✨ Add support for Response parameters to set headers, cookies, and status codes (#294)

* ✨ Add support for declaring a Response parameter to set headers and cookies

* ✅ Add source for docs and tests

* 📝 Add docs for setting headers, cookies and status code

* 📝 Add attribution to Hug for inspiring response parameters

docs/tutorial/response-change-status-code.md

@@ -0,0 +1,31 @@
+You probably read before that you can set a <a href="https://fastapi.tiangolo.com/tutorial/response-status-code/" target="_blank">default Response Status Code</a>.
+
+But in some cases you need to return a different status code than the default.
+
+## Use case
+
+For example, imagine that you want to return an HTTP status code of "OK" `200` by default.
+
+But if the data didn't exist, you want to create it, and return an HTTP status code of "CREATED" `201`.
+
+But you still want to be able to filter and convert the data you return with a `response_model`.
+
+For those cases, you can use a `Response` parameter.
+
+## Use a `Response` parameter
+
+You can declare a parameter of type `Response` in your *path operation function* (as you can do for cookies and headers).
+
+And then you can set the `status_code` in that *temporal* response object.
+
+```Python hl_lines="2 11 14"
+{!./src/response_change_status_code/tutorial001.py!}
+```
+
+And then you can return any object you need, as you normally would (a `dict`, a database model, etc).
+
+And if you declared a `response_model`, it will still be used to filter and convert the object you returned.
+
+**FastAPI** will use that *temporal* response to extract the status code (also cookies and headers), and will put them in the final response that contains the value you returned, filtered by any `response_model`.
+
+You can also declare the `Response` parameter in dependencies, and set the status code in them. But have in mind that the last one to be set will win.

docs/tutorial/response-cookies.md

@@ -1,4 +1,24 @@
-You can create (set) Cookies in your response.
+## Use a `Response` parameter
+
+You can declare a parameter of type `Response` in your *path operation function*, the same way you can declare a `Request` parameter.
+
+And then you can set headers in that *temporal* response object.
+
+```Python hl_lines="2 8 9"
+{!./src/response_cookies/tutorial002.py!}
+```
+
+And then you can return any object you need, as you normally would (a `dict`, a database model, etc).
+
+And if you declared a `response_model`, it will still be used to filter and convert the object you returned.
+
+**FastAPI** will use that *temporal* response to extract the cookies (also headers and status code), and will put them in the final response that contains the value you returned, filtered by any `response_model`.
+
+You can also declare the `Response` parameter in dependencies, and set cookies (and headers) in them.
+
+## Return a `Response` directly
+
+You can also create cookies when returning a `Response` directly in your code.
 
 To do that, you can create a response as described in <a href="https://fastapi.tiangolo.com/tutorial/response-directly/" target="_blank">Return a Response directly</a>.
 
@@ -8,6 +28,13 @@ Then set Cookies in it, and then return it:
 {!./src/response_cookies/tutorial001.py!}
 ```
 
-## More info
+!!! tip
+    Have in mind that if you return a response directly instead of using the `Response` parameter, FastAPI will return it directly. 
+
+    So, you will have to make sure your data is of the correct type. E.g. it is compatible with JSON, if you are returning a `JSONResponse`.
+
+    And also that you are not sending any data that should have been filtered by a `response_model`.
+
+### More info
 
 To see all the available parameters and options, check the <a href="https://www.starlette.io/responses/#set-cookie" target="_blank">documentation in Starlette</a>.

docs/tutorial/response-headers.md

@@ -1,4 +1,24 @@
-You can add headers to your response.
+## Use a `Response` parameter
+
+You can declare a parameter of type `Response` in your *path operation function* (as you can do for cookies), the same way you can declare a `Request` parameter.
+
+And then you can set headers in that *temporal* response object.
+
+```Python hl_lines="2 8 9"
+{!./src/response_headers/tutorial002.py!}
+```
+
+And then you can return any object you need, as you normally would (a `dict`, a database model, etc).
+
+And if you declared a `response_model`, it will still be used to filter and convert the object you returned.
+
+**FastAPI** will use that *temporal* response to extract the headers (also cookies and status code), and will put them in the final response that contains the value you returned, filtered by any `response_model`.
+
+You can also declare the `Response` parameter in dependencies, and set headers (and cookies) in them.
+
+## Return a `Response` directly
+
+You can also add headers when you return a `Response` directly.
 
 Create a response as described in <a href="https://fastapi.tiangolo.com/tutorial/response-directly/" target="_blank">Return a Response directly</a> and pass the headers as an additional parameter:
 
@@ -6,7 +26,8 @@ Create a response as described in <a href="https://fastapi.tiangolo.com/tutorial
 {!./src/response_headers/tutorial001.py!}
 ```
 
-!!! tip
-    Have in mind that custom proprietary headers can be added <a href="https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers" target="_blank">using the 'X-' prefix</a>.
+## Custom Headers
 
-    But if you have custom headers that you want a client in a browser to be able to see, you need to add them to your <a href="https://fastapi.tiangolo.com/tutorial/cors/" target="_blank">CORS configurations</a>, using the parameter `expose_headers` documented in <a href="https://www.starlette.io/middleware/#corsmiddleware" target="_blank">Starlette's CORS docs</a>.
+Have in mind that custom proprietary headers can be added <a href="https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers" target="_blank">using the 'X-' prefix</a>.
+
+But if you have custom headers that you want a client in a browser to be able to see, you need to add them to your <a href="https://fastapi.tiangolo.com/tutorial/cors/" target="_blank">CORS configurations</a>, using the parameter `expose_headers` documented in <a href="https://www.starlette.io/middleware/#corsmiddleware" target="_blank">Starlette's CORS docs</a>.

docs/tutorial/response-status-code.md

@@ -47,7 +47,6 @@ In short:
 !!! tip
     To know more about each status code and which code is for what, check the <a href="https://developer.mozilla.org/en-US/docs/Web/HTTP/Status" target="_blank"><abbr title="Mozilla Developer Network">MDN</abbr> documentation about HTTP status codes</a>.
 
-
 ## Shortcut to remember the names
 
 Let's see the previous example again:
@@ -69,3 +68,7 @@ You can use the convenience variables from `starlette.status`.
 They are just a convenience, they hold the same number, but that way you can use the editor's autocomplete to find them:
 
 <img src="/img/tutorial/response-status-code/image02.png">
+
+## Changing the default
+
+Later, in a more advanced part of the tutorial/user guide, you will see how to <a href="https://fastapi.tiangolo.com/tutorial/response-change-status-code/" target="_blank">return a different status code than the default</a> you are declaring here.