Enable Middleware Support for Blueprint Groups (#1399)

* enable blueprint group middleware support

This commit will enable the users to implement a middleware at the
blueprint group level whereby enforcing the middleware automatically to
each of the available Blueprints that are part of the group.

This will eanble a simple way in which a certain set of common features
and criteria can be enforced on a Blueprint group. i.e. authentication
and authorization

This commit will address the feature request raised as part of Issue #1386

Signed-off-by: Harsha Narayana <harsha2k4@gmail.com>

* enable indexing of BlueprintGroup object

Signed-off-by: Harsha Narayana <harsha2k4@gmail.com>

* rename blueprint group file to fix spelling error

Signed-off-by: Harsha Narayana <harsha2k4@gmail.com>

* add documentation and additional unit tests

Signed-off-by: Harsha Narayana <harsha2k4@gmail.com>

* cleanup and optimize headers in unit test file

Signed-off-by: Harsha Narayana <harsha2k4@gmail.com>

* fix Bluprint Group iteratable method

Signed-off-by: Harsha Narayana <harsha2k4@gmail.com>

* add additional unit test to check StopIteration condition

Signed-off-by: Harsha Narayana <harsha2k4@gmail.com>

* cleanup iter protocol implemenation for blueprint group and add slots

Signed-off-by: Harsha Narayana <harsha2k4@gmail.com>

* fix blueprint group middleware invocation identification

Signed-off-by: Harsha Narayana <harsha2k4@gmail.com>

* feat: enable list behavior on blueprint group object and use append instead of properly to add blueprint to group

