then-busboy
Advanced tools
Promise-based wrapper around Busboy. Process multipart/form-data content and returns it as a single object.
Promise-based wrapper around Busboy. Process 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
Breaking change: Since 4.x version then-busboy returns a Body object instead of raw data. For more information check out the Usage section of documentation and take a look at Body class in API section.
Public
busboy(request[, options]) -> {Promise<Body>}isFile(value) -> {boolean}Check if given value is a File instance.
constructor Body(entries)Create an object that allows to manipulate FormData fields taken then-busboy
isBody(value) -> {boolean}Check if given value is instance of Body
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
get length() -> {number}Return an amount of entries and files in current Body instance
get fields() -> {Body}Return a new Body that contains fields only
get 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
map(callback[, ctx]) -> {Body}Create a new Body with the results of calling a provided function on every entry in the calling Body
filter(predicate[, ctx]) -> {Body}Create a new Body with all entries that pass the test implemented in given function
true to keep the entry, false otherwise. It accepts four arguments:
forEach(callback[, ctx]) -> {Body}Execute a given callback for each entry of the 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
names() -> {Iterator}Return an iterator allows to go through the Body fields name
paths() -> {Iterator}Return an iterator allows to go through the Body fields path
Private
constructor File(options)contentsFile contents Readable stream.
streamAlias for File#contents
filenameFull name of the file
basenameName of the file without extension
extnameFile extension
mimeFile mime type
encFile contents encoding
pathDefault path of the file
read() => {Promise<Buffer>}Read a file from contents stream.
write([path]) => {Promise<void>}Write a file content to disk. Optionally you can set a custom path.
By default, file will be saved in system temporary directory os.tmpdir().
You can take this path from path property.
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"]
}
]
then-busboy works fine even with a pure Node.js HTTP server. Let's take a look to the tiny example:
import busboy from "then-busboy"
import {createServer} from "http"
function handler(req, res) {
// Get result from then-busboy
function onFulfilled(body) {
res.writeHead("Content-Type", "application/json")
// You can also do something with each file and a field.
res.end(JSON.stringify(body.json()))
}
// Handle errors
function onRejected(err) {
res.statusCode = err.status || 500
res.end(String(err))
}
// Call `then-busboy` with `req`
busboy(req).then(onFulfilled, onRejected)
}
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 busboy from "then-busboy"
const toLowerCase = string => String.prototype.toLowerCase.call(string)
const multipart = () => async (ctx, next) => {
if (["post", "put"].includes(toLowerCase(ctx.method)) === false) {
return next()
}
if (ctx.is("multipart/form-data") === false) {
return next()
}
ctx.request.body = await busboy(ctx.req).then(body => body.json())
await next()
}
export default multipart
You can check if some value is an instance of File class using isFile.
This function may help you if you're wanted to do something
with received files automatically.
import busboy, {isFile, Body} from "then-busboy"
let body = await busboy(request).then(Body.json)
body = await deepMapObject(
body, async val => (
isFile(val) // check if current element is a File
? await processFile(val) // do somethig with a file
: val // ...or just return a field
)
)
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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