const urlUtils = require('./urlUtils.js'); const Entities = require('html-entities').AllHtmlEntities; const htmlentities = new Entities().encode; const htmlparser2 = require('@joplin/fork-htmlparser2'); // [\s\S] instead of . for multiline matching // https://stackoverflow.com/a/16119722/561309 const imageRegex = //gi; const anchorRegex = //gi; const selfClosingElements = [ 'area', 'base', 'basefont', 'br', 'col', 'command', 'embed', 'frame', 'hr', 'img', 'input', 'isindex', 'keygen', 'link', 'meta', 'param', 'source', 'track', 'wbr', ]; class HtmlUtils { public headAndBodyHtml(doc: any) { const output = []; if (doc.head) output.push(doc.head.innerHTML); if (doc.body) output.push(doc.body.innerHTML); return output.join('\n'); } public isSelfClosingTag(tagName: string) { return selfClosingElements.includes(tagName.toLowerCase()); } // Returns the **encoded** URLs, so to be useful they should be decoded again before use. public extractImageUrls(html: string) { if (!html) return []; const output = []; let matches; while ((matches = imageRegex.exec(html))) { output.push(matches[2]); } return output.filter(url => !!url); } public replaceImageUrls(html: string, callback: Function) { return this.processImageTags(html, (data: any) => { const newSrc = callback(data.src); return { type: 'replaceSource', src: newSrc, }; }); } // Note that the URLs provided by this function are URL-encoded, which is // usually what you want for web URLs. But if they are file:// URLs and the // file path is going to be used, it will need to be unescaped first. The // transformed SRC, must also be escaped before being sent back to this // function. public processImageTags(html: string, callback: Function) { if (!html) return ''; return html.replace(imageRegex, (_v: string, before: string, src: string, after: string) => { const action = callback({ src: src }); if (!action) return ``; if (action.type === 'replaceElement') { return action.html; } if (action.type === 'replaceSource') { return ``; } if (action.type === 'setAttributes') { const attrHtml = this.attributesHtml(action.attrs); return ``; } throw new Error(`Invalid action: ${action.type}`); }); } public prependBaseUrl(html: string, baseUrl: string) { if (!html) return ''; return html.replace(anchorRegex, (_v: string, before: string, href: string, after: string) => { const newHref = urlUtils.prependBaseUrl(href, baseUrl); return ``; }); } public attributesHtml(attr: any) { const output = []; for (const n in attr) { if (!attr.hasOwnProperty(n)) continue; output.push(`${n}="${htmlentities(attr[n])}"`); } return output.join(' '); } public stripHtml(html: string) { const output: string[] = []; const tagStack: any[] = []; const currentTag = () => { if (!tagStack.length) return ''; return tagStack[tagStack.length - 1]; }; const disallowedTags = ['script', 'style', 'head', 'iframe', 'frameset', 'frame', 'object', 'base']; const parser = new htmlparser2.Parser({ onopentag: (name: string) => { tagStack.push(name.toLowerCase()); }, ontext: (decodedText: string) => { if (disallowedTags.includes(currentTag())) return; output.push(decodedText); }, onclosetag: (name: string) => { if (currentTag() === name.toLowerCase()) tagStack.pop(); }, }, { decodeEntities: true }); parser.write(html); parser.end(); return output.join('').replace(/\s+/g, ' '); } } export default new HtmlUtils();