Signed-off-by: Harsha Narayana <harsha2k4@gmail.com>

tests/test_blueprint_group.py

@@ -0,0 +1,180 @@
+from pytest import raises
+
+from sanic.app import Sanic
+from sanic.blueprints import Blueprint
+from sanic.request import Request
+from sanic.response import text, HTTPResponse
+
+MIDDLEWARE_INVOKE_COUNTER = {"request": 0, "response": 0}
+
+AUTH = "dGVzdDp0ZXN0Cg=="
+
+
+def test_bp_group_indexing(app: Sanic):
+    blueprint_1 = Blueprint("blueprint_1", url_prefix="/bp1")
+    blueprint_2 = Blueprint("blueprint_2", url_prefix="/bp2")
+
+    group = Blueprint.group(blueprint_1, blueprint_2)
+    assert group[0] == blueprint_1
+
+    with raises(expected_exception=IndexError) as e:
+        _ = group[3]
+
+
+def test_bp_group_with_additional_route_params(app: Sanic):
+    blueprint_1 = Blueprint("blueprint_1", url_prefix="/bp1")
+    blueprint_2 = Blueprint("blueprint_2", url_prefix="/bp2")
+
+    @blueprint_1.route(
+        "/request_path", methods=frozenset({"PUT", "POST"}), version=2
+    )
+    def blueprint_1_v2_method_with_put_and_post(request: Request):
+        if request.method == "PUT":
+            return text("PUT_OK")
+        elif request.method == "POST":
+            return text("POST_OK")
+
+    @blueprint_2.route(
+        "/route/<param>", methods=frozenset({"DELETE", "PATCH"}), name="test"
+    )
+    def blueprint_2_named_method(request: Request, param):
+        if request.method == "DELETE":
+            return text("DELETE_{}".format(param))
+        elif request.method == "PATCH":
+            return text("PATCH_{}".format(param))
+
+    blueprint_group = Blueprint.group(
+        blueprint_1, blueprint_2, url_prefix="/api"
+    )
+
+    @blueprint_group.middleware("request")
+    def authenticate_request(request: Request):
+        global AUTH
+        auth = request.headers.get("authorization")
+        if auth:
+            # Dummy auth check. We can have anything here and it's fine.
+            if AUTH not in auth:
+                return text("Unauthorized", status=401)
+        else:
+            return text("Unauthorized", status=401)
+
+    @blueprint_group.middleware("response")
+    def enhance_response_middleware(request: Request, response: HTTPResponse):
+        response.headers.add("x-test-middleware", "value")
+
+    app.blueprint(blueprint_group)
+
+    header = {"authorization": " ".join(["Basic", AUTH])}
+    _, response = app.test_client.put(
+        "/v2/api/bp1/request_path", headers=header
+    )
+    assert response.text == "PUT_OK"
+    assert response.headers.get("x-test-middleware") == "value"
+
+    _, response = app.test_client.post(
+        "/v2/api/bp1/request_path", headers=header
+    )
+    assert response.text == "POST_OK"
+
+    _, response = app.test_client.delete("/api/bp2/route/bp2", headers=header)
+    assert response.text == "DELETE_bp2"
+
+    _, response = app.test_client.patch("/api/bp2/route/bp2", headers=header)
+    assert response.text == "PATCH_bp2"
+
+    _, response = app.test_client.get("/v2/api/bp1/request_path")
+    assert response.status == 401
+
+
+def test_bp_group(app: Sanic):
+    blueprint_1 = Blueprint("blueprint_1", url_prefix="/bp1")
+    blueprint_2 = Blueprint("blueprint_2", url_prefix="/bp2")
+
+    @blueprint_1.route("/")
+    def blueprint_1_default_route(request):
+        return text("BP1_OK")
+
+    @blueprint_2.route("/")
+    def blueprint_2_default_route(request):
+        return text("BP2_OK")
+
+    blueprint_group_1 = Blueprint.group(
+        blueprint_1, blueprint_2, url_prefix="/bp"
+    )
+
+    blueprint_3 = Blueprint("blueprint_3", url_prefix="/bp3")
+
+    @blueprint_group_1.middleware("request")
+    def blueprint_group_1_middleware(request):
+        global MIDDLEWARE_INVOKE_COUNTER
+        MIDDLEWARE_INVOKE_COUNTER["request"] += 1
+
+    @blueprint_3.route("/")
+    def blueprint_3_default_route(request):
+        return text("BP3_OK")
+
+    blueprint_group_2 = Blueprint.group(
+        blueprint_group_1, blueprint_3, url_prefix="/api"
+    )
+
+    @blueprint_group_2.middleware("response")
+    def blueprint_group_2_middleware(request, response):
+        global MIDDLEWARE_INVOKE_COUNTER
+        MIDDLEWARE_INVOKE_COUNTER["response"] += 1
+
+    app.blueprint(blueprint_group_2)
+
+    @app.route("/")
+    def app_default_route(request):
+        return text("APP_OK")
+
+    _, response = app.test_client.get("/")
+    assert response.text == "APP_OK"
+
+    _, response = app.test_client.get("/api/bp/bp1")
+    assert response.text == "BP1_OK"
+
+    _, response = app.test_client.get("/api/bp/bp2")
+    assert response.text == "BP2_OK"
+
+    _, response = app.test_client.get("/api/bp3")
+    assert response.text == "BP3_OK"
+
+    assert MIDDLEWARE_INVOKE_COUNTER["response"] == 4
+    assert MIDDLEWARE_INVOKE_COUNTER["request"] == 4
+
+
+def test_bp_group_list_operations(app: Sanic):
+    blueprint_1 = Blueprint("blueprint_1", url_prefix="/bp1")
+    blueprint_2 = Blueprint("blueprint_2", url_prefix="/bp2")
+
+    @blueprint_1.route("/")
+    def blueprint_1_default_route(request):
+        return text("BP1_OK")
+
+    @blueprint_2.route("/")
+    def blueprint_2_default_route(request):
+        return text("BP2_OK")
+
+    blueprint_group_1 = Blueprint.group(
+        blueprint_1, blueprint_2, url_prefix="/bp"
+    )
+
+    blueprint_3 = Blueprint("blueprint_2", url_prefix="/bp3")
+
+    @blueprint_3.route("/second")
+    def blueprint_3_second_route(request):
+        return text("BP3_OK")
+
+    assert len(blueprint_group_1) == 2
+
+    blueprint_group_1.append(blueprint_3)
+    assert len(blueprint_group_1) == 3
+
+    del blueprint_group_1[2]
+    assert len(blueprint_group_1) == 2
+
+    blueprint_group_1[1] = blueprint_3
+    assert len(blueprint_group_1) == 2
+
+    assert blueprint_group_1.url_prefix == "/bp"