Add jandan pic support

Signed-off-by: Xuanwo <xuanwo.cn@gmail.com>

router.js

@@ -65,4 +65,7 @@ router.get('/douban/movie/intheaters', require('./routes/douban/intheaters'));
 router.get('/douban/movie/intheaters/:score', require('./routes/douban/intheaters'));
 router.get('/douban/movie/intheaters/:score/:city', require('./routes/douban/intheaters'));
 
+// 煎蛋
+router.get('/jandan/pic', require('./routes/jandan/pic'));
+
 module.exports = router;

routes/jandan/pic.js

@@ -0,0 +1,132 @@
+const axios = require('axios');
+const art = require('art-template');
+const path = require('path');
+const cheerio = require('cheerio');
+const crypto = require('crypto');
+const config = require('../../config');
+
+const md5 = (i) => crypto.createHash('md5').update(i).digest().toString('hex');
+
+const base64_decode = (i) => new Buffer(i, 'base64').toString('binary');
+
+const chr = (i) => String.fromCharCode(i);
+
+const ord = (i) => i.charCodeAt();
+
+const time = () => parseInt(new Date().getTime() / 1000);
+
+// jandan_magic will load a magic string from jandan's script, which will be used in jandan_decode.
+const jandan_magic = async (url) => {
+    const script = await axios({
+        method: 'get',
+        url: 'http:' + url,
+        headers: {
+            'User-Agent': config.ua,
+            'Referer': 'http://jandan.net'
+        }
+    });
+    const regex = /e,"([a-zA-Z0-9]{32})"/;
+    return script.data.match(regex)[1];
+};
+
+// jandan_decode is borrowed from jandan.net, which is used in function jandan_load_img.
+const jandan_decode = (m, r) => {
+    let q = 4;
+    r = md5(r);
+    let o = md5(r.substr(0, 16));
+    let n = md5(r.substr(16, 16));
+    let l = m.substr(0, q);
+    let c = o + md5(o + l);
+    let k;
+    m = m.substr(q);
+    k = base64_decode(m);
+
+    const h = new Array(256);
+    for (let g = 0; g < 256; g++) {
+        h[g] = g;
+    }
+    const b = new Array(256);
+    for (let g = 0; g < 256; g++) {
+        b[g] = c.charCodeAt(g % c.length);
+    }
+    for (let f = 0, g = 0; g < 256; g++) {
+        f = (f + h[g] + b[g]) % 256;
+        [h[g], h[f]] = [h[f], h[g]];
+    }
+
+    let t = '';
+    k = k.split('');
+    for (let p = 0, f = 0, g = 0; g < k.length; g++) {
+        p = (p + 1) % 256;
+        f = (f + h[p]) % 256;
+        [h[p], h[f]] = [h[f], h[p]];
+        t += chr(ord(k[g]) ^ h[(h[p] + h[f]) % 256]);
+    }
+    if ((t.substr(0, 10) == 0 || t.substr(0, 10) - time() > 0) && t.substr(10, 16) == md5(t.substr(26) + n).substr(0, 16)) {
+        t = t.substr(26);
+    }
+    return t;
+};
+
+
+module.exports = async (ctx) => {
+    const response = await axios({
+        method: 'get',
+        url: 'http://jandan.net/pic',
+        headers: {
+            'User-Agent': config.ua,
+            'Referer': 'http://jandan.net'
+        }
+    });
+
+    const $ = cheerio.load(response.data);
+
+    let script_url = '';
+    $('script').each((index, item) => {
+        let s = $(item).attr('src');
+        if (s && s.startsWith('//cdn.jandan.net/static/min/')) {
+            script_url = s;
+        }
+    });
+    const magic_string = await jandan_magic(script_url);
+
+    const items = Array();
+    $('.commentlist > li').each((_, item) => {
+        // Get current comment id, if comment_id is 'adsense', just need to skip..
+        const comment_id = $(item).attr('id');
+        if (comment_id === 'adsense') {
+            return;
+        }
+
+        // Get current comment's link.
+        const link = $(item).find('.righttext').find('a').attr('href');
+        if (link === undefined) {
+            return;
+        }
+
+        // Get current comment's images.
+        // TODO: should support multiple images.
+        let img_url = $(item).find('.text').find('.img-hash').html();
+        if (img_url === null) {
+            return;
+        }
+        img_url = jandan_decode(img_url, magic_string);
+        img_url = img_url.replace(/(\/\/\w+\.sinaimg\.cn\/)(\w+)(\/.+\.(gif|jpg|jpeg))/, '$1large$3');
+
+        // TODO: should load user's comments.
+
+        items.push({
+            title: comment_id,
+            description: `<img referrerpolicy="no-referrer"  src="http:${img_url}">`,
+            link: `http:${link}`
+        });
+    });
+
+    ctx.body = art(path.resolve(__dirname, '../../views/rss.art'), {
+        title: '煎蛋无聊图',
+        link: 'http://jandan.net/pic',
+        description: '煎蛋官方无聊图，无限活力的热门图区。',
+        lastBuildDate: new Date().toUTCString(),
+        item: items
+    });
+};