middleware-multipart

A multipart/form-data middleware based on busboy library.

Installation

$ npm i @marblejs/middleware-multipart

Requires @marblejs/core to be installed.

Importing

import { multipart$ } from '@marblejs/middleware-multipart';

Type declaration

multipart$ :: ParserOpts -> HttpMiddlewareEffect

Parameters

parameter

definition

options

<optional> ParserOpts

ParserOpts

parameter

definition

files

<optional> Array<string>

stream

<optional> StreamHandler

maxFileSize

<optional> number

maxFileCount

<optional> number

maxFieldSize

<optional> number

maxFieldCount

<optional> number

Usage

Make sure that you always handle the files that a user uploads. Never add it as a global middleware since a malicious user could upload files to a route that you didn't handle. Only use this it on routes where you are handling the uploaded files.

In-memory storage:

import { multipart$ } from '@marblejs/middleware-multipart';
const effect$ = r.pipe(
r.matchPath('/'),
r.matchType('POST'),
r.useEffect(req$ => req$.pipe(
use(multipart$()),
map(req => ({ body: {
files: req.files, // file data
body: req.body, // all incoming body fields
}}))
)));

Out-of-memory storage:

import { multipart$, StreamHandler } from '@marblejs/middleware-multipart';
const stream: StreamHandler = ({ file, fieldname }) => {
// stream here incoming file to different location...
const destination = // ... and grab the persisted file location
return of({ destination });
};
const effect$ = r.pipe(
r.matchPath('/'),
r.matchType('POST'),
r.useEffect(req$ => req$.pipe(
use(multipart$({
stream,
maxFileCount: 1,
files: ['image_1'],
})),
map(req => ({ body: {
files: req.files['image_1'], // file data
body: req.body, // all incoming body fields
}}))
)));

You can intercept incoming files and stream them to the different place, eg. to OS filesystem or AWS S3 bucket. The prervious example shows how you can specify constraints for multipart/form-data parsing the accepts only one image_1 field.

Each file included inside req.files object contains the following information:

key

description

fieldname

Field name specified in the form

filename

Name of the file on the user's computer

encoding

Encoding type of the file

mimetype

Mime type of the file

size

Size of the file in bytes (in-memory parsing)

destination

The place in which the file has been saved (if not in-memory parsing)

buffer

A Buffer of the entire file (in-memory parsing)

You can define the following middleware options:

key

description

maxFileCount

The total count of files that can be sent

maxFieldCount

The total count of fields that can be sent

maxFileSize

The max possible file size in bytes

files

An array of acceptable field names

stream

A handler which you can use to stream incoming files to different location