Take a website screenshot in eight programming languages

How do you take a screenshot with a headless browser?

A headless browser takes a screenshot in four calls: launch the browser, open a page, go to the address, call page.screenshot. Playwright publishes official libraries for Node.js, Python, Java and .NET^[1][2][3][4], and Puppeteer is a Node.js library with the same shape^[5]. The same numbers mark the same parts. Part 3 is missing: there is no key, and in its place you install, launch and close a browser.

What exists for PHP, Go and Ruby?

Neither Playwright nor Puppeteer publishes a library for PHP, Go or Ruby. These projects exist. They are listed in the order of the language rail and are not ranked.

• PHP

  php-webdriver

  A community project that describes itself as the "PHP language binding for Selenium WebDriver". It drives a browser through a WebDriver server that you run next to your code.^[9]

• Go

  chromedp

  A Go package that "drives browsers that speak the Chrome DevTools Protocol" and "needs no external driver". Its examples repository includes a full-page screenshot.^[7]

• Ruby

  selenium-webdriver

  The Ruby binding of the Selenium project, which documents it next to its Java, Python, C# and JavaScript bindings. driver.save_screenshot('./image.png') saves the current browsing context; the Selenium page on screenshots does not describe a full-page option.^[8]

What should every version add next?

The shortest version of a screenshot request is not the one to ship. These five additions turn any of the eight into code that survives a bad day, each shown once, in one language. The same idea carries to the other seven.

1. 1Check the HTTP status before you save

   A failed request answers with a status of 400 or higher and a short JSON message, not an image. Seven of the eight versions above would save that JSON as example.png. Save the body only when the status is 200 and the content type starts with image/.

   if (!response.ok) {
     const error = await response.json()
     throw new Error(`${response.status} ${error.error_code}: ${error.error_message}`)
   }

2. 2Set a timeout longer than the render

   A render can take as long as the timeout option allows: 30 seconds by default and 90 at most. Give your own HTTP client more than that, for example 120 seconds, or a slow page will look like a network failure.

   response = Net::HTTP.start(uri.host, uri.port, use_ssl: uri.scheme == "https", read_timeout: 120) do |http|
     http.request(request)
   end

3. 3Retry 429 and 5xx with a pause

   Status 429 means you are sending too fast or too many renders are running. Statuses 500, 502, 503 and 504 are temporary. On 429 and 503 the Retry-After header says how many seconds to wait; otherwise wait 1, 2, then 4 seconds. Do not retry 400, 401, 402 or 403: the same request fails the same way.

   for attempt in range(4):
       response = requests.get(api, params=params, headers=headers, timeout=120)
       if response.status_code not in (429, 500, 502, 503, 504):
           break
       time.sleep(int(response.headers.get("Retry-After") or 2 ** attempt))

4. 4Keep the key in an environment variable

   A key typed into a file ends up in version control and in every copy of the code. Read it from the environment instead, and set the variable where the code runs.

   export SCREENSHOT_ACCESS_KEY="YOUR_ACCESS_KEY"   # once, outside the code
   
   curl -G "$API/screenshot" \
     --data-urlencode "url=https://example.com" \
     -H "X-Access-Key: $SCREENSHOT_ACCESS_KEY" \
     --output example.png

5. 5Stream large responses to disk

   A full-page PNG of a long page or a video can be many megabytes. Copy the body to the file as it arrives instead of holding all of it in memory first.

   file, err := os.Create("example.png")
   if err != nil {
   	log.Fatal(err)
   }
   defer file.Close()
   
   if _, err := io.Copy(file, resp.Body); err != nil {
   	log.Fatal(err)
   }

Complete, runnable versions with all of this in place are in the code examples for curl, Node.js, Python, PHP, Go and Ruby, and every error code is listed in the errors reference.