微信小程序MD5加密接口的处理

通常情况下，微信小程序的接口是以url+key方式进行对接，但是有时候，接口会有MD5加密，这是为了让接口更加安全，不轻易被人调用。下图是PC网站调用数据的ajax代码（图中的url不是真实的链接，只是为方便演示）

由于小程序不自带MD5解析的底层JS，那么，我们可以在page/util文件中创建MD5.js的文件

/* 
 * A JavaScript implementation of the RSA Data Security, Inc. MD5 Message 
 * Digest Algorithm, as defined in RFC 1321. 
 * Version 1.1 Copyright (C) Paul Johnston 1999 - 2002. 
 * Code also contributed by Greg Holt 
 * See http://pajhome.org.uk/site/legal.html for details. 
 */  
  
/* 
 * Add integers, wrapping at 2^32. This uses 16-bit operations internally 
 * to work around bugs in some JS interpreters. 
 */  
function safe_add(x, y)  
{  
  var lsw = (x & 0xFFFF) + (y & 0xFFFF)  
  var msw = (x >> 16) + (y >> 16) + (lsw >> 16)  
  return (msw << 16) | (lsw & 0xFFFF)  
}  
  
/* 
 * Bitwise rotate a 32-bit number to the left. 
 */  
function rol(num, cnt)  
{  
  return (num << cnt) | (num >>> (32 - cnt))  
}  
  
/* 
 * These functions implement the four basic operations the algorithm uses. 
 */  
function cmn(q, a, b, x, s, t)  
{  
  return safe_add(rol(safe_add(safe_add(a, q), safe_add(x, t)), s), b)  
}  
function ff(a, b, c, d, x, s, t)  
{  
  return cmn((b & c) | ((~b) & d), a, b, x, s, t)  
}  
function gg(a, b, c, d, x, s, t)  
{  
  return cmn((b & d) | (c & (~d)), a, b, x, s, t)  
}  
function hh(a, b, c, d, x, s, t)  
{  
  return cmn(b ^ c ^ d, a, b, x, s, t)  
}  
function ii(a, b, c, d, x, s, t)  
{  
  return cmn(c ^ (b | (~d)), a, b, x, s, t)  
}  
  
/* 
 * Calculate the MD5 of an array of little-endian words, producing an array 
 * of little-endian words. 
 */  
function coreMD5(x)  
{  
  var a =  1732584193  
  var b = -271733879  
  var c = -1732584194  
  var d =  271733878  
  
  for(var i = 0; i < x.length; i += 16)  
  {  
    var olda = a  
    var oldb = b  
    var oldc = c  
    var oldd = d  
  
    a = ff(a, b, c, d, x[i+ 0], 7 , -680876936)  
    d = ff(d, a, b, c, x[i+ 1], 12, -389564586)  
    c = ff(c, d, a, b, x[i+ 2], 17,  606105819)  
    b = ff(b, c, d, a, x[i+ 3], 22, -1044525330)  
    a = ff(a, b, c, d, x[i+ 4], 7 , -176418897)  
    d = ff(d, a, b, c, x[i+ 5], 12,  1200080426)  
    c = ff(c, d, a, b, x[i+ 6], 17, -1473231341)  
    b = ff(b, c, d, a, x[i+ 7], 22, -45705983)  
    a = ff(a, b, c, d, x[i+ 8], 7 ,  1770035416)  
    d = ff(d, a, b, c, x[i+ 9], 12, -1958414417)  
    c = ff(c, d, a, b, x[i+10], 17, -42063)  
    b = ff(b, c, d, a, x[i+11], 22, -1990404162)  
    a = ff(a, b, c, d, x[i+12], 7 ,  1804603682)  
    d = ff(d, a, b, c, x[i+13], 12, -40341101)  
    c = ff(c, d, a, b, x[i+14], 17, -1502002290)  
    b = ff(b, c, d, a, x[i+15], 22,  1236535329)  
  
