rss-tools/vendor/github.com/andybalholm/cascadia/README.md (view raw)
| 1 | # cascadia |
| 2 | |
| 3 | [](https://travis-ci.org/andybalholm/cascadia) |
| 4 | |
| 5 | The Cascadia package implements CSS selectors for use with the parse trees produced by the html package. |
| 6 | |
| 7 | To test CSS selectors without writing Go code, check out [cascadia](https://github.com/suntong/cascadia) the command line tool, a thin wrapper around this package. |
| 8 | |
| 9 | [Refer to godoc here](https://godoc.org/github.com/andybalholm/cascadia). |
| 10 | |
| 11 | ## Example |
| 12 | |
| 13 | The following is an example of how you can use Cascadia. |
| 14 | |
| 15 | ```go |
| 16 | package main |
| 17 | |
| 18 | import ( |
| 19 | "fmt" |
| 20 | "log" |
| 21 | "strings" |
| 22 | |
| 23 | "github.com/andybalholm/cascadia" |
| 24 | "golang.org/x/net/html" |
| 25 | ) |
| 26 | |
| 27 | var pricingHtml string = ` |
| 28 | <div class="card mb-4 box-shadow"> |
| 29 | <div class="card-header"> |
| 30 | <h4 class="my-0 font-weight-normal">Free</h4> |
| 31 | </div> |
| 32 | <div class="card-body"> |
| 33 | <h1 class="card-title pricing-card-title">$0/mo</h1> |
| 34 | <ul class="list-unstyled mt-3 mb-4"> |
| 35 | <li>10 users included</li> |
| 36 | <li>2 GB of storage</li> |
| 37 | <li><a href="https://example.com">See more</a></li> |
| 38 | </ul> |
| 39 | </div> |
| 40 | </div> |
| 41 | |
| 42 | <div class="card mb-4 box-shadow"> |
| 43 | <div class="card-header"> |
| 44 | <h4 class="my-0 font-weight-normal">Pro</h4> |
| 45 | </div> |
| 46 | <div class="card-body"> |
| 47 | <h1 class="card-title pricing-card-title">$15/mo</h1> |
| 48 | <ul class="list-unstyled mt-3 mb-4"> |
| 49 | <li>20 users included</li> |
| 50 | <li>10 GB of storage</li> |
| 51 | <li><a href="https://example.com">See more</a></li> |
| 52 | </ul> |
| 53 | </div> |
| 54 | </div> |
| 55 | |
| 56 | <div class="card mb-4 box-shadow"> |
| 57 | <div class="card-header"> |
| 58 | <h4 class="my-0 font-weight-normal">Enterprise</h4> |
| 59 | </div> |
| 60 | <div class="card-body"> |
| 61 | <h1 class="card-title pricing-card-title">$29/mo</h1> |
| 62 | <ul class="list-unstyled mt-3 mb-4"> |
| 63 | <li>30 users included</li> |
| 64 | <li>15 GB of storage</li> |
| 65 | <li><a>See more</a></li> |
| 66 | </ul> |
| 67 | </div> |
| 68 | </div> |
| 69 | ` |
| 70 | |
| 71 | func Query(n *html.Node, query string) *html.Node { |
| 72 | sel, err := cascadia.Parse(query) |
| 73 | if err != nil { |
| 74 | return &html.Node{} |
| 75 | } |
| 76 | return cascadia.Query(n, sel) |
| 77 | } |
| 78 | |
| 79 | func QueryAll(n *html.Node, query string) []*html.Node { |
| 80 | sel, err := cascadia.Parse(query) |
| 81 | if err != nil { |
| 82 | return []*html.Node{} |
| 83 | } |
| 84 | return cascadia.QueryAll(n, sel) |
| 85 | } |
| 86 | |
| 87 | func AttrOr(n *html.Node, attrName, or string) string { |
| 88 | for _, a := range n.Attr { |
| 89 | if a.Key == attrName { |
| 90 | return a.Val |
| 91 | } |
| 92 | } |
| 93 | return or |
| 94 | } |
| 95 | |
| 96 | func main() { |
| 97 | doc, err := html.Parse(strings.NewReader(pricingHtml)) |
| 98 | if err != nil { |
| 99 | log.Fatal(err) |
| 100 | } |
| 101 | fmt.Printf("List of pricing plans:\n\n") |
| 102 | for i, p := range QueryAll(doc, "div.card.mb-4.box-shadow") { |
| 103 | planName := Query(p, "h4").FirstChild.Data |
| 104 | price := Query(p, ".pricing-card-title").FirstChild.Data |
| 105 | usersIncluded := Query(p, "li:first-child").FirstChild.Data |
| 106 | storage := Query(p, "li:nth-child(2)").FirstChild.Data |
| 107 | detailsUrl := AttrOr(Query(p, "li:last-child a"), "href", "(No link available)") |
| 108 | fmt.Printf( |
| 109 | "Plan #%d\nName: %s\nPrice: %s\nUsers: %s\nStorage: %s\nDetails: %s\n\n", |
| 110 | i+1, |
| 111 | planName, |
| 112 | price, |
| 113 | usersIncluded, |
| 114 | storage, |
| 115 | detailsUrl, |
| 116 | ) |
| 117 | } |
| 118 | } |
| 119 | ``` |
| 120 | The output is: |
| 121 | ``` |
| 122 | List of pricing plans: |
| 123 | |
| 124 | Plan #1 |
| 125 | Name: Free |
| 126 | Price: $0/mo |
| 127 | Users: 10 users included |
| 128 | Storage: 2 GB of storage |
| 129 | Details: https://example.com |
| 130 | |
| 131 | Plan #2 |
| 132 | Name: Pro |
| 133 | Price: $15/mo |
| 134 | Users: 20 users included |
| 135 | Storage: 10 GB of storage |
| 136 | Details: https://example.com |
| 137 | |
| 138 | Plan #3 |
| 139 | Name: Enterprise |
| 140 | Price: $29/mo |
| 141 | Users: 30 users included |
| 142 | Storage: 15 GB of storage |
| 143 | Details: (No link available) |
| 144 | ``` |