iothub_client/inc/iothub_module_client.h

// Copyright (c) Microsoft. All rights reserved.
// Licensed under the MIT license. See LICENSE file in the project root for full license information.

/** @file iothub_module_client.h
*    @brief Extends the IoTHubModuleClient_LL module with additional features.
*
*    @details IoTHubModuleClient extends the IoTHubModuleClient_LL
*             with 2 features:
*                - scheduling the work for the IoTHubModuleClient from a
*                  thread, so that the user does not need to create their
*                  own thread
*                - thread-safe APIs
*/

#ifndef IOTHUB_MODULE_CLIENT_H
#define IOTHUB_MODULE_CLIENT_H

#include <stddef.h>
#include <stdint.h>

#include "umock_c/umock_c_prod.h"
#include "iothub_transport_ll.h"
#include "iothub_client_core_ll.h"
#include "iothub_client_core.h"
#include "iothub_module_client_ll.h"

#ifndef IOTHUB_MODULE_CLIENT_INSTANCE_TYPE
/**  
* @brief   Handle corresponding to a convenience layer module client instance. 
* 
* @remarks See https://github.com/Azure/azure-iot-sdk-c/blob/main/doc/threading_notes.md for more details about convenience layer versus lower layer (LL) threading models.
*/
typedef IOTHUB_CLIENT_CORE_HANDLE IOTHUB_MODULE_CLIENT_HANDLE;
#define IOTHUB_MODULE_CLIENT_INSTANCE_TYPE
#endif // IOTHUB_CLIENT_INSTANCE


#ifdef __cplusplus
extern "C"
{
#endif

    /**
    * @brief    Creates a IoT Hub client for communication with an existing
    *             IoT Hub using the specified connection string parameter.
    *
    * @param    connectionString    Pointer to a character string
    * @param    protocol            Function pointer for protocol implementation
    *
    *            Sample connection string:
    *                <blockquote>
    *                    <pre>HostName=[IoT Hub name goes here].[IoT Hub suffix goes here, e.g., private.azure-devices-int.net];DeviceId=[Device ID goes here];SharedAccessKey=[Device key goes here];ModuleId=[Module ID goes here]</pre>
    *                   <pre>HostName=[IoT Hub name goes here].[IoT Hub suffix goes here, e.g., private.azure-devices-int.net];DeviceId=[Device ID goes here];SharedAccessSignature=SharedAccessSignature sr=[IoT Hub name goes here].[IoT Hub suffix goes here, e.g., private.azure-devices-int.net]/devices/[Device ID goes here]&sig=[SAS Token goes here]&se=[Expiry Time goes here];ModuleId=[Module ID goes here]</pre>
    *                </blockquote>
    *
    * @return    A non-NULL #IOTHUB_MODULE_CLIENT_HANDLE value that is used when
    *             invoking other functions for IoT Hub client and @c NULL on failure.
    */
    MOCKABLE_FUNCTION(, IOTHUB_MODULE_CLIENT_HANDLE, IoTHubModuleClient_CreateFromConnectionString, const char*, connectionString, IOTHUB_CLIENT_TRANSPORT_PROVIDER, protocol);

    /**
    * @brief    Disposes of resources allocated by the IoT Hub client. This is a
    *             blocking call.
    *
    * @param    iotHubModuleClientHandle    The handle created by a call to the create function.
    *
    * @warning  Do not call this function from inside any application callbacks from this SDK, e.g. your IOTHUB_CLIENT_EVENT_CONFIRMATION_CALLBACK handler.
    */
    MOCKABLE_FUNCTION(, void, IoTHubModuleClient_Destroy, IOTHUB_MODULE_CLIENT_HANDLE, iotHubModuleClientHandle);

