gitea/modules/markdown/markdown.go
Roy Marples 89845f6728 Fix SHA1 hash linking (#2143)
This changes the regex to look for a hash from 7 to 40 characters,
to match the use of abbreviated hash lookups in both git and github.
The restriction of not being a pure number is also removed because
1234567 is now considered a valid abbreviated hash, as is deadbeef.

A note has been added to the top of the code to state that the
literal regex match is fine, but no extra validation is currently
performed so some false positives are expected.

A future change could ensure that the hash exists in the repository
before rendering it as a link, although this might incur a slight
performance penalty.

Reverts part of commit 4a46613 and fixes #2053.
2017-07-12 04:26:54 +02:00

717 lines
21 KiB
Go

// 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"
"net/url"
"path"
"path/filepath"
"regexp"
"strings"
"code.gitea.io/gitea/modules/base"
"code.gitea.io/gitea/modules/log"
"code.gitea.io/gitea/modules/markup"
"code.gitea.io/gitea/modules/setting"
"github.com/Unknwon/com"
"github.com/russross/blackfriday"
"golang.org/x/net/html"
)
// Issue name styles
const (
IssueNameStyleNumeric = "numeric"
IssueNameStyleAlphanumeric = "alphanumeric"
)
// IsMarkdownFile reports whether name looks like a Markdown file
// based on its extension.
func IsMarkdownFile(name string) bool {
extension := strings.ToLower(filepath.Ext(name))
for _, ext := range setting.Markdown.FileExtensions {
if strings.ToLower(ext) == extension {
return true
}
}
return false
}
var (
// NOTE: All below regex matching do not perform any extra validation.
// Thus a link is produced even if the user does not exist, the issue does not exist, the commit does not exist, etc.
// While fast, this is also incorrect and lead to false positives.
// MentionPattern matches string that mentions someone, e.g. @Unknwon
MentionPattern = regexp.MustCompile(`(\s|^|\W)@[0-9a-zA-Z-_\.]+`)
// IssueNumericPattern matches string that references to a numeric issue, e.g. #1287
IssueNumericPattern = regexp.MustCompile(`( |^|\()#[0-9]+\b`)
// IssueAlphanumericPattern matches string that references to an alphanumeric issue, e.g. ABC-1234
IssueAlphanumericPattern = regexp.MustCompile(`( |^|\()[A-Z]{1,10}-[1-9][0-9]*\b`)
// CrossReferenceIssueNumericPattern matches string that references a numeric issue in a different repository
// e.g. gogits/gogs#12345
CrossReferenceIssueNumericPattern = regexp.MustCompile(`( |^)[0-9a-zA-Z]+/[0-9a-zA-Z]+#[0-9]+\b`)
// Sha1CurrentPattern matches string that represents a commit SHA, e.g. d8a994ef243349f321568f9e36d5c3f444b99cae
// Although SHA1 hashes are 40 chars long, the regex matches the hash from 7 to 40 chars in length
// so that abbreviated hash links can be used as well. This matches git and github useability.
Sha1CurrentPattern = regexp.MustCompile(`(?:^|\s|\()([0-9a-f]{7,40})\b`)
// ShortLinkPattern matches short but difficult to parse [[name|link|arg=test]] syntax
ShortLinkPattern = regexp.MustCompile(`(\[\[.*\]\]\w*)`)
// AnySHA1Pattern allows to split url containing SHA into parts
AnySHA1Pattern = regexp.MustCompile(`(http\S*)://(\S+)/(\S+)/(\S+)/(\S+)/([0-9a-f]{40})(?:/?([^#\s]+)?(?:#(\S+))?)?`)
// IssueFullPattern allows to split issue (and pull) URLs into parts
IssueFullPattern = regexp.MustCompile(`(?:^|\s|\()(http\S*)://((?:[^\s/]+/)+)((?:\w{1,10}-)?[1-9][0-9]*)([\?|#]\S+.(\S+)?)?\b`)
validLinksPattern = regexp.MustCompile(`^[a-z][\w-]+://`)
)
// isLink reports whether link fits valid format.
func isLink(link []byte) bool {
return validLinksPattern.Match(link)
}
// FindAllMentions matches mention patterns in given content
// and returns a list of found user names without @ prefix.
