Rust Request/Response for Amazon Alexa Skills

About

Implements Amazon Alexa Skill request/response structs following the Alexa skill specifications, including Serde JSON serialization/deserialization with some helpers to extract data from requests and format responses.

These structs can be used as the request and response using the Rust AWS Lambda runtime to implement the skill.

Usage

Simplest possible Alexa "Hello, World" skill:

extern crate lambda_runtime as lambda;
extern crate alexa_sdk;

use lambda::{lambda, Context, error::HandlerError};
use alexa_sdk::{Request,Response};
use std::error::Error;


fn my_handler(_req: Request, _ctx: Context) -> Result<Response,HandlerError> {
    Ok(Response::simple("hello", "hello world"))
}

fn main() -> Result<(), Box<dyn Error>> {
    lambda!(my_handler);

    Ok(())
}

A more complete skill, handling multiple locales and a slot:

extern crate lambda_runtime as lambda;
extern crate alexa_sdk;

use lambda::{lambda, Context, error::HandlerError};
use alexa_sdk::{Request,Response};
use alexa_sdk::request::{IntentType, Locale};
use std::error::Error;

fn handle_help(_req: &Request) -> Result<Response,HandlerError> {
    Ok(Response::simple("hello", "to say hello, tell me: say hello to someone"))
}

fn handle_hello(req: &Request) -> Result<Response,HandlerError> {
    let res = match req.locale() {
        Locale::AustralianEnglish => Response::simple("hello", "G'day mate"),
        Locale::German => Response::simple("hello", "Hallo Welt"),
        Locale::Japanese => Response::simple("hello", "こんにちは世界"),
        _ => if let Some(ref s) = req.slot_value("name") {
            Response::simple("hello", (String::from("hello ") + s).as_str())
        } else {
            Response::simple("hello", "hello world")
        },
    };
    Ok(res)
}

fn handle_cancel(_req: &Request) -> Result<Response,HandlerError> {
    Ok(Response::end())
}

fn my_handler(req: Request, _ctx: Context) -> Result<Response,HandlerError> {
    match req.intent() {
        IntentType::Help => handle_help(&req),
        IntentType::Cancel => handle_cancel(&req),
        IntentType::User(_) => handle_hello(&req),
        _ => handle_cancel (&req)
    }
}

fn main() -> Result<(), Box<dyn Error>> {
    lambda!(my_handler);

    Ok(())
}

Reponse Builder

Besides the simplifed Response constructors Response::simple and Response::end (to end a session), the SDK supports a Response builder:

let img = Image {
    small_image_url: Some(String::from("https://example.com/baaz.png")),
    large_image_url: Some(String::from("https://example.com/baazLarge.png"))
};
let mut res = Response::new(false) // should not end session
    .card(Card::standard("foo", "bar", img))
    .speech(Speech::plain("hello"));
res.add_attribute("attr", "value");

Attributes

Alexa skills support attributes, which can be used to carry simple state in a session. To set an attribute in the response, use add_attribute on the response, to read a previously set attribute on a subsequent request, use attribute_value on the request.

[TODO: example]