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Diffstat (limited to 'modules/markdown/markdown.go')
-rw-r--r-- | modules/markdown/markdown.go | 369 |
1 files changed, 369 insertions, 0 deletions
diff --git a/modules/markdown/markdown.go b/modules/markdown/markdown.go new file mode 100644 index 0000000000..aad0553afe --- /dev/null +++ b/modules/markdown/markdown.go @@ -0,0 +1,369 @@ +// Copyright 2014 The Gogs Authors. All rights reserved. +// Use of this source code is governed by a MIT-style +// license that can be found in the LICENSE file. + +package markdown + +import ( + "bytes" + "fmt" + "io" + "path" + "path/filepath" + "regexp" + "strings" + + "github.com/Unknwon/com" + "github.com/microcosm-cc/bluemonday" + "github.com/russross/blackfriday" + "golang.org/x/net/html" + + "github.com/gogits/gogs/modules/base" + "github.com/gogits/gogs/modules/setting" +) + +var Sanitizer = bluemonday.UGCPolicy() + +// BuildSanitizer initializes sanitizer with allowed attributes based on settings. +// This function should only be called once during entire application lifecycle. +func BuildSanitizer() { + // Normal markdown-stuff + Sanitizer.AllowAttrs("class").Matching(regexp.MustCompile(`[\p{L}\p{N}\s\-_',:\[\]!\./\\\(\)&]*`)).OnElements("code") + + // Checkboxes + Sanitizer.AllowAttrs("type").Matching(regexp.MustCompile(`^checkbox$`)).OnElements("input") + Sanitizer.AllowAttrs("checked", "disabled").OnElements("input") + + // Custom URL-Schemes + Sanitizer.AllowURLSchemes(setting.Markdown.CustomURLSchemes...) +} + +var validLinksPattern = regexp.MustCompile(`^[a-z][\w-]+://`) + +// isLink reports whether link fits valid format. +func isLink(link []byte) bool { + return validLinksPattern.Match(link) +} + +// IsMarkdownFile reports whether name looks like a Markdown file +// based on its extension. +func IsMarkdownFile(name string) bool { + name = strings.ToLower(name) + switch filepath.Ext(name) { + case ".md", ".markdown", ".mdown", ".mkd": + return true + } + return false +} + +// IsReadmeFile reports whether name looks like a README file +// based on its extension. +func IsReadmeFile(name string) bool { + name = strings.ToLower(name) + if len(name) < 6 { + return false + } else if len(name) == 6 { + return name == "readme" + } + return name[:7] == "readme." +} + +var ( + // MentionPattern matches string that mentions someone, e.g. @Unknwon + MentionPattern = regexp.MustCompile(`(\s|^)@[0-9a-zA-Z_\.]+`) + + // CommitPattern matches link to certain commit with or without trailing hash, + // e.g. https://try.gogs.io/gogs/gogs/commit/d8a994ef243349f321568f9e36d5c3f444b99cae#diff-2 + CommitPattern = regexp.MustCompile(`(\s|^)https?.*commit/[0-9a-zA-Z]+(#+[0-9a-zA-Z-]*)?`) + + // IssueFullPattern matches link to an issue with or without trailing hash, + // e.g. https://try.gogs.io/gogs/gogs/issues/4#issue-685 + IssueFullPattern = regexp.MustCompile(`(\s|^)https?.*issues/[0-9]+(#+[0-9a-zA-Z-]*)?`) + // IssueIndexPattern matches string that references to an issue, e.g. #1287 + IssueIndexPattern = regexp.MustCompile(`( |^|\()#[0-9]+\b`) + + // Sha1CurrentPattern matches string that represents a commit SHA, e.g. d8a994ef243349f321568f9e36d5c3f444b99cae + Sha1CurrentPattern = regexp.MustCompile(`\b[0-9a-f]{40}\b`) +) + +// Renderer is a extended version of underlying render object. +type Renderer struct { + blackfriday.Renderer + urlPrefix string +} + +// Link defines how formal links should be processed to produce corresponding HTML elements. +func (r *Renderer) Link(out *bytes.Buffer, link []byte, title []byte, content []byte) { + if len(link) > 0 && !isLink(link) { + if link[0] != '#' { + link = []byte(path.Join(r.urlPrefix, string(link))) + } + } + + r.Renderer.Link(out, link, title, content) +} + +// AutoLink defines how auto-detected links should be processed to produce corresponding HTML elements. +// Reference for kind: https://github.com/russross/blackfriday/blob/master/markdown.go#L69-L76 +func (r *Renderer) AutoLink(out *bytes.Buffer, link []byte, kind int) { + if kind != blackfriday.LINK_TYPE_NORMAL { + r.Renderer.AutoLink(out, link, kind) + return + } + + // Since this method could only possibly serve one link at a time, + // we do not need to find all. + m := CommitPattern.Find(link) + if m != nil { + m = bytes.TrimSpace(m) + i := strings.Index(string(m), "commit/") + j := strings.Index(string(m), "#") + if j == -1 { + j = len(m) + } + out.WriteString(fmt.Sprintf(` <code><a href="%s">%s</a></code>`, m, base.ShortSha(string(m[i+7:j])))) + return + } + + m = IssueFullPattern.Find(link) + if m != nil { + m = bytes.TrimSpace(m) + i := strings.Index(string(m), "issues/") + j := strings.Index(string(m), "#") + if j == -1 { + j = len(m) + } + out.WriteString(fmt.Sprintf(` <a href="%s">#%s</a>`, m, base.ShortSha(string(m[i+7:j])))) + return + } + + r.Renderer.AutoLink(out, link, kind) +} + +// ListItem defines how list items should be processed to produce corresponding HTML elements. +func (options *Renderer) ListItem(out *bytes.Buffer, text []byte, flags int) { + // Detect procedures to draw checkboxes. + switch { + case bytes.HasPrefix(text, []byte("[ ] ")): + text = append([]byte(`<input type="checkbox" disabled="" />`), text[3:]...) + case bytes.HasPrefix(text, []byte("[x] ")): + text = append([]byte(`<input type="checkbox" disabled="" checked="" />`), text[3:]...) + } + options.Renderer.ListItem(out, text, flags) +} + +// Note: this section is for purpose of increase performance and +// reduce memory allocation at runtime since they are constant literals. +var ( + svgSuffix = []byte(".svg") + svgSuffixWithMark = []byte(".svg?") + spaceBytes = []byte(" ") + spaceEncodedBytes = []byte("%20") +) + +// Image defines how images should be processed to produce corresponding HTML elements. +func (r *Renderer) Image(out *bytes.Buffer, link []byte, title []byte, alt []byte) { + prefix := strings.Replace(r.urlPrefix, "/src/", "/raw/", 1) + if len(link) > 0 { + if isLink(link) { + // External link with .svg suffix usually means CI status. + // TODO: define a keyword to allow non-svg images render as external link. + if bytes.HasSuffix(link, svgSuffix) || bytes.Contains(link, svgSuffixWithMark) { + r.Renderer.Image(out, link, title, alt) + return + } + } else { + if link[0] != '/' { + prefix += "/" + } + link = bytes.Replace([]byte((prefix + string(link))), spaceBytes, spaceEncodedBytes, -1) + fmt.Println(333, string(link)) + } + } + + out.WriteString(`<a href="`) + out.Write(link) + out.WriteString(`">`) + r.Renderer.Image(out, link, title, alt) + out.WriteString("</a>") +} + +// cutoutVerbosePrefix cutouts URL prefix including sub-path to +// return a clean unified string of request URL path. +func cutoutVerbosePrefix(prefix string) string { + count := 0 + for i := 0; i < len(prefix); i++ { + if prefix[i] == '/' { + count++ + } + if count >= 3+setting.AppSubUrlDepth { + return prefix[:i] + } + } + return prefix +} + +// RenderIssueIndexPattern renders issue indexes to corresponding links. +func RenderIssueIndexPattern(rawBytes []byte, urlPrefix string, metas map[string]string) []byte { + urlPrefix = cutoutVerbosePrefix(urlPrefix) + ms := IssueIndexPattern.FindAll(rawBytes, -1) + for _, m := range ms { + var space string + if m[0] != '#' { + space = string(m[0]) + m = m[1:] + } + if metas == nil { + rawBytes = bytes.Replace(rawBytes, m, []byte(fmt.Sprintf(`%s<a href="%s/issues/%s">%s</a>`, + space, urlPrefix, m[1:], m)), 1) + } else { + // Support for external issue tracker + metas["index"] = string(m[1:]) + rawBytes = bytes.Replace(rawBytes, m, []byte(fmt.Sprintf(`%s<a href="%s">%s</a>`, + space, com.Expand(metas["format"], metas), m)), 1) + } + } + return rawBytes +} + +// RenderSha1CurrentPattern renders SHA1 strings to corresponding links that assumes in the same repository. +func RenderSha1CurrentPattern(rawBytes []byte, urlPrefix string) []byte { + ms := Sha1CurrentPattern.FindAll(rawBytes, -1) + for _, m := range ms { + rawBytes = bytes.Replace(rawBytes, m, []byte(fmt.Sprintf( + `<a href="%s/commit/%s"><code>%s</code></a>`, urlPrefix, m, base.ShortSha(string(m)))), -1) + } + return