Downloading Images from a Website with Scala and rucola

Oct 15, 2023 · 4 min read

In this article, we will learn how to use Scala and the scalaj-http and rucola libraries to download all the images from a Wikipedia page.

—-

Overview

The goal is to extract the names, breed groups, local names, and image URLs for all dog breeds listed on this Wikipedia page. We will store the image URLs, download the images and save them to a local folder.

Here are the key steps we will cover:

  1. Import required libraries
  2. Send HTTP request to fetch the Wikipedia page
  3. Parse the page HTML using rucola
  4. Find the table with dog breed data using a CSS selector
  5. Iterate through the table rows
  6. Extract data from each column
  7. Download images and save locally
  8. Print/process extracted data

Let's go through each of these steps in detail.

Imports

We need these libraries:

import scalaj.http._
import rucola.expr._
import java.io._
  • scalaj-http - Sends HTTP requests
  • rucola - Parses HTML/XML
  • java.io - File I/O
  • Send HTTP Request

    To download the web page:

    val url = "<https://commons.wikimedia.org/wiki/List_of_dog_breeds>"
    
    val response = Http(url)
      .header("User-Agent", "ScalaScraper")
      .asString
    
    response.code match {
      case 200 =>
        // Parse HTML
      case _ =>
        println(s"Error fetching $url")
    }
    

    We make a GET request and provide a custom user-agent header.

    Parse HTML

    To parse the HTML:

    val html = XML.loadString(response.body)
    

    The rucola.expr.XML object represents parsed HTML.

    Find Breed Table

    We use a CSS selector to find the table element:

    val table = html >> element("table.wikitable.sortable")
    

    This selects the

    tag with the required CSS classes.

    Iterate Through Rows

    We loop through the rows:

    (table >> element("tr")).drop(1).foreach { row =>
    
      // Extract data
    
    }
    

    We drop the first row and iterate through the

    elements.

    Extract Column Data

    Inside the loop, we get the column data:

    val cells = row >> elements("td", "th")
    
    val name = (cells(0) >> element("a")).text
    val group = cells(1).text
    
    val localName = (cells(2) >> element("span")).text.getOrElse("")
    
    val img = cells(3) >> element("img")
    val photograph = img.attr("src").getOrElse("")
    

    We use text for text and attr() for attributes.

    Download Images

    To download and save images:

    if (photograph.nonEmpty) {
    
      val imageData = Http(photograph).asBytes
    
      val file = new File(s"dog_images/$name.jpg")
      new FileOutputStream(file) << imageData
    
    }
    

    We reuse the HTTP client and save the image bytes to a file.

    Store Extracted Data

    We store the extracted data:

    names :+= name
    groups :+= group
    localNames :+= localName
    photographs :+= photograph
    

    The arrays can then be processed as needed.

    And that's it! Here is the full code:

    // Imports
    import scalaj.http._
    import rucola.expr._
    import java.io._
    
    // Arrays to store data
    val names = ArrayBuffer[String]()
    val groups = ArrayBuffer[String]()
    val localNames = ArrayBuffer[String]()
    val photographs = ArrayBuffer[String]()
    
    // Send HTTP request
    val url = "<https://commons.wikimedia.org/wiki/List_of_dog_breeds>"
    
    val response = Http(url)
      .header("User-Agent", "ScalaScraper")
      .asString
    
    response.code match {
      case 200 =>
    
        // Parse HTML
        val html = XML.loadString(response.body)
    
        // Find table
        val table = html >> element("table.wikitable.sortable")
    
        // Iterate rows
        (table >> element("tr")).drop(1).foreach { row =>
    
          // Get cells
          val cells = row >> elements("td", "th")
    
          // Extract data
          val name = (cells(0) >> element("a")).text
          val group = cells(1).text
    
          val localName = (cells(2) >> element("span")).text.getOrElse("")
    
          val img = cells(3) >> element("img")
          val photograph = img.attr("src").getOrElse("")
    
          // Download image
          if (photograph.nonEmpty) {
    
            val imageData = Http(photograph).asBytes
    
            val file = new File(s"dog_images/$name.jpg")
            new FileOutputStream(file) << imageData
    
          }
    
          // Store data
          names :+= name
          groups :+= group
          localNames :+= localName
          photographs :+= photograph
    
        }
    
      case _ =>
        println(s"Error fetching $url")
    }
    

    This provides a complete Scala solution using scalaj-http and rucola to scrape data and images from HTML tables. The same approach can apply to many websites.

    While these examples are great for learning, scraping production-level sites can pose challenges like CAPTCHAs, IP blocks, and bot detection. Rotating proxies and automated CAPTCHA solving can help.

    Proxies API offers a simple API for rendering pages with built-in proxy rotation, CAPTCHA solving, and evasion of IP blocks. You can fetch rendered pages in any language without configuring browsers or proxies yourself.

    This allows scraping at scale without headaches of IP blocks. Proxies API has a free tier to get started. Check out the API and sign up for an API key to supercharge your web scraping.

    With the power of Proxies API combined with Python libraries like Beautiful Soup, you can scrape data at scale without getting blocked.

    Browse by tags:

    Browse by language:

    Tired of getting blocked while scraping the web?

    ProxiesAPI handles headless browsers and rotates proxies for you.
    Get access to 1,000 free API credits, no credit card required!