07

Part 7 - Accessing External APIs

In this module we show how to access an external API (3rd party REST service) with the Axios library (you might use other libraries similarly, like e.g. node-fetch). We use async/await to wait for a response from the service. We set up a connection timeout so the call comes back in time before we run out of time during an Alexa conversation turn (typically 8 seconds). We use the Progressive Response API before doing the call so Alexa gives the user a nice waiting message if the connection takes a few seconds to return.

Milestones

1. Build Tab: add celebrity birthdays intent with utterances to ask for today's birthdays (no slots)
2. Code Tab: add axios dependency to package.json
3. Code Tab: add code to access external API (with async/await), axios allows to set a timeout (use 6500 ms)
4. Code Tab: add progressive response directive and attach to external API call
5. Code Tab: add celebrity birthdays intent handler
6. Code Tab: add new handler to skill builder

Concepts

1. Fetch external API (async/await)
2. Progressive Response

Diff

1. lambda/custom/constants.js: add max birthdays to this file
2. lambda/custom/package.json: add axios dependency
3. lambda/custom/localisation.js: add all messages related to API access
4. models/xx-XX.json: add celebrity birthdays intent with utterances to ask for today's birthdays
5. lambda/custom/logic.js: add functions to return current date info and to call external API
6. lambda/custom/util: add function to create progressive response directive (callDirectiveService)
7. lambda/custom/index.js: Extend birthday greeting to mention celebrity birthdays. Add celebrity birthdays intent handler and fetch the birthdays from the API. Add new handler to skill builder