Add CORS (Cross Origin Resource Sharing) support to HTTP

homeassistant/components/http.py

@@ -16,18 +16,23 @@ from http import cookies
 from http.server import HTTPServer, SimpleHTTPRequestHandler
 from socketserver import ThreadingMixIn
 from urllib.parse import parse_qs, urlparse
+import voluptuous as vol
 
 import homeassistant.bootstrap as bootstrap
 import homeassistant.core as ha
 import homeassistant.remote as rem
 import homeassistant.util as util
 import homeassistant.util.dt as date_util
+import homeassistant.helpers.config_validation as cv
 from homeassistant.const import (
     CONTENT_TYPE_JSON, CONTENT_TYPE_TEXT_PLAIN, HTTP_HEADER_ACCEPT_ENCODING,
     HTTP_HEADER_CACHE_CONTROL, HTTP_HEADER_CONTENT_ENCODING,
     HTTP_HEADER_CONTENT_LENGTH, HTTP_HEADER_CONTENT_TYPE, HTTP_HEADER_EXPIRES,
-    HTTP_HEADER_HA_AUTH, HTTP_HEADER_VARY, HTTP_METHOD_NOT_ALLOWED,
+    HTTP_HEADER_HA_AUTH, HTTP_HEADER_VARY,
+    HTTP_HEADER_ACCESS_CONTROL_ALLOW_ORIGIN,
+    HTTP_HEADER_ACCESS_CONTROL_ALLOW_HEADERS, HTTP_METHOD_NOT_ALLOWED,
     HTTP_NOT_FOUND, HTTP_OK, HTTP_UNAUTHORIZED, HTTP_UNPROCESSABLE_ENTITY,
+    ALLOWED_CORS_HEADERS,
     SERVER_PORT, URL_ROOT, URL_API_EVENT_FORWARD)
 
 DOMAIN = "http"
@@ -38,6 +43,7 @@ CONF_SERVER_PORT = "server_port"
 CONF_DEVELOPMENT = "development"
 CONF_SSL_CERTIFICATE = 'ssl_certificate'
 CONF_SSL_KEY = 'ssl_key'
+CONF_CORS_ORIGINS = 'cors_allowed_origins'
 
 DATA_API_PASSWORD = 'api_password'
 
@@ -48,6 +54,19 @@ SESSION_KEY = 'sessionId'
 
 _LOGGER = logging.getLogger(__name__)
 
+CONFIG_SCHEMA = vol.Schema({
+    DOMAIN: vol.Schema({
+        vol.Optional(CONF_API_PASSWORD): cv.string,
+        vol.Optional(CONF_SERVER_HOST): cv.string,
+        vol.Optional(CONF_SERVER_PORT, default=SERVER_PORT):
+            vol.All(vol.Coerce(int), vol.Range(min=1, max=65535)),
+        vol.Optional(CONF_DEVELOPMENT): cv.string,
+        vol.Optional(CONF_SSL_CERTIFICATE): cv.isfile,
+        vol.Optional(CONF_SSL_KEY): cv.isfile,
+        vol.Optional(CONF_CORS_ORIGINS): cv.ensure_list
+    }),
+}, extra=vol.ALLOW_EXTRA)
+
 
 def setup(hass, config):
     """Set up the HTTP API and debug interface."""
@@ -61,11 +80,12 @@ def setup(hass, config):
     development = str(conf.get(CONF_DEVELOPMENT, "")) == "1"
     ssl_certificate = conf.get(CONF_SSL_CERTIFICATE)
     ssl_key = conf.get(CONF_SSL_KEY)
+    cors_origins = conf.get(CONF_CORS_ORIGINS, [])
 
     try:
         server = HomeAssistantHTTPServer(
             (server_host, server_port), RequestHandler, hass, api_password,
-            development, ssl_certificate, ssl_key)
+            development, ssl_certificate, ssl_key, cors_origins)
     except OSError:
         # If address already in use
         _LOGGER.exception("Error setting up HTTP server")
@@ -96,7 +116,8 @@ class HomeAssistantHTTPServer(ThreadingMixIn, HTTPServer):
 
     # pylint: disable=too-many-arguments
     def __init__(self, server_address, request_handler_class,
-                 hass, api_password, development, ssl_certificate, ssl_key):
+                 hass, api_password, development, ssl_certificate, ssl_key,
+                 cors_origins):
         """Initialize the server."""
         super().__init__(server_address, request_handler_class)
 
@@ -107,6 +128,7 @@ class HomeAssistantHTTPServer(ThreadingMixIn, HTTPServer):
         self.paths = []
         self.sessions = SessionStore()
         self.use_ssl = ssl_certificate is not None
+        self.cors_origins = cors_origins
 
         # We will lazy init this one if needed
         self.event_forwarder = None
@@ -351,6 +373,16 @@ class RequestHandler(SimpleHTTPRequestHandler):
             self.send_header(HTTP_HEADER_VARY, HTTP_HEADER_ACCEPT_ENCODING)
 
         self.send_header(HTTP_HEADER_CONTENT_LENGTH, str(len(content)))
+
+        cors_check = (self.headers.get("Origin") in self.server.cors_origins)
+
+        cors_headers = ", ".join(ALLOWED_CORS_HEADERS)
+
+        if self.server.cors_origins and cors_check:
+            self.send_header(HTTP_HEADER_ACCESS_CONTROL_ALLOW_ORIGIN,
+                             self.headers.get("Origin"))
+            self.send_header(HTTP_HEADER_ACCESS_CONTROL_ALLOW_HEADERS,
+                             cors_headers)
         self.end_headers()
 
         if self.command == 'HEAD':

homeassistant/const.py

@@ -229,6 +229,15 @@ HTTP_HEADER_VARY = "Vary"
 HTTP_HEADER_CONTENT_LENGTH = "Content-Length"
 HTTP_HEADER_CACHE_CONTROL = "Cache-Control"
 HTTP_HEADER_EXPIRES = "Expires"
+HTTP_HEADER_ORIGIN = "Origin"
+HTTP_HEADER_X_REQUESTED_WITH = "X-Requested-With"
+HTTP_HEADER_ACCEPT = "Accept"
+HTTP_HEADER_ACCESS_CONTROL_ALLOW_ORIGIN = "Access-Control-Allow-Origin"
+HTTP_HEADER_ACCESS_CONTROL_ALLOW_HEADERS = "Access-Control-Allow-Headers"
+
+ALLOWED_CORS_HEADERS = [HTTP_HEADER_ORIGIN, HTTP_HEADER_ACCEPT,
+                        HTTP_HEADER_X_REQUESTED_WITH, HTTP_HEADER_CONTENT_TYPE,
+                        HTTP_HEADER_HA_AUTH]
 
 CONTENT_TYPE_JSON = "application/json"
 CONTENT_TYPE_MULTIPART = 'multipart/x-mixed-replace; boundary={}'