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utils.go
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/
utils.go
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package archiver
import (
"encoding/base64"
"fmt"
"net/url"
"regexp"
"strings"
)
var (
rxStyleURL = regexp.MustCompile(`(?i)^url\((.+)\)$`)
)
// isValidURL checks if URL is valid.
func isValidURL(s string) bool {
_, err := url.ParseRequestURI(s)
return err == nil
}
// createAbsoluteURL convert url to absolute path based on base.
func createAbsoluteURL(uri string, base *url.URL) string {
uri = strings.TrimSpace(uri)
if uri == "" || base == nil {
return ""
}
// If it is data url, return as it is
if strings.HasPrefix(uri, "data:") {
return uri
}
// If it is fragment path, return as it is
if strings.HasPrefix(uri, "#") {
return uri
}
// If it is already an absolute URL, clean the URL then return it
tmp, err := url.ParseRequestURI(uri)
if err == nil && tmp.Scheme != "" && tmp.Hostname() != "" {
cleanURL(tmp)
return tmp.String()
}
// Otherwise, resolve against base URL.
tmp, err = url.Parse(uri)
if err != nil {
return uri
}
cleanURL(tmp)
return base.ResolveReference(tmp).String()
}
// cleanURL removes URL fragment (#fragment)
func cleanURL(uri *url.URL) {
uri.Fragment = ""
}
// sanitizeStyleURL sanitizes the URL in CSS by removing `url()`,
// quotation mark and trailing slash
func sanitizeStyleURL(uri string) string {
cssURL := rxStyleURL.ReplaceAllString(uri, "$1")
cssURL = strings.TrimSpace(cssURL)
if strings.HasPrefix(cssURL, `"`) {
return strings.Trim(cssURL, `"`)
}
if strings.HasPrefix(cssURL, `'`) {
return strings.Trim(cssURL, `'`)
}
return cssURL
}
// createDataURL returns base64 encoded data URL
func createDataURL(content []byte, contentType string) string {
b64encoded := base64.StdEncoding.EncodeToString(content)
return fmt.Sprintf("data:%s;base64,%s", contentType, b64encoded)
}