    /**
    * @brief    Asynchronous call to send the message specified by @p eventMessageHandle.
    *
    * @param    iotHubModuleClientHandle      The handle created by a call to the create function.
    * @param    eventMessageHandle            The handle to an IoT Hub message.
    * @param    eventConfirmationCallback     The callback specified by the module for receiving
    *                                         confirmation of the delivery of the IoT Hub message.
    *                                         This callback can be expected to invoke the
    *                                         ::IoTHubModuleClient_SendEventAsync function for the
    *                                         same message in an attempt to retry sending a failing
    *                                         message. The user can specify a @c NULL value here to
    *                                         indicate that no callback is required.
    * @param    userContextCallback            User specified context that will be provided to the
    *                                         callback. This can be @c NULL.
    *
    * @warning: Do not call IoTHubModuleClient_Destroy() from inside your application's callback.
    *
    * @remarks
    *           The IOTHUB_MESSAGE_HANDLE instance provided as argument is copied by the function,
    *           so this argument can be destroyed by the calling application right after IoTHubModuleClient_SendEventAsync returns.
    *           The copy of @c eventMessageHandle is later destroyed by the iothub client when the message is effectively sent, if a failure sending it occurs, or if the client is destroyed.
    * @return    IOTHUB_CLIENT_OK upon success or an error code upon failure.
    */
    MOCKABLE_FUNCTION(, IOTHUB_CLIENT_RESULT, IoTHubModuleClient_SendEventAsync, IOTHUB_MODULE_CLIENT_HANDLE, iotHubModuleClientHandle, IOTHUB_MESSAGE_HANDLE, eventMessageHandle, IOTHUB_CLIENT_EVENT_CONFIRMATION_CALLBACK, eventConfirmationCallback, void*, userContextCallback);

    /**
    * @brief    This function returns the current sending status for IoTHubModuleClient.
    *
    * @param    iotHubModuleClientHandle  The handle created by a call to the create function.
    * @param    IoTHubClientStatus        The sending state is populated at the address pointed
    *                                     at by this parameter. The value will be set to
    *                                     @c IOTHUB_CLIENT_SEND_STATUS_IDLE if there is currently
    *                                     no item to be sent and @c IOTHUB_CLIENT_SEND_STATUS_BUSY
    *                                     if there are.
    *
    * @return    IOTHUB_CLIENT_OK upon success or an error code upon failure.
    */
    MOCKABLE_FUNCTION(, IOTHUB_CLIENT_RESULT, IoTHubModuleClient_GetSendStatus, IOTHUB_MODULE_CLIENT_HANDLE, iotHubModuleClientHandle, IOTHUB_CLIENT_STATUS*, IoTHubClientStatus);

    /**
    * @brief    Sets up the message callback to be invoked when IoT Hub issues a
    *             message to the device. This is a blocking call.
    *
    * @param    iotHubModuleClientHandle      The handle created by a call to the create function.
    * @param    messageCallback               The callback specified by the device for receiving
    *                                         messages from IoT Hub.
    * @param    userContextCallback           User specified context that will be provided to the
    *                                         callback. This can be @c NULL.
    *
    * @warning: Do not call IoTHubModuleClient_Destroy() from inside your application's callback.
    *
    * @return    IOTHUB_CLIENT_OK upon success or an error code upon failure.
    */
    MOCKABLE_FUNCTION(, IOTHUB_CLIENT_RESULT, IoTHubModuleClient_SetMessageCallback, IOTHUB_MODULE_CLIENT_HANDLE, iotHubModuleClientHandle, IOTHUB_CLIENT_MESSAGE_CALLBACK_ASYNC, messageCallback, void*, userContextCallback);

    /**
    * @brief    Sets up the connection status callback to be invoked representing the status of
    * the connection to IOT Hub. This is a blocking call.
    *
    * @param    iotHubModuleClientHandle        The handle created by a call to the create function.
    * @param    connectionStatusCallback        The callback specified by the module for receiving
    *                                           updates about the status of the connection to IoT Hub.
    * @param    userContextCallback             User specified context that will be provided to the
    *                                           callback. This can be @c NULL.
    *
    * @warning: Do not call IoTHubModuleClient_Destroy() from inside your application's callback.
    *
    * @return    IOTHUB_CLIENT_OK upon success or an error code upon failure.
    */
    MOCKABLE_FUNCTION(, IOTHUB_CLIENT_RESULT, IoTHubModuleClient_SetConnectionStatusCallback, IOTHUB_MODULE_CLIENT_HANDLE, iotHubModuleClientHandle, IOTHUB_CLIENT_CONNECTION_STATUS_CALLBACK, connectionStatusCallback, void*, userContextCallback);

