examples/nanocoap_server: add coap resource accepting GET and PUT req…

…uests in nanocoap example

examples/nanocoap_server/Makefile

@@ -35,6 +35,9 @@ USEPKG += nanocoap
 # optionally enable nanocoap's debug output
 #CFLAGS += -DNANOCOAP_DEBUG
 
+# include this for nicely formatting the returned internal value
+USEMODULE += fmt
+
 # include this for printing IP addresses
 USEMODULE += shell_commands
 

examples/nanocoap_server/coap_handler.c

@@ -6,21 +6,57 @@
  * directory for more details.
  */
 
+#include <stdlib.h>
 #include <stdio.h>
 #include <string.h>
 
+#include "fmt.h"
 #include "nanocoap.h"
 
+/* internal value that can be read/written via CoAP */
+static uint8_t internal_value = 0;
+
 static ssize_t _riot_board_handler(coap_pkt_t *pkt, uint8_t *buf, size_t len)
 {
     return coap_reply_simple(pkt, buf, len,
             COAP_FORMAT_TEXT, (uint8_t*)RIOT_BOARD, strlen(RIOT_BOARD));
 }
 
+static ssize_t _riot_value_handler(coap_pkt_t *pkt, uint8_t *buf, size_t len)
+{
+    ssize_t p = 0;
+    char rsp[16];
+    unsigned code = COAP_CODE_EMPTY;
+
+    /* read coap method type in packet */
+    unsigned method_flag = coap_method2flag(coap_get_code_detail(pkt));
+
+    switch(method_flag) {
+    case COAP_GET:
+        /* write the response buffer with the internal value */
+        p += fmt_u32_dec(rsp, internal_value);
+        code = COAP_CODE_205;
+        break;
+    case COAP_PUT:
+    case COAP_POST:
+    {
+        /* convert the payload to an integer and update the internal value */
+        char payload[16] = { 0 };
+        memcpy(payload, (char*)pkt->payload, pkt->payload_len);
+        internal_value = strtol(payload, NULL, 10);
+        code = COAP_CODE_CHANGED;
+    }
+    }
+
+    return coap_reply_simple(pkt, code, buf, len,
+            COAP_FORMAT_TEXT, (uint8_t*)rsp, p);
+}
+
 /* must be sorted by path (alphabetically) */
 const coap_resource_t coap_resources[] = {
     COAP_WELL_KNOWN_CORE_DEFAULT_HANDLER,
     { "/riot/board", COAP_GET, _riot_board_handler },
+    { "/riot/value", COAP_GET | COAP_PUT | COAP_POST, _riot_value_handler },
 };
 
 const unsigned coap_resources_numof = sizeof(coap_resources) / sizeof(coap_resources[0]);