githaven-fork/modules/markup/html.go

668 lines
19 KiB
Go
Raw Blame History

This file contains ambiguous Unicode characters

This file contains Unicode characters that might be confused with other characters. If you think that this is intentional, you can safely ignore this warning. Use the Escape button to reveal them.

// Copyright 2017 The Gitea 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 markup
import (
"bytes"
"net/url"
"path"
"path/filepath"
"regexp"
"strings"
"code.gitea.io/gitea/modules/base"
"code.gitea.io/gitea/modules/setting"
"code.gitea.io/gitea/modules/util"
"github.com/Unknwon/com"
"golang.org/x/net/html"
"golang.org/x/net/html/atom"
)
// Issue name styles
const (
IssueNameStyleNumeric = "numeric"
IssueNameStyleAlphanumeric = "alphanumeric"
)
var (
// NOTE: All below regex matching do not perform any extra validation.
// Thus a link is produced even if the linked entity does not exist.
// While fast, this is also incorrect and lead to false positives.
// TODO: fix invalid linking issue
// mentionPattern matches all mentions in the form of "@user"
mentionPattern = regexp.MustCompile(`(?:\s|^|\W)(@[0-9a-zA-Z-_\.]+)`)
// issueNumericPattern matches string that references to a numeric issue, e.g. #1287
issueNumericPattern = regexp.MustCompile(`(?:\s|^|\W)(#[0-9]+)\b`)
// issueAlphanumericPattern matches string that references to an alphanumeric issue, e.g. ABC-1234
issueAlphanumericPattern = regexp.MustCompile(`(?:\s|^|\W)([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(`(?:\s|^|\W)([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|^|\W)([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(`https?://(?:\S+/){4}([0-9a-f]{40})/?([^#\s]+)?(?:#(\S+))?`)
validLinksPattern = regexp.MustCompile(`^[a-z][\w-]+://`)
// While this email regex is definitely not perfect and I'm sure you can come up
// with edge cases, it is still accepted by the CommonMark specification, as
// well as the HTML5 spec:
// http://spec.commonmark.org/0.28/#email-address
// https://html.spec.whatwg.org/multipage/input.html#e-mail-state-(type%3Demail)
emailRegex = regexp.MustCompile("[a-zA-Z0-9.!#$%&'*+\\/=?^_`{|}~-]+@[a-zA-Z0-9](?:[a-zA-Z0-9-]{0,61}[a-zA-Z0-9])?(?:\\.[a-zA-Z0-9](?:[a-zA-Z0-9-]{0,61}[a-zA-Z0-9])?)*")
// matches http/https links. used for autlinking those. partly modified from
// the original present in autolink.js
linkRegex = regexp.MustCompile(`(?:(?:http|https):\/\/(?:[\-;:&=\+\$,\w]+@)?[A-Za-z0-9\.\-]+|(?:www\.|[\-;:&=\+\$,\w]+@)[A-Za-z0-9\.\-]+)(?:(?:\/[\+~%\/\.\w\-]*)?\??(?:[\-\+:=&;%@\.\w]*)#?(?:[\.\!\/\\\w]*))?`)
)
// regexp for full links to issues/pulls
var issueFullPattern *regexp.Regexp
// IsLink reports whether link fits valid format.
func IsLink(link []byte) bool {
return isLink(link)
}
// isLink reports whether link fits valid format.
func isLink(link []byte) bool {
return validLinksPattern.Match(link)
}
func isLinkStr(link string) bool {
return validLinksPattern.MatchString(link)
}
func getIssueFullPattern() *regexp.Regexp {
if issueFullPattern == nil {
appURL := setting.AppURL
if len(appURL) > 0 && appURL[len(appURL)-1] != '/' {
appURL += "/"
}
issueFullPattern = regexp.MustCompile(appURL +
`\w+/\w+/(?:issues|pulls)/((?:\w{1,10}-)?[1-9][0-9]*)([\?|#]\S+.(\S+)?)?\b`)
}
return issueFullPattern
}
// FindAllMentions matches mention patterns in given content
// and returns a list of found user names without @ prefix.
func FindAllMentions(content string) []string {
mentions := mentionPattern.FindAllStringSubmatch(content, -1)
ret := make([]string, len(mentions))
for i, val := range mentions {
ret[i] = val[1][1:]
}
return ret
}
// 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
}
// 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
}
type postProcessError struct {
context string
err error
}
func (p *postProcessError) Error() string {
return "PostProcess: " + p.context + ", " + p.Error()
}
type processor func(ctx *postProcessCtx, node *html.Node)
var defaultProcessors = []processor{
mentionProcessor,
shortLinkProcessor,
fullIssuePatternProcessor,
issueIndexPatternProcessor,
crossReferenceIssueIndexPatternProcessor,
fullSha1PatternProcessor,
sha1CurrentPatternProcessor,
emailAddressProcessor,
linkProcessor,
}
type postProcessCtx struct {
metas map[string]string
urlPrefix string
isWikiMarkdown bool
// processors used by this context.
