Editing Dockerized Screenshot API using Puppeteer (section)

== Dockerized Screenshot API using Puppeteer ==

This guide explains how to set up a simple screenshot API using Puppeteer in a Docker container.

=== Step 1: Create a Dockerfile ===

Create a new directory for your project and create a file named '''Dockerfile''' in that directory with the following content:

<pre>
# Use the official Node.js image
FROM node:14

# Set the working directory
WORKDIR /app

# Copy package.json and package-lock.json
COPY package*.json ./

# Install dependencies
RUN npm install

# Copy the rest of the application code
COPY . .

# Expose the port
EXPOSE 3000

# Start the application
CMD ["node", "server.js"]
</pre>

=== Step 2: Create a package.json ===

In the same directory, create a '''package.json''' file with the following content:

<pre>
{
  "name": "screenshot-api",
  "version": "1.0.0",
  "main": "server.js",
  "dependencies": {
    "express": "^4.17.1",
    "puppeteer": "^10.0.0"
  }
}
</pre>

=== Step 3: Create the server code ===

Create a file named '''server.js''' in the same directory with the following content:

<pre>
const express = require('express');
const puppeteer = require('puppeteer');

const app = express();
const PORT = 3000;

app.get('/screenshot', async (req, res) => {
    const url = req.query.url;
    if (!url) {
        return res.status(400).send('URL is required');
    }

    try {
        const browser = await puppeteer.launch();
        const page = await browser.newPage();
        await page.goto(url);
        const screenshot = await page.screenshot();
        await browser.close();

        res.set('Content-Type', 'image/png');
        res.send(screenshot);
    } catch (error) {
        console.error(error);
        res.status(500).send('Error taking screenshot');
    }
});

app.listen(PORT, () => {
    console.log(`Screenshot API running at http://localhost:${PORT}`);
});
</pre>

=== Step 4: Build and Run the Docker Container ===

# Open a terminal and navigate to the directory where you created the '''Dockerfile''', '''package.json''', and '''server.js'''.
# Build the Docker image:

<pre>
docker build -t screenshot-api .
</pre>

# Run the Docker container:

<pre>
docker run -p 3000:3000 --shm-size=1gb screenshot-api
</pre>

=== Step 5: Use the Screenshot API ===

Once the container is running, you can take screenshots by making a GET request to the '''/screenshot''' endpoint with a '''url''' query parameter. For example:

<pre>
curl "http://localhost:3000/screenshot?url=https://example.com" --output screenshot.png
</pre>

This will save the screenshot of the specified URL as '''screenshot.png'''.

=== Notes ===
* Make sure you have Docker installed on your machine.
* The '''--shm-size=1gb''' option is important for Puppeteer to work correctly, as it requires shared memory for rendering.
* You can customize the server code further to add more features, such as error handling, different image formats, etc.