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December 21, 2023 16:03
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CSS-in-JS that supports strict CSP - PoC
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| <!DOCTYPE HTML> | |
| <html xmlns="http://www.w3.org/1999/xhtml"> | |
| <head> | |
| <meta charset="utf-8" /> | |
| <meta http-equiv="Content-Security-Policy" content="script-src code.jquery.com 'nonce-2726c7f26c'; style-src 'nonce-2726c7f26c'" /> | |
| <title></title> | |
| <meta name="Description" content=""/> | |
| <link rel="shortcut icon" href=""/> | |
| <!--[if IE]> | |
| <script src="http://html5shim.googlecode.com/svn/trunk/html5.js"></script> | |
| <![endif]--> | |
| <!-- | |
| <link href="css/style.css" rel="stylesheet"/> | |
| --> | |
| <script src="https://code.jquery.com/jquery-3.4.1.min.js"></script> | |
| <script nonce="2726c7f26c" src="style.js"></script> | |
| <meta name="viewport" content="width=device-width, initial-scale=1.0" /> | |
| </head> | |
| <body> | |
| <script nonce="2726c7f26c"> | |
| const nonce = '2726c7f26c'; | |
| $('<p>This is Styled Text</p>').style({ | |
| color: 'blue', | |
| background: 'darkgrey', | |
| padding: 10 | |
| }, nonce).appendTo('body'); | |
| $('<p>This is Styled Text</p>').style({ | |
| color: 'blue', | |
| background: 'darkgrey', | |
| padding: 10 | |
| }, nonce).appendTo('body'); | |
| </script> | |
| </body> | |
| </html> | |
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| (() => { | |
| const __DEBUG__ = true; | |
| // based on https://stackoverflow.com/a/18639999/387194 | |
| const crc32 = (() => { | |
| const makeCRCTable = () => { | |
| let c; | |
| const crcTable = []; | |
| for(let n =0; n < 256; n++){ | |
| c = n; | |
| for(let k =0; k < 8; k++){ | |
| c = ((c&1) ? (0xEDB88320 ^ (c >>> 1)) : (c >>> 1)); | |
| } | |
| crcTable[n] = c; | |
| } | |
| return crcTable; | |
| }; | |
| const crcTable = makeCRCTable(); | |
| return (str) => { | |
| let crc = 0 ^ (-1); | |
| for (let i = 0; i < str.length; i++ ) { | |
| crc = (crc >>> 8) ^ crcTable[(crc ^ str.charCodeAt(i)) & 0xFF]; | |
| } | |
| return (crc ^ (-1)) >>> 0; | |
| }; | |
| })(); | |
| const hash = (string) => { | |
| return crc32(string).toString(16); | |
| }; | |
| function empty_rule(sheet, class_name) { | |
| const index = sheet.cssRules.length; | |
| sheet.insertRule(`.${class_name} { }`, index); | |
| return sheet.cssRules[index]; | |
| } | |
| function make_style(nonce = null) { | |
| return $(`<style type="text/css"${nonce ? ` nonce="${nonce}"` : ''}/>`).appendTo(document.head); | |
| } | |
| function set_css(sheet, class_name, style) { | |
| const selector = `.${class_name}`; | |
| let rule = [...sheet.cssRules].find(rule => { | |
| return rule.selectorText === selector; | |
| }); | |
| if (!rule) { | |
| rule = empty_rule(sheet, class_name); | |
| } | |
| Object.assign(rule.style, style); | |
| } | |
| function dump_css(sheet) { | |
| return [...sheet.cssRules].map(rule => rule.cssText).join('\n') | |
| } | |
| const cache = new Map(); | |
| $.fn.style = function(style, nonce = null) { | |
| const repr = JSON.stringify(style); | |
| const class_name = `terminal-${hash(repr)}`; | |
| if (!cache.has(class_name)) { | |
| const $style = make_style(nonce); | |
| const { sheet } = $style.get(0); | |
| set_css(sheet, class_name, style); | |
| cache.set(class_name, true); | |
| if (__DEBUG__) { | |
| $style.text(dump_css(sheet)); | |
| } | |
| } | |
| this.addClass(class_name); | |
| return this; | |
| }; | |
| })(); |
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Live demo CSS-in-JS-with-CSP.html