procs []processor
// if set to true, when an <a> is found, instead of just returning during
// visitNode, it will recursively visit the node exclusively running
// shortLinkProcessorFull with true.
visitLinksForShortLinks bool
}
// PostProcess does the final required transformations to the passed raw HTML
// data, and ensures its validity. Transformations include: replacing links and
// emails with HTML links, parsing shortlinks in the format of [[Link]], like
// MediaWiki, linking issues in the format #ID, and mentions in the format
// @user, and others.
func PostProcess(
rawHTML []byte,
urlPrefix string,
metas map[string]string,
isWikiMarkdown bool,
) ([]byte, error) {
// create the context from the parameters
ctx := &postProcessCtx{
metas: metas,
urlPrefix: urlPrefix,
isWikiMarkdown: isWikiMarkdown,
procs: defaultProcessors,
visitLinksForShortLinks: true,
}
return ctx.postProcess(rawHTML)
}
var commitMessageProcessors = []processor{
mentionProcessor,
fullIssuePatternProcessor,
issueIndexPatternProcessor,
crossReferenceIssueIndexPatternProcessor,
fullSha1PatternProcessor,
sha1CurrentPatternProcessor,
emailAddressProcessor,
linkProcessor,
}
// RenderCommitMessage will use the same logic as PostProcess, but will disable
// the shortLinkProcessor and will add a defaultLinkProcessor if defaultLink is
// set, which changes every text node into a link to the passed default link.
func RenderCommitMessage(
rawHTML []byte,
urlPrefix, defaultLink string,
metas map[string]string,
) ([]byte, error) {
ctx := &postProcessCtx{
metas: metas,
urlPrefix: urlPrefix,
procs: commitMessageProcessors,
}
if defaultLink != "" {
// we don't have to fear data races, because being
// commitMessageProcessors of fixed len and cap, every time we append
// something to it the slice is realloc+copied, so append always
// generates the slice ex-novo.
ctx.procs = append(ctx.procs, genDefaultLinkProcessor(defaultLink))
}
return ctx.postProcess(rawHTML)
}
var byteBodyTag = []byte("<body>")
var byteBodyTagClosing = []byte("</body>")
func (ctx *postProcessCtx) postProcess(rawHTML []byte) ([]byte, error) {
if ctx.procs == nil {
ctx.procs = defaultProcessors
}
// give a generous extra 50 bytes
res := make([]byte, 0, len(rawHTML)+50)
res = append(res, byteBodyTag...)
res = append(res, rawHTML...)
res = append(res, byteBodyTagClosing...)
// parse the HTML
nodes, err := html.ParseFragment(bytes.NewReader(res), nil)
if err != nil {
return nil, &postProcessError{"invalid HTML", err}
}
for _, node := range nodes {
ctx.visitNode(node)
}
// Create buffer in which the data will be placed again. We know that the
// length will be at least that of res; to spare a few alloc+copy, we
// reuse res, resetting its length to 0.
buf := bytes.NewBuffer(res[:0])
// Render everything to buf.
for _, node := range nodes {
err = html.Render(buf, node)
if err != nil {
return nil, &postProcessError{"error rendering processed HTML", err}
}
}
// remove initial parts - because Render creates a whole HTML page.
res = buf.Bytes()
res = res[bytes.Index(res, byteBodyTag)+len(byteBodyTag) : bytes.LastIndex(res, byteBodyTagClosing)]
// Everything done successfully, return parsed data.
return res, nil
}
func (ctx *postProcessCtx) visitNode(node *html.Node) {
// We ignore code, pre and already generated links.
switch node.Type {
case html.TextNode:
ctx.textNode(node)
case html.ElementNode:
if node.Data == "a" || node.Data == "code" || node.Data == "pre" {
if node.Data == "a" && ctx.visitLinksForShortLinks {
ctx.visitNodeForShortLinks(node)
}
return
}
for n := node.FirstChild; n != nil; n = n.NextSibling {
ctx.visitNode(n)
}
}
// ignore everything else
}
func (ctx *postProcessCtx) visitNodeForShortLinks(node *html.Node) {
switch node.Type {
case html.TextNode:
shortLinkProcessorFull(ctx, node, true)
case html.ElementNode:
if node.Data == "code" || node.Data == "pre" {
return
}
for n := node.FirstChild; n != nil; n = n.NextSibling {
ctx.visitNodeForShortLinks(n)
}
}
}
// textNode runs the passed node through various processors, in order to handle
// all kinds of special links handled by the post-processing.
