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postrender.go
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postrender.go
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package writefreely
import (
"bytes"
"fmt"
"github.com/microcosm-cc/bluemonday"
stripmd "github.com/writeas/go-strip-markdown"
"github.com/writeas/saturday"
"github.com/writeas/web-core/stringmanip"
"github.com/writeas/writefreely/parse"
"html"
"html/template"
"regexp"
"strings"
"unicode"
"unicode/utf8"
)
var (
blockReg = regexp.MustCompile("<(ul|ol|blockquote)>\n")
endBlockReg = regexp.MustCompile("</([a-z]+)>\n</(ul|ol|blockquote)>")
youtubeReg = regexp.MustCompile("(https?://www.youtube.com/embed/[a-zA-Z0-9\\-_]+)(\\?[^\t\n\f\r \"']+)?")
titleElementReg = regexp.MustCompile("</?h[1-6]>")
hashtagReg = regexp.MustCompile(`#([\p{L}\p{M}\d]+)`)
markeddownReg = regexp.MustCompile("<p>(.+)</p>")
)
func (p *Post) formatContent(c *Collection, isOwner bool) {
baseURL := c.CanonicalURL()
if !isSingleUser {
baseURL = "/" + c.Alias + "/"
}
newCon := hashtagReg.ReplaceAllFunc([]byte(p.Content), func(b []byte) []byte {
// Ensure we only replace "hashtags" that have already been extracted.
// `hashtagReg` catches everything, including any hash on the end of a
// URL, so we rely on p.Tags as the final word on whether or not to link
// a tag.
for _, t := range p.Tags {
if string(b) == "#"+t {
return bytes.Replace(b, []byte("#"+t), []byte("<a href=\""+baseURL+"tag:"+t+"\" class=\"hashtag\"><span>#</span><span class=\"p-category\">"+t+"</span></a>"), -1)
}
}
return b
})
p.HTMLTitle = template.HTML(applyBasicMarkdown([]byte(p.Title.String)))
p.HTMLContent = template.HTML(applyMarkdown([]byte(newCon)))
if exc := strings.Index(string(newCon), "<!--more-->"); exc > -1 {
p.HTMLExcerpt = template.HTML(applyMarkdown([]byte(newCon[:exc])))
}
}
func (p *PublicPost) formatContent(isOwner bool) {
p.Post.formatContent(&p.Collection.Collection, isOwner)
}
func applyMarkdown(data []byte) string {
return applyMarkdownSpecial(data, false)
}
func applyMarkdownSpecial(data []byte, skipNoFollow bool) string {
mdExtensions := 0 |
blackfriday.EXTENSION_TABLES |
blackfriday.EXTENSION_FENCED_CODE |
blackfriday.EXTENSION_AUTOLINK |
blackfriday.EXTENSION_STRIKETHROUGH |
blackfriday.EXTENSION_SPACE_HEADERS |
blackfriday.EXTENSION_AUTO_HEADER_IDS
htmlFlags := 0 |
blackfriday.HTML_USE_SMARTYPANTS |
blackfriday.HTML_SMARTYPANTS_DASHES
// Generate Markdown
md := blackfriday.Markdown([]byte(data), blackfriday.HtmlRenderer(htmlFlags, "", ""), mdExtensions)
// Strip out bad HTML
policy := getSanitizationPolicy()
policy.RequireNoFollowOnLinks(!skipNoFollow)
outHTML := string(policy.SanitizeBytes(md))
// Strip newlines on certain block elements that render with them
outHTML = blockReg.ReplaceAllString(outHTML, "<$1>")
outHTML = endBlockReg.ReplaceAllString(outHTML, "</$1></$2>")
// Remove all query parameters on YouTube embed links
// TODO: make this more specific. Taking the nuclear approach here to strip ?autoplay=1
outHTML = youtubeReg.ReplaceAllString(outHTML, "$1")
return outHTML
}
func applyBasicMarkdown(data []byte) string {
mdExtensions := 0 |
blackfriday.EXTENSION_STRIKETHROUGH |
blackfriday.EXTENSION_SPACE_HEADERS |
blackfriday.EXTENSION_HEADER_IDS
htmlFlags := 0 |
blackfriday.HTML_SKIP_HTML |
blackfriday.HTML_USE_SMARTYPANTS |
blackfriday.HTML_SMARTYPANTS_DASHES
// Generate Markdown
md := blackfriday.Markdown([]byte(data), blackfriday.HtmlRenderer(htmlFlags, "", ""), mdExtensions)
// Strip out bad HTML
policy := bluemonday.UGCPolicy()
policy.AllowAttrs("class", "id").Globally()
outHTML := string(policy.SanitizeBytes(md))
outHTML = markeddownReg.ReplaceAllString(outHTML, "$1")
outHTML = strings.TrimRightFunc(outHTML, unicode.IsSpace)
return outHTML
}
func postTitle(content, friendlyId string) string {
const maxTitleLen = 80
// Strip HTML tags with bluemonday's StrictPolicy, then unescape the HTML
// entities added in by sanitizing the content.
content = html.UnescapeString(bluemonday.StrictPolicy().Sanitize(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 utf8.RuneCountInString(content) <= maxTitleLen {
return content
}
return friendlyId
}
// TODO: fix duplicated code from postTitle. postTitle is a widely used func we
// don't have time to investigate right now.
func friendlyPostTitle(content, friendlyId string) string {
const maxTitleLen = 80
// Strip HTML tags with bluemonday's StrictPolicy, then unescape the HTML
// entities added in by sanitizing the content.
content = html.UnescapeString(bluemonday.StrictPolicy().Sanitize(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 := parse.TruncToWord(parse.PostLede(content, true), maxTitleLen)
if truncd {
title += "..."
}
return title
}
func getSanitizationPolicy() *bluemonday.Policy {
policy := bluemonday.UGCPolicy()
policy.AllowAttrs("src", "style").OnElements("iframe", "video")
policy.AllowAttrs("frameborder", "width", "height").Matching(bluemonday.Integer).OnElements("iframe")
policy.AllowAttrs("allowfullscreen").OnElements("iframe")
policy.AllowAttrs("controls", "loop", "muted", "autoplay").OnElements("video")
policy.AllowAttrs("target").OnElements("a")
policy.AllowAttrs("style", "class", "id").Globally()
policy.AllowURLSchemes("http", "https", "mailto", "xmpp")
return policy
}
func sanitizePost(content string) string {
return strings.Replace(content, "<", "&lt;", -1)
}
// 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 = "Write Freely 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)))
}

File Metadata

Mime Type
text/html
Expires
Sat, Nov 23, 5:49 AM (1 d, 12 h)
Storage Engine
blob
Storage Format
Raw Data
Storage Handle
3104410

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