File API

The File API enables your application to access and manage folders and files. The API is automatically available from the inside of any Codehook function.

Install

Run npm install codehooks-js in your project code folder.

Bulk upload files

Use the CLI command coho upload to upload files from a local machine to the application.

API quick overview

• filestore.readFile(path)
• filestore.getReadStream(path)
• filestore.saveFile(path, filestream)
• filestore.deleteFile(path)
• filestore.list(path)
• filestore.getFileAsBuffer(path)
• Postman examples using the File API
  • Upload a new PDF file
  • Download a PDF file

filestore.readFile(path)

Read file content as text from the file system.

Parameters

• path: full path to file, e.g. /static/home.html

Returns: Promise with text content from file.

Error: throws exception if file is not found.

Code example for reading a file

index.js

import {app, filestore} from 'codehooks-js'

// get a file text content
app.get('/txt', async (req, res) => {
  try {
    const file = await filestore.readFile('/somefolder/myfile.txt');
    res.set('content-type', 'text/plain')
    res.end(file)
  } catch (error) {
    res.status(404).end('No file here')
  }
})

// bind to serverless runtime
export default app.init();

filestore.getReadStream(path)

Read file content as a binary stream the file system.

Parameters

• path: full path to file, e.g. /private/dummy.pdf

Returns: Promise with file stream handle.

Error: throws exception if file is not found.

Code example for reading a binary file stream

index.js

import {app, filestore} from 'codehooks-js'

// get a file binary content as stream
app.get('/pdf', async (req, res) => {
  try {
    const filestream = await filestore.getReadStream('/private/dummy.pdf');
    res.set('content-type', 'application/pdf');
    // stream content back to client    
    filestream
    .on('data', (buf) => {
      res.write(buf, 'buffer')
    })    
    .on('end', () => {
      res.end()
    })
    
  } catch (error) {
    console.error(error)
    res.status(404).end('No file here')
  }
})

// bind to serverless runtime
export default app.init();

filestore.saveFile(path, filestream)

Write a file binary stream to the file system.

Parameters

• path: full path to file, e.g. /private/dummy.pdf
• filestream: inputstream of binary buffers

Returns: Promise with upload result text.

Error: throws exception if an error occured.

Code example for writing a binary inputstream as a new file to the file system

index.js

import {app, filestore} from 'codehooks-js'
import {PassThrough} from 'stream';

// post a file binary content
app.post('/file', async (req, res) => {
  try {
    const {name} = req.query; /* e.g. /dev/file?name=/upload/dummy.pdf */
    const stream = new PassThrough();
    req.pipe(stream);
    const result = await filestore.saveFile(name, stream);
    res.end(result)    
  } catch (error) {
    console.error(error)
    res.status(404).end('Upload error')
  }
})

// bind to serverless runtime
export default app.init();

filestore.deleteFile(path)

Delete a file binary from the file system.

Parameters

• path: full path to file, e.g. /private/dummy.pdf

Returns: Promise with delete result text.

Error: throws exception if an error occured.

Code example for deleting a file from the file system

index.js

import {app, filestore} from 'codehooks-js'

// delete a file
app.delete('/file', async (req, res) => {
  try {
    const {name} = req.query;
    const result = await filestore.deleteFile(name);
    res.end(result)
  } catch (error) {
    console.error(error)
    res.status(404).end('Not found')
  }
})

// bind to serverless runtime
export default app.init();

filestore.list(path)

List files in folders from the file system.

Parameters

• path: full path to folder, e.g. /upload

Returns: Promise with JSON array of files matching path to folder.

Error: throws exception if an error occured.

Code example for listing files in a folder from the file system

index.js

import {app, filestore} from 'codehooks-js'

// list dir
app.get('/list', async (req, res) => {
  try {
    const result = await filestore.list('/');
    res.end(result)
  } catch (error) {
    console.error(error.message)
    res.status(400).end('sorry list')
  }
})

// bind to serverless runtime
export default app.init();

Example output shows folders and files:

[
    {"path":"/robots.txt","size":114,"date":"2023-09-29T12:12:10.000Z","_id":"6516f3b26c816e0015ca7b60"},
    {"path":"/upload/dummy.pdf","size":1234,"date":"2023-09-29T16:22:10.499Z","_id":"6516f9b26c816e0015ce7b6d"},
    {"path":"/upload/logo.pdf","size":259096,"date":"2023-09-30T11:48:18.003Z","_id":"6517155cd8c8a40071d6bc79"},
    {"path":"/upload/report.html","size":1320,"date":"2023-09-30T12:46:31.640Z","_id":"65180b50d8fc2b01b3b2515e"}
]

filestore.getFileAsBuffer(path)

Read file content into a Buffer.

Parameters

• path: full path to folder, e.g. /upload

Returns: Promise with Buffer.

Error: throws exception if an error occured.

Code example for reading file content into a Buffer

  // collapsed code
  const buf = await filestore.getFileAsBuffer('/images/logo.png');
  console.log(buf.length);

Postman examples using the File API

Upload a new PDF file

Download a PDF file