func (ctx *postProcessCtx) textNode(node *html.Node) {
for _, processor := range ctx.procs {
processor(ctx, node)
}
}
func createLink(href, content string) *html.Node {
textNode := &html.Node{
Type: html.TextNode,
Data: content,
}
linkNode := &html.Node{
FirstChild: textNode,
LastChild: textNode,
Type: html.ElementNode,
Data: "a",
DataAtom: atom.A,
Attr: []html.Attribute{
{Key: "href", Val: href},
},
}
textNode.Parent = linkNode
return linkNode
}
// replaceContent takes a text node, and in its content it replaces a section of
// it with the specified newNode. An example to visualize how this can work can
// be found here: https://play.golang.org/p/5zP8NnHZ03s
func replaceContent(node *html.Node, i, j int, newNode *html.Node) {
// get the data before and after the match
before := node.Data[:i]
after := node.Data[j:]
// Replace in the current node the text, so that it is only what it is
// supposed to have.
node.Data = before
// Get the current next sibling, before which we place the replaced data,
// and after that we place the new text node.
nextSibling := node.NextSibling
node.Parent.InsertBefore(newNode, nextSibling)
if after != "" {
node.Parent.InsertBefore(&html.Node{
Type: html.TextNode,
Data: after,
}, nextSibling)
}
}
func mentionProcessor(_ *postProcessCtx, node *html.Node) {
m := mentionPattern.FindStringSubmatchIndex(node.Data)
if m == nil {
return
}
// Replace the mention with a link to the specified user.
mention := node.Data[m[2]:m[3]]
replaceContent(node, m[2], m[3], createLink(util.URLJoin(setting.AppURL, mention[1:]), mention))
}
func shortLinkProcessor(ctx *postProcessCtx, node *html.Node) {
shortLinkProcessorFull(ctx, node, false)
}
func shortLinkProcessorFull(ctx *postProcessCtx, node *html.Node, noLink bool) {
m := shortLinkPattern.FindStringSubmatchIndex(node.Data)
if m == nil {
return
}
content := node.Data[m[2]:m[3]]
tail := node.Data[m[4]:m[5]]
props := make(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 := strings.Split(content, "|")
for _, v := range sl {
if equalPos := strings.IndexByte(v, '='); equalPos == -1 {
// There is no equal in this argument; this is a mandatory arg
if props["name"] == "" {
if isLinkStr(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(v)
} else {
props["name"] = v
}
} else {
props["link"] = strings.TrimSpace(v)
}
} else {
// There is an equal; optional argument.
sep := strings.IndexByte(v, '=')
key, val := v[:sep], html.UnescapeString(v[sep+1:])
// When parsing HTML, x/net/html will change all quotes which are
// not used for syntax into UTF-8 quotes. So checking val[0] won't
// be enough, since that only checks a single byte.
if (strings.HasPrefix(val, "“") && strings.HasSuffix(val, "”")) ||
(strings.HasPrefix(val, "") && strings.HasSuffix(val, "")) {
const lenQuote = len("")
val = val[lenQuote : len(val)-lenQuote]
}
props[key] = val
}
}
var name, 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 += tail
image := false
switch ext := filepath.Ext(string(link)); ext {
// fast path: empty string, ignore
case "":
break
case ".jpg", ".jpeg", ".png", ".tif", ".tiff", ".webp", ".gif", ".bmp", ".ico", ".svg":
image = true
}
childNode := &html.Node{}
linkNode := &html.Node{
FirstChild: childNode,
LastChild: childNode,
Type: html.ElementNode,
Data: "a",
DataAtom: atom.A,
}
childNode.Parent = linkNode
absoluteLink := isLinkStr(link)
if !absoluteLink {
if image {
link = strings.Replace(link, " ", "+", -1)
} else {
link = strings.Replace(link, " ", "-", -1)
}
}
urlPrefix := ctx.urlPrefix
if image {
if !absoluteLink {
if IsSameDomain(urlPrefix) {
urlPrefix = strings.Replace(urlPrefix, "/src/", "/raw/", 1)
}
if ctx.isWikiMarkdown {
link = util.URLJoin("wiki", "raw", link)
}
link = util.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
}
// make the childNode an image - if we can, we also place the alt
childNode.Type = html.ElementNode
childNode.Data = "img"
childNode.DataAtom = atom.Img
childNode.Attr = []html.Attribute{
{Key: "src", Val: link},
{Key: "title", Val: title},
{Key: "alt", Val: alt},
}
if alt == "" {
childNode.Attr = childNode.Attr[:2]
}
} else {
if !absoluteLink {
if ctx.isWikiMarkdown {
link = util.URLJoin("wiki", link)
}
link = util.URLJoin(urlPrefix, link)
}
childNode.Type = html.TextNode
childNode.Data = name
}
if noLink {
linkNode = childNode
} else {
linkNode.Attr = []html.Attribute{{Key: "href", Val: link}}
}
replaceContent(node, m[0], m[1], linkNode)
}
func fullIssuePatternProcessor(ctx *postProcessCtx, node *html.Node) {
m := getIssueFullPattern().FindStringSubmatchIndex(node.Data)
if m == nil {
return
}
link := node.Data[m[0]:m[1]]
id := "#" + node.Data[m[2]:m[3]]
// TODO if m[4]:m[5] is not nil, then link is to a comment,
// and we should indicate that in the text somehow
replaceContent(node, m[0], m[1], createLink(link, id))
}
func issueIndexPatternProcessor(ctx *postProcessCtx, node *html.Node) {
prefix := cutoutVerbosePrefix(ctx.urlPrefix)
// default to numeric pattern, unless alphanumeric is requested.
