ProsecCoAP.h

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/*
CoAP library for Arduino with Observe functionality.
 
This software is released under the MIT License.
Copyright (c) 2014 Hirotaka Niisato
Copyright (c) 2026 Pasquale Lafiosca
 
Permission is hereby granted, free of charge, to any person obtaining
a copy of this software and associated documentation files (the
"Software"), to deal in the Software without restriction, including
without limitation the rights to use, copy, modify, merge, publish,
distribute, sublicense, and/or sell copies of the Software, and to
permit persons to whom the Software is furnished to do so, subject to
the following conditions:
 
The above copyright notice and this permission notice shall be
included in all copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
*/
#ifndef __SIMPLE_COAP_H__
#define __SIMPLE_COAP_H__
 
#include "Udp.h"
#ifndef COAP_MAX_CALLBACK
#define COAP_MAX_CALLBACK 10
#endif
 
#define COAP_HEADER_SIZE 4u
#define COAP_OPTION_HEADER_SIZE 1
#define COAP_PAYLOAD_MARKER 0xFF
#ifndef COAP_MAX_OPTION_NUM
#define COAP_MAX_OPTION_NUM 10
#endif
#ifndef COAP_BUF_MAX_SIZE
#define COAP_BUF_MAX_SIZE 128
#endif
#ifndef COAP_MAX_OBSERVERS
#define COAP_MAX_OBSERVERS 4
#endif
#ifndef COAP_OBSERVER_LEASE_MS
#define COAP_OBSERVER_LEASE_MS 60000UL
#endif
#ifndef COAP_MAX_OBSERVE_ENDPOINT_LEN
#define COAP_MAX_OBSERVE_ENDPOINT_LEN 32
#endif
#define COAP_DEFAULT_PORT 5683
 
#define RESPONSE_CODE(class, detail) ((class << 5) | (detail))
#define COAP_OPTION_DELTA(v, n) (v < 13 ? (*n = (0xFF & v)) : (v <= 0xFF + 13 ? (*n = 13) : (*n = 14)))
 
typedef enum
{
    COAP_CON = 0,
    COAP_NONCON = 1,
    COAP_ACK = 2,
    COAP_RESET = 3
} COAP_TYPE;
 
typedef enum
{
    COAP_GET = 1,
    COAP_POST = 2,
    COAP_PUT = 3,
    COAP_DELETE = 4
} COAP_METHOD;
 
typedef enum
{
    COAP_EMPTY = RESPONSE_CODE(0, 0),
    COAP_CREATED = RESPONSE_CODE(2, 1),
    COAP_DELETED = RESPONSE_CODE(2, 2),
    COAP_VALID = RESPONSE_CODE(2, 3),
    COAP_CHANGED = RESPONSE_CODE(2, 4),
    COAP_CONTENT = RESPONSE_CODE(2, 5),
 
    COAP_BAD_REQUEST = RESPONSE_CODE(4, 0),
    COAP_UNAUTHORIZED = RESPONSE_CODE(4, 1),
    COAP_BAD_OPTION = RESPONSE_CODE(4, 2),
    COAP_FORBIDDEN = RESPONSE_CODE(4, 3),
    COAP_NOT_FOUND = RESPONSE_CODE(4, 4),
    COAP_METHOD_NOT_ALLOWED = RESPONSE_CODE(4, 5),
    COAP_NOT_ACCEPTABLE = RESPONSE_CODE(4, 6),
    COAP_PRECONDITION_FAILED = RESPONSE_CODE(4, 12),
    COAP_REQUEST_ENTITY_TOO_LARGE = RESPONSE_CODE(4, 13),
    COAP_UNSUPPORTED_CONTENT_FORMAT = RESPONSE_CODE(4, 15),
 
