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presign
SignatureV4.presign()
pre-signs a URL with the AWS Signature V4 algorithm. Given an HTTP request description, it returns a new HTTP request with the AWS signature v4 authorization added. It returns an Object holding a url
containing the authorization information encoded in its query string, ready to use in the context of a k6 HTTP call.
Parameters
The first parameter of the presign
method consists of an Object with the following properties.
Property | Type | Description |
---|---|---|
method | string | The HTTP method of the request |
endpoint | Endpoint | The endpoint of the request. The Endpoint constructor can be imported from both the aws.js bundle, as well as the signature.js file, and takes a string of the form {scheme}://{hostname}[:{port}] as input, allowing to define the target of the request (See provided example below). |
path | string | The path of the request |
headers | Object | The headers of the HTTP request |
You can provide further options and override SignatureV4 options in the context of this specific request.
To do this, pass a second parameter to the presign
method, which is an Object with the following parameters.
Property | Type | Description |
---|---|---|
expiresIn | number | The number of seconds before the pre-signed URL expires |
signingDate | Date | overrides the Date used in the signing operation |
signingService | string | overrides the signer’s AWS service in the context of the sign operation. |
signingRegion | string | overrides the signer’s AWS region in the context of the sign operation |
unsignableHeaders | Set<string> | excludes headers from the signing process |
signableHeaders | Set<string> | mark headers as signed |
Returns
The presign
operation returns an Object with the following properties.
Property | Type | Description |
---|---|---|
headers | Object | The pre-signed request headers to use in the context of a k6 HTTP request |
url | string | The pre-signed url to use in the context of a k6 HTTP request |
Example
import http from 'k6/http';
import { check } from 'k6';
import {
AWSConfig,
Endpoint,
SignatureV4,
AMZ_CONTENT_SHA256_HEADER,
UNSIGNED_PAYLOAD,
} from 'https://jslib.k6.io/aws/0.12.3/signature.js';
const awsConfig = new AWSConfig({
region: __ENV.AWS_REGION,
accessKeyId: __ENV.AWS_ACCESS_KEY_ID,
secretAccessKey: __ENV.AWS_SECRET_ACCESS_KEY,
sessionToken: __ENV.AWS_SESSION_TOKEN,
});
export default function () {
// In order to be able to produce pre-signed URLs,
// we need to instantiate a SignatureV4 object.
const signer = new SignatureV4({
service: 's3',
region: awsConfig.region,
credentials: {
accessKeyId: awsConfig.accessKeyId,
secretAccessKey: awsConfig.secretAccessKey,
sessionToken: awsConfig.sessionToken,
},
/**
* Whether the URI should be escaped or not.
*/
uriEscapePath: false,
/**
* Whether or not the body's hash should be calculated and included
* in the request.
*/
applyChecksum: true,
});
// We can now use the signer to produce a pre-signed URL.
const presignedRequest = signer.presign(
/**
* HTTP request description
*/
{
/**
* The HTTP method we will use in the request.
*/
method: 'GET',
/**
* The endpoint of the service we will be making the request to.
*
* The endpoint is instantiated from a URL string, of the format: `{scheme}://{hostname}[:{port}]`
*/
endpoint: new Endpoint('https://s3.us-east-1.amazonaws.com'),
/**
* The path of the request.
*/
path: '/my-bucket/bonjour.txt',
/**
* The headers we will be sending in the request.
*
* Note that in the specific case of this example, requesting
* an object from S3, we want to set the `x-amz-content-sha256`
* header to `UNSIGNED_PAYLOAD`. That way, we bypass the payload
* hash calculation, and communicate that value instead, as specified.
*/
headers: { [AMZ_CONTENT_SHA256_HEADER]: 'UNSIGNED-PAYLOAD' },
},
/**
* (optional) pre-sign operation options.
*/
{
/**
* The number of seconds before the pre-signed URL expires
*/
expiresIn: 86400,
/**
* A set of strings whose representing headers that should not be hoisted
* to pre-signed request's query string. If not supplied, the pre-signer
* moves all the AWS-specific headers (starting with `x-amz-`) to the request
* query string. If supplied, these headers remain in the pre-signed request's
* header.
* All headers in the provided request will have their names converted to
* lower case and then checked for existence in the unhoistableHeaders set.
*
* In the case of pre-signing S3 URLs, the body needs to be empty.
* however, the AMZ_CONTENT_SHA256_HEADER needs to be set to
* UNSIGNED_PAYLOAD. To do this, we need to set the header,
* but declare it as unhoistable, and unsignable.
*/
unhoistableHeaders: new Set([AMZ_CONTENT_SHA256_HEADER]),
/**
* A set of strings whose members represents headers that cannot be signed.
* All headers in the provided request will have their names converted to
* lower case and then checked for existence in the unsignableHeaders set.
*
* In the case of pre-signing S3 URLs, the body needs to be empty.
* however, the AMZ_CONTENT_SHA256_HEADER needs to be set to
* UNSIGNED_PAYLOAD. To do this, we need to set the header,
* but declare it as unhoistable, and unsignable.
*/
unsignableHeaders: new Set([AMZ_CONTENT_SHA256_HEADER]),
/**
* A set of strings whose members represents headers that should be signed.
* Any values passed here will override those provided via unsignableHeaders,
* allowing them to be signed.
*
* All headers in the provided request will have their names converted to
* lower case before signing.
*/
signableHeaders: new Set(),
/**
* The date and time to be used as signature metadata. This value should be
* a Date object, a unix (epoch) timestamp, or a string that can be
* understood by the JavaScript `Date` constructor.If not supplied, the
* value returned by `new Date()` will be used.
*/
signingDate: new Date(),
/**
* The service signing name. It will override the service name of the signer
* in current invocation
*/
signingService: 's3',
/**
* The signingRegion and signingService options let the user
* specify a different region or service to pre-sign the request for.
*/
signingRegion: 'us-east-1',
}
);
console.log(`presigned URL: ${presignedRequest.url}`);
/**
* Our URL is now ready to be used.
*/
const res = http.get(presignedRequest.url, {
headers: presignedRequest.headers,
});
check(res, { 'status is 200': (r) => r.status === 200 });
}