Diff: iothub_client_ll.h

Revision:

9:3ec7e2695f98

Parent:

0:e393db310d89

Child:

10:38383e246675

--- a/iothub_client_ll.h	Wed Sep 16 06:38:05 2015 +0000
+++ b/iothub_client_ll.h	Tue Sep 22 20:36:48 2015 -0700
@@ -1,6 +1,25 @@
 // Copyright (c) Microsoft. All rights reserved.
 // Licensed under the MIT license. See LICENSE file in the project root for full license information.
 
+/** @file iothub_client_ll.h
+*	@brief	 APIs that allow a user (usually a device) to communicate
+*		     with an Azure IoTHub.
+*
+*	@details IoTHubClient_LL is a module that allows a user (usually a
+*			 device) to communicate with an Azure IoTHub. It can send events
+*			 and receive messages. At any given moment in time there can only
+*			 be at most 1 message callback function.
+*			 
+*			 This API surface contains a set of APIs that allows the user to
+*			 interact with the lower layer portion of the IoTHubClient. These APIs
+*			 contain @c _LL_ in their name, but retain the same functionality like the
+*			 @c IoTHubClient_... APIs, with one difference. If the @c _LL_ APIs are
+*			 used then the user is responsible for scheduling when the actual work done
+*			 by the IoTHubClient happens (when the data is sent/received on/from the wire).
+*			 This is useful for constrained devices where spinning a separate thread is
+*			 often not desired.
+*/
+
 #ifndef IOTHUB_CLIENT_LL_H
 #define IOTHUB_CLIENT_LL_H
 
@@ -22,6 +41,8 @@
     IOTHUB_CLIENT_INVALID_SIZE,           \
     IOTHUB_CLIENT_INDEFINITE_TIME         \
 
+/** @brief Enumeration specifying the status of calls to various APIs in this module.
+*/
 DEFINE_ENUM(IOTHUB_CLIENT_RESULT, IOTHUB_CLIENT_RESULT_VALUES);
 
 #define IOTHUB_CLIENT_CONFIRMATION_RESULT_VALUES     \
@@ -29,12 +50,19 @@
     IOTHUB_CLIENT_CONFIRMATION_BECAUSE_DESTROY,      \
     IOTHUB_CLIENT_CONFIRMATION_ERROR                 \
 
+/** @brief Enumeration passed in by the IoT Hub when the event confirmation  
+*		   callback is invoked to indicate status of the event processing in  
+*		   the hub.
+*/
 DEFINE_ENUM(IOTHUB_CLIENT_CONFIRMATION_RESULT, IOTHUB_CLIENT_CONFIRMATION_RESULT_VALUES);
 
 #define IOTHUB_CLIENT_STATUS_VALUES       \
     IOTHUB_CLIENT_SEND_STATUS_IDLE,       \
     IOTHUB_CLIENT_SEND_STATUS_BUSY        \
 
+/** @brief Enumeration returned by the ::IoTHubClient_LL_GetSendStatus  
+*		   API to indicate the current sending status of the IoT Hub client.
+*/
 DEFINE_ENUM(IOTHUB_CLIENT_STATUS, IOTHUB_CLIENT_STATUS_VALUES);
 
 #define TRANSPORT_TYPE_VALUES \
@@ -48,32 +76,195 @@
     IOTHUBMESSAGE_REJECTED, \
     IOTHUBMESSAGE_ABANDONED
 
+/** @brief Enumeration returned by the callback which is invoked whenever the  
+*		   IoT Hub sends a message to the device.
+*/
 DEFINE_ENUM(IOTHUBMESSAGE_DISPOSITION_RESULT, IOTHUBMESSAGE_DISPOSITION_RESULT_VALUES);
 
 typedef void* IOTHUB_CLIENT_LL_HANDLE;
 typedef void(*IOTHUB_CLIENT_EVENT_CONFIRMATION_CALLBACK)(IOTHUB_CLIENT_CONFIRMATION_RESULT result, void* userContextCallback);
-typedef IOTHUBMESSAGE_DISPOSITION_RESULT (*IOTHUB_CLIENT_NOTIFICATION_CALLBACK_ASYNC)(IOTHUB_MESSAGE_HANDLE notificationMessage, void* userContextCallback);
+typedef IOTHUBMESSAGE_DISPOSITION_RESULT (*IOTHUB_CLIENT_MESSAGE_CALLBACK_ASYNC)(IOTHUB_MESSAGE_HANDLE message, void* userContextCallback);
 typedef const void*(*IOTHUB_CLIENT_TRANSPORT_PROVIDER)(void);
 
