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