uoloadfile

const env = require('config.js'); //配置文件，在这文件里配置你的OSS keyId和KeySecret,timeout:87600;
const base64 = require('base64.js');//Base64,hmac,sha1,crypto相关算法
require('hmac.js');
require('sha1.js');
const Crypto = require('crypto.js');
/*
 *上传文件到阿里云oss
 *@param - filePath :图片的本地资源路径
 *@param - dir:表示要传到哪个目录下
 *@param - successc:成功回调
 *@param - failc:失败回调
 */ 
const uploadFile = function (filePath, dir, successc, failc) {
  if (!filePath || filePath.length < 9) {
    wx.showModal({
      title: '图片错误',
      content: '请重试',
      showCancel: false,
    })
    return;
  }
  console.log('上传图片.....');
  //图片名字 可以自行定义，     这里是采用当前的时间戳 + 150内的随机数来给图片命名的
  const aliyunFileKey = dir + Math.random().toString(36).slice(-8) + new Date().getTime() + Math.floor(Math.random() * 150) + '.png';
  const aliyunServerURL = env.uploadImageUrl;//OSS地址，需要https
  const accessid = env.OSSAccessKeyId;
  const policyBase64 = getPolicyBase64();
  const signature = getSignature(policyBase64);//获取签名
  wx.uploadFile({
    url: aliyunServerURL,//开发者服务器 url
    filePath: filePath,//要上传文件资源的路径
    name: 'file',//必须填file
    formData: {
      'key': aliyunFileKey,
      'policy': policyBase64,
      'OSSAccessKeyId': accessid,
      'signature': signature,
      'success_action_status': '200',
    },
    success: function (res) {
      if (res.statusCode != 200) {
        failc(new Error('上传错误:' + JSON.stringify(res)))
        return;
      }
       successc(aliyunServerURL+aliyunFileKey);
    },
    fail: function (err) {
      err.wxaddinfo = aliyunServerURL;
      failc(err);
    },
  })
}
const getPolicyBase64 = function () {
  let date = new Date();
  date.setHours(date.getHours() + env.timeout);
  let srcT = date.toISOString();
  const policyText = {
    "expiration": srcT, //设置该Policy的失效时间，超过这个失效时间之后，就没有办法通过这个policy上传文件了 
    "conditions": [
      ["content-length-range", 0, 10 * 1024 * 1024] // 设置上传文件的大小限制,5mb
    ]
  };
  const policyBase64 = base64.encode(JSON.stringify(policyText));
  return policyBase64;
}
const getSignature = function (policyBase64) {
  const accesskey = env.AccessKeySecret;
  const bytes = Crypto.HMAC(Crypto.SHA1, policyBase64, accesskey, {
    asBytes: true
  });
  const signature = Crypto.util.bytesToBase64(bytes);
  return signature;
}
module.exports = uploadFile;

配置config文件

var fileHost = "https://xxx.oss-cn-hangzhou.aliyuncs.com/";//你的阿里云地址最后面跟上一个/   在你当前小程序的后台的uploadFile 合法域名也要配上这个域名
var config = {
   //aliyun OSS config
   uploadImageUrl: `${fileHost}`, // 默认存在根目录，可根据需求改
  AccessKeySecret: 'xxxxxxxxxxxxxxx',        // AccessKeySecret 去你的阿里云上控制台上找
  OSSAccessKeyId: 'xxxxxxxxxxx',         // AccessKeyId 去你的阿里云上控制台上找
   timeout: 87600 //这个是上传文件时Policy的失效时间
};
module.exports = config

