Parsing and Serialization

Parsing

To parse a message on your own, use one of the parsers in net_unicoap_message and unicoap_parser_result_t. The parsed message structure helps you allocate everything needed in one go.

/* Parse an RFC 7252 PDU */
uint8_t pdu[] = {
    0x40, 0x02, 0xfe, 0xb1, 0xb9, 0x61, 0x63, 0x74, 0x75, 0x61, 0x74, 0x6f, 0x72, 0x73, 0x04, 0x6c, 0x65, 0x64, 0x73, 0x11, 0x32, 0x37, 0x63, 0x6f, 0x6c, 0x6f, 0x72, 0x3d, 0x67, 0x21, 0x32, 0xff, 0x6d, 0x6f, 0x64, 0x65, 0x3d, 0x6f, 0x6e
};

unicoap_parser_result_t parsed = { 0 }; /* Zero-initialize everything */

/* Parse message */
ssize_t res = unicoap_pdu_parse_rfc7252_result(pdu, sizeof(pdu), &parsed);

/* Handle errors */
if (res < 0) {
    /* eat error */
}

/* parsed.message contains the parsed message */

Serializing

To serialize a message on your own, decide whether you need vectored data or contiguous data. To get vectored data, you use unicoap_pdu_buildv_* functions, depending on the CoAP transport you intend to use. Vectored data is represented using an iolist_t. If you want to build a contiguous storage body, refer to the unicoap_pdu_build_* methods, also depending on the transport.

/* Build an RFC 7252 PDU */
uint8_t pdu[MY_CAPACITY] = { 0 };
ssize_t size = unicoap_pdu_build_rfc7252(pdu, sizeof(pdu), message, properties);

/* Handle errors */
if (size < 0) {
    /* eat error */
}

Implementation

Parsing and serialization are each done in two steps:

1. Message header up until options is parsed/serialized by driver
2. Options are parsed/serialized by common unicoap implementation