From: Steinar H. Gunderson <sgunderson@bigfoot.com>
Date: Sun, 18 Feb 2018 19:08:45 +0000 (+0100)
Subject: Add a CORS policy to the channel endpoints, so that external applications can query... 
X-Git-Tag: 1.7.0~26
X-Git-Url: https://git.sesse.net/?p=nageru;a=commitdiff_plain;h=d3e48df512d9476d3849227067792a3537bb094e

Add a CORS policy to the channel endpoints, so that external applications can query the tally light.
---

diff --git a/httpd.cpp b/httpd.cpp
index 811e095..fe2c929 100644
--- a/httpd.cpp
+++ b/httpd.cpp
@@ -89,10 +89,13 @@ int HTTPD::answer_to_connection(MHD_Connection *connection,
 		return ret;
 	}
 	if (endpoints.count(url)) {
-		pair<string, string> contents_and_type = endpoints[url]();
+		pair<string, string> contents_and_type = endpoints[url].callback();
 		MHD_Response *response = MHD_create_response_from_buffer(
 			contents_and_type.first.size(), &contents_and_type.first[0], MHD_RESPMEM_MUST_COPY);
 		MHD_add_response_header(response, "Content-type", contents_and_type.second.c_str());
+		if (endpoints[url].cors_policy == ALLOW_ALL_ORIGINS) {
+			MHD_add_response_header(response, "Access-Control-Allow-Origin", "*");
+		}
 		int ret = MHD_queue_response(connection, MHD_HTTP_OK, response);
 		MHD_destroy_response(response);  // Only decreases the refcount; actual free is after the request is done.
 		return ret;
diff --git a/httpd.h b/httpd.h
index 878a184..509ae01 100644
--- a/httpd.h
+++ b/httpd.h
@@ -33,8 +33,12 @@ public:
 	}
 
 	// Should be called before start() (due to threading issues).
-	void add_endpoint(const std::string &url, const EndpointCallback &callback) {
-		endpoints[url] = callback;
+	enum CORSPolicy {
+		NO_CORS_POLICY,
+		ALLOW_ALL_ORIGINS
+	};
+	void add_endpoint(const std::string &url, const EndpointCallback &callback, CORSPolicy cors_policy) {
+		endpoints[url] = Endpoint{ callback, cors_policy };
 	}
 
 	void start(int port);
@@ -92,7 +96,11 @@ private:
 	MHD_Daemon *mhd = nullptr;
 	std::mutex streams_mutex;
 	std::set<Stream *> streams;  // Not owned.
-	std::unordered_map<std::string, EndpointCallback> endpoints;
+	struct Endpoint {
+		EndpointCallback callback;
+		CORSPolicy cors_policy;
+	};
+	std::unordered_map<std::string, Endpoint> endpoints;
 	std::string header;
 
 	// Metrics.
diff --git a/mixer.cpp b/mixer.cpp
index 70175a1..55604c1 100644
--- a/mixer.cpp
+++ b/mixer.cpp
@@ -356,11 +356,11 @@ Mixer::Mixer(const QSurfaceFormat &format, unsigned num_cards)
 	// Must be instantiated after VideoEncoder has initialized global_flags.use_zerocopy.
 	theme.reset(new Theme(global_flags.theme_filename, global_flags.theme_dirs, resource_pool.get(), num_cards));
 
-	httpd.add_endpoint("/channels", bind(&Mixer::get_channels_json, this));
+	httpd.add_endpoint("/channels", bind(&Mixer::get_channels_json, this), HTTPD::ALLOW_ALL_ORIGINS);
 	for (int channel_idx = 2; channel_idx < theme->get_num_channels(); ++channel_idx) {
 		char url[256];
 		snprintf(url, sizeof(url), "/channels/%d/color", channel_idx);
-		httpd.add_endpoint(url, bind(&Mixer::get_channel_color_http, this, unsigned(channel_idx)));
+		httpd.add_endpoint(url, bind(&Mixer::get_channel_color_http, this, unsigned(channel_idx)), HTTPD::ALLOW_ALL_ORIGINS);
 	}
 
 	// Start listening for clients only once VideoEncoder has written its header, if any.