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package converter
import (
"net/url"
"strings"
)
var percentEncodingReplacer = strings.NewReplacer(
" ", "%20",
"[", "%5B",
"]", "%5D",
"(", "%28",
")", "%29",
"<", "%3C",
">", "%3E",
)
func parseBaseDomain(rawDomain string) *url.URL {
if rawDomain == "" {
return nil
}
u1, err := url.Parse(rawDomain)
if err == nil && u1.Host != "" {
// Yes, we got valid domain (probably with a http/https scheme)
return u1
}
u2, err := url.Parse("http://" + rawDomain)
if err == nil && u2.Host != "" {
// Yes, we got a valid domain (by choosing a fallback scheme)
return u2
}
return nil
}
func defaultAssembleAbsoluteURL(tagName string, rawURL string, domain string) string {
rawURL = strings.TrimSpace(rawURL)
if rawURL == "#" {
// Golangs url.Parse does not seem to distinguish between
// no fragment and an empty fragment.
return rawURL
}
// Increase the chance that the url will be parsed
rawURL = strings.ReplaceAll(rawURL, "\n", "%0A")
rawURL = strings.ReplaceAll(rawURL, "\t", "%09")
u, err := url.Parse(rawURL)
if err != nil {
// We can't do anything with this url because it is invalid
return percentEncodingReplacer.Replace(rawURL)
}
if u.Scheme == "data" {
// This is a data uri (for example an inline base64 image)
return percentEncodingReplacer.Replace(rawURL)
}
// The default Query().Encode() encodes the query parameters "sorted by key".
// Instead we want to keep the original order, but still encode the parameters.
u.RawQuery = ParseAndEncodeQuery(u.RawQuery)
// For better compatibility (especially in regards to mailto links),
// instead of encoding a space with a "+" we use ""%20" to prevent
// e.g. the email reading "Hi+Johannes" instead of "Hi Johannes"
u.RawQuery = strings.ReplaceAll(u.RawQuery, "+", "%20")
if base := parseBaseDomain(domain); base != nil {
// If a "domain" is provided, we use that to convert relative links
// to absolute links.
u = base.ResolveReference(u)
}
return percentEncodingReplacer.Replace(u.String())
}
// - - - - //
func decodeAndEncode(original string) string {
s, err := url.QueryUnescape(original)
if err != nil {
return original
}
return url.QueryEscape(s)
}
func ParseAndEncodeQuery(rawQuery string) string {
if rawQuery == "" {
return ""
}
rawParts := strings.Split(rawQuery, "&")
encodedParts := make([]string, len(rawParts))
for i, part := range rawParts {
splitted := strings.SplitN(part, "=", 2)
if len(splitted) == 1 {
// A: Just the key
encodedParts[i] = decodeAndEncode(splitted[0])
} else if splitted[1] == "" {
// B: The key and the equal sign
encodedParts[i] = decodeAndEncode(splitted[0]) + "="
} else {
// C: The key and the equal sign and the value
encodedParts[i] = decodeAndEncode(splitted[0]) + "=" + decodeAndEncode(splitted[1])
}
}
return strings.Join(encodedParts, "&")
}
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