How to Use Superagent-Proxy for Web Scraping

Web scraping is growing exponentially to extract the vast riches of data across the internet. Entire companies are built around scraping to inform investing decisions, price monitoring, market research, and various data products. Developers, too, utilize these techniques to power an endless array of apps and services.

With so much valuable data at stake, websites are fighting back with increasingly sophisticated bot detection and mitigation technology. We're in the midst of an arms race between scrapers trying to gather data and sites attempting to protect it.

Simply put, if you're not scraping responsibly and evading detection, you're not scraping for long.

That's why we put together this comprehensive guide covering not just how to integrate proxies for basic scraping, but more importantly, best practices to scrape confidently at scale long-term.

The Role of Proxies in Web Scraping

Proxies act as intermediaries between scrapers and websites to mask scrapers' true IP addresses. By routing requests through a rotating pool of residential IPs, scrapers appear as a normal human visitor.

However, proxies are just one piece of an effective web scraping solution. Even robust residential proxy networks get blocked once sites identify patterns among the traffic.

You also need advanced evasion capabilities to combat the various bot mitigation vectors in play:

• CAPTCHAs – Over 2 million CAPTCHAs are solved every day. Scrapers require specialized computer vision and OCR techniques to reliably bypass them.
• JavaScript Analysis – Heuristics detect non-human behavior patterns like unusual mouse movements. Scrapers emulate lifelike actions to avoid red flags.
• Device Fingerprinting – High entropy factors like browser/OS specs, fonts, WebGL, etc fingerprint browsers. Regular spoofing and randomization evades this.
• Behavior Analysis – Signals like past browsing history, session time, activity pace hint at bots. Maintaining user profiles and human-like actions outsmarts these systems.
• IP Reputation – Sites tag and blacklist IPs with high scraping activity. Rapid rotation ensures scrapers stay ahead of IP burns.

As you can see, a scraping strategy demands an orchestration of various technical components – proxies being only one foundational pillar.

In this guide, we'll cover proxy integration in depth while framing it within the greater context of scraping best practices.

Setting Up a Superagent Web Scraper

Superagent provides a handy API for making HTTP requests from Node.js and browsers. Before we add proxies, let's build a simple scraper with superagent first.

Prerequisites

Assuming you have Node.js and npm set up, create a new project directory:

mkdir superagent-scraper
cd superagent-scraper
npm init -y

This will initialize a new Node.js project including a package.json file.

Next, install superagent:

npm install superagent

We also need to handle promises for asynchronous requests and errors:

npm install bluebird

Optionally, tools like nodemon make development easier by automatically restarting Node when files change.

Import Superagent Package

In your main server file, import superagent to start using it:

We assign the superagent library to request for convenience.

Make Asynchronous Requests

Superagent supports asynchronous logic out of the box with promises. This avoids blocking code execution while making requests.

Let's define an anonymous async function:

(async () => {

  // Request code here  

})();

The async keyword enables promise-based handling while ()() invokes the function immediately.

Inside we can make requests like:

const response = await request.get('https://example.com');

The await operator pauses execution until the Promise returns, then assigns the response to work with.

Handle Errors

Things don't always go smoothly when scraping websites. Servers can be down, IPs get blocked, network issues can happen, and more.

Wrapping our scraper code in try/catch blocks catches errors gracefully:

try {

  const response = await request.get('https://example.com');
  
  // scraper logic here
  
} catch (error) {

  console.log(error); 

}

This avoids abrupt crashes by dealing with exceptions cleanly.

We can further improve on this with libraries like Winston to log different severity levels. Reporting helps uncover systemic issues.

Configure Request Options

Superagent provides extensive request configuration like setting headers and query parameters:

request
  .get('https://example.com')
  .set('User-Agent', 'Foo Browser') 
  .query({ page: 2, sort: 'desc' })

This additional context helps sites see a valid browser and scrape intelligently.