pattern := issueNumericPattern
if ctx.metas["style"] == IssueNameStyleAlphanumeric {
pattern = issueAlphanumericPattern
}
match := pattern.FindStringSubmatchIndex(node.Data)
if match == nil {
return
}
id := node.Data[match[2]:match[3]]
var link *html.Node
if ctx.metas == nil {
link = createLink(util.URLJoin(prefix, "issues", id[1:]), id)
} else {
// Support for external issue tracker
if ctx.metas["style"] == IssueNameStyleAlphanumeric {
ctx.metas["index"] = id
} else {
ctx.metas["index"] = id[1:]
}
link = createLink(com.Expand(ctx.metas["format"], ctx.metas), id)
}
replaceContent(node, match[2], match[3], link)
}
func crossReferenceIssueIndexPatternProcessor(ctx *postProcessCtx, node *html.Node) {
m := crossReferenceIssueNumericPattern.FindStringSubmatchIndex(node.Data)
if m == nil {
return
}
ref := node.Data[m[2]:m[3]]
parts := strings.SplitN(ref, "#", 2)
repo, issue := parts[0], parts[1]
replaceContent(node, m[2], m[3],
createLink(util.URLJoin(setting.AppURL, repo, "issues", issue), ref))
}
// fullSha1PatternProcessor renders SHA containing URLs
func fullSha1PatternProcessor(ctx *postProcessCtx, node *html.Node) {
m := anySHA1Pattern.FindStringSubmatchIndex(node.Data)
if m == nil {
return
}
// take out what's relevant
urlFull := node.Data[m[0]:m[1]]
hash := node.Data[m[2]:m[3]]
var subtree, line string
// optional, we do them depending on the length.
if m[7] > 0 {
line = node.Data[m[6]:m[7]]
}
if m[5] > 0 {
subtree = node.Data[m[4]:m[5]]
}
text := base.ShortSha(hash)
if subtree != "" {
text += "/" + subtree
}
if line != "" {
text += " ("
text += line
text += ")"
}
replaceContent(node, m[0], m[1], createLink(urlFull, text))
}
// sha1CurrentPatternProcessor renders SHA1 strings to corresponding links that
// are assumed to be in the same repository.
func sha1CurrentPatternProcessor(ctx *postProcessCtx, node *html.Node) {
m := sha1CurrentPattern.FindStringSubmatchIndex(node.Data)
if m == nil {
return
}
hash := node.Data[m[2]:m[3]]
// 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.
replaceContent(node, m[2], m[3],
createLink(util.URLJoin(ctx.urlPrefix, "commit", hash), base.ShortSha(hash)))
}
// emailAddressProcessor replaces raw email addresses with a mailto: link.
func emailAddressProcessor(ctx *postProcessCtx, node *html.Node) {
m := emailRegex.FindStringIndex(node.Data)
if m == nil {
return
}
mail := node.Data[m[0]:m[1]]
replaceContent(node, m[0], m[1], createLink("mailto:"+mail, mail))
}
// linkProcessor creates links for any HTTP or HTTPS URL not captured by
// markdown.
func linkProcessor(ctx *postProcessCtx, node *html.Node) {
m := linkRegex.FindStringIndex(node.Data)
if m == nil {
return
}
uri := node.Data[m[0]:m[1]]
replaceContent(node, m[0], m[1], createLink(uri, uri))
}
func genDefaultLinkProcessor(defaultLink string) processor {
return func(ctx *postProcessCtx, node *html.Node) {
ch := &html.Node{
Parent: node,
Type: html.TextNode,
Data: node.Data,
}
node.Type = html.ElementNode
node.Data = "a"
node.DataAtom = atom.A
node.Attr = []html.Attribute{{Key: "href", Val: defaultLink}}
node.FirstChild, node.LastChild = ch, ch
}
}