rawBytes +} + +// RenderSpecialLink renders mentions, indexes and SHA1 strings to corresponding links. +func RenderSpecialLink(rawBytes []byte, urlPrefix string, metas map[string]string) []byte { + ms := MentionPattern.FindAll(rawBytes, -1) + for _, m := range ms { + m = bytes.TrimSpace(m) + rawBytes = bytes.Replace(rawBytes, m, + []byte(fmt.Sprintf(`<a href="%s/%s">%s</a>`, setting.AppSubUrl, m[1:], m)), -1) + } + + rawBytes = RenderIssueIndexPattern(rawBytes, urlPrefix, metas) + rawBytes = RenderSha1CurrentPattern(rawBytes, urlPrefix) + return rawBytes +} + +// RenderRaw renders Markdown to HTML without handling special links. +func RenderRaw(body []byte, urlPrefix string) []byte { + htmlFlags := 0 + htmlFlags |= blackfriday.HTML_SKIP_STYLE + htmlFlags |= blackfriday.HTML_OMIT_CONTENTS + renderer := &Renderer{ + Renderer: blackfriday.HtmlRenderer(htmlFlags, "", ""), + urlPrefix: urlPrefix, + } + + // set up the parser + extensions := 0 + extensions |= blackfriday.EXTENSION_NO_INTRA_EMPHASIS + extensions |= blackfriday.EXTENSION_TABLES + extensions |= blackfriday.EXTENSION_FENCED_CODE + extensions |= blackfriday.EXTENSION_AUTOLINK + extensions |= blackfriday.EXTENSION_STRIKETHROUGH + extensions |= blackfriday.EXTENSION_SPACE_HEADERS + extensions |= blackfriday.EXTENSION_NO_EMPTY_LINE_BEFORE_BLOCK + + if setting.Markdown.EnableHardLineBreak { + extensions |= blackfriday.EXTENSION_HARD_LINE_BREAK + } + + body = blackfriday.Markdown(body, renderer, extensions) + return body +} + +var ( + leftAngleBracket = []byte("</") + rightAngleBracket = []byte(">") +) + +var noEndTags = []string{"img", "input", "br", "hr"} + +// PostProcess treats different types of HTML differently, +// and only renders special links for plain text blocks. +func PostProcess(rawHtml []byte, urlPrefix string, metas map[string]string) []byte { + startTags := make([]string, 0, 5) + var buf bytes.Buffer + tokenizer := html.NewTokenizer(bytes.NewReader(rawHtml)) + +OUTER_LOOP: + for html.ErrorToken != tokenizer.Next() { + token := tokenizer.Token() + switch token.Type { + case html.TextToken: + buf.Write(RenderSpecialLink([]byte(token.String()), urlPrefix, metas)) + + case html.StartTagToken: + buf.WriteString(token.String()) + tagName := token.Data + // If this is an excluded tag, we skip processing all output until a close tag is encountered. + if strings.EqualFold("a", tagName) || strings.EqualFold("code", tagName) || strings.EqualFold("pre", tagName) { + stackNum := 1 + for html.ErrorToken != tokenizer.Next() { + token = tokenizer.Token() + + // Copy the token to the output verbatim + buf.WriteString(token.String()) + + if token.Type == html.StartTagToken { + stackNum++ + } + + // If this is the close tag to the outer-most, we are done + if token.Type == html.EndTagToken { + stackNum-- + + if stackNum <= 0 && strings.EqualFold(tagName, token.Data) { + break + } + } + } + continue OUTER_LOOP + } + + if !com.IsSliceContainsStr(noEndTags, token.Data) { + startTags = append(startTags, token.Data) + } + + case html.EndTagToken: + if len(startTags) == 0 { + buf.WriteString(token.String()) + break + } + + buf.Write(leftAngleBracket) + buf.WriteString(startTags[len(startTags)-1]) + buf.Write(rightAngleBracket) + startTags = startTags[:len(startTags)-1] + default: + buf.WriteString(token.String()) + } + } + + if io.EOF == tokenizer.Err() { + return buf.Bytes() + } + + // If we are not at the end of the input, then some other parsing error has occurred, + // so return the input verbatim. + return rawHtml +} + +// Render renders Markdown to HTML with special links. +func Render(rawBytes []byte, urlPrefix string, metas map[string]string) []byte { + result := RenderRaw(rawBytes, urlPrefix) + result = PostProcess(result, urlPrefix, metas) + result = Sanitizer.SanitizeBytes(result) + return result +} + +// RenderString renders Markdown to HTML with special links and returns string type. +func RenderString(raw, urlPrefix string, metas map[string]string) string { + return string(Render([]byte(raw), urlPrefix, metas)) +} |