Process Response Data

Once the promise resolves, numerous response fields contain information:

console.log(response.status) // 200
console.log(response.header) // {...} 

const $ = cheerio.load(response.text) // Parse HTML

What we do with the response data depends on our specific scraper. But superagent handles all the heavy lifting of fetching and surfacing it.

This covers the basics of setting up a superagent web scraper. Next let's enhance it further with proxies.

Adding Proxy Support with Superagent-Proxy

Superagent Proxy extends superagent to route requests through proxy servers, providing built-in proxy management.

Superagent proxy sits as intermediary layer handling communication logic

The core value is keeping proxy complexity separate from your scraper code itself.

Installation

Install via npm:

npm install superagent-proxy

Key Compatibility Notes:

• Works with major proxy protocols like HTTP, SOCKS5
• Supports authentication with most proxy services
• Actively maintained and updated

Importing and Initialization

In your server code, import superagent-proxy and attach it to the base superagent instance:

const request = require('superagent'); 
require('superagent-proxy')(request);

This enhances request with new proxy methods.

Defining Proxy Endpoints

Proxies typically expose a basic URL string to configure traffic routing through them:

const proxyUrl = 'hostname:port';

For superagent, this base URL sets the proxy target.

You also need to acquire endpoints from a proxy provider like Bright Data, which offers over 72 million residential IPs perfect for scraping.

Creating Proxied Requests

With Proxy URL in hand, invoke the .proxy() method on any request:

request
  .get('https://example.com') 
  .proxy(proxyUrl)

This seamlessly routes the request through your configured proxy instead of directly.

No other logic needs to change – superagent handles sending traffic through the proxy endpoint.

Rotating Multiple Proxies

A common mistake beginners make is reusing the same proxy perpetually. This is easily detected and blocked.

The key is rotating amongst a large, ever-changing pool of proxy endpoints:

const proxyList = [
  'pr1', 'pr2', // ...
];

function getRandomProxy() {
  // Grab random endpoint 
}

request
  .get(url)  
  .proxy(getRandomProxy()); // Rotate randomly

Structuring your code this way allows endless experimentation with proxy cycling tactics.

Authenticating Proxy Requests

Many proxy services require authentication to access their endpoints, similar to needing a username and password.

Superagent-proxy can automatically handle authentication during proxying:

.proxy(endpoint, {
  auth: 'username:password'   
})

The auth field passes the necessary credentials.

For services like Bright Data, this happens transparently without any coding. But for DIY or custom proxies, authentication works the exact same way.

Proxy Rotation Patterns and Strategies

Choosing when and how to cycle proxies makes a huge difference in scraping resilience. Here we explore various rotation strategies and considerations when determining a robust approach.

Fixed vs Random Proxy Selection

Fixed Cycling rotates proxies sequentially from a list. So Request 1 uses Proxy 1, Request 2 uses Proxy 2, and so on round-robin style.

Random Cycling grabs proxies randomly at runtime. This technique is generally superior as patterns are much harder to identify.

// Fixed
const proxyList = [A, B, C] 
let counter = 0;

function getProxy() {
  const proxy = proxyList[counter % proxyList.length];  
  counter++;
  
  return proxy; 
}

// Random 
function getRandomProxy() {

  return proxyList[Math.floor(Math.random() * list.length)];

}

Code-wise, random cycling takes a tiny bit more work but pays off in greater scraping resilience.

Rotation Frequency

Rotating every request via round-robin or randomizing is ideal for mass scraping scenarios. However, more work means more infrastructure cost.

A balanced approach is allocating several requests per proxy before rotating. If pushing extremely high volumes, somewhere between 50 to 100 requests per residential IP maximizes efficiency.

Datacenter proxies on the other hand block much quicker, as low as 3 to 5 requests in some cases. Their transient nature mandates extreme cycling.

Balancing performance, costs, and blocks to determine rotation frequency.

Aim to experiment with different thresholds and settle on an optimal rotation policy for your use case.

