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https://github.com/mhart/aws4fetch
A compact AWS client and signing utility for modern JS environments
https://github.com/mhart/aws4fetch
Last synced: 14 days ago
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A compact AWS client and signing utility for modern JS environments
- Host: GitHub
- URL: https://github.com/mhart/aws4fetch
- Owner: mhart
- License: mit
- Created: 2018-12-20T21:15:10.000Z (almost 6 years ago)
- Default Branch: master
- Last Pushed: 2024-04-23T11:41:06.000Z (7 months ago)
- Last Synced: 2024-05-01T22:35:48.328Z (7 months ago)
- Language: JavaScript
- Homepage:
- Size: 136 KB
- Stars: 512
- Watchers: 8
- Forks: 39
- Open Issues: 16
-
Metadata Files:
- Readme: README.md
- License: LICENSE
Awesome Lists containing this project
README
# aws4fetch
A compact (6.4kb minified, 2.5kb gzipped) [AWS](https://aws.amazon.com/) client for environments that support
[`fetch`](https://developer.mozilla.org/en-US/docs/Web/API/Fetch_API) and
[`SubtleCrypto`](https://developer.mozilla.org/en-US/docs/Web/API/SubtleCrypto) – that is, modern web browsers and
JS platforms like [Cloudflare Workers](https://www.cloudflare.com/products/cloudflare-workers/). Also retries
requests with an [exponential backoff with full jitter](https://aws.amazon.com/blogs/architecture/exponential-backoff-and-jitter/)
strategy by default.
# Example
```js
import { AwsClient } from 'aws4fetch'
const aws = new AwsClient({ accessKeyId: MY_ACCESS_KEY, secretAccessKey: MY_SECRET_KEY })
// https://docs.aws.amazon.com/lambda/latest/dg/API_Invoke.html
const LAMBDA_FN_API = 'https://lambda.us-east-1.amazonaws.com/2015-03-31/functions'
async function invokeMyLambda(event) {
const res = await aws.fetch(`${LAMBDA_FN_API}/my-lambda/invocations`, { body: JSON.stringify(event) })
// `res` is a standard Response object: https://developer.mozilla.org/en-US/docs/Web/API/Response
return res.json()
}
invokeMyLambda({my: 'event'}).then(json => console.log(json))
```
You can see a more detailed example, a Cloudflare Worker script you can use as
a replacement for [API Gateway](https://aws.amazon.com/api-gateway/), in the [`example`](./example) directory.
# API
`aws4fetch` exports two classes: `AwsClient` and `AwsV4Signer`
## `new AwsClient(options)`
You can use the same instance of `AwsClient` for all your service calls as the service and region will be determined
at fetch time – or you can create separate instances if you have different needs, eg no retrying for some service.
```js
import { AwsClient } from 'aws4fetch'
const aws = new AwsClient({
accessKeyId, // required, akin to AWS_ACCESS_KEY_ID
secretAccessKey, // required, akin to AWS_SECRET_ACCESS_KEY
sessionToken, // akin to AWS_SESSION_TOKEN if using temp credentials
service, // AWS service, by default parsed at fetch time
region, // AWS region, by default parsed at fetch time
cache, // credential cache, defaults to `new Map()`
retries, // number of retries before giving up, defaults to 10, set to 0 for no retrying
initRetryMs, // defaults to 50 – timeout doubles each retry
})
```
### `Promise aws.fetch(input[, init])`
Has the same signature as the [global fetch function](https://developer.mozilla.org/en-US/docs/Web/API/fetch#syntax)
```js
import { AwsClient } from 'aws4fetch'
const aws = new AwsClient(opts)
async function doFetch() {
const response = await aws.fetch(url, {
method, // if not supplied, will default to 'POST' if there's a body, otherwise 'GET'
headers, // standard JS object literal, or Headers instance
body, // optional, String or ArrayBuffer/ArrayBufferView – ie, remember to stringify your JSON
// and any other standard fetch options, eg keepalive, etc
// optional, largely if you want to override options in the AwsClient instance
aws: {
signQuery, // set to true to sign the query string instead of the Authorization header
accessKeyId, // same as in AwsClient constructor above
secretAccessKey, // same as in AwsClient constructor above
sessionToken, // same as in AwsClient constructor above
service, // same as in AwsClient constructor above
region, // same as in AwsClient constructor above
cache, // same as in AwsClient constructor above
datetime, // defaults to now, to override use the form '20150830T123600Z'
appendSessionToken, // set to true to add X-Amz-Security-Token after signing, defaults to true for iot
allHeaders, // set to true to force all headers to be signed instead of the defaults
singleEncode, // set to true to only encode %2F once (usually only needed for testing)
},
})
console.log(await response.json())
}
```
NB: Due to the way bodies are handled in [`Request`](https://developer.mozilla.org/en-US/docs/Web/API/Request)
instances, it's faster to invoke the function as above – using a URL as the `input`
argument and passing the `body` in the `init` argument – instead of the form of
invocation that uses a `Request` object directly as `input`.
