Added Server.headers and updated docs for it

Author: michalpokusa

adafruit_httpserver/server.py

@@ -8,7 +8,7 @@
 """
 
 try:
-    from typing import Callable, Protocol, Union, List, Set, Tuple
+    from typing import Callable, Protocol, Union, List, Set, Tuple, Dict
     from socket import socket
     from socketpool import SocketPool
 except ImportError:
@@ -25,14 +25,15 @@
     InvalidPathError,
     ServingFilesDisabledError,
 )
+from .headers import Headers
 from .methods import GET, HEAD
 from .request import Request
 from .response import Response, FileResponse
 from .route import _Routes, _Route
 from .status import BAD_REQUEST_400, UNAUTHORIZED_401, FORBIDDEN_403, NOT_FOUND_404
 
 
-class Server:
+class Server:  # pylint: disable=too-many-instance-attributes
     """A basic socket-based HTTP server."""
 
     host: str = None
@@ -57,6 +58,7 @@ def __init__(
         self._routes = _Routes()
         self._socket_source = socket_source
         self._sock = None
+        self.headers = Headers()
         self.root_path = root_path
         if root_path in ["", "/"] and debug:
             _debug_warning_exposed_files(root_path)
@@ -306,6 +308,12 @@ def _handle_request(
                 status=NOT_FOUND_404,
             )
 
+    def _set_default_server_headers(self, response: Response) -> None:
+        for name, value in self.headers.items():
+            response._headers.setdefault(  # pylint: disable=protected-access
+                name, value
+            )
+
     def poll(self):
         """
         Call this method inside your main loop to get the server to check for new incoming client
@@ -334,6 +342,8 @@ def poll(self):
                 if response is None:
                     return
 
+                self._set_default_server_headers(response)
+
                 # Send the response
                 response._send()  # pylint: disable=protected-access
 
@@ -366,6 +376,27 @@ def require_authentication(self, auths: List[Union[Basic, Bearer]]) -> None:
         """
         self._auths = auths
 
+    @property
+    def headers(self) -> Headers:
+        """
+        Headers to be sent with every response, without the need to specify them in each handler.
+
+        If a header is specified in both the handler and the server, the handler's header will be
+        used.
+
+        Example::
+
+            server = Server(pool, "/static")
+            server.headers = {
+                "Access-Control-Allow-Origin": "*",
+            }
+        """
+        return self._headers
+
+    @headers.setter
+    def headers(self, value: Union[Headers, Dict[str, str]]) -> None:
+        self._headers = value.copy() if isinstance(value, Headers) else Headers(value)
+
     @property
     def request_buffer_size(self) -> int:
         """

docs/examples.rst

@@ -97,9 +97,12 @@ Get CPU information
 You can return data from sensors or any computed value as JSON.
 That makes it easy to use the data in other applications.
 
+If you want to use the data in a web browser, it might be necessary to enable CORS.
+More info: https://developer.mozilla.org/en-US/docs/Web/HTTP/CORS
+
 .. literalinclude:: ../examples/httpserver_cpu_information.py
     :caption: examples/httpserver_cpu_information.py
-    :emphasize-lines: 9,27
+    :emphasize-lines: 9,14-17,32
     :linenos:
 
 Handling different methods
@@ -233,12 +236,15 @@ Using ``.serve_forever()`` for this is not possible because of it's blocking beh
 
 Each server **must have a different port number**.
 
+In order to distinguish between responses from different servers a 'X-Server' header is added to each response.
+**This is an optional step**, both servers will work without it.
+
 In combination with separate authentication and diffrent ``root_path`` this allows creating moderately complex setups.
 You can share same handler functions between servers or use different ones for each server.
 
 .. literalinclude:: ../examples/httpserver_multiple_servers.py
     :caption: examples/httpserver_multiple_servers.py
-    :emphasize-lines: 13-14,17,25,33-34,45-46,51-52
+    :emphasize-lines: 13-14,16-17,20,28,36-37,48-49,54-55
     :linenos:
 
 Debug mode

examples/httpserver_cpu_information.py

@@ -11,6 +11,11 @@
 pool = socketpool.SocketPool(wifi.radio)
 server = Server(pool, debug=True)
 
+# (Optional) Allow cross-origin requests.
+server.headers = {
+    "Access-Control-Allow-Origin": "*",
+}
+
 
 @server.route("/cpu-information", append_slash=True)
 def cpu_information_handler(request: Request):

examples/httpserver_multiple_servers.py

@@ -11,7 +11,10 @@
 pool = socketpool.SocketPool(wifi.radio)
 
 bedroom_server = Server(pool, "/bedroom", debug=True)
+bedroom_server.headers["X-Server"] = "Bedroom"
+
 office_server = Server(pool, "/office", debug=True)
+office_server.headers["X-Server"] = "Office"
 
 
 @bedroom_server.route("/bedroom")