    /**
    * @brief    Sets the Retry Policy feature to control how immediatelly and frequently the SDK will attempt to re-connect to the Azure IoT Hub in case a connection issue occurs.
    *
    * @param    iotHubModuleClientHandle         The handle created by a call to the create function.
    * @param    retryPolicy                      The policy to use to reconnect to IoT Hub when a
    *                                            connection drops.
    * @param    retryTimeoutLimitInSeconds       Maximum amount of time(seconds) to attempt reconnection when a
    *                                            connection drops to IOT Hub.
    *
    * @return    IOTHUB_CLIENT_OK upon success or an error code upon failure.
    */
    MOCKABLE_FUNCTION(, IOTHUB_CLIENT_RESULT, IoTHubModuleClient_SetRetryPolicy, IOTHUB_MODULE_CLIENT_HANDLE, iotHubModuleClientHandle, IOTHUB_CLIENT_RETRY_POLICY, retryPolicy, size_t, retryTimeoutLimitInSeconds);

    /**
    * @brief    Gets the Retry Policy setting and timeout value for the current retry policy.
    *
    * @param    iotHubModuleClientHandle         The handle created by a call to the create function.
    * @param    retryPolicy                      Out parameter containing the policy to use to reconnect to IoT Hub.
    * @param    retryTimeoutLimitInSeconds       Out parameter containing maximum amount of time, in seconds, to attempt reconnection
    *                                            to IOT Hub for the specified retry policy.
    *
    * @return    IOTHUB_CLIENT_OK upon success or an error code upon failure.
    */
    MOCKABLE_FUNCTION(, IOTHUB_CLIENT_RESULT, IoTHubModuleClient_GetRetryPolicy, IOTHUB_MODULE_CLIENT_HANDLE, iotHubModuleClientHandle, IOTHUB_CLIENT_RETRY_POLICY*, retryPolicy, size_t*, retryTimeoutLimitInSeconds);

    /**
    * @brief    This function returns in the out parameter @p lastMessageReceiveTime
    *             what was the value of the @c time function when the last message was
    *             received at the client.
    *
    * @param    iotHubModuleClientHandle        The handle created by a call to the create function.
    * @param    lastMessageReceiveTime          Out parameter containing the value of @c time function
    *                                           when the last message was received.
    *
    * @return    IOTHUB_CLIENT_OK upon success or an error code upon failure.
    */
    MOCKABLE_FUNCTION(, IOTHUB_CLIENT_RESULT, IoTHubModuleClient_GetLastMessageReceiveTime, IOTHUB_MODULE_CLIENT_HANDLE, iotHubModuleClientHandle, time_t*, lastMessageReceiveTime);

    /**
    * @brief    This API sets a runtime option identified by parameter @p optionName
    *             to a value pointed to by @p value. @p optionName and the data type
    *             @p value is pointing to are specific for every option.
    *
    * @param    iotHubModuleClientHandle    The handle created by a call to the create function.
    * @param    optionName                  Name of the option.
    * @param    value                       The value.
    *
    * 
    * @remarks  Documentation for configuration options is available at https://github.com/Azure/azure-iot-sdk-c/blob/main/doc/Iothub_sdk_options.md.
    *
    * @return   IOTHUB_CLIENT_OK upon success or an error code upon failure.
    */
    MOCKABLE_FUNCTION(, IOTHUB_CLIENT_RESULT, IoTHubModuleClient_SetOption, IOTHUB_MODULE_CLIENT_HANDLE, iotHubModuleClientHandle, const char*, optionName, const void*, value);

    /**
    * @brief    This API specifies a call back to be used when the module receives a state update.
    *
    * @param    iotHubModuleClientHandle The handle created by a call to the create function.
    * @param    moduleTwinCallback       The callback specified by the module client to be used for updating
    *                                    the desired state. The callback will be called in response to a
    *                                    request send by the IoT Hub services. The payload will be passed to the
    *                                    callback, along with two version numbers:
    *                                        - Desired:
    *                                        - LastSeenReported:
    * @param    userContextCallback      User specified context that will be provided to the
    *                                    callback. This can be @c NULL.
    *
    * @warning: Do not call IoTHubModuleClient_Destroy() from inside your application's callback.
    *
    * @return    IOTHUB_CLIENT_OK upon success or an error code upon failure.
    */
    MOCKABLE_FUNCTION(, IOTHUB_CLIENT_RESULT, IoTHubModuleClient_SetModuleTwinCallback, IOTHUB_MODULE_CLIENT_HANDLE, iotHubModuleClientHandle, IOTHUB_CLIENT_DEVICE_TWIN_CALLBACK, moduleTwinCallback, void*, userContextCallback);