func FindAllMentions(content string) []string {
mentions := MentionPattern.FindAllString(content, -1)
for i := range mentions {
mentions[i] = mentions[i][strings.Index(mentions[i], "@")+1:] // Strip @ character
}
return mentions
}
// Renderer is a extended version of underlying render object.
type Renderer struct {
blackfriday.Renderer
urlPrefix string
isWikiMarkdown bool
}
// 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] != '#' {
lnk := string(link)
if r.isWikiMarkdown {
lnk = URLJoin("wiki", lnk)
}
mLink := URLJoin(r.urlPrefix, lnk)
link = []byte(mLink)
}
}
r.Renderer.Link(out, link, title, content)
}
// List renders markdown bullet or digit lists to HTML
func (r *Renderer) List(out *bytes.Buffer, text func() bool, flags int) {
marker := out.Len()
if out.Len() > 0 {
out.WriteByte('\n')
}
if flags&blackfriday.LIST_TYPE_DEFINITION != 0 {
out.WriteString("<dl>")
} else if flags&blackfriday.LIST_TYPE_ORDERED != 0 {
out.WriteString("<ol class='ui list'>")
} else {
out.WriteString("<ul class='ui list'>")
}
if !text() {
out.Truncate(marker)
return
}
if flags&blackfriday.LIST_TYPE_DEFINITION != 0 {
out.WriteString("</dl>\n")
} else if flags&blackfriday.LIST_TYPE_ORDERED != 0 {
out.WriteString("</ol>\n")
} else {
out.WriteString("</ul>\n")
}
}
// ListItem defines how list items should be processed to produce corresponding HTML elements.
func (r *Renderer) ListItem(out *bytes.Buffer, text []byte, flags int) {
// Detect procedures to draw checkboxes.
prefix := ""
if bytes.HasPrefix(text, []byte("<p>")) {
prefix = "<p>"
}
switch {
case bytes.HasPrefix(text, []byte(prefix+"[ ] ")):
text = append([]byte(`<span class="ui fitted disabled checkbox"><input type="checkbox" disabled="disabled" /><label /></span>`), text[3+len(prefix):]...)
if prefix != "" {
text = bytes.Replace(text, []byte(prefix), []byte{}, 1)
}
case bytes.HasPrefix(text, []byte(prefix+"[x] ")):
text = append([]byte(`<span class="ui checked fitted disabled checkbox"><input type="checkbox" checked="" disabled="disabled" /><label /></span>`), text[3+len(prefix):]...)
if prefix != "" {
text = bytes.Replace(text, []byte(prefix), []byte{}, 1)
}
}
r.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?")
)
// 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 := r.urlPrefix
if r.isWikiMarkdown {
prefix = URLJoin(prefix, "wiki", "src")
}
prefix = strings.Replace(prefix, "/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 {
lnk := string(link)
lnk = URLJoin(prefix, lnk)
lnk = strings.Replace(lnk, " ", "+", -1)
link = []byte(lnk)
}
}
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 {
if len(prefix) == 0 || prefix[0] != '/' {
return prefix
}
count := 0
for i := 0; i < len(prefix); i++ {
if prefix[i] == '/' {
count++
}
if count >= 3+setting.AppSubURLDepth {
return prefix[:i]
}
}
return prefix
}
// URLJoin joins url components, like path.Join, but preserving contents
func URLJoin(base string, elems ...string) string {
u, err := url.Parse(base)
if err != nil {
log.Error(4, "URLJoin: Invalid base URL %s", base)
return ""
}
joinArgs := make([]string, 0, len(elems)+1)
joinArgs = append(joinArgs, u.Path)
joinArgs = append(joinArgs, elems...)
u.Path = path.Join(joinArgs...)
return u.String()
}
// RenderIssueIndexPattern renders issue indexes to corresponding links.
