111 lines
2.7 KiB
Go
111 lines
2.7 KiB
Go
package atom
|
|
|
|
import (
|
|
"encoding/xml"
|
|
"fmt"
|
|
"strings"
|
|
)
|
|
|
|
type Link struct {
|
|
XMLName xml.Name `xml:"link"`
|
|
*CommonAttributes
|
|
Title string `xml:"title,attr,omitempty"`
|
|
Href string `xml:"href,attr"` // IRI
|
|
Rel string `xml:"rel,attr,omitempty"`
|
|
Type string `xml:"type,attr,omitempty"` // MediaType
|
|
HrefLang string `xml:"hreflang,attr,omitempty"` // LanguageTag
|
|
Length uint `xml:"length,attr,omitempty"`
|
|
}
|
|
|
|
// NewLink creates a new Link. It returns a *Link and an error.
|
|
func NewLink(href string) (*Link, error) {
|
|
if !isValidIRI(href) {
|
|
return nil, fmt.Errorf("href %v not correctly formatted", href)
|
|
}
|
|
|
|
return &Link{Href: href}, nil
|
|
}
|
|
|
|
// SetType sets the Type attribute of the Link. It returns an error.
|
|
func (l *Link) SetType(t string) error {
|
|
if !isValidMediaType(t) {
|
|
return fmt.Errorf("type %v invalid media type", t)
|
|
}
|
|
|
|
return nil
|
|
}
|
|
|
|
// SetHrefLang sets the HrefLang attribute of the Link. It returns an error.
|
|
func (l *Link) SetHrefLang(h string) error {
|
|
if !isValidLanguageTag(h) {
|
|
return fmt.Errorf("hreflang %v invalid language tag", h)
|
|
}
|
|
|
|
return nil
|
|
}
|
|
|
|
// Check checks the Link for incompatibilities with RFC4287. It returns an
|
|
// error.
|
|
func (l *Link) Check() error {
|
|
if l.Href == "" {
|
|
return fmt.Errorf("href attribute of link %v empty", l)
|
|
} else {
|
|
if !isValidIRI(l.Href) {
|
|
return fmt.Errorf("href attribute of link %v not correctly formatted", l)
|
|
}
|
|
}
|
|
|
|
if l.Rel != "" {
|
|
if strings.Contains(l.Rel, ":") && !isValidIRI(l.Rel) {
|
|
return fmt.Errorf("rel attribute of link %v not correctly formatted", l)
|
|
}
|
|
}
|
|
|
|
if l.Type != "" {
|
|
if !isValidMediaType(l.Type) {
|
|
return fmt.Errorf("type attribute of link %v invalid media type", l)
|
|
}
|
|
}
|
|
|
|
if l.HrefLang != "" {
|
|
if !isValidLanguageTag(l.HrefLang) {
|
|
return fmt.Errorf("hreflang attribute of link %v invalid language tag", l)
|
|
}
|
|
}
|
|
|
|
return nil
|
|
}
|
|
|
|
// hasAlternateDuplicateLinks checks whether multiple Links with Rel
|
|
// "alternate" also have Type and HrefLang in common. It returns a bool.
|
|
// atom:feed/entry elements MUST NOT contain more than one atom:link element
|
|
// with a rel attribute value of "alternate" that has the same combination of
|
|
// type and hreflang attribute values.
|
|
func hasAlternateDuplicateLinks(l []*Link) bool {
|
|
linkMap := make(map[string]bool)
|
|
|
|
for _, link := range l {
|
|
if link.Rel == "alternate" {
|
|
key := fmt.Sprint(link.Type, "|", link.HrefLang)
|
|
if linkMap[key] {
|
|
return true
|
|
}
|
|
linkMap[key] = true
|
|
}
|
|
}
|
|
|
|
return false
|
|
}
|
|
|
|
// alternateRelExists checks whether multiple Links with Rel "alternate" exist.
|
|
// It returns a bool.
|
|
func alternateRelExists(l []*Link) bool {
|
|
for _, link := range l {
|
|
if link.Rel == "alternate" {
|
|
return true
|
|
}
|
|
}
|
|
|
|
return false
|
|
}
|