V2routing

README.md

@@ -1,3 +1,192 @@
 # Sanic Routing
 
-Internal handler routing for Sanic beginning with v21.3.
+## Background
+
+Beginning in v21.3, Sanic makes use of this new AST-style router in two use cases:
+
+1. Routing paths; and
+2. Routing signals.
+
+Therefore, this package comes with a `BaseRouter` that needs to be subclassed in order to be used for its specific needs. 
+
+Most Sanic users should never need to concern themselves with the details here.
+
+## Basic Example
+
+A simple implementation:
+
+```python
+import logging
+
+from sanic_routing import BaseRouter
+
+logging.basicConfig(level=logging.DEBUG)
+
+
+class Router(BaseRouter):
+    def get(self, path, *args, **kwargs):
+        return self.resolve(path, *args, **kwargs)
+
+
+router = Router()
+
+router.add("/<foo>", lambda: ...)
+router.finalize()
+router.tree.display()
+logging.info(router.find_route_src)
+
+route, handler, params = router.get("/matchme", method="BASE", extra=None)
+```
+
+The above snippet uses `router.tree.display()` to show how the router has decided to arrange the routes into a tree. In this simple example:
+
+```
+<Node: level=0>
+    <Node: part=__dynamic__:str, level=1, groups=[<RouteGroup: path=<foo:str> len=1>], dynamic=True>
+```
+
+We can can see the code that the router has generated for us. It is available as a string at `router.find_route_src`.
+
+```python
+def find_route(path, method, router, basket, extra):
+    parts = tuple(path[1:].split(router.delimiter))
+    num = len(parts)
+
+    # node=1 // part=__dynamic__:str
+    if num == 1:  # CHECK 1
+        try:
+            basket['__matches__'][0] = str(parts[0])
+        except ValueError:
+            pass
+        else:
+            # Return 1
+            return router.dynamic_routes[('<__dynamic__:str>',)][0], basket
+    raise NotFound
+```
+
+_FYI: If you are on Python 3.9, you can see a representation of the source after compilation at `router.find_route_src_compiled`_
+
+## What's it doing?
+
+Therefore, in general implementation requires you to:
+
+1. Define a router with a `get` method;
+2. Add one or more routes;
+3. Finalize the router (`router.finalize()`); and
+4. Call the router's `get` method.
+
+_NOTE: You can call `router.finalize(False)` if you do not want to compile the source code into executable form. This is useful if you only intend to review the generated output._
+
+Every time you call `router.add` you create one (1) new `Route` instance. Even if that one route is created with multiple methods, it generates a single instance. If you `add()` another `Route` that has a similar path structure (but, perhaps has differen methods) they will be grouped together into a `RouteGroup`. It is worth also noting that a `RouteGroup` is created the first time you call `add()`, but subsequent similar routes will reuse the existing grouping instance.
+
+
+When you call `finalize()`, it is taking the defined route groups and arranging them into "nodes" in a hierarchical tree. A single node is a path segment. A `Node` instance can have one or more `RouteGroup` on it where the `Node` is the termination point for that path.
+
+Perhaps an example is easier:
+
+```python
+router.add("/path/to/<foo>", lambda: ...)
+router.add("/path/to/<foo:int>", lambda: ...)
+router.add("/path/to/different/<foo>", lambda: ...)
+router.add("/path/to/different/<foo>", lambda: ..., methods=["one", "two"])
+```
+
+The generated `RouteGroup` instances (3):
+
+```
+<RouteGroup: path=path/to/<foo:str> len=1>
+<RouteGroup: path=path/to/<foo:int> len=1>
+<RouteGroup: path=path/to/different/<foo:str> len=2>
+```
+
+The generated `Route` instances (4):
+
+```
+<Route: path=path/to/<foo:str>>
+<Route: path=path/to/<foo:int>>
+<Route: path=path/to/different/<foo:str>>
+<Route: path=path/to/different/<foo:str>>
+```
+
+The Node Tree:
+
+```
+<Node: level=0>
+    <Node: part=path, level=1>
+        <Node: part=to, level=2>
