Scraping Web with Proxies: The Basics of Effective and Ethical Scraping in 2022
When effectively managed, web scraping can be extremely useful: it provides a business with valuable marketing insights, enhances its decision making, and helps to beat the competition. In the meantime, geographic and rate limitations used by websites make it challenging to handle a continuous data flow. This article describes how proxies help to overcome these barriers and add value to your scraping project.
Web scraping explained
What is web scraping?
Without getting into specifics, web scraping or web harvesting means extracting data from a website. Unlike manual extraction, this process is automated and structured. The use of automated tools allows extracting thousands of data sets within a short time. The data is, then, organized in a format appropriate to its further use such as a spreadsheet or an Application Programming Interface (API). In this manner, the data scraped is turned into the information that improves decision making.
Some large platforms such as Twitter or Facebook allow extracting their data in a structured manner by providing access to their APIs. Most websites, however, do not have APIs at all or have very basic APIs that are incomplete or poorly written. This is why it is a good idea to learn the basics of scraping to be able to extract the insights you need.
How it works
Most commonly, the data extraction process is carried out by two agents: a crawler and a scraper. The former finds appropriate URLs and guides the latter through the Internet. The scraper, in turn, extracts the target information from the links. A scraping tool can extract the data that is visible to all users of the website or collect associated data, which the website stores in its databases and reveals upon an HTTP request. Depending on the task, the scraper can either extract everything from a web page or focus on a particular type of information. For example, the task might be specified to only extract product prices and to disregard product availability or review rates.
Scraping tools can be of different types and it might be useful to learn more about each of them to choose the tool that best meets your needs. The three most common types of scrapers are
- Browser extension scrapers: These scrapers are easy to use and perfect for extracting small data sets. Their major limitation is that they only scrape one page at a time.
- Software scrapers: Once installed, these scrapers allow extracting small-to-medium data sets. They can be set to complete different tasks and work with more than one page at a time.
- Cloud-based scrapers: The scrapers are an excellent solution for those who need to scrape large volumes of data and would like the scraper to complete the whole job independently without any intervention on the user’s part.
Is web scraping legal?
Web scraping is not illegal as long as the data you extract is publicly available which means it can be accessed by any Internet user. The simplest clues that tell the data is publicly available are as follows:
- The owner of the data has made it public.
- To access the data, the user does not have to create an account on the website.
- The robot exclusion protocol (REP) does not block scrapers on the web page.
To sum up, the best way to keep your scraping legal is to stick with publicly available data, avoid extracting personal information or intellectual property, and ensure your scrapers do not overload the website.
When using web scraping
The range of web scraping applications is enormous. Here are the most popular areas, in which it is used.
- Pricing: E-commerce businesses heavily use web harvesting for price intelligence. They extract data to track, compare, and analyze competitors’ prices and make smart pricing decisions.
- Market analysis and lead generation: Scraped information enables companies to analyze market trends and identify directions for further development. Extracted insights can be used to understand customers’ needs and design products that should meet those needs best.
- Finances: By extracting relevant insights, investors evaluate a company’s financial health and choose an optimal investment strategy to stick with.
- Real estate: Extracted data enables real estate agents to effectively appraise home value, monitor prices, and estimate property yields.
- Media: Web scraping helps companies to monitor news and social media content. The data scraped informs investment decisions, strategic communications, and promotion campaigns, to name but a few.
- Industry insights: By harvesting large volumes of data and statistics related to a specific industry, one can create a comprehensive industry report, which can be further sold to businesses working in this industry.
Put simply, web scraping is, above all else, an effective decision-making tool. With its help, companies turn large volumes of disorganized data into logically structured information that helps them to make smart decisions and maintain their competitive advantage.
Using proxies for web scraping
Why use proxies for scraping
While working, a scraper makes a lot of requests to a server. If all those requests come from a single IP, there are risks that you get the Slow Down, Too Many Requests From This IP warning or the server simply blocks your IP to stop the activity. The use of proxies helps to prevent this. In short, a proxy server acts as an intermediary between you and a website. It routes your request through its own IP so that your identity remains hidden. Read more on how proxy servers work here.
Besides the IP ban that proxies help to avoid, they likewise allow bypassing geographic restrictions meaning that you can access content, which is not displayed in your region. This is why it is a good idea to use proxies or even better a proxy pool for your scraping projects.
