How to Use a Proxy with Ruby‘s Faraday HTTP Client

If you‘re doing any serious web scraping with Ruby, you‘ve almost certainly used the excellent Faraday HTTP client library to fetch data from websites. With its simple, intuitive API and support for multiple backend adapters, Faraday makes it a breeze to make requests and parse responses.

But once you start scaling up your scraping, you‘ll quickly run into issues with your IP getting blocked if you hammer a site with too many requests from a single client. That‘s where proxies come in – by routing requests through an intermediary server, you can spread the load across multiple IPs and keep your scraper running smoothly.

In this comprehensive guide, we‘ll dive deep into the nuts and bolts of effectively using proxies with Faraday and share some hard-earned tips to supercharge your Ruby web scraping. You‘ll learn:

• Why proxies are essential for large scale web scraping
• Step-by-step instructions for configuring Faraday to use proxies
• Best practices for proxy rotation to maximize success rates
• Advanced proxy techniques like sticky sessions and geotargeting
• How to use a proxy service like ScrapingBee to simplify proxy management

Whether you‘re new to web scraping in Ruby or a seasoned veteran, this guide will equip you with the knowledge you need to use proxies like a pro. Let‘s get started!

The Case for Proxies in Web Scraping

So what exactly are proxies and why should you bother with them for web scraping? In simplest terms, a proxy is an intermediary server that sits between your scraper and the target website you want to fetch data from.

Instead of your scraper sending requests directly to the target site, the requests get routed through the proxy first. The proxy then forwards the request to the target site, receives the response, and passes it back to your scraper. To the target website, it appears as if the request is coming from the proxy‘s IP address instead of your scraper‘s real IP.

There are a few key reasons you‘d want to use proxies for web scraping:

1. Avoiding IP Blocking – When you send a large number of requests to a website in a short period of time, you can quickly get your IP blocked or rate limited. By using multiple proxies and rotating your requests between them, you can avoid hitting these limits.

2. Anonymity – Proxies allow you to hide your real IP address from the sites you‘re scraping. This makes it much harder for them to detect and block your scraper.

3. Geotargeting – Some proxies let you select an IP from a specific country or city. This is useful if you need to test how a site behaves for users in different locations.

To illustrate the impact proxies can have on web scraping, here are some benchmark statistics from our own large scale scraping:

As you can see, using rotating proxies allowed us to make nearly 30x more requests per minute while keeping our success rate high and avoiding IP blocks. Simply put, proxies are essential for scraping at scale.

Now that we understand why proxies are so important, let‘s walk through how to actually configure Faraday to use them in your Ruby scraping code.

Configuring Faraday to Use a Proxy

Faraday makes it easy to use a proxy when initializing a connection. You simply need to pass in the :proxy option with the full URL of your proxy:

proxy = ‘http://user:[email protected]:4321‘
conn = Faraday.new(url: ‘https://scrapingtarget.com‘, proxy: proxy)

A few things to note here:

• The proxy URL should include the scheme (http or https), IP or hostname, and port
• If using an authenticated proxy that requires a username and password, include them in the URL with the format user:pass@ before the host
• For SSL proxies using the https scheme, you‘ll need to have the https Faraday adapter enabled:

conn = Faraday.new(url, proxy: proxy, ssl: {verify: false}) do |conn|
  conn.adapter :net_http 
end

Faraday also allows setting the proxy individually for each request by passing the :proxy option to get, post, etc:

conn.get(‘/some-path‘, nil, proxy: proxy)

This can be handy if you need to use different proxies for different requests to the same host.

Environment Variables for Proxy Config

Faraday will also automatically use the HTTP_PROXY or HTTPS_PROXY environment variables to set a proxy if present. To use this approach, simply set one of those variables in your shell before running your scraper:

export HTTP_PROXY=http://user:[email protected]:4321

Then instantiate your Faraday connection without an explicit proxy:

conn = Faraday.new(url: ‘https://scrapingtarget.com‘)

The big benefit of using environment variables for your proxy config is you can easily switch between different proxy setups without touching your code. This is very useful when running your scraper in different environments like development and production.

Proxy Rotation Techniques

While using a single proxy is a good start, to really fool websites you‘ll want to spread your requests across multiple proxy IPs. Most large websites can detect patterns in headers, request rate, and content accessed that identify automated scrapers, even if the IP is different each time.

Here are a few of the key techniques for effective proxy rotation:

1. Round Robin – The simplest approach is to just cycle through a list of proxies in order, sending one request to each in turn. To implement this in Faraday:

proxies = [
  ‘http://proxy1.yoursite.com‘,
  ‘http://proxy2.yoursite.com‘,
  ‘http://proxy3.yoursite.com‘,
]

conn = Faraday.new(url: ‘https://scrapingtarget.com‘)

proxies.cycle do |proxy|
  conn.proxy = proxy 
  response = conn.get(‘/some-path‘)
  # process response
end

2. Weighted Round Robin – Building on simple round robin, this method assigns each proxy a "weight" and distributes requests proportionally to those weights. So a proxy with weight 2 would receive twice as many requests as a proxy with weight 1. This is useful when you have proxies with varying speed and reliability.

3. Least Recently Used – This strategy always sends the request to the proxy that was used furthest in the past. It ensures an even distribution of requests and can help avoid rate limiting issues.

What‘s the optimal rotation strategy? The real answer is it depends – on your specific proxies, target websites, and scraping speed and volume. In our experience testing many different approaches, a weighted round robin technique with a pool of at least 20 or so proxies hits the sweet spot for most scraping tasks.

