- // Copyright 2020 The Gitea Authors. All rights reserved.
- // Use of this source code is governed by a MIT-style
- // license that can be found in the LICENSE file.
-
- package markdown
-
- import (
- "errors"
- "strings"
-
- "gopkg.in/yaml.v2"
- )
-
- func isYAMLSeparator(line string) bool {
- line = strings.TrimSpace(line)
- for i := 0; i < len(line); i++ {
- if line[i] != '-' {
- return false
- }
- }
- return len(line) > 2
- }
-
- // ExtractMetadata consumes a markdown file, parses YAML frontmatter,
- // and returns the frontmatter metadata separated from the markdown content
- func ExtractMetadata(contents string, out interface{}) (string, error) {
- var front, body []string
- lines := strings.Split(contents, "\n")
- for idx, line := range lines {
- if idx == 0 {
- // First line has to be a separator
- if !isYAMLSeparator(line) {
- return "", errors.New("frontmatter must start with a separator line")
- }
- continue
- }
- if isYAMLSeparator(line) {
- front, body = lines[1:idx], lines[idx+1:]
- break
- }
- }
-
- if len(front) == 0 {
- return "", errors.New("could not determine metadata")
- }
-
- if err := yaml.Unmarshal([]byte(strings.Join(front, "\n")), out); err != nil {
- return "", err
- }
- return strings.Join(body, "\n"), nil
- }
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