From 16f1aa8ddc1f069b7fa0ec04e992dd3ef4bc1a04 Mon Sep 17 00:00:00 2001
From: Olaf Bergmann <bergmann@tzi.org>
Date: Sun, 11 Dec 2011 15:46:00 +0100
Subject: [PATCH] added example resource handler

---
 coap-server.c | 135 ++++++++++++++++++++++++++++++++++++++++++++++----
 1 file changed, 126 insertions(+), 9 deletions(-)

diff --git a/coap-server.c b/coap-server.c
index 130efe7d..40b1fdee 100644
--- a/coap-server.c
+++ b/coap-server.c
@@ -1,4 +1,7 @@
-/*
+/* coap-server.c -- Example CoAP server using Contiki and libcoap
+ *
+ * Copyright (C) 2011 Olaf Bergmann <bergmann@tzi.org>
+ *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
@@ -27,22 +30,18 @@
  *
  */
 
-#include "contiki.h"
-#include "contiki-lib.h"
-#include "contiki-net.h"
+#include "config.h"
+#include "net/uip-debug.h"
 
 #include <string.h>
 
-#ifndef DEBUG
-#define DEBUG DEBUG_PRINT
-#include "net/uip-debug.h"
-#endif
-
 #include "debug.h"
 #include "coap.h"
 
 static coap_context_t *coap_context;
 
+/* changeable clock base (see handle_put_time()) */
+static clock_time_t my_clock_base = 0;
 
 PROCESS(coap_server_process, "CoAP server process");
 AUTOSTART_PROCESSES(&coap_server_process);
@@ -62,12 +61,130 @@ init_coap() {
     coap_log(LOG_CRIT, "cannot create CoAP context\r\n");
 }
 
+/*---------------------------------------------------------------------------*/
+#ifndef min
+# define min(a,b) ((a) < (b) ? (a) : (b))
+#endif
+
+void 
+hnd_get_time(coap_context_t  *ctx, struct coap_resource_t *resource, 
+	     coap_address_t *peer, coap_pdu_t *request, coap_tid_t id) {
+  coap_opt_iterator_t opt_iter;
+  coap_opt_t *token;
+  coap_pdu_t *response;
+  size_t size = sizeof(coap_hdr_t) + 32;
+  int type;
+  unsigned char buf[2];
+  time_t now;
+  coap_tick_t t;
+  unsigned char code;
+
+  /* FIXME: return time, e.g. in human-readable by default and ticks
+   * when query ?ticks is given. */
+
+  /* if my_clock_base was deleted, we pretend to have no such resource */
+  code = my_clock_base ? COAP_RESPONSE_CODE(205) : COAP_RESPONSE_CODE(404);
+
+  if (request->hdr->type == COAP_MESSAGE_CON)
+    type = COAP_MESSAGE_ACK;
+  else 
+    type = COAP_MESSAGE_NON;
+
+  token = coap_check_option(request, COAP_OPTION_TOKEN, &opt_iter);
+  if (token)
+    size += COAP_OPT_SIZE(token);
+
+  response = coap_pdu_init(type, code, request->hdr->id, size);
+
+  if (!response) {
+    debug("cannot create response for message %d\n", request->hdr->id);
+    return;
+  }
+
+  if (my_clock_base)
+    coap_add_option(response, COAP_OPTION_CONTENT_TYPE,
+		    coap_encode_var_bytes(buf, COAP_MEDIATYPE_TEXT_PLAIN), buf);
+
+  coap_add_option(response, COAP_OPTION_MAXAGE,
+	  coap_encode_var_bytes(buf, 0x01), buf);
+    
+  if (token)
+    coap_add_option(response, COAP_OPTION_TOKEN,
+		    COAP_OPT_LENGTH(token), COAP_OPT_VALUE(token));
+
+  if (my_clock_base) {
+
+    /* calculate current time */
+    coap_ticks(&t);
+    now = my_clock_base + (t / COAP_TICKS_PER_SECOND);
+    
+    if (coap_check_option(request, COAP_OPTION_URI_QUERY, &opt_iter)
+	&& memcmp(COAP_OPT_VALUE(opt_iter.option), "ticks",
+		  min(5, COAP_OPT_LENGTH(opt_iter.option))) == 0) {
+      /* output ticks */
+#if 0
+      response->length += snprintf((char *)response->data, 
+				   response->max_size - response->length,
+				   "%u", (unsigned int)now);
+#endif
+
+    } else {			/* @todo: output human-readable time */
+    }
+  }
+
+  if (coap_send(ctx, peer, response) == COAP_INVALID_TID) {
+    debug("hnd_get_time: cannot send response for message %d\n", 
+	  request->hdr->id);
+    coap_delete_pdu(response);
+  }
+}
+
+void
+init_resources(coap_context_t *ctx) {
+  coap_resource_t *r;
+#if 0
+  r = coap_resource_init(NULL, 0, 0);
+  coap_register_handler(r, COAP_REQUEST_GET, hnd_get_index);
+
+  coap_add_attr(r, (unsigned char *)"ct", 2, (unsigned char *)"0", 1, 0);
+  coap_add_attr(r, (unsigned char *)"title", 5, (unsigned char *)"\"General Info\"", 14, 0);
+  coap_add_resource(ctx, r);
+#endif
+  /* store clock base to use in /time */
+  my_clock_base = clock_offset;
+
+  r = coap_resource_init((unsigned char *)"time", 4, 0);
+  coap_register_handler(r, COAP_REQUEST_GET, hnd_get_time);
+#if 0
+  coap_register_handler(r, COAP_REQUEST_PUT, hnd_put_time);
+  coap_register_handler(r, COAP_REQUEST_DELETE, hnd_delete_time);
+#endif
+  coap_add_attr(r, (unsigned char *)"ct", 2, (unsigned char *)"0", 1, 0);
+  coap_add_attr(r, (unsigned char *)"title", 5, (unsigned char *)"\"Internal Clock\"", 16, 0);
+  coap_add_attr(r, (unsigned char *)"rt", 2, (unsigned char *)"\"Ticks\"", 7, 0);
+  /* coap_add_attr(r, (unsigned char *)"obs", 3, NULL, 0, 0); */
+  coap_add_attr(r, (unsigned char *)"if", 2, (unsigned char *)"\"clock\"", 7, 0);
+
+  coap_add_resource(ctx, r);
+#if 0
+#ifndef WITHOUT_ASYNC
+  r = coap_resource_init((unsigned char *)"async", 5, 0);
+  coap_register_handler(r, COAP_REQUEST_GET, hnd_get_async);
+
+  coap_add_attr(r, (unsigned char *)"ct", 2, (unsigned char *)"0", 1, 0);
+  coap_add_resource(ctx, r);
+#endif /* WITHOUT_ASYNC */
+#endif
+}
+
 /*---------------------------------------------------------------------------*/
 PROCESS_THREAD(coap_server_process, ev, data)
 {
   PROCESS_BEGIN();
 
   init_coap();
+  init_resources(coap_context);
+
   if (!coap_context) {
     coap_log(LOG_EMERG, "cannot create context\n");
     PROCESS_EXIT();