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File uploads, downloads and the file system

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You might want to use (binary) files in your browser checks. For example, you might want to upload a file to an upload form in your webapp. Or, you might want to validate some aspect of a file that is available for download on your app.

Testing downloads with the download event and Download object

Playwright has a download event that you can use to intercept downloads. You can also use the Download object to retrieve the contents and metadata of the downloaded file(s).

In some cases, you immediately want to also test a related upload functionality using the downloaded file. In that case, you can for instance spawn a new page, and use the .setInputFiles() method to upload the downloaded file.

import { test } from '@playwright/test'

test('Downloads a PDF file', async ({ page, context }) => {
  // Download a file.
  await page.goto('https://demo.borland.com/testsite/download_testpage.php')
  await page.getByText('attachment + filename').click()
  const downloadPromise = page.waitForEvent('download')
  await page.getByRole('button', { name: 'Download' }).click()
  const download = await downloadPromise
  await download.saveAs(download.suggestedFilename())
  
  //  Upload a file.
  const uploadPage = await context.newPage()
  await uploadPage.goto('https://www.file.io/')
  const inputFile = await uploadPage.$('input[type=file]')
  await inputFile!.setInputFiles(download.suggestedFilename())
})

const { test } = require('@playwright/test')

test('Downloads a PDF file', async ({ page, context }) => {
  // Download a file.
  await page.goto('https://demo.borland.com/testsite/download_testpage.php')
  await page.getByText('attachment + filename').click()
  const downloadPromise = page.waitForEvent('download')
  await page.getByRole('button', { name: 'Download' }).click()
  const download = await downloadPromise
  await download.saveAs(download.suggestedFilename())

  //  Upload a file.
  const uploadPage = await context.newPage()
  await uploadPage.goto('https://www.file.io/')
  const inputFile = await uploadPage.$('input[type=file]')
  await inputFile.setInputFiles(download.suggestedFilename())  
})

Check the official docs right here

Testing uploads with the browser’s File API

To test any upload features with Playwright’s .setInputFiles() method, you need to provide a file object. Currently, Checkly does not have a dedicated storage layer where you could upload that file, so you need to host it yourself at a (publicly) accessible location like an AWS S3 bucket, Dropbox or any other file hosting service.

In the example below, we do not need to interact with the file system. We can just:

  1. Fetch a file from a public URL using the request object.
  2. Pass the resulting Buffer into the .setInputFiles() method.
  3. Wait for the upload to finish.
import { test, expect } from '@playwright/test'

test('upload a file', async ({ page, request }) => {
  // fetch the file to upload  
  const fileUrl = 'https://www.w3.org/WAI/ER/tests/xhtml/testfiles/resources/pdf/dummy.pdf'
  const fileBuffer  = await request.get(fileUrl)
    
  // upload the file  
  await page.goto('https://filebin.net/')
  await page.getByLabel('Select files to upload').setInputFiles({
    name: 'file.pdf',
    mimeType: 'application/pdf',
    buffer: await fileBuffer.body()
  })
    
  // validate the upload was successful  
  await expect(page.getByRole('link', { name: 'Download file' })).toBeVisible()
  await page.screenshot({ path: 'filebin.png' })
})

const { test, expect } = require('@playwright/test')

test('upload a file', async ({ page, request }) => {
  // fetch the file to upload
  const fileUrl = 'https://www.w3.org/WAI/ER/tests/xhtml/testfiles/resources/pdf/dummy.pdf'
  const fileBuffer  = await request.get(fileUrl)

  // upload the file  
  await page.goto('https://filebin.net/')
  await page.getByLabel('Select files to upload').setInputFiles({
    name: 'file.pdf',
    mimeType: 'application/pdf',
    buffer: await fileBuffer.body()
  })
  
  // validate the upload was successful
  await expect(page.getByRole('link', { name: 'Download file' })).toBeVisible()
  await page.screenshot({ path: 'filebin.png' })
})

Notice we don’t need to interact with the file system, we can just pass buffers around.

Testing uploads using HTTP POST requests

You can also “upload” files using a simple HTTP POST request with a (binary) body using Playwright’s built-in request object. You would use this when you want to test a file upload feature that is not using the browser’s File API, but just an HTTP/REST endpoint that accepts a file upload.

import { test, expect } from '@playwright/test'

test('Upload a file using a POST request', async ({ request }) => {
  const fileUrl  = 'https://www.w3.org/WAI/ER/tests/xhtml/testfiles/resources/pdf/dummy.pdf'
  const fileBuffer  = await request.get(fileUrl)
  const response = await request.post('https://filebin.net/pp9on3zvwv7zq6lm/dummy.pdf', {
    data: await fileBuffer.body(),
  })
  await expect(response).toBeOK()
})

const { test, expect } = require('@playwright/test')

test('Upload a file using a POST request', async ({ request }) => {
  const fileUrl  = 'https://www.w3.org/WAI/ER/tests/xhtml/testfiles/resources/pdf/dummy.pdf'
  const fileBuffer  = await request.get(fileUrl)
  const response = await request.post('https://filebin.net/pp9on3zvwv7zq6lm/dummy.pdf', {
    data: await fileBuffer.body(),
  })
  await expect(response).toBeOK()
})

Using the file system

Sometimes, you do want to explicitly save a file to disk. This is what you need to know.

Checkly creates a sandboxed directory for each check run. During the run you can use this directory to save or upload artifacts. This directory is destroyed after a check is finished.

import path from 'path'
import fs from 'fs'
import { test } from '@playwright/test'

test('Save file in directory', async ({ page }) => {
  const image = await page.goto('https://picsum.photos/200/300')
  const imagePath = path.join('example.jpg')
  const buffer = await image.body()
  fs.writeFileSync(imagePath, buffer)
  const readFileFromDisk = fs.readFileSync(imagePath)
})

const path = require('path')
const fs = require('fs')
const { test } = require('@playwright/test')

test('Save file in directory', async ({ page }) => {
  const image = await page.goto('https://picsum.photos/200/300')
  const imagePath = path.join('example.jpg')
  const buffer = await image.body()
  fs.writeFileSync(imagePath, buffer)
  const readFileFromDisk = fs.readFileSync(imagePath)
})

Due to this sandbox, certain Node.js variables are adapted to our platform and have values we set for them. The behaviour is slightly different when creating a browser check in the Web UI or using the Checkly CLI.

When creating a browser check in the Web UI, the variables are:

  • __dirname will have the value of /
  • __filename will have the value of /script.js

When creating a browser check using the Checkly CLI the variables are:

  • __dirname will have the value of /
  • __filename will have the value of the actual file in your code base, relative to the project root.
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Last updated on March 27, 2024. You can contribute to this documentation by editing this page on Github