From b8e3f0c5775753f210e43d3abfc7c14b94979098 Mon Sep 17 00:00:00 2001
From: Krzysztof Rudnicki <krzysztofrudnicki0@gmail.com>
Date: Thu, 14 Nov 2024 20:52:38 +0100
Subject: [PATCH] wip: websocket server in C

---
 C/websocketServer/main.c | 100 +++++++++++++++++++++++++++++++++++++++
 1 file changed, 100 insertions(+)
 create mode 100644 C/websocketServer/main.c

diff --git a/C/websocketServer/main.c b/C/websocketServer/main.c
new file mode 100644
index 0000000..654a9cd
--- /dev/null
+++ b/C/websocketServer/main.c
@@ -0,0 +1,100 @@
+#include <libwebsockets.h>
+#include <string.h>
+#include <signal.h>
+
+static int interrupted;
+static struct lws_context *context;
+
+// Callback for WebSocket communication
+static int callback_function(struct lws *wsi, enum lws_callback_reasons reason,
+                             void *user, void *in, size_t len) {
+    switch (reason) {
+        case LWS_CALLBACK_CLIENT_ESTABLISHED:
+            printf("WebSocket connection established\n");
+            break;
+
+        case LWS_CALLBACK_CLIENT_RECEIVE:
+            printf("Received data: %s\n", (char *)in);
+            break;
+
+        case LWS_CALLBACK_CLIENT_WRITEABLE: {
+            const char *msg = "Hello, WebSocket server!";
+            unsigned char buf[LWS_PRE + 512];
+            size_t msg_len = strlen(msg);
+            memcpy(&buf[LWS_PRE], msg, msg_len);
+            lws_write(wsi, &buf[LWS_PRE], msg_len, LWS_WRITE_TEXT);
+            break;
+        }
+
+        case LWS_CALLBACK_CLOSED:
+            printf("WebSocket connection closed\n");
+            interrupted = 1;
+            break;
+
+        default:
+            break;
+    }
+    return 0;
+}
+
+// Signal handler for clean exit
+static void sigint_handler(int sig) {
+    interrupted = 1;
+    lws_cancel_service(context);
+}
+
+int main(void) {
+    struct lws_protocols protocols[] = {
+        {
+            "ws-protocol",   // Protocol name
+            callback_function, // Callback function
+            0,               // Per-session data size
+            0,
+        },
+        {NULL, NULL, 0, 0}  // End of list
+    };
+
+    struct lws_client_connect_info ccinfo = {0};
+    struct lws_context_creation_info info = {0};
+    info.port = CONTEXT_PORT_NO_LISTEN;
+    info.protocols = protocols;
+    info.options = LWS_SERVER_OPTION_DO_SSL_GLOBAL_INIT;
+
+    // Create WebSocket context
+    context = lws_create_context(&info);
+    if (!context) {
+        fprintf(stderr, "Failed to create context\n");
+        return -1;
+    }
+
+    signal(SIGINT, sigint_handler);
+
+    // Configure connection details
+    ccinfo.context = context;
+    ccinfo.address = "echo.websocket.org";  // WebSocket server address
+    ccinfo.port = 443;                      // Port (for WSS use 443)
+    ccinfo.path = "/";                      // Path on the server
+    ccinfo.host = lws_canonical_hostname(context);
+    ccinfo.origin = "origin";
+    ccinfo.protocol = protocols[0].name;
+    ccinfo.ssl_connection = LCCSCF_USE_SSL;  // Use SSL for secure WebSocket
+
+    // Initiate the WebSocket connection
+    struct lws *wsi = lws_client_connect_via_info(&ccinfo);
+    if (!wsi) {
+        fprintf(stderr, "Failed to initiate WebSocket connection\n");
+        lws_context_destroy(context);
+        return -1;
+    }
+
+    // Event loop
+    while (!interrupted) {
+        lws_service(context, 1000);
+    }
+
+    // Cleanup
+    lws_context_destroy(context);
+    printf("Exiting...\n");
+    return 0;
+}
+