AWSLex Class Reference

Inherits from AWSService : NSObject
Declared in AWSLexService.h
AWSLexService.m

Overview

Amazon Lex provides both build and runtime endpoints. Each endpoint provides a set of operations (API). Your conversational bot uses the runtime API to understand user utterances (user input text or voice). For example, suppose a user says "I want pizza", your bot sends this input to Amazon Lex using the runtime API. Amazon Lex recognizes that the user request is for the OrderPizza intent (one of the intents defined in the bot). Then Amazon Lex engages in user conversation on behalf of the bot to elicit required information (slot values, such as pizza size and crust type), and then performs fulfillment activity (that you configured when you created the bot). You use the build-time API to create and manage your Amazon Lex bot. For a list of build-time operations, see the build-time API, .

  configuration

The service configuration used to instantiate this service client.

@property (nonatomic, strong, readonly) AWSServiceConfiguration *configuration

Discussion

Warning: Once the client is instantiated, do not modify the configuration object. It may cause unspecified behaviors.

Declared In

AWSLexService.h

+ defaultLex

Returns the singleton service client. If the singleton object does not exist, the SDK instantiates the default service client with defaultServiceConfiguration from [AWSServiceManager defaultServiceManager]. The reference to this object is maintained by the SDK, and you do not need to retain it manually.

+ (instancetype)defaultLex

Return Value

The default service client.

Discussion

For example, set the default service configuration in - application:didFinishLaunchingWithOptions:

Swift

 func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplicationLaunchOptionsKey: Any]?) -> Bool {
    let credentialProvider = AWSCognitoCredentialsProvider(regionType: .USEast1, identityPoolId: "YourIdentityPoolId")
    let configuration = AWSServiceConfiguration(region: .USEast1, credentialsProvider: credentialProvider)
    AWSServiceManager.default().defaultServiceConfiguration = configuration

    return true
}

Objective-C

 - (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {
      AWSCognitoCredentialsProvider *credentialsProvider = [[AWSCognitoCredentialsProvider alloc] initWithRegionType:AWSRegionUSEast1
                                                                                                      identityPoolId:@"YourIdentityPoolId"];
      AWSServiceConfiguration *configuration = [[AWSServiceConfiguration alloc] initWithRegion:AWSRegionUSEast1
                                                                           credentialsProvider:credentialsProvider];
      [AWSServiceManager defaultServiceManager].defaultServiceConfiguration = configuration;

      return YES;
  }

Then call the following to get the default service client:

Swift

 let Lex = AWSLex.default()

Objective-C

 AWSLex *Lex = [AWSLex defaultLex];

Declared In

AWSLexService.h

+ registerLexWithConfiguration:forKey:

Creates a service client with the given service configuration and registers it for the key.

+ (void)registerLexWithConfiguration:(AWSServiceConfiguration *)configuration forKey:(NSString *)key

Parameters

configuration

A service configuration object.
key

A string to identify the service client.

Discussion

For example, set the default service configuration in - application:didFinishLaunchingWithOptions:

Swift

 func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplicationLaunchOptionsKey: Any]?) -> Bool {
    let credentialProvider = AWSCognitoCredentialsProvider(regionType: .USEast1, identityPoolId: "YourIdentityPoolId")
    let configuration = AWSServiceConfiguration(region: .USWest2, credentialsProvider: credentialProvider)
    AWSLex.register(with: configuration!, forKey: "USWest2Lex")

    return true
}

Objective-C

 - (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {
     AWSCognitoCredentialsProvider *credentialsProvider = [[AWSCognitoCredentialsProvider alloc] initWithRegionType:AWSRegionUSEast1
                                                                                                     identityPoolId:@"YourIdentityPoolId"];
     AWSServiceConfiguration *configuration = [[AWSServiceConfiguration alloc] initWithRegion:AWSRegionUSWest2
                                                                          credentialsProvider:credentialsProvider];

     [AWSLex registerLexWithConfiguration:configuration forKey:@"USWest2Lex"];

     return YES;
 }

Then call the following to get the service client:

Swift

 let Lex = AWSLex(forKey: "USWest2Lex")

Objective-C

 AWSLex *Lex = [AWSLex LexForKey:@"USWest2Lex"];

Warning: After calling this method, do not modify the configuration object. It may cause unspecified behaviors.