func RenderIssueIndexPattern(rawBytes []byte, urlPrefix string, metas map[string]string) []byte {
urlPrefix = cutoutVerbosePrefix(urlPrefix)
pattern := IssueNumericPattern
if metas["style"] == IssueNameStyleAlphanumeric {
pattern = IssueAlphanumericPattern
}
ms := pattern.FindAll(rawBytes, -1)
for _, m := range ms {
if m[0] == ' ' || m[0] == '(' {
m = m[1:] // ignore leading space or opening parentheses
}
var link string
if metas == nil {
link = fmt.Sprintf(`<a href="%s">%s</a>`, URLJoin(urlPrefix, "issues", string(m[1:])), m)
} else {
// Support for external issue tracker
if metas["style"] == IssueNameStyleAlphanumeric {
metas["index"] = string(m)
} else {
metas["index"] = string(m[1:])
}
link = fmt.Sprintf(`<a href="%s">%s</a>`, com.Expand(metas["format"], metas), m)
}
rawBytes = bytes.Replace(rawBytes, m, []byte(link), 1)
}
return rawBytes
}
// IsSameDomain checks if given url string has the same hostname as current Gitea instance
func IsSameDomain(s string) bool {
if strings.HasPrefix(s, "/") {
return true
}
if uapp, err := url.Parse(setting.AppURL); err == nil {
if u, err := url.Parse(s); err == nil {
return u.Host == uapp.Host
}
return false
}
return false
}
// renderFullSha1Pattern renders SHA containing URLs
func renderFullSha1Pattern(rawBytes []byte, urlPrefix string) []byte {
ms := AnySHA1Pattern.FindAllSubmatch(rawBytes, -1)
for _, m := range ms {
all := m[0]
protocol := string(m[1])
paths := string(m[2])
path := protocol + "://" + paths
author := string(m[3])
repoName := string(m[4])
path = URLJoin(path, author, repoName)
ltype := "src"
itemType := m[5]
if IsSameDomain(paths) {
ltype = string(itemType)
} else if string(itemType) == "commit" {
ltype = "commit"
}
sha := m[6]
var subtree string
if len(m) > 7 && len(m[7]) > 0 {
subtree = string(m[7])
}
var line []byte
if len(m) > 8 && len(m[8]) > 0 {
line = m[8]
}
urlSuffix := ""
text := base.ShortSha(string(sha))
if subtree != "" {
urlSuffix = "/" + subtree
text += urlSuffix
}
if line != nil {
value := string(line)
urlSuffix += "#"
urlSuffix += value
text += " ("
text += value
text += ")"
}
rawBytes = bytes.Replace(rawBytes, all, []byte(fmt.Sprintf(
`<a href="%s">%s</a>`, URLJoin(path, ltype, string(sha))+urlSuffix, text)), -1)
}
return rawBytes
}
// renderFullIssuePattern renders issues-like URLs
func renderFullIssuePattern(rawBytes []byte, urlPrefix string) []byte {
ms := IssueFullPattern.FindAllSubmatch(rawBytes, -1)
for _, m := range ms {
all := m[0]
protocol := string(m[1])
paths := bytes.Split(m[2], []byte("/"))
paths = paths[:len(paths)-1]
if bytes.HasPrefix(paths[0], []byte("gist.")) {
continue
}
path := protocol + "://" + string(m[2])
id := string(m[3])
path = URLJoin(path, id)
var comment []byte
if len(m) > 3 {
comment = m[4]
}
urlSuffix := ""
text := "#" + id
if comment != nil {
urlSuffix += string(comment)
text += " <i class='comment icon'></i>"
}
rawBytes = bytes.Replace(rawBytes, all, []byte(fmt.Sprintf(
`<a href="%s%s">%s</a>`, path, urlSuffix, text)), -1)
}
return rawBytes
}
func firstIndexOfByte(sl []byte, target byte) int {
for i := 0; i < len(sl); i++ {
if sl[i] == target {
return i
}
}
return -1
}
func lastIndexOfByte(sl []byte, target byte) int {
for i := len(sl) - 1; i >= 0; i-- {
if sl[i] == target {
return i
}
}
return -1
}
// RenderShortLinks processes [[syntax]]
//
// noLink flag disables making link tags when set to true
// so this function just replaces the whole [[...]] with the content text
//
// isWikiMarkdown is a flag to choose linking url prefix
func RenderShortLinks(rawBytes []byte, urlPrefix string, noLink bool, isWikiMarkdown bool) []byte {
ms := ShortLinkPattern.FindAll(rawBytes, -1)
for _, m := range ms {
orig := bytes.TrimSpace(m)
