Busboy : HTML form data parser

更新时间：

2024-05-15

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Busboy : HTML form data parser

A module for parsing incoming HTML form data. It support Readable stream for file.

User can use the following code to import the Busboy module.

var Busboy = require('middleware').Busboy;

Support

The following shows Busboy module APIs available for each permissions.

	User Mode	Privilege Mode
Busboy	●	●

Busboy Class

Busboy is Writable stream.

Busboy(config)

config {Object} Creates and returns a new Busboy instance. The constructor takes the following valid config settings:
- headers {Object} These are the HTTP headers of the incoming request, which are used by individual parsers.
- highWaterMark {Integer} highWaterMark to use for this Busboy instance, default: WritableStream.
- fileHwm {Integer} highWaterMark to use for file streams, default: ReadableStream.
- defCharset {String} Default character set to use when one isn't defined, default: 'utf8'.
- preservePath {Boolean} If paths in the multipart 'filename' field shall be preserved. default: false.
- limits {Object} Various limits on incoming data. Valid properties are:
  - fieldNameSize {Integer} Max field name size (in bytes) default: 100 bytes.
  - fieldSize {Integer} Max field value size (in bytes) default: 1MB.
  - fields {Integer} Max number of non-file fields default: Infinity.
  - fileSize {Integer} For multipart forms, the max file size (in bytes) default: Infinity.
  - files {Integer} For multipart forms, the max number of file fields default: Infinity.
  - parts {Integer} For multipart forms, the max number of parts (fields + files) default: Infinity.
  - headerPairs {Integer} For multipart forms, the max number of header key=>value pairs to parse default: 2000.

The constructor can throw errors:

Unsupported content type: $type - The Content-Type isn't one Busboy can parse.
Missing Content-Type - The provided headers don't include Content-Type at all.

Events

file

Emitted for each new file form field found. Arguments:

fieldname {String} Field name.
stream {ReadableStream} Rdadable stream of file data.
filename {String} original File name.
transferEncoding {String} Contains the 'Content-Transfer-Encoding' value for the file stream.
mimeType {String} Contains the 'Content-Type' value for the file stream.

If you listen for this event, you should always handle the stream no matter if you care about the file contents or not (e.g. you can simply just do stream.resume(); if you want to discard the contents), otherwise the finish event will never fire on the Busboy instance. However, if you don't care about any incoming files, you can simply not listen for the file event at all and any/all files will be automatically and safely discarded (these discarded files do still count towards files and parts limits).

If a configured file size limit was reached, stream will both have a boolean property truncated (best checked at the end of the stream) and emit a limit event to notify you when this happens.

field

Emitted for each new non-file field found. Arguments:

fieldname {String} Field name.
fieldvalue {String} Field value.
fieldnameTruncated {Boolean} If field name truncated.
valueTruncated {Boolean} If value truncated.
transferEncoding {String} Contains the 'Content-Transfer-Encoding' value for the field value.
mimeType {String} Contains the 'Content-Type' value for the field value.

partsLimit

Emitted when specified parts limit has been reached. No more file or field events will be emitted.

filesLimit

Emitted when specified files limit has been reached. No more file events will be emitted.

fieldsLimit

Emitted when specified fields limit has been reached. No more field events will be emitted.

Example

Parsing (multipart) with default options.

var socket = require('socket');
var WebApp = require('webapp');
var iosched = require('iosched');
var Busboy = require('middleware').Busboy;

// Create app.
var app = WebApp.create('app', 0, socket.sockaddr(socket.INADDR_ANY, 8000));

// Index.
app.get('/', (req, res) => {
  var ctx =
  `<html><head></head><body>\
  <form action="/test1" method="POST" enctype="multipart/form-data">\
    <input type="text" name="textfield"><br />\
    <input type="file" name="filefield"><br />\
    <input type="submit">\
  </form>\
  </body></html>`;
  res.send(ctx);
});

// Handle form data.
app.post('/test1', (req, res, next) => {
  var busboy = new Busboy({ headers: req.headers });
  busboy.on('file', function (fieldname, file, filename, encoding, mimetype) {
    console.log('File [' + fieldname + ']: filename: ' + filename + ', encoding: ' + encoding + ', mimetype: ' + mimetype);
    file.on('data', function (data) {
      console.log('File [' + fieldname + '] got ' + data.length + ' bytes');
    });
    file.on('end', function () {
      console.log('File [' + fieldname + '] Finished');
    });
  });
  busboy.on('field', function (fieldname, val, fieldnameTruncated, valTruncated, encoding, mimetype) {
    console.log('Field [' + fieldname + ']: value: ' + val);
  });
  busboy.on('finish', function () {
    console.log('Done parsing form!');
    res.writeHead(303, { Connection: 'close', Location: '/' });
    res.end();
  });
  req.pipe(busboy);
});

// Error handler.
app.use(function(err, req, res, next) {
  if (res.headersSent) {
    return next(err);
  }
  var status = err.status ? err.status : res.status();
  status = status < 400 ? 500 : status;
  res.status(status).json({status: status, msg: err.message});
});

// Start app.
app.start();

// Event loop.
iosched.forever();

Save all incoming files to disk.

var fs = require('fs');
var path = require('path');
var socket = require('socket');
var WebApp = require('webapp');
var iosched = require('iosched');
var Busboy = require('middleware').Busboy;

// Create app.
var app = WebApp.create('app', 0, socket.sockaddr(socket.INADDR_ANY, 8000));

// Index.
app.get('/', (req, res) => {
  var ctx =
  `<html><head></head><body>\
  <form action="/test2" method="POST" enctype="multipart/form-data">\
    <input type="file" name="filefield"><br />\
    <input type="submit">\
  </form>\
  </body></html>`;
  res.send(ctx);
});

// Handle file.
app.post('/test2', function(req, res, next) {
  var busboy = new Busboy({ headers: req.headers });
  var error = undefined;
  busboy.on('file', function(fieldname, file, filename, encoding, mimetype) {
    var saveTo = path.join('./' + filename);
    var outStream = fs.createWriteStream(saveTo);
    file.pipe(outStream);
    file.on('error', (err) => {
      outStream.destroy();
      error = err;
    });
  });
  busboy.on('finish', function() {
    if (error) {
      next(error);
    } else {
      res.writeHead(200, { 'Connection': 'close' });
      res.end("That's all folks!");
    }
  });
  req.pipe(busboy);
});

// Error handler.
app.use(function(err, req, res, next) {
  if (res.headersSent) {
    return next(err);
  }
  var status = err.status ? err.status : res.status();
  status = status < 400 ? 500 : status;
  res.status(status).json({status: status, msg: err.message});
});

// Start app.
app.start();

// Event loop.
iosched.forever();

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WebProxy

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Busboy : HTML form data parser

# Busboy : HTML form data parser

# Support

# Busboy Class

# Busboy(config)

# Events

# file

# field

# partsLimit

# filesLimit

# fieldsLimit

# Example

Busboy : HTML form data parser

Support

Busboy Class

Busboy(config)

Events

file

field

partsLimit

filesLimit

fieldsLimit

Example