jdocset/vendor/github.com/yhat/scrape/README.md

scrape

A simple, higher level interface for Go web scraping.

When scraping with Go, I find myself redefining tree traversal and other utility functions.

This package is a place to put some simple tools which build on top of the Go HTML parsing library.

For the full interface check out the godoc

Sample

Scrape defines traversal functions like Find and FindAll while attempting to be generic. It also defines convenience functions such as Attr and Text.

// Parse the page
root, err := html.Parse(resp.Body)
if err != nil {
    // handle error
}
// Search for the title
title, ok := scrape.Find(root, scrape.ByTag(atom.Title))
if ok {
    // Print the title
    fmt.Println(scrape.Text(title))
}

A full example: Scraping Hacker News

package main

import (
	"fmt"
	"net/http"

	"github.com/yhat/scrape"
	"golang.org/x/net/html"
	"golang.org/x/net/html/atom"
)

func main() {
	// request and parse the front page
	resp, err := http.Get("https://news.ycombinator.com/")
	if err != nil {
		panic(err)
	}
	root, err := html.Parse(resp.Body)
	if err != nil {
		panic(err)
	}

	// define a matcher
	matcher := func(n *html.Node) bool {
		// must check for nil values
		if n.DataAtom == atom.A && n.Parent != nil && n.Parent.Parent != nil {
			return scrape.Attr(n.Parent.Parent, "class") == "athing"
		}
		return false
	}
	// grab all articles and print them
	articles := scrape.FindAll(root, matcher)
	for i, article := range articles {
		fmt.Printf("%2d %s (%s)\n", i, scrape.Text(article), scrape.Attr(article, "href"))
	}
}