fixup! coap-chat: a simple chat application using gCoAP

coap-chat/README.md

@@ -2,7 +2,7 @@
 
 This application provides a simple command line chat using (g)CoAP as transport.
 It allows to send (short) messages to any (IPv6) address reachable by the node.
-All messages are send to and received for a CoAP resource with path `/chat`.
+All messages are sent to and received for a CoAP resource with path `/chat`.
 
 ## Usage
 
@@ -18,9 +18,15 @@ chat <destination> <nickname> <message>
 
 The message format is plain text and will be send as *nickname: message*, the
 maximum message size is 63 chars - so keep *nickname*  and *message* short :)
+Please be aware that all CoAP messages are sent as non-confirmable, hence there
+is no retransmission in case of packet loss.
 
 ## Notes
 
+The code base of this application aims for simplicity, thus it only provides
+a minimalistic set of functions. An advanced CoAP application can be found in
+the [RIOT examples](https://github.com/RIOT-OS/RIOT/tree/master/examples/gcoap).
+
 The application also ships with a number of standard shell commands, such as
 `ifconfig` to allow for network interface configuration. Just type `help` in
 the shell to see a full list and description of all available commands.

coap-chat/coap.c

@@ -105,12 +105,10 @@ int coap_post(char *addr, char *msgbuf, size_t msglen)
     uint8_t buf[GCOAP_PDU_BUF_SIZE];
     size_t len = 0;
 
-    gcoap_req_init(&pdu, (uint8_t *)&buf[0], GCOAP_PDU_BUF_SIZE, COAP_POST, COAP_CHAT_PATH);
+    gcoap_req_init(&pdu, buf, GCOAP_PDU_BUF_SIZE, COAP_POST, COAP_CHAT_PATH);
 
     memcpy(pdu.payload, msgbuf, msglen);
 
-    coap_hdr_set_type(pdu.hdr, COAP_TYPE_NON);
-
     len = gcoap_finish(&pdu, msglen, COAP_FORMAT_TEXT);
 
     DEBUG("[CoAP] coap_post: sending msg ID %u, %u bytes\n",