+            <Node: part=different, level=3>
+                <Node: part=__dynamic__:str, level=4, groups=[<RouteGroup: path=path/to/different/<foo:str> len=2>], dynamic=True>
+            <Node: part=__dynamic__:int, level=3, groups=[<RouteGroup: path=path/to/<foo:int> len=1>], dynamic=True>
+            <Node: part=__dynamic__:str, level=3, groups=[<RouteGroup: path=path/to/<foo:str> len=1>], dynamic=True>
+```
+
+And, the generated source code:
+
+```python
+def find_route(path, method, router, basket, extra):
+    parts = tuple(path[1:].split(router.delimiter))
+    num = len(parts)
+
+    # node=1 // part=path
+    if num > 1:  # CHECK 1
+        if parts[0] == "path":  # CHECK 4
+
+            # node=1.1 // part=to
+            if num > 2:  # CHECK 1
+                if parts[1] == "to":  # CHECK 4
+
+                    # node=1.1.1 // part=different
+                    if num > 3:  # CHECK 1
+                        if parts[2] == "different":  # CHECK 4
+
+                            # node=1.1.1.1 // part=__dynamic__:str
+                            if num == 4:  # CHECK 1
+                                try:
+                                    basket['__matches__'][3] = str(parts[3])
+                                except ValueError:
+                                    pass
+                                else:
+                                    if method in frozenset({'one', 'two'}):
+                                        route_idx = 0
+                                    elif method in frozenset({'BASE'}):
+                                        route_idx = 1
+                                    else:
+                                        raise NoMethod
+                                    # Return 1.1.1.1
+                                    return router.dynamic_routes[('path', 'to', 'different', '<__dynamic__:str>')][route_idx], basket
+
+                    # node=1.1.2 // part=__dynamic__:int
+                    if num >= 3:  # CHECK 1
+                        try:
+                            basket['__matches__'][2] = int(parts[2])
+                        except ValueError:
+                            pass
+                        else:
+                            if num == 3:  # CHECK 5
+                                # Return 1.1.2
+                                return router.dynamic_routes[('path', 'to', '<__dynamic__:int>')][0], basket
+
+                    # node=1.1.3 // part=__dynamic__:str
+                    if num >= 3:  # CHECK 1
+                        try:
+                            basket['__matches__'][2] = str(parts[2])
+                        except ValueError:
+                            pass
+                        else:
+                            if num == 3:  # CHECK 5
+                                # Return 1.1.3
+                                return router.dynamic_routes[('path', 'to', '<__dynamic__:str>')][0], basket
+    raise NotFound
+```
+
+## Special cases
+
+The above example only shows routes that have a dynamic path segment in them (example: `<foo>`). But, there are other use cases that are covered differently:
+
+1. *fully static paths* - These are paths with no parameters (example: `/user/login`). These are basically matched against a key/value store.
+2. *regex paths* - If a route as a single regular expression match, then the whole route will be matched via regex. In general, this happens inline not too dissimilar than what we see in the above example.
+3. *special regex paths* - The router comes with a special `path` type (example: `<foo:path>`) that can match on an expanded delimiter. This is also true for any regex that uses the path delimiter in it. These cannot be matched in the normal course since they are of unknown length.
+
+## What's next?
+
+The current plan is for this code to live outside of the main project, and be merged into `sanic-org/sanic` for the Sanic 21.9 release.

