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https://github.com/mscdex/busboy

A streaming parser for HTML form data for node.js
https://github.com/mscdex/busboy

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A streaming parser for HTML form data for node.js

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README 

        
# Description



A node.js module for parsing incoming HTML form data.



Changes (breaking or otherwise) in v1.0.0 can be found [here](https://github.com/mscdex/busboy/issues/266).



**Note:** If you are using node v18.0.0 or newer, please be aware of the node.js

HTTP(S) server's [`requestTimeout`](https://nodejs.org/docs/latest/api/http.html#httpcreateserveroptions-requestlistener)

configuration setting that is now enabled by default, which could cause upload

interruptions if the upload takes too long.



# Requirements



* [node.js](http://nodejs.org/) -- v10.16.0 or newer



# Install



    npm install busboy



# Examples



* Parsing (multipart) with default options:



```js

const http = require('http');



const busboy = require('busboy');



http.createServer((req, res) => {

  if (req.method === 'POST') {

    console.log('POST request');

    const bb = busboy({ headers: req.headers });

    bb.on('file', (name, file, info) => {

      const { filename, encoding, mimeType } = info;

      console.log(

        `File [${name}]: filename: %j, encoding: %j, mimeType: %j`,

        filename,

        encoding,

        mimeType

      );

      file.on('data', (data) => {

        console.log(`File [${name}] got ${data.length} bytes`);

      }).on('close', () => {

        console.log(`File [${name}] done`);

      });

    });

    bb.on('field', (name, val, info) => {

      console.log(`Field [${name}]: value: %j`, val);

    });

    bb.on('close', () => {

      console.log('Done parsing form!');

      res.writeHead(303, { Connection: 'close', Location: '/' });

      res.end();

    });

    req.pipe(bb);

  } else if (req.method === 'GET') {

    res.writeHead(200, { Connection: 'close' });

    res.end(`

      

        

        

          

            


            


            

          

        

      

    `);

  }

}).listen(8000, () => {

  console.log('Listening for requests');

});



// Example output:

//

// Listening for requests

//   < ... form submitted ... >

// POST request

// File [filefield]: filename: "logo.jpg", encoding: "binary", mime: "image/jpeg"

// File [filefield] got 11912 bytes

// Field [textfield]: value: "testing! :-)"

// File [filefield] done

// Done parsing form!

```



* Save all incoming files to disk:



```js

const { randomFillSync } = require('crypto');

const fs = require('fs');

const http = require('http');

const os = require('os');

const path = require('path');



const busboy = require('busboy');



const random = (() => {

  const buf = Buffer.alloc(16);

  return () => randomFillSync(buf).toString('hex');

})();



http.createServer((req, res) => {

  if (req.method === 'POST') {

    const bb = busboy({ headers: req.headers });

    bb.on('file', (name, file, info) => {

      const saveTo = path.join(os.tmpdir(), `busboy-upload-${random()}`);

      file.pipe(fs.createWriteStream(saveTo));

    });

    bb.on('close', () => {

      res.writeHead(200, { 'Connection': 'close' });

      res.end(`That's all folks!`);

    });

    req.pipe(bb);

    return;

  }

  res.writeHead(404);

  res.end();

}).listen(8000, () => {

  console.log('Listening for requests');

});

```



# API



## Exports



`busboy` exports a single function:



**( _function_ )**(< _object_ >config) - Creates and returns a new _Writable_ form parser stream.



* Valid `config` properties:



    * **headers** - _object_ - These are the HTTP headers of the incoming request, which are used by individual parsers.



    * **highWaterMark** - _integer_ - highWaterMark to use for the parser stream. **Default:** node's _stream.Writable_ default.



    * **fileHwm** - _integer_ - highWaterMark to use for individual file streams. **Default:** node's _stream.Readable_ default.



    * **defCharset** - _string_ - Default character set to use when one isn't defined. **Default:** `'utf8'`.



    * **defParamCharset** - _string_ - For multipart forms, the default character set to use for values of part header parameters (e.g. filename) that are not extended parameters (that contain an explicit charset). **Default:** `'latin1'`.



    * **preservePath** - _boolean_ - If paths in filenames from file parts in a `'multipart/form-data'` request 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`.



        * **fieldSize** - _integer_ - Max field value size (in bytes). **Default:** `1048576` (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` (same as node's http module).



This function can throw exceptions if there is something wrong with the values in `config`. For example, if the Content-Type in `headers` is missing entirely, is not a supported type, or is missing the boundary for `'multipart/form-data'` requests.



## (Special) Parser stream events



* **file**(< _string_ >name, < _Readable_ >stream, < _object_ >info) - Emitted for each new file found. `name` contains the form field name. `stream` is a _Readable_ stream containing the file's data. No transformations/conversions (e.g. base64 to raw binary) are done on the file's data. `info` contains the following properties:



    * `filename` - _string_ - If supplied, this contains the file's filename. **WARNING:** You should almost _never_ use this value as-is (especially if you are using `preservePath: true` in your `config`) as it could contain malicious input. You are better off generating your own (safe) filenames, or at the very least using a hash of the filename.



    * `encoding` - _string_ - The file's `'Content-Transfer-Encoding'` value.



    * `mimeType` - _string_ - The file's `'Content-Type'` value.



    **Note:** If you listen for this event, you should always consume the `stream` whether you care about its contents or not (you can simply do `stream.resume();` if you want to discard/skip the contents), otherwise the `'finish'`/`'close'` event will never fire on the busboy parser stream.

    However, if you aren't accepting files, you can either simply not listen for the `'file'` event at all or set `limits.files` to `0`, and any/all files will be automatically skipped (these skipped files will still count towards any configured `limits.files` and `limits.parts` limits though).



    **Note:** If a configured `limits.fileSize` limit was reached for a file, `stream` will both have a boolean property `truncated` set to `true` (best checked at the end of the stream) and emit a `'limit'` event to notify you when this happens.



* **field**(< _string_ >name, < _string_ >value, < _object_ >info) - Emitted for each new non-file field found. `name` contains the form field name. `value` contains the string value of the field. `info` contains the following properties:



    * `nameTruncated` - _boolean_ - Whether `name` was truncated or not (due to a configured `limits.fieldNameSize` limit)



    * `valueTruncated` - _boolean_ - Whether `value` was truncated or not (due to a configured `limits.fieldSize` limit)



    * `encoding` - _string_ - The field's `'Content-Transfer-Encoding'` value.



    * `mimeType` - _string_ - The field's `'Content-Type'` value.



* **partsLimit**() - Emitted when the configured `limits.parts` limit has been reached. No more `'file'` or `'field'` events will be emitted.



* **filesLimit**() - Emitted when the configured `limits.files` limit has been reached. No more `'file'` events will be emitted.



* **fieldsLimit**() - Emitted when the configured `limits.fields` limit has been reached. No more `'field'` events will be emitted.