Declared In

AWSLexService.h

+ LexForKey:

Retrieves the service client associated with the key. You need to call + registerLexWithConfiguration:forKey: before invoking this method.

+ (instancetype)LexForKey:(NSString *)key

Parameters

key

A string to identify the service client.

Return Value

An instance of the service client.

Discussion

For example, set the default service configuration in - application:didFinishLaunchingWithOptions:

Swift

 func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplicationLaunchOptionsKey: Any]?) -> Bool {
    let credentialProvider = AWSCognitoCredentialsProvider(regionType: .USEast1, identityPoolId: "YourIdentityPoolId")
    let configuration = AWSServiceConfiguration(region: .USWest2, credentialsProvider: credentialProvider)
    AWSLex.register(with: configuration!, forKey: "USWest2Lex")

    return true
}

Objective-C

 - (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {
     AWSCognitoCredentialsProvider *credentialsProvider = [[AWSCognitoCredentialsProvider alloc] initWithRegionType:AWSRegionUSEast1
                                                                                                     identityPoolId:@"YourIdentityPoolId"];
     AWSServiceConfiguration *configuration = [[AWSServiceConfiguration alloc] initWithRegion:AWSRegionUSWest2
                                                                          credentialsProvider:credentialsProvider];

     [AWSLex registerLexWithConfiguration:configuration forKey:@"USWest2Lex"];

     return YES;
 }

Then call the following to get the service client:

Swift

 let Lex = AWSLex(forKey: "USWest2Lex")

Objective-C

 AWSLex *Lex = [AWSLex LexForKey:@"USWest2Lex"];

Declared In

AWSLexService.h

+ removeLexForKey:

Removes the service client associated with the key and release it.

+ (void)removeLexForKey:(NSString *)key

Parameters

key

A string to identify the service client.

Discussion

Warning: Before calling this method, make sure no method is running on this client.

Declared In

AWSLexService.h

– postContent:

Sends user input (text or speech) to Amazon Lex. Clients use this API to send text and audio requests to Amazon Lex at runtime. Amazon Lex interprets the user input using the machine learning model that it built for the bot.

The PostContent operation supports audio input at 8kHz and 16kHz. You can use 8kHz audio to achieve higher speech recognition accuracy in telephone audio applications.

In response, Amazon Lex returns the next message to convey to the user. Consider the following example messages:

  • For a user input "I would like a pizza," Amazon Lex might return a response with a message eliciting slot data (for example, PizzaSize): "What size pizza would you like?".

  • After the user provides all of the pizza order information, Amazon Lex might return a response with a message to get user confirmation: "Order the pizza?".

  • After the user replies "Yes" to the confirmation prompt, Amazon Lex might return a conclusion statement: "Thank you, your cheese pizza has been ordered.".

Not all Amazon Lex messages require a response from the user. For example, conclusion statements do not require a response. Some messages require only a yes or no response. In addition to the message, Amazon Lex provides additional context about the message in the response that you can use to enhance client behavior, such as displaying the appropriate client user interface. Consider the following examples:

  • If the message is to elicit slot data, Amazon Lex returns the following context information:

    • x-amz-lex-dialog-state header set to ElicitSlot

    • x-amz-lex-intent-name header set to the intent name in the current context

    • x-amz-lex-slot-to-elicit header set to the slot name for which the message is eliciting information

    • x-amz-lex-slots header set to a map of slots configured for the intent with their current values

  • If the message is a confirmation prompt, the x-amz-lex-dialog-state header is set to Confirmation and the x-amz-lex-slot-to-elicit header is omitted.

  • If the message is a clarification prompt configured for the intent, indicating that the user intent is not understood, the x-amz-dialog-state header is set to ElicitIntent and the x-amz-slot-to-elicit header is omitted.

In addition, Amazon Lex also returns your application-specific sessionAttributes. For more information, see Managing Conversation Context.

- (AWSTask<AWSLexPostContentResponse*> *)postContent:(AWSLexPostContentRequest *)request

Parameters

request

A container for the necessary parameters to execute the PostContent service method.

