Add Web Socket functionality

CMakeLists.txt

@@ -80,6 +80,7 @@ cmake_dependent_option(SDLNET_RELOCATABLE "Create relocatable SDL_net package" "
 option(SDLNET_WERROR "Treat warnings as errors" OFF)
 
 option(SDLNET_SAMPLES "Build the SDL3_net sample program(s)" ${SDLNET_SAMPLES_DEFAULT})
+option(SDLNET_WS_SAMPLE "Build the SDL3_net sample web socket server" OFF)
 cmake_dependent_option(SDLNET_SAMPLES_INSTALL "Install the SDL3_net sample program(s)" OFF "SDLNET_SAMPLES;SDLNET_INSTALL" OFF)
 
 # Save BUILD_SHARED_LIBS variable
@@ -317,3 +318,21 @@ if(SDLNET_SAMPLES)
     # Build at least one example in C90
     set_property(TARGET get-local-addrs PROPERTY C_STANDARD 90)
 endif()
+
+if(SDLNET_WS_SAMPLE)
+    find_package(OpenSSL REQUIRED)
+
+    add_executable(ws-server examples/web-socket-server.c)
+    sdl_add_warning_options(ws-server WARNING_AS_ERROR ${SDLTTF_WERROR})
+    sdl_target_link_options_no_undefined(ws-server)
+    target_link_libraries(ws-server PRIVATE SDL3_net::${sdl3_net_target_name})
+    target_link_libraries(ws-server PRIVATE ${sdl3_target_name})
+    target_link_libraries(ws-server PRIVATE OpenSSL::SSL)
+    set_property(TARGET ws-server PROPERTY C_STANDARD 99)
+    set_property(TARGET ws-server PROPERTY C_EXTENSIONS FALSE)
+    if(SDLNET_SAMPLES_INSTALL)
+        install(TARGETS ws-server
+            RUNTIME DESTINATION "${CMAKE_INSTALL_LIBEXECDIR}/installed-tests/SDL3_net"
+        )
+    endif()
+endif()

