fix SERVER_NAME enforcement in url_for and request.args documentation (#1708)

* 🐛 fix SERVER_NAME enforcement in url_for

fixes #1707

* 💡 add additional documentation for using request.args

fixes #1704

* ✅ add additional test to check url_for without SERVER_NAME

* 📝 add changelog for fixes

changelogs/1704.doc.rst

@@ -0,0 +1,3 @@
+Fix documentation for `get` and `getlist` of the `request.args`
+
+Add additional example for showing the usage of `getlist` and fix the documentation string for `request.args` behavior

changelogs/1707.bugfix.rst

@@ -0,0 +1,4 @@
+Fix `url_for` behavior with missing SERVER_NAME
+
+If the `SERVER_NAME` was missing in the `app.config` entity, the `url_for` on the `request` and  `app` were failing
+due to an `AttributeError`. This fix makes the availability of `SERVER_NAME` on our `app.config` an optional behavior.

docs/sanic/request_data.md

@@ -204,9 +204,8 @@ The output will be:
 
 ## Accessing values using `get` and `getlist`
 
-The request properties which return a dictionary actually return a subclass of
-`dict` called `RequestParameters`. The key difference when using this object is
-the distinction between the `get` and `getlist` methods.
+The `request.args` returns a subclass of `dict` called `RequestParameters`. 
+The key difference when using this object is the distinction between the `get` and `getlist` methods.
 
 - `get(key, default=None)` operates as normal, except that when the value of
   the given key is a list, *only the first item is returned*.
@@ -223,6 +222,19 @@ args.get('titles') # => 'Post 1'
 args.getlist('titles') # => ['Post 1', 'Post 2']
 ```
 
+```python
+from sanic import Sanic
+from sanic.response import json
+
+app = Sanic(name="example")
+
+@app.route("/")
+def get_handler(request):
+    return json({
+        "p1": request.args.getlist("p1")
+    })
+```
+
 ## Accessing the handler name with the request.endpoint attribute
 
 The `request.endpoint` attribute holds the handler's name. For instance, the below

sanic/request.py

@@ -519,8 +519,11 @@ class Request:
         :rtype: str
         """
         # Full URL SERVER_NAME can only be handled in app.url_for
+        try:
             if "//" in self.app.config.SERVER_NAME:
                 return self.app.url_for(view_name, _external=True, **kwargs)
+        except AttributeError:
+            pass
 
         scheme = self.scheme
         host = self.server_name

tests/test_requests.py

@@ -2103,3 +2103,19 @@ async def test_endpoint_blueprint_asgi():
     request, response = await app.asgi_client.get("/bp")
 
     assert request.endpoint == "named.my_blueprint.bp_root"
+
+
+def test_url_for_without_server_name(app):
+    @app.route("/sample")
+    def sample(request):
+        return json({"url": request.url_for("url_for")})
+
+    @app.route("/url-for")
+    def url_for(request):
+        return text("url-for")
+
+    request, response = app.test_client.get("/sample")
+    assert (
+        response.json["url"]
+        == f"http://127.0.0.1:{app.test_client.port}/url-for"
+    )