defining MqttClient classes

Author: andreagilardoni

api/net/MqttClient.cpp

@@ -0,0 +1,48 @@
+#include "MqttClient.h"
+
+//TODO define constant value for pimpl not instantiated
+int MqttClient::connect(IPAddress ip, uint16_t port) {
+    return impl != nullptr? impl->connect(ip, port) : -1;
+}
+
+int MqttClient::connect(const char *host, uint16_t port) {
+    return impl != nullptr? impl->connect(host, port) : -1;
+}
+
+void MqttClient::disconnect() {
+    if(impl != nullptr) {
+        return impl->disconnect();
+    }
+}
+
+uint8_t MqttClient::connected() {
+    return impl != nullptr? impl->connected() : 0;
+}
+
+MqttClient::operator bool() {
+    // FIXME
+    return impl != nullptr? impl->operator bool() : false;
+}
+
+error_t MqttClient::subscribe(Topic t, MqttQos qos) {
+    return impl != nullptr? impl->subscribe(t, qos) : -1;
+}
+
+error_t MqttClient::publish(Topic t, uint8_t payload[], size_t size, MqttQos qos) {
+    return impl != nullptr? impl->publish(t, payload, size, qos) : -1;
+}
+
+error_t MqttClient::unsubscribe(Topic t) {
+    return impl != nullptr? impl->unsubscribe(t) : -1;
+}
+
+void MqttClient::poll() {
+    if(impl != nullptr) {
+        return impl->poll();
+    }
+}
+
+error_t MqttClient::ping() {
+    return impl != nullptr? impl->ping() : -1;
+}
+

api/net/MqttClient.h

@@ -0,0 +1,97 @@
+#pragma once
+#include <functional>
+#include <memory>
+
+#include <api/Client.h>
+
+// https://github.com/arduino-libraries/ArduinoMqttClient/
+
+// The Idea for this section of the library is to allow the usage of different implementation for Mqtt Clients
+// while preserving the possibility of having an Arduino standardized interface for Mqtt protocol
+// One should implement MqttClientInterface and provide a way to instantiate the implementation
+
+// namespace arduino { // namespace net { namespace mqtt {
+
+using Topic = const char* const;
+
+// for incoming published messages
+// TODO double check with typename
+using MqttReceiveCallback = std::function<void(Topic, const uint8_t[], size_t)>;
+
+// TODO define callback for mqtt events. one should be the default, but the user can always change it
+
+typedef int error_t; // TODO move this to be generally available
+
+enum MqttQos: uint8_t {
+    MqttQos0 = 0, // At Most once
+    MqttQos1 = 1, // At least once
+    MqttQos2 = 2, // Exactly once
+};
+
+// TODO define mqtt version
+
+constexpr MqttQos QosDefault = MqttQos0;
+constexpr size_t MqttClientIdMaxLength = 256;
+
+class MqttClientInterface: public arduino::ClientConnect{
+public:
+    // virtual ~MqttClientInterface() = default; // not needed if deriving from ClientConnect
+
+    virtual error_t subscribe(Topic t, MqttQos qos = QosDefault) = 0;
+    virtual error_t publish(Topic t,  uint8_t payload[], size_t size, MqttQos qos = QosDefault) = 0;
+    // TODO define a publish that can stream a message
+
+    virtual error_t unsubscribe(Topic t) = 0;
+    virtual void poll() = 0;
+    virtual error_t ping() = 0;
+
+    virtual void setReceiveCallback(MqttReceiveCallback cbk) { _cbk = cbk; }
+
+    // nullptr means generate it randomly
+    // TODO should this be pure virtual?
+    virtual void setClientId(const char* const clientid = nullptr) { // TODO put this in .cpp file
+        if(clientid == nullptr) {
+            // TODO generate it randomly
+        } else {
+            strncpy(_clientid, clientid, MqttClientIdMaxLength);
+        }
+    }
+
+    // TODO Will stuff
+    // TODO auth stuff, also related to MQTT 5.0
+protected:
+    char _clientid[MqttClientIdMaxLength+1];
+
+    // TODO single callback for every incoming message or a callback for everything?
+    MqttReceiveCallback _cbk;
+};
+
+
+// this could be generally available, outside of namespaces
+class MqttClient: public MqttClientInterface {
+public:
+
+    int connect(IPAddress ip, uint16_t port) override;
+    int connect(const char *host, uint16_t port) override;
+    void disconnect() override;
+
+    uint8_t connected() override;
+    operator bool() override;
+
+    //TODO wrap method
+    error_t subscribe(Topic t, MqttQos qos = QosDefault) override;
+    error_t publish(Topic t, uint8_t[], size_t, MqttQos qos = QosDefault) override;
+    error_t unsubscribe(Topic t) override;
+    void poll() override;
+    error_t ping() override;
+
+    static void setFactory(std::function<std::unique_ptr<MqttClientInterface>()> factory) {
+        _factory = factory;
+    }
+protected:
+    static std::function<std::unique_ptr<MqttClientInterface>()> _factory;
+
+    std::unique_ptr<MqttClientInterface> impl;
+};
+
+// } // }}