69 lines
2.3 KiB
Go
69 lines
2.3 KiB
Go
// 长文的自动摘要与自动封面：站主没填这两项时从正文派生——
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// 摘要取正文开头的一段纯文本，封面取正文第一张图。
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// 更新路径只在「新值与旧值都为空」时才生成，站主主动清空的要保得住。
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package admin
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import (
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"regexp"
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"strings"
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"oneblog/internal/model"
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)
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const autoSummaryLen = 110
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var (
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mdImageRe = regexp.MustCompile(`!\[[^\]]*\]\(([^)\s]+)[^)]*\)`)
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mdCodeFence = regexp.MustCompile("(?s)```.*?```")
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mdLinkRe = regexp.MustCompile(`\[([^\]]*)\]\([^)]*\)`)
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mdHeadingRe = regexp.MustCompile(`(?m)^#{1,6}\s+.*$`) // 标题行整行不进摘要（与文章标题重复）
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mdNoiseRe = regexp.MustCompile(`(?m)^([>\s*-]+|\d+\.\s)+`)
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mdEmphasis = strings.NewReplacer("**", "", "__", "", "~~", "", "*", "", "_", "")
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wsRe = regexp.MustCompile(`\s+`)
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)
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// autoMeta 按需填充 in.Summary / in.CoverURL。
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// cur 为更新前的旧文章（新建时传 nil）。
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func autoMeta(in *model.PostInput, cur *model.Post) {
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if in.Kind != model.KindLong || strings.TrimSpace(in.ContentMd) == "" {
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return
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}
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if strings.TrimSpace(in.Summary) == "" && (cur == nil || strings.TrimSpace(cur.Summary) == "") {
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in.Summary = summarizeMarkdown(in.ContentMd, autoSummaryLen)
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}
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if strings.TrimSpace(in.CoverURL) == "" && (cur == nil || strings.TrimSpace(cur.CoverURL) == "") {
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in.CoverURL = firstImage(in.ContentMd)
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}
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}
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// summarizeMarkdown 剥掉 markdown 语法后取正文开头一段纯文本
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func summarizeMarkdown(md string, maxRunes int) string {
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s := mdCodeFence.ReplaceAllString(md, " ") // 代码块整段不进摘要
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s = mdHeadingRe.ReplaceAllString(s, " ")
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s = mdImageRe.ReplaceAllString(s, " ")
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s = mdLinkRe.ReplaceAllString(s, "$1")
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s = mdNoiseRe.ReplaceAllString(s, " ")
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s = mdEmphasis.Replace(s)
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s = strings.ReplaceAll(s, "`", "")
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s = wsRe.ReplaceAllString(s, " ")
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s = strings.TrimSpace(s)
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runes := []rune(s)
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if len(runes) > maxRunes {
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return string(runes[:maxRunes]) + "…"
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}
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return s
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}
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// firstImage 取正文第一张图片的地址（markdown 图；http/站内路径均可）
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func firstImage(md string) string {
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m := mdImageRe.FindStringSubmatch(md)
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if m == nil {
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return ""
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}
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u := m[1]
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if strings.HasPrefix(u, "http://") || strings.HasPrefix(u, "https://") || strings.HasPrefix(u, "/uploads/") {
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return u
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}
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return ""
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}
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