    a = gg(a, b, c, d, x[i+ 1], 5 , -165796510)  
    d = gg(d, a, b, c, x[i+ 6], 9 , -1069501632)  
    c = gg(c, d, a, b, x[i+11], 14,  643717713)  
    b = gg(b, c, d, a, x[i+ 0], 20, -373897302)  
    a = gg(a, b, c, d, x[i+ 5], 5 , -701558691)  
    d = gg(d, a, b, c, x[i+10], 9 ,  38016083)  
    c = gg(c, d, a, b, x[i+15], 14, -660478335)  
    b = gg(b, c, d, a, x[i+ 4], 20, -405537848)  
    a = gg(a, b, c, d, x[i+ 9], 5 ,  568446438)  
    d = gg(d, a, b, c, x[i+14], 9 , -1019803690)  
    c = gg(c, d, a, b, x[i+ 3], 14, -187363961)  
    b = gg(b, c, d, a, x[i+ 8], 20,  1163531501)  
    a = gg(a, b, c, d, x[i+13], 5 , -1444681467)  
    d = gg(d, a, b, c, x[i+ 2], 9 , -51403784)  
    c = gg(c, d, a, b, x[i+ 7], 14,  1735328473)  
    b = gg(b, c, d, a, x[i+12], 20, -1926607734)  
  
    a = hh(a, b, c, d, x[i+ 5], 4 , -378558)  
    d = hh(d, a, b, c, x[i+ 8], 11, -2022574463)  
    c = hh(c, d, a, b, x[i+11], 16,  1839030562)  
    b = hh(b, c, d, a, x[i+14], 23, -35309556)  
    a = hh(a, b, c, d, x[i+ 1], 4 , -1530992060)  
    d = hh(d, a, b, c, x[i+ 4], 11,  1272893353)  
    c = hh(c, d, a, b, x[i+ 7], 16, -155497632)  
    b = hh(b, c, d, a, x[i+10], 23, -1094730640)  
    a = hh(a, b, c, d, x[i+13], 4 ,  681279174)  
    d = hh(d, a, b, c, x[i+ 0], 11, -358537222)  
    c = hh(c, d, a, b, x[i+ 3], 16, -722521979)  
    b = hh(b, c, d, a, x[i+ 6], 23,  76029189)  
    a = hh(a, b, c, d, x[i+ 9], 4 , -640364487)  
    d = hh(d, a, b, c, x[i+12], 11, -421815835)  
    c = hh(c, d, a, b, x[i+15], 16,  530742520)  
    b = hh(b, c, d, a, x[i+ 2], 23, -995338651)  
  
    a = ii(a, b, c, d, x[i+ 0], 6 , -198630844)  
    d = ii(d, a, b, c, x[i+ 7], 10,  1126891415)  
    c = ii(c, d, a, b, x[i+14], 15, -1416354905)  
    b = ii(b, c, d, a, x[i+ 5], 21, -57434055)  
    a = ii(a, b, c, d, x[i+12], 6 ,  1700485571)  
    d = ii(d, a, b, c, x[i+ 3], 10, -1894986606)  
    c = ii(c, d, a, b, x[i+10], 15, -1051523)  
    b = ii(b, c, d, a, x[i+ 1], 21, -2054922799)  
    a = ii(a, b, c, d, x[i+ 8], 6 ,  1873313359)  
    d = ii(d, a, b, c, x[i+15], 10, -30611744)  
    c = ii(c, d, a, b, x[i+ 6], 15, -1560198380)  
    b = ii(b, c, d, a, x[i+13], 21,  1309151649)  
    a = ii(a, b, c, d, x[i+ 4], 6 , -145523070)  
    d = ii(d, a, b, c, x[i+11], 10, -1120210379)  
    c = ii(c, d, a, b, x[i+ 2], 15,  718787259)  
    b = ii(b, c, d, a, x[i+ 9], 21, -343485551)  
  
    a = safe_add(a, olda)  
    b = safe_add(b, oldb)  
    c = safe_add(c, oldc)  
    d = safe_add(d, oldd)  
  }  
  return [a, b, c, d]  
}  
  
/* 
 * Convert an array of little-endian words to a hex string. 
 */  
function binl2hex(binarray)  
{  
  var hex_tab = "0123456789abcdef"  
  var str = ""  
  for(var i = 0; i < binarray.length * 4; i++)  
  {  
    str += hex_tab.charAt((binarray[i>>2] >> ((i%4)*8+4)) & 0xF) +  
           hex_tab.charAt((binarray[i>>2] >> ((i%4)*8)) & 0xF)  
  }  
  return str  
}  
  
