Fix button for uploading OPML

opml.go

@@ -0,0 +1,94 @@
+package main
+
+import "encoding/xml"
+
+type opml struct {
+	Head struct {
+		Title string `xml:"title"`
+	} `xml:"head"`
+	Body Body `xml:"body"`
+}
+
+type Body struct {
+	Outlines []Outline `xml:"outline"`
+}
+
+type Outline struct {
+	Outlines []Outline `xml:"outline"`
+	XmlUrl   string    `xml:"xmlUrl,attr,omitempty"`
+	HtmlUrl  string    `xml:"htmlUrl,attr,omitempty"`
+}
+
+func (o *opml) ParseString(s string) error {
+	return xml.Unmarshal([]byte(s), o)
+}
+
+func (o *opml) String() (string, error) {
+	b, err := xml.Marshal(o)
+	if err != nil {
+		return "", err
+	}
+	return xml.Header + string(b), nil
+}
+
+type linksFromOpml struct {
+	XMLLinks  []string `json:"xmlLinks"`
+	HTMLLinks []string `json:"htmlLinks"`
+}
+
+func removeDuplicates(s []string) []string {
+	seen := make(map[string]struct{}, len(s))
+	j := 0
+	for _, v := range s {
+		if _, ok := seen[v]; ok {
+			continue
+		}
+		seen[v] = struct{}{}
+		s[j] = v
+		j++
+	}
+	return s[:j]
+}
+
+func ParseOpml(s string) (linksFromOpml, error) {
+	// Get all the feeds from the OPML and return them as linksFromOpml
+	opml := &opml{}
+	err := opml.ParseString(s)
+	if err != nil {
+		return linksFromOpml{}, err
+	}
+
+	links := linksFromOpml{}
+	for _, outline := range opml.Body.Outlines {
+		links.XMLLinks = append(links.XMLLinks, outline.XmlUrl)
+		links.HTMLLinks = append(links.HTMLLinks, outline.HtmlUrl)
+	}
+
+	// Also check outlines for nested outlines
+	for _, outline := range opml.Body.Outlines {
+		for _, nestedOutline := range outline.Outlines {
+			links.XMLLinks = append(links.XMLLinks, nestedOutline.XmlUrl)
+			links.HTMLLinks = append(links.HTMLLinks, nestedOutline.HtmlUrl)
+		}
+	}
+
+	// Remove any empty strings
+	for i := 0; i < len(links.XMLLinks); i++ {
+		if links.XMLLinks[i] == "" {
+			links.XMLLinks = append(links.XMLLinks[:i], links.XMLLinks[i+1:]...)
+			i--
+		}
+	}
+	for i := 0; i < len(links.HTMLLinks); i++ {
+		if links.HTMLLinks[i] == "" {
+			links.HTMLLinks = append(links.HTMLLinks[:i], links.HTMLLinks[i+1:]...)
+			i--
+		}
+	}
+
+	// Remove any duplicates
+	links.XMLLinks = removeDuplicates(links.XMLLinks)
+	links.HTMLLinks = removeDuplicates(links.HTMLLinks)
+
+	return links, nil
+}