/* * Copyright © 2018 A Bunch Tell LLC. * * This file is part of WriteFreely. * * WriteFreely is free software: you can redistribute it and/or modify * it under the terms of the GNU Affero General Public License, included * in the LICENSE file in this source code package. */ package writefreely import ( "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/config" "github.com/writeas/writefreely/parse" "html" "html/template" "regexp" "strings" "unicode" "unicode/utf8" ) var ( blockReg = regexp.MustCompile("<(ul|ol|blockquote)>\n") endBlockReg = regexp.MustCompile("\n") youtubeReg = regexp.MustCompile("(https?://www.youtube.com/embed/[a-zA-Z0-9\\-_]+)(\\?[^\t\n\f\r \"']+)?") titleElementReg = regexp.MustCompile("") hashtagReg = regexp.MustCompile(`{{\[\[\|\|([^|]+)\|\|\]\]}}`) markeddownReg = regexp.MustCompile("

(.+)

") ) func (p *Post) formatContent(cfg *config.Config, c *Collection, isOwner bool) { baseURL := c.CanonicalURL() if !isSingleUser { baseURL = "/" + c.Alias + "/" } p.HTMLTitle = template.HTML(applyBasicMarkdown([]byte(p.Title.String))) p.HTMLContent = template.HTML(applyMarkdown([]byte(p.Content), baseURL, cfg)) if exc := strings.Index(string(p.Content), ""); exc > -1 { p.HTMLExcerpt = template.HTML(applyMarkdown([]byte(p.Content[:exc]), baseURL, cfg)) } } func (p *PublicPost) formatContent(cfg *config.Config, isOwner bool) { p.Post.formatContent(cfg, &p.Collection.Collection, isOwner) } func applyMarkdown(data []byte, baseURL string, cfg *config.Config) string { return applyMarkdownSpecial(data, false, baseURL, cfg) } func applyMarkdownSpecial(data []byte, skipNoFollow bool, baseURL string, cfg *config.Config) 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 if baseURL != "" { htmlFlags |= blackfriday.HTML_HASHTAGS } // Generate Markdown md := blackfriday.Markdown([]byte(data), blackfriday.HtmlRenderer(htmlFlags, "", ""), mdExtensions) if baseURL != "" { // Replace special text generated by Markdown parser tagPrefix := baseURL + "tag:" if cfg.App.Chorus { tagPrefix = "/read/t/" } md = []byte(hashtagReg.ReplaceAll(md, []byte("#$1"))) } // 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, "") // 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", "audio") policy.AllowAttrs("src", "type").OnElements("source") 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("controls", "loop", "muted", "autoplay", "preload").OnElements("audio") 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, "<", "<", -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 = "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))) }