    COAP_INTERNAL_SERVER_ERROR = RESPONSE_CODE(5, 0),
    COAP_NOT_IMPLEMENTED = RESPONSE_CODE(5, 1),
    COAP_BAD_GATEWAY = RESPONSE_CODE(5, 2),
    COAP_SERVICE_UNAVAILABLE = RESPONSE_CODE(5, 3),
    COAP_GATEWAY_TIMEOUT = RESPONSE_CODE(5, 4),
    COAP_PROXYING_NOT_SUPPORTED = RESPONSE_CODE(5, 5)
} COAP_RESPONSE_CODE;
 
typedef enum
{
    COAP_IF_MATCH = 1,
    COAP_URI_HOST = 3,
    COAP_E_TAG = 4,
    COAP_IF_NONE_MATCH = 5,
    COAP_OBSERVE = 6,
    COAP_URI_PORT = 7,
    COAP_LOCATION_PATH = 8,
    COAP_URI_PATH = 11,
    COAP_CONTENT_FORMAT = 12,
    COAP_MAX_AGE = 14,
    COAP_URI_QUERY = 15,
    COAP_ACCEPT = 17,
    COAP_LOCATION_QUERY = 20,
    COAP_PROXY_URI = 35,
    COAP_PROXY_SCHEME = 39,
    COAP_SIZE1 = 60
} COAP_OPTION_NUMBER;
 
typedef enum
{
    COAP_OBSERVE_VALUE_REGISTER = 0, // https://datatracker.ietf.org/doc/html/rfc7641#section-2
    COAP_OBSERVE_VALUE_DEREGISTER = 1
} COAP_OBSERVE_VALUE;
 
typedef enum
{
    COAP_NONE = -1,
    COAP_TEXT_PLAIN = 0,
    COAP_APPLICATION_LINK_FORMAT = 40,
    COAP_APPLICATION_XML = 41,
    COAP_APPLICATION_OCTET_STREAM = 42,
    COAP_APPLICATION_EXI = 47,
    COAP_APPLICATION_JSON = 50,
    COAP_APPLICATION_CBOR = 60
} COAP_CONTENT_TYPE;
 
class CoapOption
{
public:
    uint8_t number;
    uint8_t length;
    uint8_t *value;
};
 
class CoapPacket
{
public:
    uint8_t type = 0;
    uint8_t code = 0;
    const uint8_t *token = NULL;
    uint8_t tokenLength = 0;
    const uint8_t *payload = NULL;
    size_t payloadLength = 0;
    uint16_t messageId = 0;
    uint8_t optionCount = 0;
    CoapOption options[COAP_MAX_OPTION_NUM];
 
    void addOption(uint8_t number, uint8_t length, uint8_t *value);
 
    bool getObserveValue(COAP_OBSERVE_VALUE &value);
};
 
#if defined(ESP8266)
#include <functional>
typedef std::function<void(CoapPacket &, IPAddress, int)> CoapCallback;
#elif defined(ESP32)
#include <functional>
typedef std::function<void(CoapPacket &, IPAddress, int)> CoapCallback;
#else
typedef void (*CoapCallback)(CoapPacket &, IPAddress, int);
#endif
 
class CoapUri
{
private:
    String urls[COAP_MAX_CALLBACK];
    CoapCallback callbacks[COAP_MAX_CALLBACK];
 
public:
    CoapUri()
    {
        for (int i = 0; i < COAP_MAX_CALLBACK; i++)
        {
            urls[i] = "";
            callbacks[i] = NULL;
        }
    };
 
    void add(CoapCallback call, String url)
    {
        for (int i = 0; i < COAP_MAX_CALLBACK; i++)
            if (callbacks[i] != NULL && urls[i].equals(url))
            {
                callbacks[i] = call;
                return;
            }
        for (int i = 0; i < COAP_MAX_CALLBACK; i++)
        {
            if (callbacks[i] == NULL)
            {
                callbacks[i] = call;
                urls[i] = url;
                return;
            }
        }
    };
 
