The increasing importance of web scraping for businesses and personal use points to the need to have a web scraper. You can either purchase such a tool from a reliable service provider. Alternatively, you can create one from scratch using programming languages and frameworks best suited for web scraping. Python, PHP, NodeJS, Ruby, and Golang are some examples of such languages. This article will explore the Golang web scraper, detailing 3 Golang tips for web scraping like a professional. Let’s start.
What is Web Scraping?
Web scraping refers to the practice of using bots, known as web scrapers, to extract publicly available data from websites. It offers numerous benefits to both businesses and individuals. For instance, companies can collect publicly available data on the number of competitors in a market, their pricing strategies, and products in the market. By analyzing this data, companies can develop better go-to-market strategies (if they are new to the market) or competitive prices for their products and services. On the other hand, people can use web scraping to gather real-time updates from job or news aggregation sites.
As stated, businesses and people can create web scrapers using several programming languages, including Golang.
What is Golang?
Golang or Go is a general-purpose compiled programming language invented by Google in 2007 and released to the public in 2012. It is based on the C programming language. Golang boasts numerous functionality that has influenced its popularity within the developer community.
Go is renowned for the following features:
- Memory safety
- Garbage collection
- Simplicity
- Speed
- Run-time efficiency
- Built-in concurrency
- Multiprocessing and high-performance networking capabilities
- High usability
- A comprehensive suite of tools and frameworks
Developers have capitalized on these features to extend Golang’s usability beyond what its inventors had initially envisioned. Google’s developers had created Go for use in networking and infrastructure. Currently, however, Golang is used in game development, creating back-end applications (Application Programming Interfaces or APIs), automation of DevOps and site reliability functions, web scraping, and more.
Web Scraping: Building a Golang Web Scraper
With Golang, you can extract data from websites like a pro. This is because there are different web scraping frameworks containing prewritten code tools. These frameworks ensure that you do not have to write the code from scratch. This, coupled with the fact that the Go language is easy to learn, fast, simplistic, and has built-in concurrency (which enables it to undertake multiple tasks simultaneously), makes Golang web scrapers extremely useful.
What should you look out for when creating a Golang web scraper? Here are 3 Golang tips that will help you scrape like a pro:
- Pick the right frameworks
- Use multiple collectors
- Ensure your callbacks are ordered correctly
Right Framework
There are numerous Golang web scraping frameworks. These include Colly, soup (not to be confused with BeautifulSoup Python library), Ferret, Hakrawler, and Gocrawl. Colly is the most popular of the listed frameworks. Its popularity implies that multiple tutorials on using it are already available, either in written or video formats. For this reason, Colly offers convenience and ease of use.
At the same time, Colly has numerous features that make it the ideal framework for creating a Golang web scraper. These features are:
- Caching capabilities;
- Support for request delays and the ability to limit the maximum number of concurrent tasks per domain – this is particularly useful as it helps mimic human behavior, preventing the website from blocking the requests on the grounds of suspicious activities;
- It offers Robots.txt support, enabling the Golang web scraper to avoid restricted web pages;
- Colly enables parallel/async/sync scraping;
- It is fast;
- This framework automatically handles sessions and cookies.
Use Multiple Collectors
A Collector object is the main entity in the Colly framework. It oversees communication within a network. It also ensures that the attached callback functions are executed while the collector object runs.
It is noteworthy that the collector object limits the scope of a web scraping job. To circumvent this problem and ensure that the Golang web scraper can undertake large-scale web scraping, you can use multiple Collector objects.
Order the Callbacks Correctly
A callback is a function attached to the Collector object that controls data extraction from websites. For successful data extraction, the callback functions should be ordered such that the procedure mimics how a web-based application would ordinarily send requests and receive responses. The various callback functions include:
- Onrequest;
- OnError;
- OnResponseHeaders;
- OnResponse;
- OnHTML (uses a CSS selector to extract text from different HTML elements);
- OnXML;
- OnScraped.
Notably, the OnHTML function can also be used to create a CSV file on which the scraped data can then be written.
Going through the Go Colly documentation is also an essential step that guarantees success.
Conclusion
Golang is a fast programming language whose numerous features make it ideal for applications such as creating web scrapers. To build a Golang web scraper, choose the proper framework, use Collector objects, and order the callback functions correctly. If you’re searching for an in-depth tutorial on building a Golang web scraper, Oxylabs wrote a blog post that will help you.
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