client/src/app/core/renderer/markdown.service.ts

   1 import * as MarkdownIt from 'markdown-it'
   2 import { Injectable } from '@angular/core'
   3 import { buildVideoLink, decorateVideoLink } from '@shared/core-utils'
   4 import {
   5   COMPLETE_RULES,
   6   ENHANCED_RULES,
   7   ENHANCED_WITH_HTML_RULES,
   8   TEXT_RULES,
   9   TEXT_WITH_HTML_RULES
  10 } from '@shared/core-utils/renderer/markdown'
  11 import { HtmlRendererService } from './html-renderer.service'
  12
  13 type MarkdownParsers = {
  14   textMarkdownIt: MarkdownIt
  15   textWithHTMLMarkdownIt: MarkdownIt
  16
  17   enhancedMarkdownIt: MarkdownIt
  18   enhancedWithHTMLMarkdownIt: MarkdownIt
  19
  20   unsafeMarkdownIt: MarkdownIt
  21
  22   customPageMarkdownIt: MarkdownIt
  23 }
  24
  25 type MarkdownConfig = {
  26   rules: string[]
  27   html: boolean
  28   breaks: boolean
  29   escape?: boolean
  30 }
  31
  32 type MarkdownParserConfigs = {
  33   [id in keyof MarkdownParsers]: MarkdownConfig
  34 }
  35
  36 @Injectable()
  37 export class MarkdownService {
  38   private markdownParsers: MarkdownParsers = {
  39     textMarkdownIt: null,
  40     textWithHTMLMarkdownIt: null,
  41
  42     enhancedMarkdownIt: null,
  43     enhancedWithHTMLMarkdownIt: null,
  44
  45     unsafeMarkdownIt: null,
  46
  47     customPageMarkdownIt: null
  48   }
  49   private parsersConfig: MarkdownParserConfigs = {
  50     textMarkdownIt: { rules: TEXT_RULES, breaks: true, html: false },
  51     textWithHTMLMarkdownIt: { rules: TEXT_WITH_HTML_RULES, breaks: true, html: true, escape: true },
  52
  53     enhancedMarkdownIt: { rules: ENHANCED_RULES, breaks: true, html: false },
  54     enhancedWithHTMLMarkdownIt: { rules: ENHANCED_WITH_HTML_RULES, breaks: true, html: true, escape: true },
  55
  56     unsafeMarkdownIt: { rules: COMPLETE_RULES, breaks: true, html: true, escape: false },
  57
  58     customPageMarkdownIt: { rules: COMPLETE_RULES, breaks: false, html: true, escape: true }
  59   }
  60
  61   private emojiModule: any
  62
  63   constructor (private htmlRenderer: HtmlRendererService) {}
  64
  65   textMarkdownToHTML (markdown: string, withHtml = false, withEmoji = false) {
  66     if (withHtml) return this.render({ name: 'textWithHTMLMarkdownIt', markdown, withEmoji })
  67
  68     return this.render({ name: 'textMarkdownIt', markdown, withEmoji })
  69   }
  70
  71   enhancedMarkdownToHTML (markdown: string, withHtml = false, withEmoji = false) {
  72     if (withHtml) return this.render({ name: 'enhancedWithHTMLMarkdownIt', markdown, withEmoji })
  73
  74     return this.render({ name: 'enhancedMarkdownIt', markdown, withEmoji })
  75   }
  76
  77   unsafeMarkdownToHTML (markdown: string, _trustedInput: true) {
  78     return this.render({ name: 'unsafeMarkdownIt', markdown, withEmoji: true })
  79   }
  80
  81   customPageMarkdownToHTML (markdown: string, additionalAllowedTags: string[]) {
  82     return this.render({ name: 'customPageMarkdownIt', markdown, withEmoji: true, additionalAllowedTags })
  83   }
  84
  85   processVideoTimestamps (videoShortUUID: string, html: string) {
  86     return html.replace(/((\d{1,2}):)?(\d{1,2}):(\d{1,2})/g, function (str, _, h, m, s) {
  87       const t = (3600 * +(h || 0)) + (60 * +(m || 0)) + (+(s || 0))
  88
  89       const url = decorateVideoLink({
  90         url: buildVideoLink({ shortUUID: videoShortUUID }),
  91         startTime: t
  92       })
  93       return `<a class="video-timestamp" href="${url}">${str}</a>`
  94     })
  95   }
  96
  97   private async render (options: {
  98     name: keyof MarkdownParsers
  99     markdown: string
 100     withEmoji: boolean
 101     additionalAllowedTags?: string[]
 102   }) {
 103     const { name, markdown, withEmoji, additionalAllowedTags } = options
 104     if (!markdown) return ''
 105
 106     const config = this.parsersConfig[ name ]
 107     if (!this.markdownParsers[ name ]) {
 108       this.markdownParsers[ name ] = await this.createMarkdownIt(config)
 109
 110       if (withEmoji) {
 111         if (!this.emojiModule) {
 112           this.emojiModule = (await import('markdown-it-emoji/light')).default
 113         }
 114
 115         this.markdownParsers[ name ].use(this.emojiModule)
 116       }
 117     }
 118
 119     let html = this.markdownParsers[ name ].render(markdown)
 120     html = this.avoidTruncatedTags(html)
 121
 122     if (config.escape) return this.htmlRenderer.toSafeHtml(html, additionalAllowedTags)
 123
 124     return html
 125   }
 126
 127   private async createMarkdownIt (config: MarkdownConfig) {
 128     // FIXME: import('...') returns a struct module, containing a "default" field
 129     const MarkdownItClass: typeof import ('markdown-it') = (await import('markdown-it') as any).default
 130
 131     const markdownIt = new MarkdownItClass('zero', { linkify: true, breaks: config.breaks, html: config.html })
 132
 133     for (const rule of config.rules) {
 134       markdownIt.enable(rule)
 135     }
 136
 137     this.setTargetToLinks(markdownIt)
 138
 139     return markdownIt
 140   }
 141
 142   private setTargetToLinks (markdownIt: MarkdownIt) {
 143     // Snippet from markdown-it documentation: https://github.com/markdown-it/markdown-it/blob/master/docs/architecture.md#renderer
 144     const defaultRender = markdownIt.renderer.rules.link_open || function (tokens, idx, options, env, self) {
 145       return self.renderToken(tokens, idx, options)
 146     }
 147
 148     markdownIt.renderer.rules.link_open = function (tokens, index, options, env, self) {
 149       const token = tokens[index]
 150
 151       const targetIndex = token.attrIndex('target')
 152       if (targetIndex < 0) token.attrPush([ 'target', '_blank' ])
 153       else token.attrs[targetIndex][1] = '_blank'
 154
 155       const relIndex = token.attrIndex('rel')
 156       if (relIndex < 0) token.attrPush([ 'rel', 'noopener noreferrer' ])
 157       else token.attrs[relIndex][1] = 'noopener noreferrer'
 158
 159       // pass token to default renderer.
 160       return defaultRender(tokens, index, options, env, self)
 161     }
 162   }
 163
 164   private avoidTruncatedTags (html: string) {
 165     return html.replace(/\*\*?([^*]+)$/, '$1')
 166       .replace(/<a[^>]+>([^<]+)<\/a>\s*...((<\/p>)|(<\/li>)|(<\/strong>))?$/mi, '$1...')
 167       .replace(/\[[^\]]+\]\(([^\)]+)$/m, '$1')
 168       .replace(/\s?\[[^\]]+\]?[.]{3}<\/p>$/m, '...</p>')
 169   }
 170 }