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gitea/web_src/js/markup/mermaid.js
silverwind 616146f904
Various Mermaid improvements (#18776)
* Various Mermaid improvments

- Render into iframe for improved security
- Use built-in dark theme instead of color inversion
- Remove flexbox attributes, resulting in more consistent size rendering
- Update API usage and update to latest version

* restart ci

* misc tweaks

* remove unneccesary declaration

* make it work without allow-same-origin, add loading=lazy

* remove loading attribute, does not seem to work

* rename variable

* skip roundtrip to DOM for rendering

* don't guess chart height

* update comment to make it clear it's intentional

* tweak

* replace deprecated 'scrolling' property

* remove unused css file

Co-authored-by: Lunny Xiao <xiaolunwen@gmail.com>
2022-02-16 11:28:29 +08:00

67 lines
2.2 KiB
JavaScript

import {isDarkTheme} from '../utils.js';
const {mermaidMaxSourceCharacters} = window.config;
const iframeCss = `
body {margin: 0; padding: 0}
#mermaid {display: block; margin: 0 auto}
`;
function displayError(el, err) {
el.closest('pre').classList.remove('is-loading');
const errorNode = document.createElement('div');
errorNode.setAttribute('class', 'ui message error markup-block-error mono');
errorNode.textContent = err.str || err.message || String(err);
el.closest('pre').before(errorNode);
}
export async function renderMermaid() {
const els = document.querySelectorAll('.markup code.language-mermaid');
if (!els.length) return;
const {default: mermaid} = await import(/* webpackChunkName: "mermaid" */'mermaid');
mermaid.initialize({
startOnLoad: false,
theme: isDarkTheme() ? 'dark' : 'neutral',
securityLevel: 'strict',
});
for (const el of els) {
const source = el.textContent;
if (mermaidMaxSourceCharacters >= 0 && source.length > mermaidMaxSourceCharacters) {
displayError(el, new Error(`Mermaid source of ${source.length} characters exceeds the maximum allowed length of ${mermaidMaxSourceCharacters}.`));
continue;
}
let valid;
try {
valid = mermaid.parse(source);
} catch (err) {
displayError(el, err);
}
if (!valid) {
el.closest('pre').classList.remove('is-loading');
continue;
}
try {
// can't use bindFunctions here because we can't cross the iframe boundary. This
// means js-based interactions won't work but they aren't intended to work either
mermaid.mermaidAPI.render('mermaid', source, (svgStr) => {
const heightStr = (svgStr.match(/height="(.+?)"/) || [])[1];
if (!heightStr) return displayError(el, new Error('Could not determine chart height'));
const iframe = document.createElement('iframe');
iframe.classList.add('markup-render');
iframe.sandbox = 'allow-scripts';
iframe.style.height = `${Math.ceil(parseFloat(heightStr))}px`;
iframe.srcdoc = `<html><head><style>${iframeCss}</style></head><body>${svgStr}</body></html>`;
el.closest('pre').replaceWith(iframe);
});
} catch (err) {
displayError(el, err);
}
}
}