The Cascadia package implements CSS selectors for use with the parse trees produced by the html package.
To test CSS selectors without writing Go code, check out cascadia the command line tool, a thin wrapper around this package.
The following is an example of how you can use Cascadia.
package main
import (
"fmt"
"log"
"strings"
"github.com/andybalholm/cascadia"
"golang.org/x/net/html"
)
var pricingHtml string = `
<div class="card mb-4 box-shadow">
<div class="card-header">
<h4 class="my-0 font-weight-normal">Free</h4>
</div>
<div class="card-body">
<h1 class="card-title pricing-card-title">$0/mo</h1>
<ul class="list-unstyled mt-3 mb-4">
<li>10 users included</li>
<li>2 GB of storage</li>
<li><a href="https://example.com">See more</a></li>
</ul>
</div>
</div>
<div class="card mb-4 box-shadow">
<div class="card-header">
<h4 class="my-0 font-weight-normal">Pro</h4>
</div>
<div class="card-body">
<h1 class="card-title pricing-card-title">$15/mo</h1>
<ul class="list-unstyled mt-3 mb-4">
<li>20 users included</li>
<li>10 GB of storage</li>
<li><a href="https://example.com">See more</a></li>
</ul>
</div>
</div>
<div class="card mb-4 box-shadow">
<div class="card-header">
<h4 class="my-0 font-weight-normal">Enterprise</h4>
</div>
<div class="card-body">
<h1 class="card-title pricing-card-title">$29/mo</h1>
<ul class="list-unstyled mt-3 mb-4">
<li>30 users included</li>
<li>15 GB of storage</li>
<li><a>See more</a></li>
</ul>
</div>
</div>
`
func Query(n *html.Node, query string) *html.Node {
sel, err := cascadia.Parse(query)
if err != nil {
return &html.Node{}
}
return cascadia.Query(n, sel)
}
func QueryAll(n *html.Node, query string) []*html.Node {
sel, err := cascadia.Parse(query)
if err != nil {
return []*html.Node{}
}
return cascadia.QueryAll(n, sel)
}
func AttrOr(n *html.Node, attrName, or string) string {
for _, a := range n.Attr {
if a.Key == attrName {
return a.Val
}
}
return or
}
func main() {
doc, err := html.Parse(strings.NewReader(pricingHtml))
if err != nil {
log.Fatal(err)
}
fmt.Printf("List of pricing plans:\n\n")
for i, p := range QueryAll(doc, "div.card.mb-4.box-shadow") {
planName := Query(p, "h4").FirstChild.Data
price := Query(p, ".pricing-card-title").FirstChild.Data
usersIncluded := Query(p, "li:first-child").FirstChild.Data
storage := Query(p, "li:nth-child(2)").FirstChild.Data
detailsUrl := AttrOr(Query(p, "li:last-child a"), "href", "(No link available)")
fmt.Printf(
"Plan #%d\nName: %s\nPrice: %s\nUsers: %s\nStorage: %s\nDetails: %s\n\n",
i+1,
planName,
price,
usersIncluded,
storage,
detailsUrl,
)
}
}The output is:
List of pricing plans:
Plan #1
Name: Free
Price: $0/mo
Users: 10 users included
Storage: 2 GB of storage
Details: https://example.com
Plan #2
Name: Pro
Price: $15/mo
Users: 20 users included
Storage: 10 GB of storage
Details: https://example.com
Plan #3
Name: Enterprise
Price: $29/mo
Users: 30 users included
Storage: 15 GB of storage
Details: (No link available)
