const config = require('@/config').value;
const cheerio = require('cheerio');
const logger = require('@/utils/logger');
// match path or sub-path
const matchPath = (path, paths) => {
for (const p of paths) {
if (path.startsWith(p) && (path.length === p.length || path[p.length] === '/')) {
return true;
}
}
return false;
};
// return ture if the path needs to be processed
const filterPath = (path) => {
const include = config.hotlink.includePaths;
const exclude = config.hotlink.excludePaths;
return !(include && !matchPath(path, include)) && !(exclude && matchPath(path, exclude));
};
const interpolate = (str, obj) => str.replace(/\${([^}]+)}/g, (_, prop) => obj[prop]);
// I don't want to keep another regex and
// URL will be the standard way to parse URL
const parseUrl = (str) => {
let url;
try {
url = new URL(str);
} catch (e) {
logger.error(`Failed to parse ${str}`);
}
return url;
};
const replaceUrls = (body, template) => {
// const $ = cheerio.load(body, { decodeEntities: false, xmlMode: true });
// ` ` => ` `
// so awful...
// "In HTML, using a closing tag on an empty element is usually invalid."
// https://developer.mozilla.org/en-US/docs/Glossary/Empty_element
// I guess it is just a workaround to drop ``, so this is what we exactly need:
const $ = cheerio.load(body, null, false);
$('img').each(function () {
const old_src = $(this).attr('src');
const url = parseUrl(old_src);
if (url) {
const new_src = interpolate(template, url);
$(this).attr('src', new_src);
}
});
return $.root().html();
};
module.exports = async (ctx, next) => {
await next();
const template = config.hotlink.template;
if (!template || !filterPath(ctx.request.path)) {
return;
}
// Assume that only description include image link
// and here we will only check them in description.
// Use Cheerio to load the description as html and filter all
// image link
if (ctx.state.data) {
if (ctx.state.data.description) {
ctx.state.data.description = replaceUrls(ctx.state.data.description, template);
}
ctx.state.data.item &&
ctx.state.data.item.forEach((item) => {
if (item.description) {
item.description = replaceUrls(item.description, template);
}
});
}
};