Golang : How to extract links from web page ?
Golang's third party package goquery provides excellent tools to assist developers in building HTML parser/crawler. In this tutorial, we will learn how to use goquery to extract links from a web page. The code below will scan a part of the web page that is within the <div class=".nav-collapse ..." >
and <ul class=".nav..">
and extract the links.
package main
import (
"fmt"
"github.com/PuerkitoBio/goquery"
"strings"
)
func ScrapeLinks(url string) {
doc, err := goquery.NewDocument(url)
if err != nil {
panic(err)
}
// process this part :
// <div class="nav-collapse collapse navbar-responsive-collapse">
// <ul class="nav nav-pills">
// <li>
// <a href="/references">References</a>
// </li>
// <li>
// <a href="/tutorials">Tutorials</a>
// </li>
// </ul>
// </div>
doc.Find(".nav-collapse .nav").Each(func(i int, s *goquery.Selection) {
Title := strings.TrimSpace(s.Find("li").Text()) // https://www.socketloop.com/tutorials/trim-white-spaces-string-golang
// convert string to array
Fields := strings.Fields(Title)
// go deeper by 1 level to get the <a href=""></a>
doc.Find(".nav-collapse .nav a").Each(func(i int, s *goquery.Selection) {
Link, _ := s.Attr("href")
Link = url + Link
fmt.Printf("Title is [%s] and link is [%s]\n", Fields[i], Link)
})
})
}
func main() {
ScrapeLinks("https://socketloop.com")
}
Output :
Title is [References] and link is [https://socketloop.com/references]
Title is [Tutorials] and link is [https://socketloop.com/tutorials]
Bear in mind that goquery's doc.Find only look for first part of the <div class="nav-collapse collapse navbar-responsive-collapse">
.. i.e .. only
doc.Find(".nav-collapse") // will do.
in this tutorial case, because we want to dig 1 level deeper to <ul class="nav...">
we use this instead
doc.Find(".nav-collapse .nav")
Reference :
By Adam Ng
IF you gain some knowledge or the information here solved your programming problem. Please consider donating to the less fortunate or some charities that you like. Apart from donation, planting trees, volunteering or reducing your carbon footprint will be great too.
Advertisement
Tutorials
+8k Golang : Go as a script or running go with shebang/hashbang style
+3.9k PHP : Extract part of a string starting from the middle
+9k Golang : Random Rune generator
+18.3k Golang : How to Set or Add Header http.ResponseWriter?
+12k CodeIgniter : "Fatal error: Cannot use object of type stdClass as array" message
+8.9k Golang : Find and replace data in all files recursively
+10.4k SSL : The certificate is not trusted because no issuer chain was provided
+6.9k Golang : Load DSA public key from file example
+10.6k CodeIgniter : Import Linkedin data
+28k Golang : missing Git command
+6.9k Golang : Regular Expression find string example
+7.9k Golang : io.Reader causing panic: runtime error: invalid memory address or nil pointer dereference