examples/web-socket-server.c

@@ -0,0 +1,281 @@
+#define SDL_WEBSOCKET_ACCEPT_KEY_FUNCTION
+
+#include <SDL3/SDL_main.h>
+#include <SDL3/SDL.h>
+#include <SDL3_net/SDL_net.h>
+
+#include <openssl/evp.h>
+#include <openssl/sha.h>
+
+bool onPreamble(NET_WSStream *, const char*, const char*, const char*, void*);
+bool onHeader(NET_WSStream *, const char*, const char*, void*);
+bool onOpen(NET_WSStream *, void*);
+bool onData(NET_WSStream *, Uint8, void*, int);
+void onClose(NET_WSStream *, void*);
+
+Uint16 server_port = 2382;
+
+int main(int argc, char **argv)
+{
+	const char *interface = NULL;
+    int simulate_failure = 0;
+
+    for (int i = 1; i < argc; i++) {
+        const char *arg = argv[i];
+        if ((SDL_strcmp(arg, "--port") == 0) && (i < (argc-1))) {
+            server_port = (Uint16) SDL_atoi(argv[++i]);
+        } else if ((SDL_strcmp(arg, "--simulate-failure") == 0) && (i < (argc-1))) {
+            simulate_failure = (int) SDL_atoi(argv[++i]);
+        } else {
+            interface = arg;
+        }
+    }
+
+	if (!NET_Init()) {
+        SDL_Log("NET_Init failed: %s\n", SDL_GetError());
+        SDL_Quit();
+        return 1;
+    }
+
+    if (interface) {
+        SDL_Log("Attempting to listen on interface '%s', port %d", interface, (int) server_port);
+    } else {
+        SDL_Log("Attempting to listen on all interfaces, port %d", (int) server_port);
+    }
+
+    NET_Address *server_addr = NULL;
+    if (interface) {
+        server_addr = NET_ResolveHostname(interface);
+        if (!server_addr || (NET_WaitUntilResolved(server_addr, -1) != NET_SUCCESS)) {
+            SDL_Log("Failed to resolve interface for '%s': %s", interface, SDL_GetError());
+            if (server_addr) {
+                NET_UnrefAddress(server_addr);
+            }
+            NET_Quit();
+            SDL_Quit();
+            return 1;
+        } else {
+            SDL_Log("Interface '%s' resolves to '%s' ...", interface, NET_GetAddressString(server_addr));
+        }
+    }
+
+    NET_Server *server = NET_CreateServer(server_addr, server_port);
+    if (!server) {
+        SDL_Log("Failed to create server: %s", SDL_GetError());
+    } else {
+        SDL_Log("Server is ready! Open http://%s:%d in your browser",
+        	interface == NULL ? "localhost" : interface, (int) server_port);
+        int num_vsockets = 1;
+        void *vsockets[128];
+        SDL_zeroa(vsockets);
+        vsockets[0] = server;
+        while (NET_WaitUntilInputAvailable(vsockets, num_vsockets, -1) >= 0) {
+            NET_StreamSocket *streamsocket = NULL;
+            if (!NET_AcceptClient(server, &streamsocket)) {
+                SDL_Log("NET_AcceptClient failed: %s", SDL_GetError());
+                break;
+            } else if (streamsocket) { // new connection!
+                SDL_Log("New connection from %s!", NET_GetAddressString(NET_GetStreamSocketAddress(streamsocket)));
+                if (num_vsockets >= (int) (SDL_arraysize(vsockets) - 1)) {
+                    SDL_Log("  (too many connections, though, so dropping immediately.)");
+                    NET_DestroyStreamSocket(streamsocket);
+                } else {
+                    if (simulate_failure) {
+                        NET_SimulateStreamPacketLoss(streamsocket, simulate_failure);
+                    }
+                    NET_WSStream * ws = NET_CreateWSStream(streamsocket, onPreamble, onHeader, onOpen, onData, onClose, streamsocket);
+                    if (!ws) {
+                    	SDL_Log("NET_CreateWSStream: %s\n", SDL_GetError());
+                    	break;
+                    }
+                    vsockets[num_vsockets++] = ws;
+                }
+            }
+
+            for (int i = 1; i < num_vsockets; i++) {
+                NET_WSStream * ws = (NET_WSStream *) vsockets[i];
+            	if(!ws || !NET_UpdateWSStream(ws)){
+            		SDL_Log("Dropping connection to '%s'\n", NET_GetAddressString(NET_GetWSStreamAddress(ws)));
+                    NET_DestroyWSStream(ws);
+                    vsockets[i] = NULL;
+                    if (i < (num_vsockets - 1)) {
+                        SDL_memmove(&vsockets[i], &vsockets[i+1], sizeof (vsockets[0]) * ((num_vsockets - i) - 1));
+                    }
+                    num_vsockets--;
+                    i--;
+            	}
+            }
+        }
+
+        SDL_Log("Destroying server...");
+        NET_DestroyServer(server);
+    }
+
+    SDL_Log("Shutting down...");
+    NET_Quit();
+    SDL_Quit();
+    return 0;
+}
+
+const char* indexFormat = "<!DOCTYPE html>"
+"<head>"
+"	<title>SDL3 Web Socket Server Test</title>"
+"</head>"
+"<body>"
+"	<script>"
+"		const ws = new WebSocket('ws://%s:%d/ws');"
+"		ws.addEventListener('open', function(){"
+"			console.log('Connection opened');"
+"			let button = document.getElementById('button');"
+"			button.removeAttribute('disabled');"
+"		});"
+"		ws.addEventListener('close', function(){"
+"			console.log('Connection closed');"
+"			let button = document.getElementById('button');"
+"			button.setAttribute('disabled', true);"
+"		});"
+"		ws.addEventListener('message', function(e){"
+"			let label = document.createElement('li');"
+"			label.innerText = e.data;"
+"			let output = document.getElementById('output');"
+"			output.append(label);"
+"		});"
+"		ws.addEventListener('error', function(e){"
+"			console.error(e);"
+"		});"
+"		function send() {"
+"			let input = document.getElementById('input');"
+"			if(!input.value){"
+"				return;"
+"			}"
+"			ws.send(input.value);"
+"			input.value = '';"
+"		}"
+"		function sendFiles(event) {"
+"			for(let file of event.currentTarget.files) {"
+"				const reader = new FileReader();"
+"				reader.onload = () =>  ws.send(reader.result);"
+"				reader.readAsArrayBuffer(file);"
+"			}"
+"		}"
+"	</script>"
+"	<div style='display: grid; grid-template-columns: 1fr 1fr;'>"
+"		<div>"
+"			<div>"
+"				<input id='input' placeholder='Enter text to send' />"
+"				<button id='button' onclick='send(event)' disabled>Send</button>"
+"			</div>"
+"			<div style='position: fixed; bottom: 0; left: 0;'>"
+"				<label for='file'>Open File to Send</label>"
+"				<input id='file' type='file' onchange='sendFiles(event)'>"
+"			</div>"
+"		</div>"
+"		<ul id='output'>"
+"		</ul>"
+"	</div>"
+"</body>"
+"</html>";
+
+bool onPreamble(NET_WSStream *ws, const char *method, const char *route, const char *protocol, void *userdata)
+{
+	(void)ws;
+	bool isWebSocket = false;
+	bool logPreamble = false;
+	char header[128];
+	NET_StreamSocket *streamsocket = (NET_StreamSocket *)userdata;
+	if (SDL_strcmp(method, "GET") == 0 && SDL_strcmp(route, "/") == 0) {
+		char response[2048];
+
+		const int responseSize = SDL_snprintf(response, sizeof(response),
+			indexFormat, NET_GetAddressString(NET_GetStreamSocketAddress(streamsocket)), server_port);
+
+		const int headerSize = SDL_snprintf(header, sizeof(header),
+			"HTTP/1.1 200 OK\r\n"
+			"Connection: close\r\n"
+			"Content-Type: text/html\r\n"
+			"Content-Length: %d\r\n"
+			"\r\n",
+			responseSize);
+
+		NET_WriteToStreamSocket(streamsocket, header, headerSize);
+		NET_WriteToStreamSocket(streamsocket, response, responseSize);
+		logPreamble = true;
+	} else if (SDL_strcmp(method, "GET") == 0 && SDL_strcmp(route, "/ws") == 0){
+		isWebSocket = true;
+		logPreamble = true;
+	} else {
+		const int headerSize = SDL_snprintf(header, sizeof(header),
+			"HTTP/1.1 400 Bad Request\r\n"
+			"Connection: close\r\n"
+			"\r\n");
+		NET_WriteToStreamSocket(streamsocket, header, headerSize);
+	}
+
+	if (logPreamble) {
+		SDL_Log("Method: %s; Route: %s; Protocol: %s\n", method, route, protocol);
+	}
+	return isWebSocket;
+}
+
+bool onHeader(NET_WSStream *ws, const char *key, const char *value, void *userdata)
+{
+	(void)ws;
+	(void)userdata;
+	SDL_Log("Header %s=%s\n", key, value);
+	return true;
+}
+
+bool onOpen(NET_WSStream *ws, void *userdata)
+{
+	(void)ws;
+	(void)userdata;
+	return true;
+}
+
+bool onData(NET_WSStream *ws, Uint8 opcode, void *buf, int len)
+{
+	if(opcode == NET_WS_OP_CODE_TEXT) {
+		SDL_Log("Received: %.*s\n", len, (char*)buf);
+
+	} else {
+		SDL_Log("Received: %d bytes\n", len);
+	}
+	return NET_SendPayloadToWSStream(ws, opcode, buf, len);
+}
+
+void onClose(NET_WSStream *ws, void *userdata)
+{
+	(void)ws;
+	(void)userdata;
+}
+
+bool NET_ConvertToSecWebSocketAcceptKey(SDL_INOUT_Z_CAP(maxlen) char *wsKeyPlusMagicString, int maxlen)
+{
+	char *buffer = SDL_strdup(wsKeyPlusMagicString);
+	if (!buffer) {
+		return false;
+	}
+
+	// Prepare to perform SHA1 hash
+    EVP_MD_CTX *ctx = EVP_MD_CTX_create();
+    const EVP_MD *md = EVP_sha1();
+    EVP_DigestInit_ex(ctx, md, NULL);
+
+	// SHA1 hash the key + magic string
+    EVP_DigestUpdate(ctx, wsKeyPlusMagicString, strlen(wsKeyPlusMagicString));
+
+    unsigned int len;
+    EVP_DigestFinal_ex(ctx, (unsigned char*)buffer, &len);
+    EVP_MD_CTX_destroy(ctx);
+    EVP_cleanup();
+
+    if((int)len >= maxlen) {
+    	return false;
+    }
+
+  	// Base64 encode the contents of buffer and place into key + magic string
+    EVP_EncodeBlock((unsigned char*)wsKeyPlusMagicString, (unsigned char*)buffer, len);
+    SDL_free(buffer);
+    SDL_Log("Key=%s\n", wsKeyPlusMagicString);
+    return true;
+}