Return Value

An instance of AWSTask. On successful execution, task.result will contain an instance of AWSLexPostContentResponse. On failed execution, task.error may contain an NSError with AWSLexErrorDomain domain and the following error code: AWSLexErrorNotFound, AWSLexErrorBadRequest, AWSLexErrorLimitExceeded, AWSLexErrorInternalFailure, AWSLexErrorConflict, AWSLexErrorUnsupportedMediaType, AWSLexErrorNotAcceptable, AWSLexErrorRequestTimeout, AWSLexErrorDependencyFailed, AWSLexErrorBadGateway, AWSLexErrorLoopDetected.

See Also

Declared In

AWSLexService.h

– postContent:completionHandler:

Sends user input (text or speech) to Amazon Lex. Clients use this API to send text and audio requests to Amazon Lex at runtime. Amazon Lex interprets the user input using the machine learning model that it built for the bot.

The PostContent operation supports audio input at 8kHz and 16kHz. You can use 8kHz audio to achieve higher speech recognition accuracy in telephone audio applications.

In response, Amazon Lex returns the next message to convey to the user. Consider the following example messages:

  • For a user input "I would like a pizza," Amazon Lex might return a response with a message eliciting slot data (for example, PizzaSize): "What size pizza would you like?".

  • After the user provides all of the pizza order information, Amazon Lex might return a response with a message to get user confirmation: "Order the pizza?".

  • After the user replies "Yes" to the confirmation prompt, Amazon Lex might return a conclusion statement: "Thank you, your cheese pizza has been ordered.".

Not all Amazon Lex messages require a response from the user. For example, conclusion statements do not require a response. Some messages require only a yes or no response. In addition to the message, Amazon Lex provides additional context about the message in the response that you can use to enhance client behavior, such as displaying the appropriate client user interface. Consider the following examples:

  • If the message is to elicit slot data, Amazon Lex returns the following context information:

    • x-amz-lex-dialog-state header set to ElicitSlot

    • x-amz-lex-intent-name header set to the intent name in the current context

    • x-amz-lex-slot-to-elicit header set to the slot name for which the message is eliciting information

    • x-amz-lex-slots header set to a map of slots configured for the intent with their current values

  • If the message is a confirmation prompt, the x-amz-lex-dialog-state header is set to Confirmation and the x-amz-lex-slot-to-elicit header is omitted.

  • If the message is a clarification prompt configured for the intent, indicating that the user intent is not understood, the x-amz-dialog-state header is set to ElicitIntent and the x-amz-slot-to-elicit header is omitted.

In addition, Amazon Lex also returns your application-specific sessionAttributes. For more information, see Managing Conversation Context.

- (void)postContent:(AWSLexPostContentRequest *)request completionHandler:(void ( ^ _Nullable ) ( AWSLexPostContentResponse *_Nullable response , NSError *_Nullable error ))completionHandler

Parameters

request

A container for the necessary parameters to execute the PostContent service method.
completionHandler

The completion handler to call when the load request is complete. response - A response object, or nil if the request failed. error - An error object that indicates why the request failed, or nil if the request was successful. On failed execution, error may contain an NSError with AWSLexErrorDomain domain and the following error code: AWSLexErrorNotFound, AWSLexErrorBadRequest, AWSLexErrorLimitExceeded, AWSLexErrorInternalFailure, AWSLexErrorConflict, AWSLexErrorUnsupportedMediaType, AWSLexErrorNotAcceptable, AWSLexErrorRequestTimeout, AWSLexErrorDependencyFailed, AWSLexErrorBadGateway, AWSLexErrorLoopDetected.

See Also

Declared In

AWSLexService.h

– postText:

Sends user input (text-only) to Amazon Lex. Client applications can use this API to send requests to Amazon Lex at runtime. Amazon Lex then interprets the user input using the machine learning model it built for the bot.

In response, Amazon Lex returns the next message to convey to the user an optional responseCard to display. Consider the following example messages:

  • For a user input "I would like a pizza", Amazon Lex might return a response with a message eliciting slot data (for example, PizzaSize): "What size pizza would you like?"

  • After the user provides all of the pizza order information, Amazon Lex might return a response with a message to obtain user confirmation "Proceed with the pizza order?".

  • After the user replies to a confirmation prompt with a "yes", Amazon Lex might return a conclusion statement: "Thank you, your cheese pizza has been ordered.".