The key is to experiment, measure your success rate and errors, and continue to tweak your proxy rotation config. Even small adjustments can have a big impact on your results.

Advanced Proxy Techniques

Beyond just rotating proxies, there are a few more advanced techniques that can really supercharge your scraping and make it even harder to detect:

1. Sticky Sessions – Some scrapers need to login to a website and persist cookies across multiple requests. With basic proxy rotation, you‘d lose the session every time you switched proxies. The solution is "sticky sessions" where each session gets tied to a specific proxy and all requests for that session keep going through the same IP.

2. Geotargeting – More and more websites customize content based on the user‘s inferred location. If you need to scrape localized data, you can use a geotargeted proxy from a provider like ScrapingRobot to get an IP in a specific country, state, or city.

3. Request Headers – Varying your request headers is another way to appear like organic traffic from different users. You can configure Faraday to send a random User Agent string on each request:

USER_AGENTS = [
  "Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/91.0.4472.114 Safari/537.36",
  "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/91.0.4472.124 Safari/537.36 Edg/91.0.864.59",
  "Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:89.0) Gecko/20100101 Firefox/89.0"
]

conn.headers[‘User-Agent‘] = USER_AGENTS.sample

Mixing up other headers like Accept-Language and Referer can also help make your scraper traffic appear more organic.

Proxy Services for Easier Management

Managing your own pool of proxies certainly gives you the most control and flexibility, but it can also be a major operational headache. You need to source high quality proxies, monitor their performance and availability, and manually implement the rotation logic in your scraping code.

An alternative approach that can greatly simplify things is to use a dedicated proxy service like ScrapingBee. Instead of sending requests directly to a proxy you manage, you send them through the ScrapingBee API which automatically routes them through a new proxy from their large pool on each request.

Here‘s an example of how to use ScrapingBee with Faraday:

conn = Faraday.new(‘https://app.scrapingbee.com‘) do |conn|
  conn.request :json
  conn.response :json 
end

response = conn.post(‘/api/v1‘) do |req|
  req.params[‘api_key‘] = ‘YOUR_API_KEY‘ 
  req.params[‘url‘] = ‘https://scrapingtarget.com‘
  req.params[‘render_js‘] = false
end

puts response.body

As you can see, there‘s no proxy config to worry about at all in your code. You just structure your request for the target URL and the ScrapingBee API handles all the proxy rotation and other headaches transparently.

ScrapingBee and similar services usually have additional beneficial features like JavaScript rendering, custom headers, and global IP coverage through their APIs. Of course, you‘re trading some control for that convenience, but for many scraping projects the benefits can really outweigh the costs.

Choosing the Right Proxy Approach

We‘ve covered a lot about the different techniques for using proxies in web scraping – from simple rotation to advanced techniques like sticky sessions and geotargeting, as well as using a managed proxy service. So what‘s the right approach for your specific project?

As with many engineering decisions, the answer is it depends. Here‘s a quick summary of the key tradeoffs between managing your own proxies and using a service:

Self-Managed Proxies:

• Full control over proxy config
• Can be cheaper for small scraping projects
• Requires significant time to source, test, and maintain proxies
• Have to manually implement rotation and other techniques

Proxy Services:

• Easy to set up and integrate with your scraper
• Handles all the proxy management complexity
• Can be more expensive, especially for high volume scraping
• Less flexibility and control over proxy settings

In our experience running thousands of large scale web scraping projects, a managed proxy service is the right call for most scraping tasks. The time saved and reduction in technical complexity makes the additional cost well worth it. You can focus on parsing and analyzing the data you retrieve instead of babysitting proxies.

That said, if you have a small scraping project, very specific proxy requirements, or constraints that prevent using a third-party service, self-managed proxies can work great. Just be prepared to invest significant engineering time to get your proxy infrastructure running smoothly.

Putting It All Together

Integrating proxies with your Ruby web scraping can seem daunting at first, especially with all the different rotation techniques and configuration options we‘ve covered. But the Faraday library makes it quite approachable to get up and running.

To recap, here‘s a quick checklist for what you need to scrape effectively with proxies and Faraday:

1. Get access to a pool of reliable, anonymous proxies (either self-managed or from a service)
2. Configure Faraday to route requests through a proxy using the :proxy option
3. Implement a proxy rotation strategy to spread requests across multiple IPs
4. Monitor your success rate and errors and tweak your rotation approach
5. Consider more advanced techniques like sticky sessions and geotargeting for complex scraping projects
6. Evaluate the tradeoffs of self-managed proxies vs. a managed proxy service for your situation

With those pieces in place and a bit of experimentation and iteration, you‘ll be well on your way to scraping even the most complex websites with Ruby and Faraday.

Closing Thoughts

Web scraping is a powerful tool for gathering data from across the internet, but it‘s critical to be a good citizen and respect the websites you scrape. Use the minimum request rate and concurrent connections that get the job done. Respect robots.txt files. And don‘t hammer small sites with more traffic than they can handle.

Responsible scraping practices combined with effective proxy usage will allow you to build high quality datasets while minimizing the impact on the sites you scrape. It‘s a win-win for everyone.

Hopefully this guide has equipped you with the knowledge and tools you need to integrate proxies into your Ruby scraping projects. The team at ScrapingBee is always happy to chat about your scraping needs and answer any other questions you might have. Happy scraping!