需要以下算法
base64，crypto，hmac，sha1

base64

var base64EncodeChars = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
var base64DecodeChars = new Array(
    -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
    -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
    -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, 62, -1, -1, -1, 63,
    52, 53, 54, 55, 56, 57, 58, 59, 60, 61, -1, -1, -1, -1, -1, -1,
    -1, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14,
    15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, -1, -1, -1, -1, -1,
    -1, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40,
    41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, -1, -1, -1, -1, -1);
function encode(str) {
    var out, i, len;
    var c1, c2, c3;
    len = str.length;
    i = 0;
    out = "";
    while (i < len) {
        c1 = str.charCodeAt(i++) & 0xff;
        if (i == len) {
            out += base64EncodeChars.charAt(c1 >> 2);
            out += base64EncodeChars.charAt((c1 & 0x3) << 4);
            out += "==";
            break;
        }
        c2 = str.charCodeAt(i++);
        if (i == len) {
            out += base64EncodeChars.charAt(c1 >> 2);
            out += base64EncodeChars.charAt(((c1 & 0x3) << 4) | ((c2 & 0xF0) >> 4));
            out += base64EncodeChars.charAt((c2 & 0xF) << 2);
            out += "=";
            break;
        }
        c3 = str.charCodeAt(i++);
        out += base64EncodeChars.charAt(c1 >> 2);
        out += base64EncodeChars.charAt(((c1 & 0x3) << 4) | ((c2 & 0xF0) >> 4));
        out += base64EncodeChars.charAt(((c2 & 0xF) << 2) | ((c3 & 0xC0) >> 6));
        out += base64EncodeChars.charAt(c3 & 0x3F);
    }
    return out;
}
function decode(str) {
    var c1, c2, c3, c4;
    var i, len, out;
    len = str.length;
    i = 0;
    out = "";
    while (i < len) {
        /* c1 */
        do {
            c1 = base64DecodeChars[str.charCodeAt(i++) & 0xff];
        } while (i < len && c1 == -1);
        if (c1 == -1)
            break;
        /* c2 */
        do {
            c2 = base64DecodeChars[str.charCodeAt(i++) & 0xff];
        } while (i < len && c2 == -1);
        if (c2 == -1)
            break;
        out += String.fromCharCode((c1 << 2) | ((c2 & 0x30) >> 4));
        /* c3 */
        do {
            c3 = str.charCodeAt(i++) & 0xff;
            if (c3 == 61)
                return out;
            c3 = base64DecodeChars[c3];
        } while (i < len && c3 == -1);
        if (c3 == -1)
            break;
        out += String.fromCharCode(((c2 & 0XF) << 4) | ((c3 & 0x3C) >> 2));
        /* c4 */
        do {
            c4 = str.charCodeAt(i++) & 0xff;
            if (c4 == 61)
                return out;
            c4 = base64DecodeChars[c4];
        } while (i < len && c4 == -1);
        if (c4 == -1)
            break;
        out += String.fromCharCode(((c3 & 0x03) << 6) | c4);
    }
    return out;
}
function utf16to8(str) {
    var out, i, len, c;
    out = "";
    len = str.length;
    for (i = 0; i < len; i++) {
        c = str.charCodeAt(i);
        if ((c >= 0x0001) && (c <= 0x007F)) {
            out += str.charAt(i);
        } else if (c > 0x07FF) {
            out += String.fromCharCode(0xE0 | ((c >> 12) & 0x0F));
            out += String.fromCharCode(0x80 | ((c >> 6) & 0x3F));
            out += String.fromCharCode(0x80 | ((c >> 0) & 0x3F));
        } else {
            out += String.fromCharCode(0xC0 | ((c >> 6) & 0x1F));
            out += String.fromCharCode(0x80 | ((c >> 0) & 0x3F));
        }
    }
    return out;
}
function utf8to16(str) {
    var out, i, len, c;
    var char2, char3;
    out = "";
    len = str.length;
    i = 0;
    while (i < len) {
        c = str.charCodeAt(i++);
        switch (c >> 4) {
            case 0: case 1: case 2: case 3: case 4: case 5: case 6: case 7:
                // 0xxxxxxx
                out += str.charAt(i - 1);
                break;
            case 12: case 13:
                // 110x xxxx 10xx xxxx
                char2 = str.charCodeAt(i++);
                out += String.fromCharCode(((c & 0x1F) << 6) | (char2 & 0x3F));
                break;
            case 14:
                // 1110 xxxx 10xx xxxx 10xx xxxx
                char2 = str.charCodeAt(i++);
                char3 = str.charCodeAt(i++);
                out += String.fromCharCode(((c & 0x0F) << 12) |
                    ((char2 & 0x3F) << 6) |
                    ((char3 & 0x3F) << 0));
                break;
        }
    }
    return out;
}
module.exports = {
    encode: encode,
    decode: decode,
    utf16to8: utf16to8,
    utf8to16: utf8to16
}

