From af90cf71922b4a7461e2abc464f7fea731cf5bff Mon Sep 17 00:00:00 2001
From: Xuanwo <xuanwo.cn@gmail.com>
Date: Sun, 27 May 2018 21:17:46 +0800
Subject: [PATCH] Fix jandon pic algorithm (#219)

* Fix jandon pic algorithm

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

* Make eslint happy

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

* Use Buffer.from instead for new Buffer

Signed-off-by: Xuanwo <xuanwo.cn@gmail.com>
---
 routes/jandan/pic.js | 79 ++------------------------------------------
 1 file changed, 3 insertions(+), 76 deletions(-)

diff --git a/routes/jandan/pic.js b/routes/jandan/pic.js
index d38d6a7f0..4aba1afca 100644
--- a/routes/jandan/pic.js
+++ b/routes/jandan/pic.js
@@ -1,75 +1,11 @@
 const axios = require('../../utils/axios');
 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];
-};
+const base64_decode = (i) => Buffer.from(i, 'base64').toString('binary');
 
 // jandan_decode is borrowed from jandan.net, which is used in function jandan_load_img.
-const jandan_decode = (m, r) => {
-    const q = 4;
-    r = md5(r);
-    const o = md5(r.substr(0, 16));
-    const n = md5(r.substr(16, 16));
-    const l = m.substr(0, q);
-    const 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;
-};
+const jandan_decode = (m) => base64_decode(m);
 
 module.exports = async (ctx) => {
     const response = await axios({
@@ -83,15 +19,6 @@ module.exports = async (ctx) => {
 
     const $ = cheerio.load(response.data);
 
-    let script_url = '';
-    $('script').each((index, item) => {
-        const 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..
@@ -118,7 +45,7 @@ module.exports = async (ctx) => {
         if (img_url === null) {
             return;
         }
-        img_url = jandan_decode(img_url, magic_string);
+        img_url = jandan_decode(img_url);
         img_url = img_url.replace(/(\/\/\w+\.sinaimg\.cn\/)(\w+)(\/.+\.(gif|jpg|jpeg))/, '$1large$3');
 
         // TODO: should load user's comments.