README
¶
cascadia
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.
Example
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)
Documentation
¶
Overview ¶
Package cascadia is an implementation of CSS selectors.
Index ¶
Constants ¶
This section is empty.
Variables ¶
This section is empty.
Functions ¶
Types ¶
type Matcher ¶
Matcher is the interface for basic selector functionality. Match returns whether a selector matches n.
type Sel ¶
type Sel interface {
Matcher
Specificity() Specificity
// Returns a CSS input compiling to this selector.
String() string
// Returns a pseudo-element, or an empty string.
PseudoElement() string
}
Sel is the interface for all the functionality provided by selectors.
func Parse ¶
Parse parses a selector. Use `ParseWithPseudoElement` if you need support for pseudo-elements.
func ParseWithPseudoElement ¶
ParseWithPseudoElement parses a single selector, with support for pseudo-element.
type Selector ¶
A Selector is a function which tells whether a node matches or not.
This type is maintained for compatibility; I recommend using the newer and more idiomatic interfaces Sel and Matcher.
func Compile ¶
Compile parses a selector and returns, if successful, a Selector object that can be used to match against html.Node objects.
func MustCompile ¶
MustCompile is like Compile, but panics instead of returning an error.
type SelectorGroup ¶
type SelectorGroup []Sel
A SelectorGroup is a list of selectors, which matches if any of the individual selectors matches.
func ParseGroup ¶
func ParseGroup(sel string) (SelectorGroup, error)
ParseGroup parses a selector, or a group of selectors separated by commas. Use `ParseGroupWithPseudoElements` if you need support for pseudo-elements.
func ParseGroupWithPseudoElements ¶
func ParseGroupWithPseudoElements(sel string) (SelectorGroup, error)
ParseGroupWithPseudoElements parses a selector, or a group of selectors separated by commas. It supports pseudo-elements.
func (SelectorGroup) Match ¶
func (s SelectorGroup) Match(n *html.Node) bool
Match returns true if the node matches one of the single selectors.
func (SelectorGroup) String ¶
func (c SelectorGroup) String() string
type Specificity ¶
type Specificity [3]int
Specificity is the CSS specificity as defined in https://www.w3.org/TR/selectors/#specificity-rules with the convention Specificity = [A,B,C].
func (Specificity) Add ¶
func (s Specificity) Add(other Specificity) Specificity
func (Specificity) Less ¶
func (s Specificity) Less(other Specificity) bool
returns `true` if s < other (strictly), false otherwise
Source Files
Directories