m = orig[2:]
tailPos := lastIndexOfByte(m, ']') + 1
tail := []byte{}
if tailPos < len(m) {
tail = m[tailPos:]
m = m[:tailPos-1]
}
m = m[:len(m)-2]
props := map[string]string{}
// MediaWiki uses [[link|text]], while GitHub uses [[text|link]]
// It makes page handling terrible, but we prefer GitHub syntax
// And fall back to MediaWiki only when it is obvious from the look
// Of text and link contents
sl := bytes.Split(m, []byte("|"))
for _, v := range sl {
switch bytes.Count(v, []byte("=")) {
// Piped args without = sign, these are mandatory arguments
case 0:
{
sv := string(v)
if props["name"] == "" {
if isLink(v) {
// If we clearly see it is a link, we save it so
// But first we need to ensure, that if both mandatory args provided
// look like links, we stick to GitHub syntax
if props["link"] != "" {
props["name"] = props["link"]
}
props["link"] = strings.TrimSpace(sv)
} else {
props["name"] = sv
}
} else {
props["link"] = strings.TrimSpace(sv)
}
}
// Piped args with = sign, these are optional arguments
case 1:
{
sep := firstIndexOfByte(v, '=')
key, val := string(v[:sep]), html.UnescapeString(string(v[sep+1:]))
lastCharIndex := len(val) - 1
if (val[0] == '"' || val[0] == '\'') && (val[lastCharIndex] == '"' || val[lastCharIndex] == '\'') {
val = val[1:lastCharIndex]
}
props[key] = val
}
}
}
var name string
var link string
if props["link"] != "" {
link = props["link"]
} else if props["name"] != "" {
link = props["name"]
}
if props["title"] != "" {
name = props["title"]
} else if props["name"] != "" {
name = props["name"]
} else {
name = link
}
name += string(tail)
image := false
ext := filepath.Ext(string(link))
if ext != "" {
switch ext {
case ".jpg", ".jpeg", ".png", ".tif", ".tiff", ".webp", ".gif", ".bmp", ".ico", ".svg":
{
image = true
}
}
}
absoluteLink := isLink([]byte(link))
if !absoluteLink {
link = strings.Replace(link, " ", "+", -1)
}
if image {
if !absoluteLink {
if IsSameDomain(urlPrefix) {
urlPrefix = strings.Replace(urlPrefix, "/src/", "/raw/", 1)
}
if isWikiMarkdown {
link = URLJoin("wiki", "raw", link)
}
link = URLJoin(urlPrefix, link)
}
title := props["title"]
if title == "" {
title = props["alt"]
}
if title == "" {
title = path.Base(string(name))
}
alt := props["alt"]
if alt == "" {
alt = name
}
if alt != "" {
alt = `alt="` + alt + `"`
}
name = fmt.Sprintf(`<img src="%s" %s title="%s" />`, link, alt, title)
} else if !absoluteLink {
if isWikiMarkdown {
link = URLJoin("wiki", link)
}
link = URLJoin(urlPrefix, link)
}
if noLink {
rawBytes = bytes.Replace(rawBytes, orig, []byte(name), -1)
} else {
rawBytes = bytes.Replace(rawBytes, orig,
[]byte(fmt.Sprintf(`<a href="%s">%s</a>`, link, name)), -1)
}
}
return rawBytes
}
// RenderCrossReferenceIssueIndexPattern renders issue indexes from other repositories to corresponding links.
func RenderCrossReferenceIssueIndexPattern(rawBytes []byte, urlPrefix string, metas map[string]string) []byte {
ms := CrossReferenceIssueNumericPattern.FindAll(rawBytes, -1)
for _, m := range ms {
if m[0] == ' ' || m[0] == '(' {
m = m[1:] // ignore leading space or opening parentheses
}
repo := string(bytes.Split(m, []byte("#"))[0])
issue := string(bytes.Split(m, []byte("#"))[1])
link := fmt.Sprintf(`<a href="%s">%s</a>`, URLJoin(setting.AppURL, repo, "issues", issue), m)
rawBytes = bytes.Replace(rawBytes, m, []byte(link), 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.FindAllSubmatch(rawBytes, -1)
for _, m := range ms {
hash := m[1]
// The regex does not lie, it matches the hash pattern.
// However, a regex cannot know if a hash actually exists or not.
// We could assume that a SHA1 hash should probably contain alphas AND numerics
// but that is not always the case.