crypto

const Crypto = {};
(function(){
var base64map = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
// Crypto utilities
var util = Crypto.util = {
    // Bit-wise rotate left
    rotl: function (n, b) {
        return (n << b) | (n >>> (32 - b));
    },
    // Bit-wise rotate right
    rotr: function (n, b) {
        return (n << (32 - b)) | (n >>> b);
    },
    // Swap big-endian to little-endian and vice versa
    endian: function (n) {
        // If number given, swap endian
        if (n.constructor == Number) {
            return util.rotl(n,  8) & 0x00FF00FF |
                   util.rotl(n, 24) & 0xFF00FF00;
        }
        // Else, assume array and swap all items
        for (var i = 0; i < n.length; i++)
            n[i] = util.endian(n[i]);
        return n;
    },
    // Generate an array of any length of random bytes
    randomBytes: function (n) {
        for (var bytes = []; n > 0; n--)
            bytes.push(Math.floor(Math.random() * 256));
        return bytes;
    },
    // Convert a string to a byte array
    stringToBytes: function (str) {
        var bytes = [];
        for (var i = 0; i < str.length; i++)
            bytes.push(str.charCodeAt(i));
        return bytes;
    },
    // Convert a byte array to a string
    bytesToString: function (bytes) {
        var str = [];
        for (var i = 0; i < bytes.length; i++)
            str.push(String.fromCharCode(bytes[i]));
        return str.join("");
    },
    // Convert a string to big-endian 32-bit words
    stringToWords: function (str) {
        var words = [];
        for (var c = 0, b = 0; c < str.length; c++, b += 8)
            words[b >>> 5] |= str.charCodeAt(c) << (24 - b % 32);
        return words;
    },
    // Convert a byte array to big-endian 32-bits words
    bytesToWords: function (bytes) {
        var words = [];
        for (var i = 0, b = 0; i < bytes.length; i++, b += 8)
            words[b >>> 5] |= bytes[i] << (24 - b % 32);
        return words;
    },
    // Convert big-endian 32-bit words to a byte array
    wordsToBytes: function (words) {
        var bytes = [];
        for (var b = 0; b < words.length * 32; b += 8)
            bytes.push((words[b >>> 5] >>> (24 - b % 32)) & 0xFF);
        return bytes;
    },
    // Convert a byte array to a hex string
    bytesToHex: function (bytes) {
        var hex = [];
        for (var i = 0; i < bytes.length; i++) {
            hex.push((bytes[i] >>> 4).toString(16));
            hex.push((bytes[i] & 0xF).toString(16));
        }
        return hex.join("");
    },
    // Convert a hex string to a byte array
    hexToBytes: function (hex) {
        var bytes = [];
        for (var c = 0; c < hex.length; c += 2)
            bytes.push(parseInt(hex.substr(c, 2), 16));
        return bytes;
    },
    // Convert a byte array to a base-64 string
    bytesToBase64: function (bytes) {
        // Use browser-native function if it exists
        if (typeof btoa == "function") return btoa(util.bytesToString(bytes));
        var base64 = [],
            overflow;
        for (var i = 0; i < bytes.length; i++) {
            switch (i % 3) {
                case 0:
                    base64.push(base64map.charAt(bytes[i] >>> 2));
                    overflow = (bytes[i] & 0x3) << 4;
                    break;
                case 1:
                    base64.push(base64map.charAt(overflow | (bytes[i] >>> 4)));
                    overflow = (bytes[i] & 0xF) << 2;
                    break;
                case 2:
                    base64.push(base64map.charAt(overflow | (bytes[i] >>> 6)));
                    base64.push(base64map.charAt(bytes[i] & 0x3F));
                    overflow = -1;
            }
        }
        // Encode overflow bits, if there are any
        if (overflow != undefined && overflow != -1)
            base64.push(base64map.charAt(overflow));
        // Add padding
        while (base64.length % 4 != 0) base64.push("=");
        return base64.join("");
    },
    // Convert a base-64 string to a byte array
    base64ToBytes: function (base64) {
        // Use browser-native function if it exists
        if (typeof atob == "function") return util.stringToBytes(atob(base64));
        // Remove non-base-64 characters
        base64 = base64.replace(/[^A-Z0-9+\/]/ig, "");
        var bytes = [];
        for (var i = 0; i < base64.length; i++) {
            switch (i % 4) {
                case 1:
                    bytes.push((base64map.indexOf(base64.charAt(i - 1)) << 2) |
                               (base64map.indexOf(base64.charAt(i)) >>> 4));
                    break;
                case 2:
                    bytes.push(((base64map.indexOf(base64.charAt(i - 1)) & 0xF) << 4) |
                               (base64map.indexOf(base64.charAt(i)) >>> 2));
                    break;
                case 3:
                    bytes.push(((base64map.indexOf(base64.charAt(i - 1)) & 0x3) << 6) |
                               (base64map.indexOf(base64.charAt(i))));
                    break;
            }
        }
        return bytes;
    }
};
// Crypto mode namespace
Crypto.mode = {};
})();
module.exports = Crypto;