+/** @brief	This struct captures IoTHub client configuration. */
 typedef struct IOTHUB_CLIENT_CONFIG_TAG
 {
+	/** @brief A function pointer that is passed into the @c IoTHubClientCreate.
+	*	A function definition for AMQP, @c DeviceClientProvideAmqpResources,
+	*	is defined in the include @c iothubtransportamqp.h.  A function
+	*	definition for HTTP, @c DeviceClientProvideHttpResources, is defined
+	*	in the include @c iothubtransporthttp.h */
     IOTHUB_CLIENT_TRANSPORT_PROVIDER protocol;
+
+    /** @brief	A string that identifies the device. */
     const char* deviceId;
+    
+	/** @brief	The device key used to authenticate the device. */
     const char* deviceKey;
+
+    /** @brief	The IoT Hub name to which the device is connecting. */
     const char* iotHubName;
+    
+	/** @brief	IoT Hub suffix goes here, e.g., private.azure-devices-int.net. */
     const char* iotHubSuffix;
+
     const char* protocolGatewayHostName;
 } IOTHUB_CLIENT_CONFIG;
 
+/**
+ * @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];</pre>
+ *				</blockquote>
+ * 
+ * @return	A non-NULL @c IOTHUB_CLIENT_LL_HANDLE value that is used when
+ * 			invoking other functions for IoT Hub client and @c NULL on failure.
+ */
 extern IOTHUB_CLIENT_LL_HANDLE IoTHubClient_LL_CreateFromConnectionString(const char* connectionString, IOTHUB_CLIENT_TRANSPORT_PROVIDER protocol);
+
+/**
+ * @brief	Creates a IoT Hub client for communication with an existing IoT
+ * 			Hub using the specified parameters.
+ *
+ * @param	config	Pointer to an @c IOTHUB_CLIENT_CONFIG structure
+ *
+ *			The API does not allow sharing of a connection across multiple
+ *			devices. This is a blocking call.
+ * 
+ * @return	A non-NULL @c IOTHUB_CLIENT_LL_HANDLE value that is used when
+ * 			invoking other functions for IoT Hub client and @c NULL on failure.
+ */
 extern IOTHUB_CLIENT_LL_HANDLE IoTHubClient_LL_Create(const IOTHUB_CLIENT_CONFIG* config);
+
+/**
+ * @brief	Disposes of resources allocated by the IoT Hub client. This is a
+ * 			blocking call.
+ *
+ * @param	iotHubClientHandle	The handle created by a call to the create function.
+ */
 extern void IoTHubClient_LL_Destroy(IOTHUB_CLIENT_LL_HANDLE iotHubClientHandle);
 
