mirror of
https://github.com/go-gitea/gitea
synced 2024-08-20 06:11:16 +02:00
This PR adds mathematical rendering with KaTeX. The first step is to add a Goldmark extension that detects the latex (and tex) mathematics delimiters. The second step to make this extension only run if math support is enabled. The second step is to then add KaTeX CSS and JS to the head which will load after the dom is rendered. Fix #3445 Signed-off-by: Andrew Thornton <art27@cantab.net> Signed-off-by: Andrew Thornton <art27@cantab.net> Co-authored-by: silverwind <me@silverwind.io> Co-authored-by: Lunny Xiao <xiaolunwen@gmail.com>
166 lines
5.7 KiB
Go
166 lines
5.7 KiB
Go
// Copyright 2017 The Gitea Authors. All rights reserved.
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// Copyright 2017 The Gogs Authors. All rights reserved.
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// Use of this source code is governed by a MIT-style
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// license that can be found in the LICENSE file.
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package markup
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import (
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"io"
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"regexp"
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"sync"
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"code.gitea.io/gitea/modules/setting"
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"github.com/microcosm-cc/bluemonday"
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)
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// Sanitizer is a protection wrapper of *bluemonday.Policy which does not allow
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// any modification to the underlying policies once it's been created.
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type Sanitizer struct {
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defaultPolicy *bluemonday.Policy
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rendererPolicies map[string]*bluemonday.Policy
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init sync.Once
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}
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var sanitizer = &Sanitizer{}
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// NewSanitizer initializes sanitizer with allowed attributes based on settings.
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// Multiple calls to this function will only create one instance of Sanitizer during
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// entire application lifecycle.
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func NewSanitizer() {
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sanitizer.init.Do(func() {
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InitializeSanitizer()
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})
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}
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// InitializeSanitizer (re)initializes the current sanitizer to account for changes in settings
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func InitializeSanitizer() {
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sanitizer.rendererPolicies = map[string]*bluemonday.Policy{}
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sanitizer.defaultPolicy = createDefaultPolicy()
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for name, renderer := range renderers {
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sanitizerRules := renderer.SanitizerRules()
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if len(sanitizerRules) > 0 {
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policy := createDefaultPolicy()
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addSanitizerRules(policy, sanitizerRules)
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sanitizer.rendererPolicies[name] = policy
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}
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}
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}
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func createDefaultPolicy() *bluemonday.Policy {
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policy := bluemonday.UGCPolicy()
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// For JS code copy and Mermaid loading state
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policy.AllowAttrs("class").Matching(regexp.MustCompile(`^code-block( is-loading)?$`)).OnElements("pre")
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// For Chroma markdown plugin
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policy.AllowAttrs("class").Matching(regexp.MustCompile(`^(chroma )?language-[\w-]+( display)?( is-loading)?$`)).OnElements("code")
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// Checkboxes
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policy.AllowAttrs("type").Matching(regexp.MustCompile(`^checkbox$`)).OnElements("input")
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policy.AllowAttrs("checked", "disabled", "data-source-position").OnElements("input")
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// Custom URL-Schemes
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if len(setting.Markdown.CustomURLSchemes) > 0 {
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policy.AllowURLSchemes(setting.Markdown.CustomURLSchemes...)
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}
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// Allow classes for anchors
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policy.AllowAttrs("class").Matching(regexp.MustCompile(`ref-issue( ref-external-issue)?`)).OnElements("a")
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// Allow classes for task lists
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policy.AllowAttrs("class").Matching(regexp.MustCompile(`task-list-item`)).OnElements("li")
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// Allow icons
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policy.AllowAttrs("class").Matching(regexp.MustCompile(`^icon(\s+[\p{L}\p{N}_-]+)+$`)).OnElements("i")
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// Allow unlabelled labels
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policy.AllowNoAttrs().OnElements("label")
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// Allow classes for emojis
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policy.AllowAttrs("class").Matching(regexp.MustCompile(`emoji`)).OnElements("img")
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// Allow icons, emojis, chroma syntax and keyword markup on span
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policy.AllowAttrs("class").Matching(regexp.MustCompile(`^((icon(\s+[\p{L}\p{N}_-]+)+)|(emoji)|(language-math display)|(language-math inline))$|^([a-z][a-z0-9]{0,2})$|^` + keywordClass + `$`)).OnElements("span")
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// Allow 'style' attribute on text elements.
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policy.AllowAttrs("style").OnElements("span", "p")
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// Allow 'color' property for the style attribute on text elements.
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policy.AllowStyles("color").OnElements("span", "p")
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// Allow generally safe attributes
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generalSafeAttrs := []string{
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"abbr", "accept", "accept-charset",
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"accesskey", "action", "align", "alt",
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"aria-describedby", "aria-hidden", "aria-label", "aria-labelledby",
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"axis", "border", "cellpadding", "cellspacing", "char",
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"charoff", "charset", "checked",
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"clear", "cols", "colspan", "color",
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"compact", "coords", "datetime", "dir",
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"disabled", "enctype", "for", "frame",
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"headers", "height", "hreflang",
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"hspace", "ismap", "label", "lang",
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"maxlength", "media", "method",
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"multiple", "name", "nohref", "noshade",
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"nowrap", "open", "prompt", "readonly", "rel", "rev",
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"rows", "rowspan", "rules", "scope",
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"selected", "shape", "size", "span",
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"start", "summary", "tabindex", "target",
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"title", "type", "usemap", "valign", "value",
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"vspace", "width", "itemprop",
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}
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generalSafeElements := []string{
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"h1", "h2", "h3", "h4", "h5", "h6", "h7", "h8", "br", "b", "i", "strong", "em", "a", "pre", "code", "img", "tt",
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"div", "ins", "del", "sup", "sub", "p", "ol", "ul", "table", "thead", "tbody", "tfoot", "blockquote",
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"dl", "dt", "dd", "kbd", "q", "samp", "var", "hr", "ruby", "rt", "rp", "li", "tr", "td", "th", "s", "strike", "summary",
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"details", "caption", "figure", "figcaption",
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"abbr", "bdo", "cite", "dfn", "mark", "small", "span", "time", "wbr",
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}
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policy.AllowAttrs(generalSafeAttrs...).OnElements(generalSafeElements...)
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policy.AllowAttrs("itemscope", "itemtype").OnElements("div")
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// FIXME: Need to handle longdesc in img but there is no easy way to do it
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// Custom keyword markup
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addSanitizerRules(policy, setting.ExternalSanitizerRules)
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return policy
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}
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func addSanitizerRules(policy *bluemonday.Policy, rules []setting.MarkupSanitizerRule) {
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for _, rule := range rules {
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if rule.AllowDataURIImages {
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policy.AllowDataURIImages()
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}
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if rule.Element != "" {
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if rule.Regexp != nil {
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policy.AllowAttrs(rule.AllowAttr).Matching(rule.Regexp).OnElements(rule.Element)
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} else {
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policy.AllowAttrs(rule.AllowAttr).OnElements(rule.Element)
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}
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}
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}
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}
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// Sanitize takes a string that contains a HTML fragment or document and applies policy whitelist.
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func Sanitize(s string) string {
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NewSanitizer()
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return sanitizer.defaultPolicy.Sanitize(s)
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}
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// SanitizeReader sanitizes a Reader
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func SanitizeReader(r io.Reader, renderer string, w io.Writer) error {
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NewSanitizer()
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policy, exist := sanitizer.rendererPolicies[renderer]
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if !exist {
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policy = sanitizer.defaultPolicy
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}
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return policy.SanitizeReaderToWriter(r, w)
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}
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