77 lines
1.7 KiB
Go
77 lines
1.7 KiB
Go
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package resolver
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import (
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"encoding/base64"
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"fmt"
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"net/url"
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"strings"
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)
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type DataURL struct {
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mimeType string
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data string
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isBase64 bool
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}
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func ParseDataURL(url string) (parsed DataURL, ok bool) {
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if strings.HasPrefix(url, "data:") {
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if comma := strings.IndexByte(url, ','); comma != -1 {
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parsed.mimeType = url[len("data:"):comma]
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parsed.data = url[comma+1:]
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if strings.HasSuffix(parsed.mimeType, ";base64") {
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parsed.mimeType = parsed.mimeType[:len(parsed.mimeType)-len(";base64")]
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parsed.isBase64 = true
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}
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ok = true
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}
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}
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return
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}
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type MIMEType uint8
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const (
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MIMETypeUnsupported MIMEType = iota
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MIMETypeTextCSS
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MIMETypeTextJavaScript
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MIMETypeApplicationJSON
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)
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func (parsed DataURL) DecodeMIMEType() MIMEType {
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// Remove things like ";charset=utf-8"
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mimeType := parsed.mimeType
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if semicolon := strings.IndexByte(mimeType, ';'); semicolon != -1 {
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mimeType = mimeType[:semicolon]
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}
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// Hard-code a few supported types
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switch mimeType {
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case "text/css":
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return MIMETypeTextCSS
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case "text/javascript":
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return MIMETypeTextJavaScript
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case "application/json":
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return MIMETypeApplicationJSON
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default:
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return MIMETypeUnsupported
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}
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}
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func (parsed DataURL) DecodeData() (string, error) {
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// Try to read base64 data
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if parsed.isBase64 {
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bytes, err := base64.StdEncoding.DecodeString(parsed.data)
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if err != nil {
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return "", fmt.Errorf("could not decode base64 data: %s", err.Error())
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}
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return string(bytes), nil
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}
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// Try to read percent-escaped data
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content, err := url.PathUnescape(parsed.data)
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if err != nil {
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return "", fmt.Errorf("could not decode percent-escaped data: %s", err.Error())
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}
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return content, nil
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}
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