then-busboy
Advanced tools
Promise-based wrapper around Busboy. Processes multipart/form-data content and returns it as a single object.
Promise-based wrapper around Busboy. Processes multipart/form-data content and returns it as a single object.
You can install then-busboy from npm:
npm install --save then-busboy
Or with yarn:
yarn add then-busboy
then-busboy is framework agnostic module, which means you can use it with different HTTP frameworks, or you can choose to use it pure Node.js HTTP server to hanlde multipart/form-data requests.
Let's take a look at the example with http module from Node.js.
We'll write a simple server that will parse form-data request, read files content and then send them back as JSON:
import {createServer} from "http"
import {parse} from "then-busboy"
const handler = (req, res) => parse(req)
.then(async body => {
const result = []
for (const [path, value] of body) {
result.push([path, isFile(value) ? await value.text() : value])
}
res.setHeader("Content-Type", "application/json")
res.end(JSON.stringify(Body.json(result)))
})
.catch(error => {
res.statusCode = error.status || 500
res.end(error.message)
})
createServer(handler)
.listen(2319, () => console.log("Server started on http://localhost:2319"))
Note: You can use asynchronous function syntax, because then-busboy always returns a Promise.
So, let's see on a simple middleware example for Koa.js:
import {promises as fs} from "fs"
import {parse} from "then-busboy"
const toLowerCase = string => String.prototype.toLowerCase.call(string)
const unlinkFile = ({path}) => fs.unlink(path)
async function multipart(ctx, next) {
if (["post", "put"].includes(toLowerCase(ctx.method)) === false) {
return next()
}
if (ctx.is("multipart/form-data") === false) {
return next()
}
const body = await parse(ctx.req)
ctx.request.body = body.json()
return next()
}
export default multipart
parse(request[, options]) -> {Promise<Body>}constructor Body(entries)Create an object that allows to manipulate FormData fields taken then-busboy
from(entries) -> {Body}Create a new Body from given entries. An alias of new Body(entries)
then-busboyjson(value) -> {object}Return an object with data taken from given entries or Body
formData(value) -> {FormData}Return a FormData instance with data taken from given entries or Body
length -> {number}Return an amount of entries and files in current Body instance
fields() -> {Body}Return a new Body that contains fields only
files() -> {Body}Return a new Body that contains files only
json() -> {object}Return an object with data taken the current Body instance
formData() -> {FormData}Return a FormData with data taken the current Body instance
entries() -> {Array<[string[], any]>}Return an array of entries in current Body instance
values() -> {Iterator}Return an iterator allows to go through the Body values
keys() -> {Iterator}Return an iterator allows to go through the Body fields path
interface BodyFileThis interface reflects internal representation of a File. It is not meant to be constructed manually, but since it's compatible with files from the browsers, you can use these in Body if you need to.
nameContains original name of file taken from the filename property within the form-data.
typeFile MIME type
encContains a value from transfer encoding header
pathPath to the file on disk
stream() -> {Readable}Returns a Readable stream allowing to consume file's content
then-busboy can restore an object structure from form-data field names if you will follow the naming formats with dots or square brackets:
This notation looks similarly to JS object properties accessiong syntax:
# Flat objects looks the same in both notations
# Note that the following notation examples is just a pseudo code
name = "John Doe"
age = 25
then-busboy will return the this object for an example from above:
{
name: "John Doe",
// By default, non-string values will be converted to their initial type.
// So, "25" -> 25, "null" -> null, "false" -> false etc.
age: 25
}
For deep objects or collections, use dot or brackets as a separator. But don't mix them.
rootField.nestedField = "Some text here"
{
rootField: {
nestedField: "Some text here"
}
}
rootField[nestedField] = "I beat Twilight Sparkle and all I got was this lousy t-shirt"
Becomes
{
rootField: {
nestedField: "I beat Twilight Sparkle and all I got was this lousy t-shirt"
}
}
You can also send an arrays and collections using bracket format:
message[sender] = "John Doe"
message[text] = "Some whatever text message."
message[attachments][0][file] = <here is the file content>
message[attachments][0][description] = "Here is a description of the file"
then-busboy returns the following object:
{
message: {
sender: "John Doe",
text: "Some whatever text message.",
attachments: [
{
"file": File, // this field will be represended as a File instance
"description": "Here is a description of the file"
}
]
}
}
Collections allowed too:
[0][firstName] = "John"
[0][lastName] = "Doe"
[0][dob][day] = "1"
[0][dob][month] = "Jan."
[0][dob][year] = "1989"
[0][skills][0] = "Node.js"
[0][skills][1] = "CoffeeScript"
[0][skills][2] = "JavaScript"
[0][skills][3] = "Babel"
[1][firstName] = "Max"
[1][lastName] = "Doe"
[1][dob][day] = "12"
[1][dob][month] = "Mar."
[1][dob][year] = "1992"
[1][skills][0] = "Python"
[1][skills][1] = "Flask"
[1][skills][2] = "JavaScript"
[1][skills][3] = "Babel"
[1][skills][4] = "React"
[1][skills][5] = "Redux"
Then you will receive:
[
{
firstName: "John",
lastName: "Doe",
dob: {
day: 1,
month: "Jan.",
year: 1989
},
skills: ["Node.js", "CoffeeScript", "JavaScript", "Babel"]
}, {
firstName: "Max",
lastName: "Doe",
dob: {
day: 12,
month: "Mar.",
year: 1992
},
skills: ["Python", "Flask", "JavaScript", "Babel", "React", "Redux"]
}
]
Whenlimits options are set, then-busboy may reject with HTTP 413 error if specified limit(s) exceeded. That will be a regular error from object http-errors package.
FAQs
Promise-based wrapper around Busboy. Processes multipart/form-data request body and returns it in a single object.
The npm package then-busboy receives a total of 81 weekly downloads. As such, then-busboy popularity was classified as not popular.
We found that then-busboy demonstrated a not healthy version release cadence and project activity because the last version was released a year ago. It has 1 open source maintainer collaborating on the project.
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