    /**
    * @brief    This API sends a report of the module's properties and their current values.
    *
    * @param    iotHubModuleClientHandle The handle created by a call to the create function.
    * @param    reportedState            The current module property values to be 'reported' to the IoT Hub.
    * @param    size                        Number of bytes in @c reportedState.
    * @param    reportedStateCallback    The callback specified by the module client to be called with the
    *                                    result of the transaction.
    * @param    userContextCallback      User specified context that will be provided to the
    *                                    callback. This can be @c NULL.
    *
    * @warning: Do not call IoTHubModuleClient_Destroy() from inside your application's callback.
    *
    * @return    IOTHUB_CLIENT_OK upon success or an error code upon failure.
    */
    MOCKABLE_FUNCTION(, IOTHUB_CLIENT_RESULT, IoTHubModuleClient_SendReportedState, IOTHUB_MODULE_CLIENT_HANDLE, iotHubModuleClientHandle, const unsigned char*, reportedState, size_t, size, IOTHUB_CLIENT_REPORTED_STATE_CALLBACK, reportedStateCallback, void*, userContextCallback);

    /**
    * @brief    This API provides a way to retrieve the complete module Twin properties on-demand.
    *
    * @param    iotHubModuleClientHandle    The handle created by a call to the create function.
    * @param    moduleTwinCallback          The callback invoked to provide the complete Module Twin properties once its retrieval is completed by the client.
    *                                       If any failures occur, the callback is invoked passing @c NULL as payLoad and zero as size.
    * @param    userContextCallback         User specified context that will be provided to the
    *                                       callback. This can be @c NULL.
    *
    * @warning: Do not call IoTHubModuleClient_Destroy() from inside your application's callback.
    *
    * @return    IOTHUB_CLIENT_OK upon success or an error code upon failure.
    */
    MOCKABLE_FUNCTION(, IOTHUB_CLIENT_RESULT, IoTHubModuleClient_GetTwinAsync, IOTHUB_MODULE_CLIENT_HANDLE, iotHubModuleClientHandle, IOTHUB_CLIENT_DEVICE_TWIN_CALLBACK, moduleTwinCallback, void*, userContextCallback);

    /**
    * @brief    This API sets callback for async cloud to module method call.
    *
    * @param    IoTHubClientHandle              The handle created by a call to the create function.
    * @param    methodCallback                  The callback which will be called by IoT Hub.
    * @param    userContextCallback             User specified context that will be provided to the
    *                                           callback. This can be @c NULL.
    *
    * @return    IOTHUB_CLIENT_OK upon success or an error code upon failure.
    */
    MOCKABLE_FUNCTION(, IOTHUB_CLIENT_RESULT, IoTHubModuleClient_SetModuleMethodCallback, IOTHUB_MODULE_CLIENT_HANDLE, IoTHubClientHandle, IOTHUB_CLIENT_DEVICE_METHOD_CALLBACK_ASYNC, methodCallback, void*, userContextCallback);

    /**
    * @brief    Asynchronous call to send the message specified by @p eventMessageHandle.
    *
    * @param    iotHubModuleClientHandle      The handle created by a call to the create function.
    * @param    eventMessageHandle            The handle to an IoT Hub message.
    * @param    outputName                    The name of the queue to send the message to.
    * @param    eventConfirmationCallback     The callback specified by the module for receiving
    *                                         confirmation of the delivery of the IoT Hub message.
    *                                         This callback can be expected to invoke the
    *                                         IoTHubModuleClient_SendEventAsync function for the
    *                                         same message in an attempt to retry sending a failing
    *                                         message. The user can specify a @c NULL value here to
    *                                         indicate that no callback is required.
    * @param    userContextCallback           User specified context that will be provided to the
    *                                         callback. This can be @c NULL.
    *
    * @warning: Do not call IoTHubModuleClient_Destroy() from inside your application's callback.
    *
    * @return    IOTHUB_CLIENT_OK upon success or an error code upon failure.
    */
    MOCKABLE_FUNCTION(, IOTHUB_CLIENT_RESULT, IoTHubModuleClient_SendEventToOutputAsync, IOTHUB_MODULE_CLIENT_HANDLE, iotHubModuleClientHandle, IOTHUB_MESSAGE_HANDLE, eventMessageHandle, const char*, outputName, IOTHUB_CLIENT_EVENT_CONFIRMATION_CALLBACK, eventConfirmationCallback, void*, userContextCallback);


