file-type-filter

A stream filter that allows only specified file types to pass, blocking all the others. The file type is detected using file-type.

Installation

npm install --save file-type-filter

Example

const FileTypeFilter = require('file-type-filter')
 
// Create a filter that allows only JPEGs to pass
const filter = new FileTypeFilter('image/jpeg')
 
// Will succeed
fs.createReadStrem('something.jpg').pipe(filter).pipe(fs.createWriteStream('output.jpg'))
 
// Will fail (block)
fs.createReadStrem('something.png').pipe(filter).pipe(fs.createWriteStream('output.jpg'))
filter.on('error', () => console.log('File blocked'))
 

File Type Specification

File types that are allowed to pass are specified when a filter object is created, by passing an argument. The argument can be any of the following

• A string consisting of an allowed MIME type, for example image/jpeg
• An array of strings of one or more allowed MIME types, for example ['application/zip', 'image/jpeg']
• A function, that receives the MIME type as a parameter and returns true if the file is allowed to pass.