HTTP/3 Support (#2378)

sanic/touchup/schemes/__init__.py

@@ -1,3 +1,4 @@
+from .altsvc import AltSvcCheck  # noqa
 from .base import BaseScheme
 from .ode import OptionalDispatchEvent  # noqa
 

sanic/touchup/schemes/altsvc.py

@@ -0,0 +1,56 @@
+from __future__ import annotations
+
+from ast import Assign, Constant, NodeTransformer, Subscript
+from typing import TYPE_CHECKING, Any, List
+
+from sanic.http.constants import HTTP
+
+from .base import BaseScheme
+
+
+if TYPE_CHECKING:
+    from sanic import Sanic
+
+
+class AltSvcCheck(BaseScheme):
+    ident = "ALTSVC"
+
+    def visitors(self) -> List[NodeTransformer]:
+        return [RemoveAltSvc(self.app, self.app.state.verbosity)]
+
+
+class RemoveAltSvc(NodeTransformer):
+    def __init__(self, app: Sanic, verbosity: int = 0) -> None:
+        self._app = app
+        self._verbosity = verbosity
+        self._versions = {
+            info.settings["version"] for info in app.state.server_info
+        }
+
+    def visit_Assign(self, node: Assign) -> Any:
+        if any(self._matches(target) for target in node.targets):
+            if self._should_remove():
+                return None
+            assert isinstance(node.value, Constant)
+            node.value.value = self.value()
+        return node
+
+    def _should_remove(self) -> bool:
+        return len(self._versions) == 1
+
+    @staticmethod
+    def _matches(node) -> bool:
+        return (
+            isinstance(node, Subscript)
+            and isinstance(node.slice, Constant)
+            and node.slice.value == "alt-svc"
+        )
+
+    def value(self):
+        values = []
+        for info in self._app.state.server_info:
+            port = info.settings["port"]
+            version = info.settings["version"]
+            if version is HTTP.VERSION_3:
+                values.append(f'h3=":{port}"')
+        return ", ".join(values)

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__]

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
 
@@ -20,16 +18,8 @@ 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).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)]
 
     def _sync_events(self):
         all_events = set()

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