    CoapCallback find(String url)
    {
        for (int i = 0; i < COAP_MAX_CALLBACK; i++)
            if (callbacks[i] != NULL && urls[i].equals(url))
                return callbacks[i];
        return NULL;
    };
};
 
class Observer
{
 
    friend class Coap; // Give full access to Coap class.
 
private:
    bool active = false;
    IPAddress ip;
    uint16_t port = 0;
    uint8_t token[8] = {0};
    uint8_t tokenLength = 0;
    uint32_t observationSequentialNumber = 0;
    unsigned long lastSeenMs = 0; // TODO: Implement cleaning up old observers.
    char endpoint[COAP_MAX_OBSERVE_ENDPOINT_LEN] = {0};
 
public:
    bool remove();
 
    unsigned long getLastSeenMs();
};
 
class Coap
{
private:
    UDP *_udp;
    CoapUri uri;
    CoapCallback responseHandler = NULL;
    int _port;
    size_t coapBufferSize;
    uint8_t *txBuffer = NULL;
    uint8_t *rxBuffer = NULL;
 
    Observer observers[COAP_MAX_OBSERVERS];
 
    uint16_t sendPacket(CoapPacket &packet, IPAddress ip);
 
    uint16_t sendPacket(CoapPacket &packet, IPAddress ip, int port);
 
    int parseOption(CoapOption *option, uint16_t *running_delta, uint8_t **buf, size_t buflen);
 
public:
    Coap(
        UDP &udp,
        size_t coapBufferSize = COAP_BUF_MAX_SIZE);
 
    ~Coap();
 
    int notifyObservers(const char *observed_endpoint, const char *payload, int payload_len, COAP_CONTENT_TYPE type);
 
    int addObserver(Observer **observer_out, const char *endpoint, IPAddress ip, int port, const uint8_t *token, uint8_t tokenLength);
 
    bool removeObserver(const char *endpoint, IPAddress ip, int port, const uint8_t *token, uint8_t tokenLength);
 
    bool start();
 
    bool start(int port);
 
    void response(CoapCallback c) { responseHandler = c; }
 
    void server(CoapCallback c, String url) { uri.add(c, url); }
 
    uint16_t sendResponse(IPAddress ip, int port, uint16_t messageId);
 
    uint16_t sendResponse(IPAddress ip, int port, uint16_t messageId, const char *payload);
 
    uint16_t sendResponse(IPAddress ip, int port, uint16_t messageId, const char *payload, size_t payloadLength);
 
    uint16_t sendResponse(IPAddress ip, int port, uint16_t messageId, const char *payload, size_t payloadLength, COAP_RESPONSE_CODE code, COAP_CONTENT_TYPE type, const uint8_t *token, int tokenLength);
 
    uint16_t get(IPAddress ip, int port, const char *url);
 
    uint16_t put(IPAddress ip, int port, const char *url, const char *payload);
 
    uint16_t put(IPAddress ip, int port, const char *url, const char *payload, size_t payloadLength);
 
    uint16_t post(IPAddress ip, int port, const char *url, const char *payload);
 
    uint16_t post(IPAddress ip, int port, const char *url, const char *payload, size_t payloadLength);
 
    uint16_t send(IPAddress ip, int port, const char *url, COAP_TYPE type, COAP_METHOD method, const uint8_t *token, uint8_t tokenLength, const uint8_t *payload, size_t payloadLength);
 
    uint16_t send(IPAddress ip, int port, const char *url, COAP_TYPE type, COAP_METHOD method, const uint8_t *token, uint8_t tokenLength, const uint8_t *payload, size_t payloadLength, COAP_CONTENT_TYPE contentType);
 
    uint16_t send(IPAddress ip, int port, const char *url, COAP_TYPE type, COAP_METHOD method, const uint8_t *token, uint8_t tokenLength, const uint8_t *payload, size_t payloadLength, COAP_CONTENT_TYPE contentType, uint16_t messageId);
 
    bool loop();
};
 
#endif