Files

The Extra Horizon SDK can be used on different platforms, each handling binary data slightly different. So we've collected a few examples on how to upload/download binary data for each of the supported platforms.

Web

In browsers the File and Blob classes can be used for uploads.

A download results in an ArrayBuffer.

File upload example

const fileInputElement = document.querySelector('input[type="file"]');
const file = fileInputElement.files[0];

const uploadResult = await exh.files.create(file.name, file);

Blob upload example

const content = 'Hello, world!';
const fileName = 'example.txt';
const mimeType = 'text/plain';

const blob = new Blob([content], { type: mimeType });

const uploadResult = await exh.files.create(fileName, blob);

Download example

// A file token pointing to a text file containing 'Hello, world!'
const fileToken = '66030067d7342660dbc63303-49e4fa23-2079-4b91-acb1-5221ecee8393';

const arrayBuffer = await exh.files.retrieve(fileToken);
const content = await new Response(arrayBuffer).text();

console.log(content); // Shows 'Hello, world!'

React Native

Currently React Native provides limited support for binary data upload using FormData. As this is the basis for our file upload, for now only uploading from the file system is properly supported.

A download results in an ArrayBuffer.

Upload example expo-file-system

https://docs.expo.dev/versions/latest/sdk/filesystem/

import * as FileSystem from 'expo-file-system';

const content = 'Hello, world!';
const fileName = 'example.txt';
const mimeType = 'text/plain';

const uri = FileSystem.cacheDirectory + fileName;

await FileSystem.writeAsStringAsync(uri, content);

const uploadResult = await exh.files.create(fileName, {
  uri,
  name: fileName,
  type: mimeType,
});

Upload example expo-image-picker

https://docs.expo.dev/versions/latest/sdk/imagepicker/

import * as ImagePicker from 'expo-image-picker';

const fileName = 'myImage.jpeg'; // File name is not returned by the picker on iOS

const imagePickerResult = await ImagePicker.launchCameraAsync();
const image = imagePickerResult.assets[0];

const uploadResult = await exh.files.create(fileName, {
  uri: image.uri,
  name: fileName,
  type: image.mimeType, // Must be a valid MIME type, so not just `image.type`
});

Download example

// A file token pointing to a text file containing 'Hello, world!'
const fileToken = '66030067d7342660dbc63303-49e4fa23-2079-4b91-acb1-5221ecee8393';

const arrayBuffer = await exh.files.retrieve(fileToken);
const content = await new Response(arrayBuffer).text();

console.log(content); // Shows 'Hello, world!'

Node.js

The form-data package is used to allow strings, buffers and streams to be uploaded.

A download results in a Buffer.

String upload example

const content = 'Hello, World!';
const fileName = 'test.txt';

const uploadResult = await exh.files.create(fileName, content);

Buffer upload example

import * as fs from 'fs/promises';

const fileName = 'test.txt';
const buffer = await fs.readFile(fileName);

const uploadResult = await exh.files.create(fileName, buffer);

Stream upload example

import * as fs from 'fs';

const fileName = 'test.txt';
const stream = fs.createReadStream(fileName);

const uploadResult = await exh.files.create(fileName, stream);

Buffer download example

// A file token pointing to a text file containing 'Hello, world!'
const fileToken = '66030067d7342660dbc63303-49e4fa23-2079-4b91-acb1-5221ecee8393';

const buffer = await exh.files.retrieve(fileToken);
const content = buffer.toString();

console.log(content); // Shows 'Hello, world!'

Stream download example

// A file token pointing to a text file containing 'Hello, world!'
const fileToken = '66030067d7342660dbc63303-49e4fa23-2079-4b91-acb1-5221ecee8393';

const streamResponse = await exh.files.retrieveStream(fileToken);
const stream = streamResponse.data;

const buffer = await new Promise((resolve, reject) => {
  const chunks = [];
  stream.on('data', chunk => chunks.push(chunk));
  stream.on('error', reject);
  stream.on('end', () => resolve(Buffer.concat(chunks)));
});

const content = buffer.toString();

console.log(content); // Shows 'Hello, world!'

Abort request example

const controller = new AbortController();
const signal = controller.signal;
     
try {
  await exh.files.create(file, { signal });
} catch (error) {
  if (error instanceof RequestAbortedError) {
    console.log('File upload was cancelled, ignoring error');
    return;
  }
  throw error; // Handle other errors
}
     
// To cancel the upload, call:
controller.abort();