http1_response(status, res.processed_headers)
         if data:
             ret += data
diff --git a/sanic/touchup/schemes/__init__.py b/sanic/touchup/schemes/__init__.py
index 87057a5f..dd4145ab 100644
--- a/sanic/touchup/schemes/__init__.py
+++ b/sanic/touchup/schemes/__init__.py
@@ -1,3 +1,4 @@
+from .altsvc import AltSvcCheck  # noqa
 from .base import BaseScheme
 from .ode import OptionalDispatchEvent  # noqa
 
diff --git a/sanic/touchup/schemes/base.py b/sanic/touchup/schemes/base.py
index d16619b2..9e32c323 100644
--- a/sanic/touchup/schemes/base.py
+++ b/sanic/touchup/schemes/base.py
@@ -1,5 +1,8 @@
 from abc import ABC, abstractmethod
-from typing import Set, Type
+from ast import NodeTransformer, parse
+from inspect import getsource
+from textwrap import dedent
+from typing import Any, Dict, List, Set, Type
 
 
 class BaseScheme(ABC):
@@ -10,11 +13,26 @@ class BaseScheme(ABC):
         self.app = app
 
     @abstractmethod
-    def run(self, method, module_globals) -> None:
+    def visitors(self) -> List[NodeTransformer]:
         ...
 
     def __init_subclass__(cls):
         BaseScheme._registry.add(cls)
 
-    def __call__(self, method, module_globals):
-        return self.run(method, module_globals)
+    def __call__(self):
+        return self.visitors()
+
+    @classmethod
+    def build(cls, method, module_globals, app):
+        raw_source = getsource(method)
+        src = dedent(raw_source)
+        node = parse(src)
+
+        for scheme in cls._registry:
+            for visitor in scheme(app)():
+                node = visitor.visit(node)
+
+        compiled_src = compile(node, method.__name__, "exec")
+        exec_locals: Dict[str, Any] = {}
+        exec(compiled_src, module_globals, exec_locals)  # nosec
+        return exec_locals[method.__name__]
diff --git a/sanic/touchup/schemes/ode.py b/sanic/touchup/schemes/ode.py
index 7c6ed3d7..c9b78c8b 100644
--- a/sanic/touchup/schemes/ode.py
+++ b/sanic/touchup/schemes/ode.py
@@ -1,7 +1,5 @@
-from ast import Attribute, Await, Dict, Expr, NodeTransformer, parse
-from inspect import getsource
-from textwrap import dedent
-from typing import Any
+from ast import Attribute, Await, Expr, NodeTransformer
+from typing import Any, List
 
 from sanic.log import logger
 
@@ -20,18 +18,10 @@ class OptionalDispatchEvent(BaseScheme):
             signal.name for signal in app.signal_router.routes
         ]
 
-    def run(self, method, module_globals):
-        raw_source = getsource(method)
-        src = dedent(raw_source)
-        tree = parse(src)
-        node = RemoveDispatch(
-            self._registered_events, self.app.state.verbosity
-        ).visit(tree)
-        compiled_src = compile(node, method.__name__, "exec")
-        exec_locals: Dict[str, Any] = {}
-        exec(compiled_src, module_globals, exec_locals)  # nosec
-
-        return exec_locals[method.__name__]
+    def visitors(self) -> List[NodeTransformer]:
+        return [
+            RemoveDispatch(self._registered_events, self.app.state.verbosity)
+        ]
 
     def _sync_events(self):
         all_events = set()
diff --git a/sanic/touchup/service.py b/sanic/touchup/service.py
index 95792dca..b1b996fb 100644
--- a/sanic/touchup/service.py
+++ b/sanic/touchup/service.py
@@ -21,10 +21,8 @@ class TouchUp:
 
             module = getmodule(target)
             module_globals = dict(getmembers(module))
-
-            for scheme in BaseScheme._registry:
-                modified = scheme(app)(method, module_globals)
-                setattr(target, method_name, modified)
+            modified = BaseScheme.build(method, module_globals, app)
+            setattr(target, method_name, modified)
 
             target.__touched__ = True