Not all Amazon Lex messages require a user response. For example, a conclusion statement does not require a response. Some messages require only a "yes" or "no" user response. In addition to the message, Amazon Lex provides additional context about the message in the response that you might use to enhance client behavior, for example, to display the appropriate client user interface. These are the slotToElicit, dialogState, intentName, and slots fields in the response. Consider the following examples:

  • If the message is to elicit slot data, Amazon Lex returns the following context information:

    • dialogState set to ElicitSlot

    • intentName set to the intent name in the current context

    • slotToElicit set to the slot name for which the message is eliciting information

    • slots set to a map of slots, configured for the intent, with currently known values

  • If the message is a confirmation prompt, the dialogState is set to ConfirmIntent and SlotToElicit is set to null.

  • If the message is a clarification prompt (configured for the intent) that indicates that user intent is not understood, the dialogState is set to ElicitIntent and slotToElicit is set to null.

In addition, Amazon Lex also returns your application-specific sessionAttributes. For more information, see Managing Conversation Context.

- (AWSTask<AWSLexPostTextResponse*> *)postText:(AWSLexPostTextRequest *)request

Parameters

request

A container for the necessary parameters to execute the PostText service method.

Return Value

An instance of AWSTask. On successful execution, task.result will contain an instance of AWSLexPostTextResponse. On failed execution, task.error may contain an NSError with AWSLexErrorDomain domain and the following error code: AWSLexErrorNotFound, AWSLexErrorBadRequest, AWSLexErrorLimitExceeded, AWSLexErrorInternalFailure, AWSLexErrorConflict, AWSLexErrorDependencyFailed, AWSLexErrorBadGateway, AWSLexErrorLoopDetected.

See Also

Declared In

AWSLexService.h

– postText:completionHandler:

Sends user input (text-only) to Amazon Lex. Client applications can use this API to send requests to Amazon Lex at runtime. Amazon Lex then interprets the user input using the machine learning model it built for the bot.

In response, Amazon Lex returns the next message to convey to the user an optional responseCard to display. Consider the following example messages:

  • For a user input "I would like a pizza", Amazon Lex might return a response with a message eliciting slot data (for example, PizzaSize): "What size pizza would you like?"

  • After the user provides all of the pizza order information, Amazon Lex might return a response with a message to obtain user confirmation "Proceed with the pizza order?".

  • After the user replies to a confirmation prompt with a "yes", Amazon Lex might return a conclusion statement: "Thank you, your cheese pizza has been ordered.".

Not all Amazon Lex messages require a user response. For example, a conclusion statement does not require a response. Some messages require only a "yes" or "no" user response. In addition to the message, Amazon Lex provides additional context about the message in the response that you might use to enhance client behavior, for example, to display the appropriate client user interface. These are the slotToElicit, dialogState, intentName, and slots fields in the response. Consider the following examples:

  • If the message is to elicit slot data, Amazon Lex returns the following context information:

    • dialogState set to ElicitSlot

    • intentName set to the intent name in the current context

    • slotToElicit set to the slot name for which the message is eliciting information

    • slots set to a map of slots, configured for the intent, with currently known values

  • If the message is a confirmation prompt, the dialogState is set to ConfirmIntent and SlotToElicit is set to null.

  • If the message is a clarification prompt (configured for the intent) that indicates that user intent is not understood, the dialogState is set to ElicitIntent and slotToElicit is set to null.

In addition, Amazon Lex also returns your application-specific sessionAttributes. For more information, see Managing Conversation Context.

- (void)postText:(AWSLexPostTextRequest *)request completionHandler:(void ( ^ _Nullable ) ( AWSLexPostTextResponse *_Nullable response , NSError *_Nullable error ))completionHandler

Parameters

request

A container for the necessary parameters to execute the PostText service method.
completionHandler

The completion handler to call when the load request is complete. response - A response object, or nil if the request failed. error - An error object that indicates why the request failed, or nil if the request was successful. On failed execution, error may contain an NSError with AWSLexErrorDomain domain and the following error code: AWSLexErrorNotFound, AWSLexErrorBadRequest, AWSLexErrorLimitExceeded, AWSLexErrorInternalFailure, AWSLexErrorConflict, AWSLexErrorDependencyFailed, AWSLexErrorBadGateway, AWSLexErrorLoopDetected.

See Also

Declared In

AWSLexService.h