Book Image

Go Web Scraping Quick Start Guide

By : Vincent Smith
Book Image

Go Web Scraping Quick Start Guide

By: Vincent Smith

Overview of this book

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.
Table of Contents (10 chapters)

sync package helpers

Goroutines and channels, being the core constructs of concurrent programming in Go, will provide most of the utility that you will need. However, there are many helpful objects that the Go standard library provides that are also useful to know. We have already seen how sync.Mutex and sync.RWMutex work, but let's take a look at some of the other objects offered.

Conditions

Now that you are able to launch scraper tasks into multiple threads, some controls will need to be put into place so things don't get too out of hand. It is very simple in Go to launch 1,000 goroutines to scrape 1,000 pages simultaneously from a single program. However, your machine most likely cannot handle the same load. The...