Learn how some Go-specific language features help to simplify building web scrapers along with common pitfalls and best practices regarding web scraping.
- Use Go libraries like Goquery and Colly to scrape the web
- Common pitfalls and best practices to effectively scrape and crawl
- Learn how to scrape using the Go concurrency model
Web scraping is the process of extracting information from the web using various tools that perform scraping and crawling. Go is emerging as the language of choice for scraping using a variety of libraries. This book will quickly explain to you, how to scrape data data from various websites using Go libraries such as Colly and Goquery.
The book starts with an introduction to the use cases of building a web scraper and the main features of the Go programming language, along with setting up a Go environment. It then moves on to HTTP requests and responses and talks about how Go handles them. You will also learn about a number of basic web scraping etiquettes.
You will be taught how to navigate through a website, using a breadth-first and then a depth-first search, as well as find and follow links. You will get to know about the ways to track history in order to avoid loops and to protect your web scraper using proxies.
Finally the book will cover the Go concurrency model, and how to run scrapers in parallel, along with large-scale distributed web scraping.
What you will learn
- Implement Cache-Control to avoid unnecessary network calls
- Coordinate concurrent scrapers
- Design a custom, larger-scale scraping system
- Discover how to search using the "strings" and "regexp" packages
- Set up a Go development environment
- Retrieve information from an HTML document
- Protect your web scraper from being blocked by using proxies
Who this book is for
Data scientists, and web developers with a basic knowledge of Golang wanting to collect web data and analyze them for effective reporting and visualization.
Table of Contents
- Title Page
- Copyright and Credits
- About Packt
- Introducing Web Scraping and Go
The Request/Response Cycle
- What do HTTP requests look like?
- What do HTTP responses look like?
- What are HTTP status codes?
- What do HTTP requests/responses look like in Go?
- Web Scraping Etiquette
- What is the HTML format?
- Searching using the strings package
- Searching using the regexp package
- Searching using XPath queries
- Searching using Cascading Style Sheets selectors
- Web Scraping Navigation
- Protecting Your Web Scraper
- Scraping with Concurrency
- Scraping at 100x
- Other Books You May Enjoy
- Title: Go Web Scraping Quick Start Guide
- Release date: January 2019
- Publisher(s): Packt Publishing
- ISBN: 9781789615708