How to choose optimal proxies for your scraping project
There are three major types of proxies to choose from:
- Datacenter proxies: This is the most common type of proxies, it is cheap and easy to get. Datacenter proxy providers use IPs unrelated to Internet Service Providers (ISPs). While there are a lot of cheap datacenter proxies available, one should be prepared for the fact that their IPs are blacklisted by many websites.
- Residential proxies: These proxy servers route your online activity through IPs from the local ISP databases. The central drawback is that this proxy solution is a costly one: you should hardly find free residential proxies in the market. The routing speed might likewise be worse than the one offered by datacenter proxies. The central advantage of residential proxies is that they are rarely banned by websites. Check this article to learn more on how to set up residential proxies.
- Mobile proxies: These proxies use IPs of real mobile devices and so the content which can be scraped with their help is mainly the content available to the mobile device. Mobile proxies are expensive and hard to get but they are rarely blocked.
Choosing the right type of proxies for your scraping project is a challenging task. Two core factors that need to be considered are the budget and the technical skills available to the project team. In addition, whatever type of proxies you choose, you still end up with your requests routed through a particular IP. As we know, however, the key issue with scraping is that websites tend to use rate-limiting algorithms and blacklist IPs that make too many requests. Thus, although using a proxy server helps you avoid the ban of your own IP, it does not prevent the ban of the IP used by the server itself. This is why an optimal solution is to build a proxy pool that contains a variety of IPs, through which your requests are routed. The use of a proxy pool enables you to bypass rate limitations and make as many concurrent requests as necessary. You can build a pool of your own or use one of the public IP pools.
How to manage a proxy pool
At a certain point, some IPs from the proxy pool will get blacklisted and the quality of the data that the pool returns will degrade. To prevent this and maintain the efficiency of your proxy pool, consider taking a few precautions:
- Make sure the proxies in your pool can detect and manage different types of blocking strategies.
- If a proxy has encountered a problem that it cannot manage (e.g., captchas or blocks), try using another proxy server on this website.
- Add random delays to prevent the website from mistaking your activity for a DDoS attack.
- Carefully study the geographic restrictions for each website to decide which proxies from your pool should be enabled.
Final considerations for successful scraping
In the end, here are a few strategies that will help to ensure your scraping is both effective and ethical:
- Respect the rules: Whenever you interact with a website, it is a good idea to remember that this website is someone’s property and its owner expects you to act by the rules. The first thing you might want to do is to check whether a website has its own API. If an API is unavailable, take the time to carefully study the terms and conditions and make sure your actions respect REP.
- Keep it courteous: A good way to give your scraping an ethical start is to ask the site’s administrator for permission to extract the target data. If you have already begun harvesting without permission, make sure to add a User-Agent string so that the administrator can contact you if necessary.
Be mindful: Whatever you do, it is always useful to reflect upon how your actions affect others. Thus, for instance, aggressive scraping can overload the site which should have a negative impact on users’ experience. To prevent this, try to scrape during off-peak hours and give back by bringing good traffic to the website in a post whenever possible.
Although the two terms are often used interchangeably, scraping and crawling are different processes. In a nutshell, the former is about extracting target data from websites, whereas the latter is about finding web links. As a rule, your data extraction project will involve both processes.
In some rare cases, you can, indeed, try to do without a scraping tool and extract the data manually. In the meantime, the more web pages you plan to process, the more time-consuming and error-prone the harvesting process will be. More than that, to use the extracted data for further decision-making, you need to organize it in a structured manner, which is hardly accomplishable without a scraper.
Most web scraping tools have paid plans but offer a free trial version. Some of them provide new users with a pack of free credits. It is a good idea to carefully study the description of the software before purchasing the plan: some tools are specifically designed for programmers and require the knowledge of coding, while others can be used by non-specialists.
The simplest way to decide whether your scraping project needs proxies is to examine potential barriers. Do the websites use geo-targeting? How will you manage the risk of getting the Too Many Requests error? Can you afford to slow down with harvesting? In a nutshell, if your scraping project is a large-scale one and also rather urgent, it might benefit from the use of proxies.
If your company needs to collect a large amount of data on an ongoing basis, it might be useful to outsource this task to professionals. Outsourcing opens access to advanced harvesting infrastructure, ensures a better quality of the extracted data, and allows your business to focus on its core functions.