API on AWS with SST
Create and deploy a serverless API in AWS with SST.
We are going to build a serverless API, add an S3 Bucket for file uploads, and deploy it to AWS using SST.
Before you get started, make sure to configure your AWS credentials.
1. Create a project
Let’s start by creating our app.
mkdir my-ts-app && cd my-ts-appnpm init -y
Init SST
Now let’s initialize SST in our app.
npx sst@latest initnpm install
Select the defaults and pick AWS. This’ll create a sst.config.ts
file in your project root.
2. Add an API
Let’s add an API using Amazon API Gateway. Update your sst.config.ts
.
async run() { const api = new sst.aws.ApiGatewayV2("MyApi"); api.route("GET /", { handler: "index.upload", }); api.route("GET /latest", { handler: "index.latest", });}
We are adding two routes, one for uploading an image and another for getting the latest uploaded image.
Start dev mode
Start your app in dev mode. This runs your functions Live.
npx sst dev
This will give you the URL of your API.
+ Complete MyApi: https://y9ink9nh96.execute-api.us-east-1.amazonaws.com
3. Add an S3 Bucket
Let’s add an S3 Bucket for file uploads. Update your sst.config.ts
.
const bucket = new sst.aws.Bucket("MyBucket");
Add this above the Api
component.
Link the bucket
Now, link the bucket to the API routes.
api.route("GET /", { link: [bucket], handler: "index.upload",});api.route("GET /latest", { link: [bucket], handler: "index.latest",});
4. Upload a file
We want the /
route of our API to generate a pre-signed URL to upload a file to our S3 Bucket. Create an index.ts
file and add the following.
export async function upload() { const command = new PutObjectCommand({ Key: crypto.randomUUID(), Bucket: Resource.MyBucket.name, });
return { statusCode: 200, body: await getSignedUrl(s3, command), };}
Add the relevant imports.
import { Resource } from "sst";import { getSignedUrl } from "@aws-sdk/s3-request-presigner";import { S3Client, GetObjectCommand, PutObjectCommand, ListObjectsV2Command,} from "@aws-sdk/client-s3";
const s3 = new S3Client({});
And install the npm packages.
npm install @aws-sdk/client-s3 @aws-sdk/s3-request-presigner
5. Download a file
We want the /latest
route of our API to generate a pre-signed URL to download the last uploaded file in our S3 Bucket. Add this to your index.ts
file.
export async function latest() { const objects = await s3.send( new ListObjectsV2Command({ Bucket: Resource.MyBucket.name, }) );
const latestFile = objects.Contents!.sort( (a, b) => (b.LastModified?.getTime() ?? 0) - (a.LastModified?.getTime() ?? 0) )[0];
const command = new GetObjectCommand({ Key: latestFile.Key, Bucket: Resource.MyBucket.name, });
return { statusCode: 302, headers: { Location: await getSignedUrl(s3, command), }, };}
Test your app
Let’s try uploading a file from your project root. Make sure to use your API URL.
curl --upload-file package.json "$(curl https://y9ink9nh96.execute-api.us-east-1.amazonaws.com)"
Now head over to https://y9ink9nh96.execute-api.us-east-1.amazonaws.com/latest
in your browser and it’ll download the file you just uploaded.
6. Deploy your app
Now let’s deploy your app to production.
npx sst deploy --stage production
You can use any stage name here but it’s good to create a new stage for production.
Connect the console
As a next step, you can setup the SST Console to git push to deploy your app and monitor it for any issues.
You can create a free account and connect it to your AWS account.