    /**
    * @brief    This API sets callback for method call that is directed to specified 'inputName' queue (e.g. messages from IoTHubModuleClient_SendEventToOutputAsync)
    *
    * @param    iotHubModuleClientHandle      The handle created by a call to the create function.
    * @param    inputName                     The name of the queue to listen on for this moduleMethodCallback/userContextCallback.
    * @param    eventHandlerCallback          The callback which will be called by IoT Hub.
    * @param    userContextCallback           User specified context that will be provided to the
    *                                         callback. This can be @c NULL.
    *
    * @return    IOTHUB_CLIENT_OK upon success or an error code upon failure.
    */
    MOCKABLE_FUNCTION(, IOTHUB_CLIENT_RESULT, IoTHubModuleClient_SetInputMessageCallback, IOTHUB_MODULE_CLIENT_HANDLE, iotHubModuleClientHandle, const char*, inputName, IOTHUB_CLIENT_MESSAGE_CALLBACK_ASYNC, eventHandlerCallback, void*, userContextCallback);

#ifdef USE_EDGE_MODULES
    /**
    * @brief    This API creates a module handle based on environment variables set in the Edge runtime.
    *           NOTE: It is *ONLY* valid when the code is running in a container initiated by Edge.
    *
    *
    * @param    protocol            Function pointer for protocol implementation.  This *MUST* be MQTT_Protocol.
    *
    * @remarks  The protocol parameter MUST be set to MQTT_Protocol.  Using other values will cause undefined behavior.
    *
    * @return    A non-NULL #IOTHUB_MODULE_CLIENT_HANDLE value that is used when
    *           invoking other functions for IoT Hub client and @c NULL on failure.
    */
    MOCKABLE_FUNCTION(, IOTHUB_MODULE_CLIENT_HANDLE, IoTHubModuleClient_CreateFromEnvironment, IOTHUB_CLIENT_TRANSPORT_PROVIDER, protocol);

    /**
    * @brief    This API invokes a device method on a specified device
    *
    * @param    iotHubModuleClientHandle        The handle created by a call to a create function
    * @param    deviceId                        The device id of the device to invoke a method on
    * @param    methodName                      The name of the method
    * @param    methodPayload                   The method payload (in json format)
    *
    * @warning  The timeout parameter is ignored.  See https://github.com/Azure/azure-iot-sdk-c/issues/1378.
    *           The timeout used will be the default for IoT Edge.
    *
    * @param    responseStatus                  This pointer will be filled with the response status after invoking the device method
    * @param    responsePayload                 This pointer will be filled with the response payload
    * @param    responsePayloadSize             This pointer will be filled with the response payload size
    *
    * @return   IOTHUB_CLIENT_OK upon success, or an error code upon failure.
    */
    MOCKABLE_FUNCTION(, IOTHUB_CLIENT_RESULT, IoTHubModuleClient_DeviceMethodInvokeAsync, IOTHUB_MODULE_CLIENT_HANDLE, iotHubModuleClientHandle, const char*, deviceId, const char*, methodName, const char*, methodPayload, unsigned int, timeout, IOTHUB_METHOD_INVOKE_CALLBACK, methodInvokeCallback, void*, context);

    /**
    * @brief    This API invokes a module method on a specified module
    *
    * @param    iotHubModuleClientHandle        The handle created by a call to a create function
    * @param    deviceId                        The device id of the device to invoke a method on
    * @param    moduleId                        The module id of the module to invoke a method on
    * @param    methodName                      The name of the method
    * @param    methodPayload                   The method payload (in json format)
    * @param    timeout                         The time in seconds before a timeout occurs
    *
    * @warning  The timeout parameter is ignored.  See https://github.com/Azure/azure-iot-sdk-c/issues/1378.
    *           The timeout used will be the default for IoT Edge.
    *
    * @param    responseStatus                  This pointer will be filled with the response status after invoking the module method
    * @param    responsePayload                 This pointer will be filled with the response payload
    * @param    responsePayloadSize             This pointer will be filled with the response payload size
    *
    * @return   IOTHUB_CLIENT_OK upon success, or an error code upon failure.
    */
    MOCKABLE_FUNCTION(, IOTHUB_CLIENT_RESULT, IoTHubModuleClient_ModuleMethodInvokeAsync, IOTHUB_MODULE_CLIENT_HANDLE, iotHubModuleClientHandle, const char*, deviceId, const char*, moduleId, const char*, methodName, const char*, methodPayload, unsigned int, timeout, IOTHUB_METHOD_INVOKE_CALLBACK, methodInvokeCallback, void*, context);