+/**
+ * @brief	Asynchronous call to send the message specified by @p eventMessageHandle. 
+ *
+ * @param	iotHubClientHandle		   	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 device for receiving
+ * 										confirmation of the delivery of the IoT Hub message.
+ * 										This callback can be expected to invoke the
+ * 										::IoTHubClient_LL_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.
+ *
+ *			@b NOTE: The application behavior is undefined if the user calls
+ *			the ::IoTHubClient_LL_Destroy function from within any callback.
+ * 
+ * @return	IOTHUB_CLIENT_OK upon success or an error code upon failure.
+ */
 extern IOTHUB_CLIENT_RESULT IoTHubClient_LL_SendEventAsync(IOTHUB_CLIENT_LL_HANDLE iotHubClientHandle, IOTHUB_MESSAGE_HANDLE eventMessageHandle, IOTHUB_CLIENT_EVENT_CONFIRMATION_CALLBACK eventConfirmationCallback, void* userContextCallback);
+
+/**
+ * @brief	This function returns the current sending status for IoTHubClient.
+ *
+ * @param	iotHubClientHandle		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 IOTHUBCLIENT_SENDSTATUS_IDLE if there is currently
+ * 								    no item to be sent and @c IOTHUBCLIENT_SENDSTATUS_BUSY
+ * 								    if there are.
+ *
+ * @return	IOTHUB_CLIENT_OK upon success or an error code upon failure.
+ */
 extern IOTHUB_CLIENT_RESULT IoTHubClient_LL_GetSendStatus(IOTHUB_CLIENT_LL_HANDLE iotHubClientHandle, IOTHUB_CLIENT_STATUS *iotHubClientStatus);
-extern IOTHUB_CLIENT_RESULT IoTHubClient_LL_SetNotificationCallback(IOTHUB_CLIENT_LL_HANDLE iotHubClientHandle, IOTHUB_CLIENT_NOTIFICATION_CALLBACK_ASYNC notificationCallback, void* userContextCallback);
-extern IOTHUB_CLIENT_RESULT IoTHubClient_LL_GetLastNotificationReceiveTime(IOTHUB_CLIENT_LL_HANDLE iotHubClientHandle, time_t* lastNotificationReceiveTime);
+
+/**
+ * @brief	Sets up the message callback to be invoked when IoT Hub issues a
+ * 			message to the device. This is a blocking call.
+ *
+ * @param	iotHubClientHandle		   	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.
+ *
+ *			@b NOTE: The application behavior is undefined if the user calls
+ *			the ::IoTHubClient_LL_Destroy function from within any callback.
+ * 
+ * @return	IOTHUB_CLIENT_OK upon success or an error code upon failure.
+ */
+extern IOTHUB_CLIENT_RESULT IoTHubClient_LL_SetMessageCallback(IOTHUB_CLIENT_LL_HANDLE iotHubClientHandle, IOTHUB_CLIENT_MESSAGE_CALLBACK_ASYNC messageCallback, void* userContextCallback);
+
+/**
+ * @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	iotHubClientHandle				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.
+ */
+extern IOTHUB_CLIENT_RESULT IoTHubClient_LL_GetLastMessageReceiveTime(IOTHUB_CLIENT_LL_HANDLE iotHubClientHandle, time_t* lastMessageReceiveTime);
+
+/**
+ * @brief	This function is meant to be called by the user when work
+ * 			(sending/receiving) can be done by the IoTHubClient.
+ *
+ * @param	iotHubClientHandle	The handle created by a call to the create function.
+ *
+ *			All IoTHubClient interactions (in regards to network traffic
+ *			and/or user level callbacks) are the effect of calling this
+ *			function and they take place synchronously inside _DoWork.
+ */
 extern void IoTHubClient_LL_DoWork(IOTHUB_CLIENT_LL_HANDLE iotHubClientHandle);
+
+/**
+ * @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	iotHubClientHandle	The handle created by a call to the create function.
+ * @param	optionName		  	Name of the option.
+ * @param	value			  	The value.
+ *
+ *			The options that can be set via this API are:
+ *				- @b timeout - the maximum time in milliseconds a communication is  
+ *				  allowed to use. @p value is a pointer to an @c unsigned @c int with
+ *				  the timeout value in milliseconds. This is only supported for the HTTP
+ *				  protocol as of now. When the HTTP protocol uses CURL, the meaning of
+ *				  the parameter is <em>total request time</em>. When the HTTP protocol uses
+ *				  winhttp, the meaning is the same as the @c dwSendTimeout and
+ *				  @c dwReceiveTimeout parameters of the
+ *				  <a href="https://msdn.microsoft.com/en-us/library/windows/desktop/aa384116(v=vs.85).aspx">
+ *				  WinHttpSetTimeouts</a> API.
+ *				- @b CURLOPT_LOW_SPEED_LIMIT - only available for HTTP protocol and only  
+ *				  when CURL is used. It has the same meaning as CURL's option with the same
+ *				  name. @p value is pointer to a long.
+ *				- @b CURLOPT_LOW_SPEED_TIME - only available for HTTP protocol and only  
+ *				  when CURL is used. It has the same meaning as CURL's option with the same
+ *				  name. @p value is pointer to a long.
+ *				- @b CURLOPT_FORBID_REUSE - only available for HTTP protocol and only  
+ *				  when CURL is used. It has the same meaning as CURL's option with the same
+ *				  name. @p value is pointer to a long.
+ *				- @b CURLOPT_FRESH_CONNECT - only available for HTTP protocol and only  
+ *				  when CURL is used. It has the same meaning as CURL's option with the same
+ *				  name. @p value is pointer to a long.
+ *				- @b CURLOPT_VERBOSE - only available for HTTP protocol and only  
+ *				  when CURL is used. It has the same meaning as CURL's option with the same
+ *				  name. @p value is pointer to a long.
+ * 
+ * @return	IOTHUB_CLIENT_OK upon success or an error code upon failure.
+ */
 extern IOTHUB_CLIENT_RESULT IoTHubClient_LL_SetOption(IOTHUB_CLIENT_LL_HANDLE iotHubClientHandle, const char* optionName, const void* value);
 
 #ifdef __cplusplus