websocket_client.c 6.2 KB

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  1. /*
  2. * Copyright (c) 2014 the Civetweb developers
  3. * Copyright (c) 2014 Jordan Shelley
  4. * https://github.com/jshelley
  5. * License http://opensource.org/licenses/mit-license.php MIT License
  6. */
  7. // Simple example program on how to use websocket client embedded C interface.
  8. #ifdef _WIN32
  9. #include <Windows.h>
  10. #define sleep(x) Sleep(1000*(x))
  11. #else
  12. #include <unistd.h>
  13. #endif
  14. #include <assert.h>
  15. #include <string.h>
  16. #include "civetweb.h"
  17. #define DOCUMENT_ROOT "."
  18. #define PORT "8888"
  19. #define SSL_CERT "./ssl/server.pem"
  20. const char * websocket_welcome_msg = "websocket welcome\n";
  21. const size_t websocket_welcome_msg_len = 18 /* strlen(websocket_welcome_msg) */ ;
  22. const char * websocket_acknowledge_msg = "websocket msg ok\n";
  23. const size_t websocket_acknowledge_msg_len = 17 /* strlen(websocket_acknowledge_msg) */ ;
  24. const char * websocket_goodbye_msg = "websocket bye\n";
  25. const size_t websocket_goodbye_msg_len = 14 /* strlen(websocket_goodbye_msg) */ ;
  26. /*************************************************************************************/
  27. /* WEBSOCKET SERVER */
  28. /*************************************************************************************/
  29. int websock_server_connect(const struct mg_connection * conn)
  30. {
  31. printf("Server: Websocket connected\n");
  32. return 0; /* return 0 to accept every connection */
  33. }
  34. void websocket_server_ready(struct mg_connection * conn)
  35. {
  36. printf("Server: Websocket ready\n");
  37. /* Send websocket welcome message */
  38. mg_lock_connection(conn);
  39. mg_websocket_write(conn, WEBSOCKET_OPCODE_TEXT, websocket_welcome_msg, websocket_welcome_msg_len);
  40. mg_unlock_connection(conn);
  41. }
  42. int websocket_server_data(struct mg_connection * conn, int bits, char *data, size_t data_len)
  43. {
  44. printf("Server: Got %u bytes from the client\n", data_len);
  45. if (data_len<3 || 0!=memcmp(data, "bye", 3)) {
  46. /* Send websocket acknowledge message */
  47. mg_lock_connection(conn);
  48. mg_websocket_write(conn, WEBSOCKET_OPCODE_TEXT, websocket_acknowledge_msg, websocket_acknowledge_msg_len);
  49. mg_unlock_connection(conn);
  50. } else {
  51. /* Send websocket acknowledge message */
  52. mg_lock_connection(conn);
  53. mg_websocket_write(conn, WEBSOCKET_OPCODE_TEXT, websocket_goodbye_msg, websocket_goodbye_msg_len);
  54. mg_unlock_connection(conn);
  55. }
  56. return 1; /* return 1 to keep the connetion open */
  57. }
  58. void websocket_server_connection_close(struct mg_connection * conn)
  59. {
  60. printf("Server: Close connection\n");
  61. /* Can not send a websocket goodbye message here - the connection is already closed */
  62. }
  63. struct mg_context * start_websocket_server()
  64. {
  65. const char * options[] = { "document_root", DOCUMENT_ROOT,
  66. "ssl_certificate", SSL_CERT,
  67. "listening_ports", PORT, 0
  68. };
  69. struct mg_callbacks callbacks;
  70. struct mg_context *ctx;
  71. memset(&callbacks, 0, sizeof(callbacks));
  72. callbacks.websocket_connect = websock_server_connect;
  73. callbacks.websocket_ready = websocket_server_ready;
  74. callbacks.websocket_data = websocket_server_data;
  75. callbacks.connection_close = websocket_server_connection_close;
  76. ctx = mg_start(&callbacks, 0, options);
  77. return ctx;
  78. }
  79. /*************************************************************************************/
  80. /* WEBSOCKET CLIENT */
  81. /*************************************************************************************/
  82. struct {
  83. void * data;
  84. size_t len;
  85. } client_data;
  86. static int websocket_client_data_handler(struct mg_connection *conn, int flags, char *data, size_t data_len)
  87. {
  88. printf("From server: ");
  89. fwrite(data, 1, data_len, stdout);
  90. printf("\n");
  91. /* TODO: extra arg (instead of global client_data) */
  92. client_data.data = malloc(data_len);
  93. assert(client_data.data != NULL);
  94. memcpy(client_data.data, data, data_len);
  95. client_data.len = data_len;
  96. return 1;
  97. }
  98. int main(int argc, char *argv[])
  99. {
  100. struct mg_context *ctx;
  101. struct mg_connection* newconn;
  102. char ebuf[100];
  103. assert(websocket_welcome_msg_len == strlen(websocket_welcome_msg));
  104. /* First set up a websocket server */
  105. ctx = start_websocket_server();
  106. assert(ctx != NULL);
  107. /* Then connect a client */
  108. newconn = mg_websocket_client_connect("localhost", atoi(PORT), 0,
  109. ebuf, sizeof(ebuf),
  110. "/websocket", NULL, websocket_client_data_handler /* TODO: extra arg (instead of global client_data) */);
  111. if (newconn == NULL)
  112. {
  113. printf("Error: %s", ebuf);
  114. return 1;
  115. }
  116. sleep(1); /* Should get the websocket welcome message */
  117. assert(client_data.data != NULL);
  118. assert(client_data.len == websocket_welcome_msg_len);
  119. assert(!memcmp(client_data.data, websocket_welcome_msg, websocket_welcome_msg_len));
  120. free(client_data.data);
  121. client_data.data = NULL;
  122. client_data.len = 0;
  123. mg_websocket_write(newconn, WEBSOCKET_OPCODE_TEXT, "data1", 5);
  124. sleep(1); /* Should get the acknowledge message */
  125. assert(client_data.data != NULL);
  126. assert(client_data.len == websocket_acknowledge_msg_len);
  127. assert(!memcmp(client_data.data, websocket_acknowledge_msg, websocket_acknowledge_msg_len));
  128. free(client_data.data);
  129. client_data.data = NULL;
  130. client_data.len = 0;
  131. mg_websocket_write(newconn, WEBSOCKET_OPCODE_TEXT, "data2", 5);
  132. sleep(1); /* Should get the acknowledge message */
  133. assert(client_data.data != NULL);
  134. assert(client_data.len == websocket_acknowledge_msg_len);
  135. assert(!memcmp(client_data.data, websocket_acknowledge_msg, websocket_acknowledge_msg_len));
  136. free(client_data.data);
  137. client_data.data = NULL;
  138. client_data.len = 0;
  139. mg_websocket_write(newconn, WEBSOCKET_OPCODE_TEXT, "bye", 3);
  140. sleep(1); /* Should get the goodbye message */
  141. assert(client_data.data != NULL);
  142. assert(client_data.len == websocket_goodbye_msg_len);
  143. assert(!memcmp(client_data.data, websocket_goodbye_msg, websocket_goodbye_msg_len));
  144. free(client_data.data);
  145. client_data.data = NULL;
  146. client_data.len = 0;
  147. mg_close_connection(newconn);
  148. sleep(1); /* Won't get any message */
  149. mg_stop(ctx);
  150. printf("Server shutdown\n");
  151. sleep(10);
  152. return 0;
  153. }