sanic_routing/group.py

@@ -1,10 +1,29 @@
+from __future__ import annotations
+
+from typing import FrozenSet, List, Sequence
+
+from sanic_routing.route import Requirements, Route
 from sanic_routing.utils import Immutable
 
 from .exceptions import InvalidUsage, RouteExists
 
 
 class RouteGroup:
     methods_index: Immutable
+    passthru_properties = (
+        "labels",
+        "params",
+        "parts",
+        "path",
+        "pattern",
+        "raw_path",
+        "regex",
+        "router",
+        "segments",
+        "strict",
+        "unquote",
+        "uri",
+    )
 
     def __init__(self, *routes) -> None:
         if len(set(route.parts for route in routes)) > 1:
@@ -25,12 +44,26 @@ def __str__(self):
         )
         return f"<{self.__class__.__name__}: {display}>"
 
+    def __repr__(self) -> str:
+        return str(self)
+
     def __iter__(self):
         return iter(self.routes)
 
     def __getitem__(self, key):
         return self.routes[key]
 
+    def __getattr__(self, key):
+        # There are a number of properties that all of the routes in the group
+        # share in common. We pass thrm through to make them available
+        # on the RouteGroup, and then cache them so that they are permanent.
+        if key in self.passthru_properties:
+            value = getattr(self[0], key)
+            setattr(self, key, value)
+            return value
+
+        raise AttributeError(f"RouteGroup has no '{key}' attribute")
+
     def finalize(self):
         self.methods_index = Immutable(
             {
@@ -43,7 +76,39 @@ def finalize(self):
     def reset(self):
         self.methods_index = dict(self.methods_index)
 
-    def merge(self, group, overwrite: bool = False, append: bool = False):
+    def merge(
+        self, group: RouteGroup, overwrite: bool = False, append: bool = False
+    ) -> None:
+        """
+        The purpose of merge is to group routes with the same path, but
+        declarared individually. In other words to group these:
+
+            @app.get("/path/to")
+            def handler1(...):
+                ...
+
+            @app.post("/path/to")
+            def handler2(...):
+                ...
+
+        The other main purpose is to look for conflicts and
+        raise ``RouteExists``
+
+        A duplicate route is when:
+        1. They have the same path and any overlapping methods; AND
+        2. If they have requirements, they are the same
+
+        :param group: Incoming route group
+        :type group: RouteGroup
+        :param overwrite: whether to allow an otherwise duplicate route group
+            to overwrite the existing, if ``True`` will not raise exception
+            on duplicates, defaults to False
+        :type overwrite: bool, optional
+        :param append: whether to allow an otherwise duplicate route group to
+            append its routes to the existing route group, defaults to False
+        :type append: bool, optional
+        :raises RouteExists: Raised when there is a duplicate
+        """
         _routes = list(self._routes)
         for other_route in group.routes:
             for current_route in self:
@@ -68,55 +133,26 @@ def merge(self, group, overwrite: bool = False, append: bool = False):
         self._routes = tuple(_routes)
 
     @property
-    def labels(self):
-        return self[0].labels
+    def depth(self) -> int:
+        return len(self[0].parts)
 
     @property
-    def methods(self):
-        return frozenset(
-            [method for route in self for method in route.methods]
+    def dynamic_path(self) -> bool:
+        return any(
+            (param.label == "path") or (r"/" in param.label)
+            for param in self.params.values()
         )
 
     @property
-    def params(self):
-        return self[0].params
-
-    @property
-    def parts(self):
-        return self[0].parts
-
-    @property
-    def path(self):
-        return self[0].path
-
-    @property
-    def pattern(self):
-        return self[0].pattern
-
-    @property
-    def raw_path(self):
-        return self[0].raw_path
-
-    @property
-    def regex(self):
-        return self[0].regex
-
-    @property
-    def requirements(self):
-        return [route.requirements for route in self if route.requirements]
+    def methods(self) -> FrozenSet[str]:
+        return frozenset(
+            [method for route in self for method in route.methods]
+        )
 
     @property
-    def routes(self):
+    def routes(self) -> Sequence[Route]:
         return self._routes
 
     @property
-    def router(self):
-        return self[0].router
-
-    @property
-    def strict(self):
-        return self[0].strict
-
-    @property
-    def unquote(self):
-        return self[0].unquote
+    def requirements(self) -> List[Requirements]:
+        return [route.requirements for route in self if route.requirements]