@aws-sdk/util-create-request

This package provides function to create request object from given client and command. You can supply either Node client or browser client. A common use case for it can be generating request object and then supply to presigners to create presigned url.

When calling the createRequest(), the initialize and serialize middlewares from both client and command are extracted and resolved into a handler. This handler will return a promise of HttpRequest object. So any modifications happen in build and finalize middleware won't be reflected to generated httpRequest object. For example, the Content-Length header won't be included in the result.

Import:

//JavaScript:
const createRequest = require("@aws-sdk/util-create-request").createRequest;
//TypeScript:
import { createRequest } from "@aws-sdk/util-create-request";

JavaScript usage examples:

const { S3Client, GetObjectCommand } = require("@aws-sdk/client-s3");

const request = await createRequest(
  new S3Client({}),
  new GetObjectCommand({
    Bucket: "bucket",
    Key: "key",
  })
);
/**
{
  protocol: 'https:',
  path: '/js-sdk-test-bucket/key',
  hostname: 's3.us-east-2.amazonaws.com',
  body: null,
  headers: {},
  method: 'GET',
  query: {}
}
*/

TypeScript usage example:

import { S3Client } from "@aws-sdk/client-s3";
import { GetObjectCommand } from "@aws-sdk/client-s3";
import { GetObjectCommandInput, GetObjectCommandOutput } from "@aws-sdk/client-s3";
import { Readable } from "stream";

const request = await createRequest<any, GetObjectCommandInput, GetObjectCommandOutput>(
  new S3Client({}),
  new GetObjectCommand({
    Bucket: "bucket",
    Key: "key",
  })
);

You can omit the generics in this function and rely on the type inference. In this way, you will lose the type safety for insuring client and command comes from the same service.

import { DynamoDBClient } from "@aws-sdk/client-dynamodb";
import { GetObjectCommand } from "@aws-sdk/client-s3";
/*THIS IS WRONG, but TypeScript won't tell you*/
const request = await createRequest(
  new DynamoDBClient({}),
  new GetObjectCommand({
    Bucket: "bucket",
    Key: "key",
  })
);