/* 
 * Convert an array of little-endian words to a base64 encoded string. 
 */  
function binl2b64(binarray)  
{  
  var tab = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/"  
  var str = ""  
  for(var i = 0; i < binarray.length * 32; i += 6)  
  {  
    str += tab.charAt(((binarray[i>>5] << (i%32)) & 0x3F) |  
                      ((binarray[i>>5+1] >> (32-i%32)) & 0x3F))  
  }  
  return str  
}  
  
/* 
 * Convert an 8-bit character string to a sequence of 16-word blocks, stored 
 * as an array, and append appropriate padding for MD4/5 calculation. 
 * If any of the characters are >255, the high byte is silently ignored. 
 */  
function str2binl(str)  
{  
  var nblk = ((str.length + 8) >> 6) + 1 // number of 16-word blocks  
  var blks = new Array(nblk * 16)  
  for(var i = 0; i < nblk * 16; i++) blks[i] = 0  
  for(var i = 0; i < str.length; i++)  
    blks[i>>2] |= (str.charCodeAt(i) & 0xFF) << ((i%4) * 8)  
  blks[i>>2] |= 0x80 << ((i%4) * 8)  
  blks[nblk*16-2] = str.length * 8  
  return blks  
}  
  
/* 
 * Convert a wide-character string to a sequence of 16-word blocks, stored as 
 * an array, and append appropriate padding for MD4/5 calculation. 
 */  
function strw2binl(str)  
{  
  var nblk = ((str.length + 4) >> 5) + 1 // number of 16-word blocks  
  var blks = new Array(nblk * 16)  
  for(var i = 0; i < nblk * 16; i++) blks[i] = 0  
  for(var i = 0; i < str.length; i++)  
    blks[i>>1] |= str.charCodeAt(i) << ((i%2) * 16)  
  blks[i>>1] |= 0x80 << ((i%2) * 16)  
  blks[nblk*16-2] = str.length * 16  
  return blks  
}  
  
/* 
 * External interface 
 */  
function hexMD5 (str) { return binl2hex(coreMD5( str2binl(str))) }  
function hexMD5w(str) { return binl2hex(coreMD5(strw2binl(str))) }  
function b64MD5 (str) { return binl2b64(coreMD5( str2binl(str))) }  
function b64MD5w(str) { return binl2b64(coreMD5(strw2binl(str))) }  
/* Backward compatibility */  
function calcMD5(str) { return binl2hex(coreMD5( str2binl(str))) }  
module.exports = {  
  hexMD5: hexMD5  
}  

而与接口进行数据交互的界面，js文件大致如下：

var util = require('../../utils/md5.js');
var app = getApp()
var timestamp = new Date().getTime();
var verify = util.hexMD5(timestamp + 'xE%(msPb}=0F!?wo')
// md5(timestamp + 'xE%(msPb}=0F!?wo'); 
var Url = "http://baidu.com/mob.php?m=mobile&c=index&a=lists&callback=success_jsonpCallback&__=992a8ae5538627c5d98608cca1de6dae&t=1492086644327&_=1492086644310";

var API_Key = "xE%(msPb}=0F!?wo";
Page({
  data: {
    title: "",
    articles: [],
    scrollTop: 0,
    scrollHeight: 0,
    __: verify,
    t: timestamp,
    /** 
        * 页面配置 
        */
    winWidth: '',
    winHeight: '',
    // tab切换  
    currentTab: 0,
  },
 
  onLoad: function() {  
    console.log("url is:"+Url)
    var that = this;  
    /** 
     * 发出https请求获取数据
     */  
     wx.request({
    url:Url+ "?station=" + that.data.inputValue + "&key=" + API_Key,
    data:{},
    header:{
      'content-type': 'application/json'
    },
 success:function(res){
        var articles = that.data.articles;
        wx.hideToast();
  			var data = res.data;
         var articles_ = data.slide;
        console.log("res.data is =")
        console.log(res.data);
         //添加新数据
         for(var i in articles_){
           articles.push(articles_[i]);
         }
  			console.log('当前数据',articles);
  			that.setData({
  				title:data.title,
  			   articles:data.slide
  			});
    }
  })