Advanced Proxy Scheduling

More advanced use cases allow setting proxy rotations based on a schedule or usage metrics too for greater control:

// Schedule - Rotate hourly  
function getProxyForHour() {

  const hour = new Date().getHours();

  return proxyList[hour % 24];

}

// Metrics - Rotate once GB used
function getLeastUsedProxy() {
  
  // Sort proxies by GB transferred
  // Return least used
}

Scheduled rotations help overcome high frequency blocks by clearing context. Usage based algorithms implement load balancing, maximizing the proxy pool.

Generally simpler is better, but opening up these options caters to sophisticated demands.

Residential Proxies vs. Datacenter Proxies

When evaluating proxy solutions, the first question should focus on underlying infrastructure.

Not all proxies operate on equal footing. Getting proxied isn't enough – you need the right type of proxy suited for web scraping to avoid blocks.

Datacenter Proxies rely on clusters of static servers sharing common subnets. They work for basic browsing but get detected instantly during scraping thanks to their concentrated nature.

	Datacenter	Residential
Infrastructure	Shared static datacenters	Distributed global household IPs
IP Refresh Rate	Low (Days or weeks)	Extremely high (Every request)
Block Rates	High – Almost instant	Low – Gradual over weeks/months
Pricing	Cheap but useless for scraping	Expensive but critical for scraping

On the other hand, residential proxies derive from real desktop browsers distributed globally through millions of home connections. This genuine user traffic blends right in.

Capital and operational expenses are 10X higher for residential infrastructure yet necessary to enable serious scraping today.

The Bot Mitigation Technology Landscape

Earlier we outlined various anti-bot measures websites employ including CAPTCHAs, fingerprinting, JavaScript analysis and more. Here we do a deeper inspection on each front.

The multi-front battle between bot mitigation and evasion

For every bot challenge, scrapers require specialized tooling and infrastructure to continue operating smoothly:

Vector	Evasion Tactics	Critical Tools
CAPTCHAs	OCR, computer vision, model training, human solvers, bypass APIs	Anti-Captcha, Bright Data
Fingerprinting	Browser emulation, header & cookie customization, fingerprint masking	Puppeteer, Bright Data
JavaScript Analysis	Trigger lifelike events and actions, simulate mouse movements, handle popups naturally	Puppeteer, Playwright
Behavior Analysis	Maintain user profiles, mimic organic browsing habits, respond to challenges	Bright Data
IP Blocks	Rapid rotation, residential proxy networks, proxy management layers	Bright Data, ScraperAPI

This framework shows why reliable scraping necessitates both robust proxying and evasion capabilities in tandem, not just one or the other.

Scraping-as-a-Service

Given the immense DevOps complexity required to scraper safely at scale, proxy management services have recently emerged combining both facets:

Scraping-as-a-service solutions remove huge infrastructure burden

Bright Data, for example, provides:

• 72+ million residential IPs providing the world's largest proxy network
• Built-in bypass solutions handling CAPTCHAs, checks, and blocks
• Powerful APIs and tools integrating easily with superagent proxy
• Detailed analytics with granular tracking of scrapers
• 24/7 customer support from proxy experts

For modest monthly fees, you offload enormous DevOps headaches to focus purely on the unique parsing and extraction logic for your project needs.

Conclusion

In this extensive guide, we explored critical concepts like:

• Setting up a basic superagent scraper
• Adding proxy capabilities through superagent-proxy
• Proxy URI configuration, authentication, and rotation patterns
• How infrastructure differences dramatically impact block rates
• The multi-layer bot mitigation landscape sites employ
• Leveraging scraping-as-a-service solutions

The key insight is recognizing high-quality proxies as just the beginning. They facilitate the foundation for web scraping, but require additional anti-detection capabilities for resilient long term scraping.

Between superagent flexibility, superagent-proxy simplicity, and Bright Data's evasion network, you now have the full stack to scrape fearlessly. No more playing cat and mouse games with complex site protections.