If you don't know which URL to call for the AWS service you want, the full list
of AWS endpoints can be found here:
https://docs.aws.amazon.com/general/latest/gr/rande.html
And the APIs are documented here: https://docs.aws.amazon.com/ (the REST APIs
are usually documented under "API Reference" for each service)
### `Promise aws.sign(input[, init])`
Returns a Promise that resolves to an
[AWS4](https://docs.aws.amazon.com/general/latest/gr/signature-version-4.html)
signed [`Request`](https://developer.mozilla.org/en-US/docs/Web/API/Request) –
has the same signature as `fetch`. Use this to create a `Request` you can send
using `fetch()` yourself.
```js
import { AwsClient } from 'aws4fetch'
const aws = new AwsClient(opts)
async function doFetch() {
const request = await aws.sign(url, {
method, // if not supplied, will default to 'POST' if there's a body, otherwise 'GET'
headers, // standard JS object literal, or Headers instance
body, // optional, String or ArrayBuffer/ArrayBufferView – ie, remember to stringify your JSON
// and any other standard fetch options, eg keepalive, etc
// optional, largely if you want to override options in the AwsClient instance
aws: {
signQuery, // set to true to sign the query string instead of the Authorization header
accessKeyId, // same as in AwsClient constructor above
secretAccessKey, // same as in AwsClient constructor above
sessionToken, // same as in AwsClient constructor above
service, // same as in AwsClient constructor above
region, // same as in AwsClient constructor above
cache, // same as in AwsClient constructor above
datetime, // defaults to now, to override use the form '20150830T123600Z'
appendSessionToken, // set to true to add X-Amz-Security-Token after signing, defaults to true for iot
allHeaders, // set to true to force all headers to be signed instead of the defaults
singleEncode, // set to true to only encode %2F once (usually only needed for testing)
},
})
const response = await fetch(request)
console.log(await response.json())
}
```
## `new AwsV4Signer(options)`
The underlying signing class for a request – use this if you just want to deal
with the raw AWS4 signed method/url/headers/body.
```js
import { AwsV4Signer } from 'aws4fetch'
const signer = new AwsV4Signer({
url, // required, the AWS endpoint to sign
accessKeyId, // required, akin to AWS_ACCESS_KEY_ID
secretAccessKey, // required, akin to AWS_SECRET_ACCESS_KEY
sessionToken, // akin to AWS_SESSION_TOKEN if using temp credentials
method, // if not supplied, will default to 'POST' if there's a body, otherwise 'GET'
headers, // standard JS object literal, or Headers instance
body, // optional, String or ArrayBuffer/ArrayBufferView – ie, remember to stringify your JSON
signQuery, // set to true to sign the query string instead of the Authorization header
service, // AWS service, by default parsed at fetch time
region, // AWS region, by default parsed at fetch time
cache, // credential cache, defaults to `new Map()`
datetime, // defaults to now, to override use the form '20150830T123600Z'
appendSessionToken, // set to true to add X-Amz-Security-Token after signing, defaults to true for iot
allHeaders, // set to true to force all headers to be signed instead of the defaults
singleEncode, // set to true to only encode %2F once (usually only needed for testing)
})
```
### `Promise<{ method, url, headers, body }> signer.sign()`
Actually perform the signing of the request and return a Promise that resolves
to an object containing the signed method, url, headers and body.
`method` will be a `String`, `url` will be an instance of [`URL`](https://developer.mozilla.org/en-US/docs/Web/API/URL),
`headers` will be an instance of [`Headers`](https://developer.mozilla.org/en-US/docs/Web/API/Headers) and
`body` will unchanged from the argument you supply to the constructor.
```js
import { AwsV4Signer } from 'aws4fetch'
const signer = new AwsV4Signer(opts)
async function sign() {
const { method, url, headers, body } = await signer.sign()
console.log(method, url, [...headers], body)
}
```
### `Promise signer.authHeader()`
Returns a Promise that resolves to the signed string to use in the
[`Authorization` header](https://docs.aws.amazon.com/general/latest/gr/sigv4-add-signature-to-request.html#sigv4-add-signature-auth-header)
Used by the `sign()` method – you shouldn't need to access this directly unless you're constructing your own requests.
### `Promise signer.signature()`
Returns a Promise that resolves to the
[hex signature](https://docs.aws.amazon.com/general/latest/gr/sigv4-calculate-signature.html#sigv4-calculate-signature)
Used by the `sign()` method – you shouldn't need to access this directly unless you're constructing your own requests.
# Installation
With [npm](http://npmjs.org/) do:
```
npm install aws4fetch
```