// Although unlikely, deadbeef and 1234567 are valid short forms of SHA1 hash
// as used by git and github for linking and thus we have to do similar.
rawBytes = bytes.Replace(rawBytes, hash, []byte(fmt.Sprintf(
`<a href="%s">%s</a>`, URLJoin(urlPrefix, "commit", string(hash)), base.ShortSha(string(hash)))), -1)
}
return rawBytes
}
// RenderSpecialLink renders mentions, indexes and SHA1 strings to corresponding links.
func RenderSpecialLink(rawBytes []byte, urlPrefix string, metas map[string]string, isWikiMarkdown bool) []byte {
ms := MentionPattern.FindAll(rawBytes, -1)
for _, m := range ms {
m = m[bytes.Index(m, []byte("@")):]
rawBytes = bytes.Replace(rawBytes, m,
[]byte(fmt.Sprintf(`<a href="%s">%s</a>`, URLJoin(setting.AppURL, string(m[1:])), m)), -1)
}
rawBytes = RenderShortLinks(rawBytes, urlPrefix, false, isWikiMarkdown)
rawBytes = RenderIssueIndexPattern(rawBytes, urlPrefix, metas)
rawBytes = RenderCrossReferenceIssueIndexPattern(rawBytes, urlPrefix, metas)
rawBytes = renderFullSha1Pattern(rawBytes, urlPrefix)
rawBytes = renderSha1CurrentPattern(rawBytes, urlPrefix)
rawBytes = renderFullIssuePattern(rawBytes, urlPrefix)
return rawBytes
}
// RenderRaw renders Markdown to HTML without handling special links.
func RenderRaw(body []byte, urlPrefix string, wikiMarkdown bool) []byte {
htmlFlags := 0
htmlFlags |= blackfriday.HTML_SKIP_STYLE
htmlFlags |= blackfriday.HTML_OMIT_CONTENTS
renderer := &Renderer{
Renderer: blackfriday.HtmlRenderer(htmlFlags, "", ""),
urlPrefix: urlPrefix,
isWikiMarkdown: wikiMarkdown,
}
// set up the parser
extensions := 0
extensions |= blackfriday.EXTENSION_NO_INTRA_EMPHASIS
extensions |= blackfriday.EXTENSION_TABLES
extensions |= blackfriday.EXTENSION_FENCED_CODE
extensions |= blackfriday.EXTENSION_STRIKETHROUGH
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, isWikiMarkdown bool) []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, isWikiMarkdown))
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.Write(RenderShortLinks([]byte(token.String()), urlPrefix, true, isWikiMarkdown))
if token.Type == html.StartTagToken && !com.IsSliceContainsStr(noEndTags, token.Data) {
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, tagName) {
startTags = append(startTags, tagName)
}
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 all specific handling stuff.
func render(rawBytes []byte, urlPrefix string, metas map[string]string, isWikiMarkdown bool) []byte {
urlPrefix = strings.Replace(urlPrefix, " ", "+", -1)
result := RenderRaw(rawBytes, urlPrefix, isWikiMarkdown)
result = PostProcess(result, urlPrefix, metas, isWikiMarkdown)
result = SanitizeBytes(result)
return result
}
// Render renders Markdown to HTML with all specific handling stuff.
func Render(rawBytes []byte, urlPrefix string, metas map[string]string) []byte {
return render(rawBytes, urlPrefix, metas, false)
}
// 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, false))
}
// RenderWiki renders markdown wiki page to HTML and return HTML string
func RenderWiki(rawBytes []byte, urlPrefix string, metas map[string]string) string {
return string(render(rawBytes, urlPrefix, metas, true))
}
var (
// MarkupName describes markup's name
MarkupName = "markdown"
)
func init() {
markup.RegisterParser(Parser{})
}
// Parser implements markup.Parser
type Parser struct {
}
// Name implements markup.Parser
func (Parser) Name() string {
return MarkupName
}
// Extensions implements markup.Parser
func (Parser) Extensions() []string {
return setting.Markdown.FileExtensions
}
// Render implements markup.Parser
func (Parser) Render(rawBytes []byte, urlPrefix string, metas map[string]string, isWiki bool) []byte {
return render(rawBytes, urlPrefix, metas, isWiki)
}