collyvsscrapy
Colly is a popular web scraping library for the Go programming language. It's designed to be fast and easy to use, and it provides a simple and flexible API for traversing and extracting information from websites.
Colly supports:
- Concurrent scraping with a simple API
- Automatic handling of cookies and sessions
- Automatic handling of redirects
- Support for parsing HTML and XML
- Support for parsing JSON and binary data
- Support for custom storage (e.g. scraping results to a database)
- Simple JavaScript rendering with Colly's built-in rendering engine.
Colly also provides several optional features, such as support for user-agents, delay between requests, rate-limiting and proxy usage.
Colly's API is quite simple, and it is easy to get started with basic web scraping tasks. It's a good choice for scraping moderate to heavy sites, and it can be useful for a wide range of use cases, such as data mining, content extraction, and more.
Additionally, you can use it together with Goquery, a library that allow you to make jquery like queries on HTML documents and it is often used together with Colly to ease the way of parsing the HTML.
Scrapy is an open-source Python library for web scraping. It allows developers to extract structured data from websites using a simple and consistent interface.
Scrapy provides:
- A built-in way to follow links and extract data from multiple pages (crawling)
- Handling common web scraping tasks such as logging in, handling cookies, and handling redirects.
Scrapy is built on top of the Twisted networking engine, which provides a non-blocking way to handle multiple requests at the same time, allowing Scrapy to efficiently scrape large websites.
It also comes with a built-in mechanism for handling common web scraping problems, such as:
- handling HTTP errors
- handling broken links
Scrapy also provide these features:
- Support for storing scraped data in various formats, such as CSV, JSON, and XML.
- Built-in support for selecting and extracting data using XPath or CSS selectors (through
parsel). - Built-in support for handling common web scraping problems (like deduplication and url filtering).
- Ability to easily extend its functionality using middlewares.
- Ability to easily extend output processing using pipelines.
Highlights
Example Use
package main
import (
"fmt"
"github.com/gocolly/colly/v2"
)
func main() {
// Instantiate default collector
c := colly.NewCollector(
// Visit only domains: hackerspaces.org, wiki.hackerspaces.org
colly.AllowedDomains("hackerspaces.org", "wiki.hackerspaces.org"),
)
// On every a element which has href attribute call callback
c.OnHTML("a[href]", func(e *colly.HTMLElement) {
link := e.Attr("href")
// Print link
fmt.Printf("Link found: %q -> %s\n", e.Text, link)
// Visit link found on page
// Only those links are visited which are in AllowedDomains
c.Visit(e.Request.AbsoluteURL(link))
})
// Before making a request print "Visiting ..."
c.OnRequest(func(r *colly.Request) {
fmt.Println("Visiting", r.URL.String())
})
// Start scraping on https://hackerspaces.org
c.Visit("https://hackerspaces.org/")
}