#endif /*USE_EDGE_MODULES*/

    /**
    * @brief    This API sends an acknowledgement to Azure IoT Hub that a cloud-to-device message has been received and frees resources associated with the message. 
    *
    * @param    iotHubModuleClientHandle        The handle created by a call to a create function.
    * @param    message                         The cloud-to-device message received through the callback provided to IoTHubModuleClient_SetMessageCallback or IoTHubModuleClient_SetInputMessageCallback.
    * @param    disposition                     Acknowledgement option for the message.
    *
    * @warning  This function is to be used only when IOTHUBMESSAGE_ASYNC_ACK is used in the callback for incoming cloud-to-device messages.
    * @remarks
    *           If your cloud-to-device message callback returned IOTHUBMESSAGE_ASYNC_ACK, it MUST call this API eventually.
    *           Beyond sending acknowledgment to the service, this method also handles freeing message's memory.
    *           Not calling this function will result in memory leaks.
    *           Depending on the protocol used, this API will acknowledge cloud-to-device messages differently:
    *           AMQP: A MESSAGE DISPOSITION is sent using the `disposition` option provided.
    *           MQTT: A PUBACK is sent if `disposition` is `IOTHUBMESSAGE_ACCEPTED`. Passing any other option results in no PUBACK sent for the message.
    *           HTTP: A HTTP request is sent using the `disposition` option provided.
    * @return   IOTHUB_CLIENT_OK upon success, or an error code upon failure.
    */
    MOCKABLE_FUNCTION(, IOTHUB_CLIENT_RESULT, IoTHubModuleClient_SendMessageDisposition, IOTHUB_MODULE_CLIENT_HANDLE, iotHubModuleClientHandle, IOTHUB_MESSAGE_HANDLE, message, IOTHUBMESSAGE_DISPOSITION_RESULT, disposition);

    /**
    * @brief      Asynchronous call to send the telemetry message specified by @p telemetryMessageHandle.
    *
    * @param[in]  iotHubModuleClientHandle        The handle created by a call to the create function.
    * @param[in]  telemetryMessageHandle          The handle to an IoT Hub message.
    * @param[in]  telemetryConfirmationCallback   Optional callback specified by the module for receiving
    *                                             confirmation of the delivery of the telemetry.
    * @param[in]  userContextCallback             User specified context that will be provided to the
    *                                             callback. This can be @c NULL.
    *
    * @remarks    The application behavior is undefined if the user calls
    *             the IoTHubModuleClient_Destroy function from within any callback.
    *
    *             The IOTHUB_MESSAGE_HANDLE instance provided as an argument is copied by the function,
    *             so this argument can be destroyed by the calling application right after IoTHubModuleClient_SendTelemetryAsync returns.
    *             The copy of @p telemetryMessageHandle is later destroyed by the iothub client when the message is successfully sent, if a failure sending it occurs, or if the client is destroyed.
    *
    * @return   IOTHUB_CLIENT_OK upon success or an error code upon failure.
    */
    MOCKABLE_FUNCTION(, IOTHUB_CLIENT_RESULT, IoTHubModuleClient_SendTelemetryAsync, IOTHUB_MODULE_CLIENT_HANDLE, iotHubModuleClientHandle, IOTHUB_MESSAGE_HANDLE, telemetryMessageHandle, IOTHUB_CLIENT_TELEMETRY_CALLBACK, telemetryConfirmationCallback, void*, userContextCallback);
    
    /**
    * @brief      Subscribe to incoming commands from IoT Hub.
    *
    * @param[in]  iotHubModuleClientHandle  The handle created by a call to the create function.
    * @param[in]  commandCallback           The callback which will be called when a command request arrives.
    * @param[in]  userContextCallback       User specified context that will be provided to the
    *                                       callback. This can be @c NULL.
    *
    * @remarks    The application behavior is undefined if the user calls
    *             the IoTHubModuleClient_Destroy function from within any callback.
    *    
    * @return     IOTHUB_CLIENT_OK upon success or an error code upon failure.
    */
    MOCKABLE_FUNCTION(, IOTHUB_CLIENT_RESULT, IoTHubModuleClient_SubscribeToCommands, IOTHUB_MODULE_CLIENT_HANDLE, iotHubModuleClientHandle, IOTHUB_CLIENT_COMMAND_CALLBACK_ASYNC, commandCallback,  void*, userContextCallback);