examples/web-socket-server.html

@@ -0,0 +1,58 @@
+<!DOCTYPE html>
+<head>
+	<title>SDL3 Web Socket Server Test</title>
+</head>
+<body>
+	<script>
+		const ws = new WebSocket('ws://%s:%d/ws');
+		ws.addEventListener('open', function(){
+			console.log('Connection opened');
+			let button = document.getElementById('button');
+			button.removeAttribute('disabled');
+		});
+		ws.addEventListener('close', function(){
+			console.log('Connection closed');
+			let button = document.getElementById('button');
+			button.setAttribute('disabled', true);
+		});
+		ws.addEventListener('message', function(e){
+			let label = document.createElement('li');
+			label.innerText = e.data;
+			let output = document.getElementById('output');
+			output.append(label);
+		});
+		ws.addEventListener('error', function(e){
+			console.error(e);
+		});
+		function send() {
+			let input = document.getElementById('input');
+			if(!input.value){
+				return;
+			}
+			ws.send(input.value);
+			input.value = '';
+		}
+		function sendFiles(event) {
+			for(let file of event.currentTarget.files) {
+				const reader = new FileReader();
+				reader.onload = () =>  ws.send(reader.result);
+				reader.readAsArrayBuffer(file);
+			}
+		}
+	</script>
+	<div style='display: grid; grid-template-columns: 1fr 1fr;'>
+		<div>
+			<div>
+				<input id='input' placeholder='Enter text to send' />
+				<button id='button' onclick='send(event)' disabled>Send</button>
+			</div>
+			<div style='position: fixed; bottom: 0; left: 0;'>
+				<label for='file'>Open File to Send</label>
+				<input id='file' type='file' onchange='sendFiles(event)'>
+			</div>
+		</div>
+		<ul id='output'>
+		</ul>
+	</div>
+</body>
+</html>