Refactor Atom parser to use an adapter

internal/reader/atom/atom_common.go

@@ -3,77 +3,91 @@
 
 package atom // import "miniflux.app/v2/internal/reader/atom"
 
-import "strings"
+import (
+	"strings"
+)
 
-type atomPerson struct {
-	Name  string `xml:"name"`
+// Specs: https://datatracker.ietf.org/doc/html/rfc4287#section-3.2
+type AtomPerson struct {
+	// The "atom:name" element's content conveys a human-readable name for the author.
+	// It MAY be the name of a corporation or other entity no individual authors can be named.
+	// Person constructs MUST contain exactly one "atom:name" element, whose content MUST be a string.
+	Name string `xml:"name"`
+
+	// The "atom:email" element's content conveys an e-mail address associated with the Person construct.
+	// Person constructs MAY contain an atom:email element, but MUST NOT contain more than one.
+	// Its content MUST be an e-mail address [RFC2822].
+	// Ordering of the element children of Person constructs MUST NOT be considered significant.
 	Email string `xml:"email"`
 }
 
-func (a *atomPerson) String() string {
-	name := ""
-
-	switch {
-	case a.Name != "":
-		name = a.Name
-	case a.Email != "":
-		name = a.Email
+func (a *AtomPerson) PersonName() string {
+	name := strings.TrimSpace(a.Name)
+	if name != "" {
+		return name
 	}
 
-	return strings.TrimSpace(name)
+	return strings.TrimSpace(a.Email)
 }
 
-type atomAuthors []*atomPerson
+type AtomPersons []*AtomPerson
 
-func (a atomAuthors) String() string {
-	var authors []string
+func (a AtomPersons) PersonNames() []string {
+	var names []string
+	authorNamesMap := make(map[string]bool)
 
 	for _, person := range a {
-		authors = append(authors, person.String())
+		personName := person.PersonName()
+		if _, ok := authorNamesMap[personName]; !ok {
+			names = append(names, personName)
+			authorNamesMap[personName] = true
+		}
 	}
 
-	return strings.Join(authors, ", ")
+	return names
 }
 
-type atomLink struct {
-	URL    string `xml:"href,attr"`
+// Specs: https://datatracker.ietf.org/doc/html/rfc4287#section-4.2.7
+type AtomLink struct {
+	Href   string `xml:"href,attr"`
 	Type   string `xml:"type,attr"`
 	Rel    string `xml:"rel,attr"`
 	Length string `xml:"length,attr"`
+	Title  string `xml:"title,attr"`
 }
 
-type atomLinks []*atomLink
+type AtomLinks []*AtomLink
 
-func (a atomLinks) originalLink() string {
+func (a AtomLinks) OriginalLink() string {
 	for _, link := range a {
 		if strings.EqualFold(link.Rel, "alternate") {
-			return strings.TrimSpace(link.URL)
+			return strings.TrimSpace(link.Href)
 		}
 
 		if link.Rel == "" && (link.Type == "" || link.Type == "text/html") {
-			return strings.TrimSpace(link.URL)
+			return strings.TrimSpace(link.Href)
 		}
 	}
 
 	return ""
 }
 
-func (a atomLinks) firstLinkWithRelation(relation string) string {
+func (a AtomLinks) firstLinkWithRelation(relation string) string {
 	for _, link := range a {
 		if strings.EqualFold(link.Rel, relation) {
-			return strings.TrimSpace(link.URL)
+			return strings.TrimSpace(link.Href)
 		}
 	}
 
 	return ""
 }
 
-func (a atomLinks) firstLinkWithRelationAndType(relation string, contentTypes ...string) string {
+func (a AtomLinks) firstLinkWithRelationAndType(relation string, contentTypes ...string) string {
 	for _, link := range a {
 		if strings.EqualFold(link.Rel, relation) {
 			for _, contentType := range contentTypes {
 				if strings.EqualFold(link.Type, contentType) {
-					return strings.TrimSpace(link.URL)
+					return strings.TrimSpace(link.Href)
 				}
 			}
 		}
@@ -81,3 +95,46 @@ func (a atomLinks) firstLinkWithRelationAndType(relation string, contentTypes ..
 
 	return ""
 }
+
+// The "atom:category" element conveys information about a category
+// associated with an entry or feed.  This specification assigns no
+// meaning to the content (if any) of this element.
+//
+// Specs: https://datatracker.ietf.org/doc/html/rfc4287#section-4.2.2
+type AtomCategory struct {
+	// The "term" attribute is a string that identifies the category to
+	// which the entry or feed belongs. Category elements MUST have a
+	// "term" attribute.
+	Term string `xml:"term,attr"`
+
+	// The "scheme" attribute is an IRI that identifies a categorization
+	// scheme. Category elements MAY have a "scheme" attribute.
+	Scheme string `xml:"scheme,attr"`
+
+	// The "label" attribute provides a human-readable label for display in
+	// end-user applications. The content of the "label" attribute is
+	// Language-Sensitive. Entities such as "&" and "<" represent
+	// their corresponding characters ("&" and "<", respectively), not
+	// markup. Category elements MAY have a "label" attribute.
+	Label string `xml:"label,attr"`
+}
+
+type AtomCategories []AtomCategory
+
+func (ac AtomCategories) CategoryNames() []string {
+	var categories []string
+
+	for _, category := range ac {
+		label := strings.TrimSpace(category.Label)
+		if label != "" {
+			categories = append(categories, label)
+		} else {
+			term := strings.TrimSpace(category.Term)
+			if term != "" {
+				categories = append(categories, term)
+			}
+		}
+	}
+
+	return categories
+}