Copy post parsing funcs to posts pkg

posts/parse.go

@@ -1,7 +1,24 @@
 package posts
 
 import (
+	"fmt"
+	stripmd "github.com/writeas/go-strip-markdown"
+	"github.com/writeas/web-core/stringmanip"
+	"regexp"
 	"strings"
+	"unicode"
+	"unicode/utf8"
+)
+
+const (
+	maxTitleLen     = 80
+	assumedTitleLen = 80
+)
+
+var (
+	titleElementReg = regexp.MustCompile("</?p>")
+	urlReg          = regexp.MustCompile("https?://")
+	imgReg          = regexp.MustCompile(`!\[([^]]+)\]\([^)]+\)`)
 )
 
 // ExtractTitle takes the given raw post text and returns a title, if explicitly
@@ -19,3 +36,130 @@ func ExtractTitle(content string) (title string, body string) {
 	body = content
 	return
 }
+
+func FriendlyPostTitle(content, friendlyId string) string {
+	content = StripHTMLWithoutEscaping(content)
+
+	content = strings.TrimLeftFunc(stripmd.Strip(content), unicode.IsSpace)
+	eol := strings.IndexRune(content, '\n')
+	blankLine := strings.Index(content, "\n\n")
+	if blankLine != -1 && blankLine <= eol && blankLine <= assumedTitleLen {
+		return strings.TrimSpace(content[:blankLine])
+	} else if eol == -1 && utf8.RuneCountInString(content) <= maxTitleLen {
+		return content
+	}
+
+	title, truncd := TruncToWord(PostLede(content, true), maxTitleLen)
+	if truncd {
+		title += "..."
+	}
+	return title
+}
+
+// PostDescription generates a description based on the given post content,
+// title, and post ID. This doesn't consider a V2 post field, `title` when
+// choosing what to generate. In case a post has a title, this function will
+// fail, and logic should instead be implemented to skip this when there's no
+// title, like so:
+//    var desc string
+//    if title == "" {
+//        desc = PostDescription(content, title, friendlyId)
+//    } else {
+//        desc = ShortPostDescription(content)
+//    }
+func PostDescription(content, title, friendlyId string) string {
+	maxLen := 140
+
+	if content == "" {
+		content = "WriteFreely is a painless, simple, federated blogging platform."
+	} else {
+		fmtStr := "%s"
+		truncation := 0
+		if utf8.RuneCountInString(content) > maxLen {
+			// Post is longer than the max description, so let's show a better description
+			fmtStr = "%s..."
+			truncation = 3
+		}
+
+		if title == friendlyId {
+			// No specific title was found; simply truncate the post, starting at the beginning
+			content = fmt.Sprintf(fmtStr, strings.Replace(stringmanip.Substring(content, 0, maxLen-truncation), "\n", " ", -1))
+		} else {
+			// There was a title, so return a real description
+			blankLine := strings.Index(content, "\n\n")
+			if blankLine < 0 {
+				blankLine = 0
+			}
+			truncd := stringmanip.Substring(content, blankLine, blankLine+maxLen-truncation)
+			contentNoNL := strings.Replace(truncd, "\n", " ", -1)
+			content = strings.TrimSpace(fmt.Sprintf(fmtStr, contentNoNL))
+		}
+	}
+
+	return content
+}
+
+func ShortPostDescription(content string) string {
+	maxLen := 140
+	fmtStr := "%s"
+	truncation := 0
+	if utf8.RuneCountInString(content) > maxLen {
+		// Post is longer than the max description, so let's show a better description
+		fmtStr = "%s..."
+		truncation = 3
+	}
+	return strings.TrimSpace(fmt.Sprintf(fmtStr, strings.Replace(stringmanip.Substring(content, 0, maxLen-truncation), "\n", " ", -1)))
+}
+
+// TruncToWord truncates the given text to the provided limit.
+func TruncToWord(s string, l int) (string, bool) {
+	truncated := false
+	c := []rune(s)
+	if len(c) > l {
+		truncated = true
+		s = string(c[:l])
+		spaceIdx := strings.LastIndexByte(s, ' ')
+		if spaceIdx > -1 {
+			s = s[:spaceIdx]
+		}
+	}
+	return s, truncated
+}
+
+// PostLede attempts to extract the first thought of the given post, generally
+// contained within the first line or sentence of text.
+func PostLede(t string, includePunc bool) string {
+	// Adjust where we truncate if we want to include punctuation
+	iAdj := 0
+	if includePunc {
+		iAdj = 1
+	}
+
+	// Find lede within first line of text
+	nl := strings.IndexRune(t, '\n')
+	if nl > -1 {
+		t = t[:nl]
+	}
+
+	// Strip certain HTML tags
+	t = titleElementReg.ReplaceAllString(t, "")
+
+	// Strip URL protocols
+	t = urlReg.ReplaceAllString(t, "")
+
+	// Strip image URL, leaving only alt text
+	t = imgReg.ReplaceAllString(t, " $1 ")
+
+	// Find lede within first sentence
+	punc := strings.Index(t, ". ")
+	if punc > -1 {
+		t = t[:punc+iAdj]
+	}
+	punc = stringmanip.IndexRune(t, '。')
+	if punc > -1 {
+		c := []rune(t)
+		t = string(c[:punc+iAdj])
+	}
+
+	return t
+}

posts/render.go

@@ -3,6 +3,7 @@ package posts
 import (
 	"github.com/microcosm-cc/bluemonday"
 	"github.com/writeas/saturday"
+	"html"
 	"regexp"
 	"strings"
 	"unicode"
@@ -61,3 +62,9 @@ func ApplyBasicMarkdown(data []byte) string {
 
 	return outHTML
 }
+
+// StripHTMLWithoutEscaping strips HTML tags with bluemonday's StrictPolicy, then unescapes the HTML
+// entities added in by sanitizing the content.
+func StripHTMLWithoutEscaping(content string) string {
+	return html.UnescapeString(bluemonday.StrictPolicy().Sanitize(content))
+}