then-busboy
Advanced tools
Promise-based wrapper around Busboy. Processes multipart/form-data request body and returns it in a single object.
Promise-based wrapper around Busboy. Processes multipart/form-data request body and returns it in a single object.
You can install then-busboy from npm:
npm install --save then-busboy
Or with yarn:
yarn add then-busboy
Because then-busboy can process multipart/form-data bodies from AsyncIterable sources, you can use it with different HTTP frameworks, or with Node.js http module, or even with Response object (see the 4th example).
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.
import {parse} from "then-busboy"
async function multipart(ctx, next) {
if (["post", "put"].includes(ctx.method.toLowerCase()) === 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
AsyncIterable value as the input. That way you can parse FormData from other that just HTTP requests. Let's take a loook at the example with form-data-encoder and formdata-node as the input:import {fileFromPath} from "formdata-node/file-from-path"
import {FormDataEncoder} from "form-data-encoder"
import {FormData} from "formdata-node"
import {parse} from "then-busboy"
const form = new FormData()
form.set("greeting", "Hello, World!")
form.set("file", new File(["On Soviet Moon landscape see binoculars through YOU"], "file.txt"))
form.set("fileFromPath", await fileFromPath("path/to/a/file"))
const encoder = new FormDataEncoder(form)
const body = await parse(encoder, {
headers: {
"content-type": encoder.contentType
}
})
console.log(body.json()) // -> {greeting: string, file: BodyFile, fileFromPath: BodyFile}
then-busboy accepts AsyncIterable as the input, you can also read Response body like that:import {Response, FormData} from "node-fetch"
import {parse} from "then-bosboy"
const form = new FormData()
form.set("greeting", "Hello, World!")
form.set("file", new File(["On Soviet Moon landscape see binoculars through YOU"], "file.txt"))
const response = new Respone(form)
// then-busboy will parse the input and return its own Body instance from which you can create a complete object by calling .json() method or a FormData using .formData() method.
// The difference with Response.formData() is that then-busboy will save all files to file system and create a *reference* to each of them,
// while Response (currently) will dump them into RAM, which can be less efficient in some scenarious
const body = await parse(response.body, {
headers: {
"content-type": response.headers.get("content-type")
}
})
body.json() // -> {greeting: string, file: BodyFile}
body.formData() // -> FormData
parse(source[, options]) -> {Promise<Body>}class Bodyconstructor(entries) -> {Body}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
class BodyFieldBodyField class in the internal representation of a regular FormData value.
constructor(value: unknown, name: string[, options]) -> {BodyField}Creates a new instance of the BodyField class.
nameReturns the name of the field.
fieldnameTruncatedIndicates whether the fieldname was truncated.
valueTruncatedIndicates whether the value was truncated.
encReturns a value from Content-Transfer-Encoding header.
typeReturns a value from Content-Type header.
valueOf() -> {unknown}Returns the value of the BodyField.
toString() -> {string}Returns string representation of the BodyField value.
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.
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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