长文自动摘要与自动封面：未填时从正文派生——摘要剥语法取开头 110 字（标题行/代码块/图链接剔除），封面取正文第一张图；更新只在「新旧都空」时补，站主主动清空的保得住；保存响应回写编辑器可见

2026-09-29 01:05:46 +08:00
parent 6e6196d68b
commit f7669badf2
4 changed files with 139 additions and 1 deletions
@@ -0,0 +1,68 @@
+// 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——
+// 摘要取正文开头的一段纯文本，封面取正文第一张图。
+// 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。
+package admin
+
+import (
+	"regexp"
+	"strings"
+
+	"oneblog/internal/model"
+)
+
+const autoSummaryLen = 110
+
+var (
+	mdImageRe   = regexp.MustCompile(`!\[[^\]]*\]\(([^)\s]+)[^)]*\)`)
+	mdCodeFence = regexp.MustCompile("(?s)```.*?```")
+	mdLinkRe    = regexp.MustCompile(`\[([^\]]*)\]\([^)]*\)`)
+	mdHeadingRe = regexp.MustCompile(`(?m)^#{1,6}\s+.*$`) // 标题行整行不进摘要（与文章标题重复）
+	mdNoiseRe   = regexp.MustCompile(`(?m)^([>\s*-]+|\d+\.\s)+`)
+	mdEmphasis  = strings.NewReplacer("**", "", "__", "", "~~", "", "*", "", "_", "")
+	wsRe        = regexp.MustCompile(`\s+`)
+)
+
+// autoMeta 按需填充 in.Summary / in.CoverURL。
+// cur 为更新前的旧文章（新建时传 nil）。
+func autoMeta(in *model.PostInput, cur *model.Post) {
+	if in.Kind != model.KindLong || strings.TrimSpace(in.ContentMd) == "" {
+		return
+	}
+	if strings.TrimSpace(in.Summary) == "" && (cur == nil || strings.TrimSpace(cur.Summary) == "") {
+		in.Summary = summarizeMarkdown(in.ContentMd, autoSummaryLen)
+	}
+	if strings.TrimSpace(in.CoverURL) == "" && (cur == nil || strings.TrimSpace(cur.CoverURL) == "") {
+		in.CoverURL = firstImage(in.ContentMd)
+	}
+}
+
+// summarizeMarkdown 剥掉 markdown 语法后取正文开头一段纯文本
+func summarizeMarkdown(md string, maxRunes int) string {
+	s := mdCodeFence.ReplaceAllString(md, " ") // 代码块整段不进摘要
+	s = mdHeadingRe.ReplaceAllString(s, " ")
+	s = mdImageRe.ReplaceAllString(s, " ")
+	s = mdLinkRe.ReplaceAllString(s, "$1")
+	s = mdNoiseRe.ReplaceAllString(s, " ")
+	s = mdEmphasis.Replace(s)
+	s = strings.ReplaceAll(s, "`", "")
+	s = wsRe.ReplaceAllString(s, " ")
+	s = strings.TrimSpace(s)
+	runes := []rune(s)
+	if len(runes) > maxRunes {
+		return string(runes[:maxRunes]) + "…"
+	}
+	return s
+}
+
+// firstImage 取正文第一张图片的地址（markdown 图；http/站内路径均可）
+func firstImage(md string) string {
+	m := mdImageRe.FindStringSubmatch(md)
+	if m == nil {
+		return ""
+	}
+	u := m[1]
+	if strings.HasPrefix(u, "http://") || strings.HasPrefix(u, "https://") || strings.HasPrefix(u, "/uploads/") {
+		return u
+	}
+	return ""
+}