    /**
    * @brief      Sends module properties to IoT Hub.
    *
    * @param[in]  iotHubModuleClientHandle     The handle created by a call to the create function.
    * @param[in]  properties                   Serialized property data to be sent to IoT Hub.  This buffer can either be
    *                                          manually serialized created with IoTHubClient_Properties_Serializer_CreateReported() 
    *                                          or IoTHubClient_Properties_Serializer_CreateWritableResponse().
    * @param[in]  propertiesLength             Number of bytes in the properties buffer.
    * @param[in]  propertyAcknowledgedCallback Optional callback specified by the application to be called with the
    *                                          result of the transaction.
    * @param[in]  userContextCallback          User specified context that will be provided to the
    *                                          callback. This can be @c NULL.
    *
    * @remarks    The application behavior is undefined if the user calls
    *             the IoTHubModuleClient_Destroy function from within any callback.
    *
    * @return     IOTHUB_CLIENT_OK upon success or an error code upon failure.
    */
    MOCKABLE_FUNCTION(, IOTHUB_CLIENT_RESULT, IoTHubModuleClient_SendPropertiesAsync, IOTHUB_MODULE_CLIENT_HANDLE, iotHubModuleClientHandle,  const unsigned char*, properties, size_t, propertiesLength, IOTHUB_CLIENT_PROPERTY_ACKNOWLEDGED_CALLBACK, propertyAcknowledgedCallback, void*, userContextCallback);

    /**
    * @brief      Retrieves all module properties from IoT Hub.
    *
    * @param[in]  iotHubModuleClientHandle The handle created by a call to the create function.
    * @param[in]  propertyCallback         Callback invoked when properties are retrieved.
    *                                      The API IoTHubClient_Deserialize_Properties() can help deserialize the raw 
    *                                      payload stream.
    * @param[in]  userContextCallback      User specified context that will be provided to the
    *                                      callback. This can be @c NULL.
    *
    * @remarks    The application behavior is undefined if the user calls
    *             the IoTHubModuleClient_Destroy function from within any callback.
    *
    * @return     IOTHUB_CLIENT_OK upon success or an error code upon failure.
    */
    MOCKABLE_FUNCTION(, IOTHUB_CLIENT_RESULT, IoTHubModuleClient_GetPropertiesAsync, IOTHUB_MODULE_CLIENT_HANDLE, iotHubModuleClientHandle,  IOTHUB_CLIENT_PROPERTIES_RECEIVED_CALLBACK, propertyCallback, void*, userContextCallback);
    
    /**
    * @brief      Retrieves all module properties from IoT Hub and also subscribes for updates to writable properties.
    *
    * @param[in]  iotHubModuleClientHandle The handle created by a call to the create function.
    * @param[in]  propertyUpdateCallback   Callback both on initial retrieval of properties stored on IoT Hub
    *                                      and subsequent service-initiated modifications of writable properties.
    *                                      The API IoTHubClient_Deserialize_Properties() can help deserialize the raw 
    *                                      payload stream.
    * @param[in]  userContextCallback      User specified context that will be provided to the
    *                                      callback. This can be @c NULL.
    *
    * @remarks    The application behavior is undefined if the user calls
    *             the IoTHubModuleClient_Destroy function from within any callback.
    *
    * @return     IOTHUB_CLIENT_OK upon success or an error code upon failure.
    */
    MOCKABLE_FUNCTION(, IOTHUB_CLIENT_RESULT, IoTHubModuleClient_GetPropertiesAndSubscribeToUpdatesAsync, IOTHUB_MODULE_CLIENT_HANDLE, iotHubModuleClientHandle, IOTHUB_CLIENT_PROPERTIES_RECEIVED_CALLBACK, propertyUpdateCallback, void*, userContextCallback);

#ifdef __cplusplus
}
#endif

#endif /* IOTHUB_MODULE_CLIENT_H */