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