Using functions for REST APIs

This lesson will walk through using functions as a REST backend.

Lesson Steps
Other examples
Complete code

Lesson Steps

Create a netlify.toml file in your project.

The netlify.toml file is where we configure how the site builds and where your serverless functions live.
In netlify.toml, add a [build] section and add publish = "site" and functions = "functions" values
We need to create this site in Netlify

Open your terminal and run the following command:
```
netlify init --manual
```
Choose "create & configure a new site", then add a site name or hit enter for one to be generated for you.
Create your API function

Create a function name api in the /functions folder
In functions/api.js, we are going to setup our API router

Use the event.path & event.httpMethod to determine how to handle the request

Create your API function

Create a function name api in the /functions folder

"See code"

exports.handler = async (event, context) => {
  const path = event.path.replace(/\.netlify\/functions\/[^/]+/, '')
  const segments = path.split('/').filter(e => e)

  switch (event.httpMethod) {
    case 'GET':
      // GET /.netlify/functions/api
      if (segments.length === 0) {
        return api.readAll(event, context)
      }
      // GET /.netlify/functions/api/123456
      if (segments.length === 1) {
        event.id = segments[0]
        return api.read(event, context)
      } else {
        return {
          statusCode: 500,
          body: 'too many segments in GET request'
        }
      }
    // POST /.netlify/functions/api
    case 'POST':
      return api.create(event, context)
    // PUT /.netlify/functions/api/123456 
    case 'PUT':
      if (segments.length === 1) {
        event.id = segments[0]
        return api.update(event, context)
      } else {
        return {
          statusCode: 500,
          body: 'invalid segments in POST request, must be /.netlify/functions/api/123456'
        }
      }
    // DELETE /.netlify/functions/api/123456
    case 'DELETE':
      if (segments.length === 1) {
        event.id = segments[0]
        return api.delete(event, context)
      } else {
        return {
          statusCode: 500,
          body: 'invalid segments in DELETE request, must be /.netlify/functions/api/123456'
        }
      }
    // Fallthrough case
    default:
      return {
        statusCode: 500,
        body: 'unrecognized HTTP Method, must be one of GET/POST/PUT/DELETE'
      }
  }
}

Create a /functions/methods folder

We will add in our logic to handling the different routes here
Install the function dependencies

Change directories into your functions folder and install the dependencies
```
cd functions && npm install
```
This will install the fauandb sdk our functions will use to talk to our database.

Install the faunaDB addon
```
netlify addons:create fauna
```
Scaffold our database schema
```
npm run setup
```
Deploy the site

Open your terminal and run the following command:
```
netlify deploy -p
```
Visit the frontend to verify your api works!

Other examples

Complete code

If you need help or get stuck refer to the completed code of this lesson

View Complete Code

billymitchell/rest-api-netlify-serverless-functions

Using functions for REST APIs

Lesson Steps

Other examples

Complete code