hmac

const Crypto = require('./crypto.js');
(function(){
// Shortcut
var util = Crypto.util;
Crypto.HMAC = function (hasher, message, key, options) {
    // Allow arbitrary length keys
    key = key.length > hasher._blocksize * 4 ?
          hasher(key, { asBytes: true }) :
          util.stringToBytes(key);
    // XOR keys with pad constants
    var okey = key,
        ikey = key.slice(0);
    for (var i = 0; i < hasher._blocksize * 4; i++) {
        okey[i] ^= 0x5C;
        ikey[i] ^= 0x36;
    }
    var hmacbytes = hasher(util.bytesToString(okey) +
                           hasher(util.bytesToString(ikey) + message, { asString: true }),
                           { asBytes: true });
    return options && options.asBytes ? hmacbytes :
           options && options.asString ? util.bytesToString(hmacbytes) :
           util.bytesToHex(hmacbytes);
};
})();
module.exports = Crypto;

sha1

const Crypto = require('./crypto.js');
(function(){
// Shortcut
var util = Crypto.util;
// Public API
var SHA1 = Crypto.SHA1 = function (message, options) {
    var digestbytes = util.wordsToBytes(SHA1._sha1(message));
    return options && options.asBytes ? digestbytes :
           options && options.asString ? util.bytesToString(digestbytes) :
           util.bytesToHex(digestbytes);
};
// The core
SHA1._sha1 = function (message) {
    var m  = util.stringToWords(message),
        l  = message.length * 8,
        w  =  [],
        H0 =  1732584193,
        H1 = -271733879,
        H2 = -1732584194,
        H3 =  271733878,
        H4 = -1009589776;
    // Padding
    m[l >> 5] |= 0x80 << (24 - l % 32);
    m[((l + 64 >>> 9) << 4) + 15] = l;
    for (var i = 0; i < m.length; i += 16) {
        var a = H0,
            b = H1,
            c = H2,
            d = H3,
            e = H4;
        for (var j = 0; j < 80; j++) {
            if (j < 16) w[j] = m[i + j];
            else {
                var n = w[j-3] ^ w[j-8] ^ w[j-14] ^ w[j-16];
                w[j] = (n << 1) | (n >>> 31);
            }
            var t = ((H0 << 5) | (H0 >>> 27)) + H4 + (w[j] >>> 0) + (
                     j < 20 ? (H1 & H2 | ~H1 & H3) + 1518500249 :
                     j < 40 ? (H1 ^ H2 ^ H3) + 1859775393 :
                     j < 60 ? (H1 & H2 | H1 & H3 | H2 & H3) - 1894007588 :
                              (H1 ^ H2 ^ H3) - 899497514);
            H4 =  H3;
            H3 =  H2;
            H2 = (H1 << 30) | (H1 >>> 2);
            H1 =  H0;
            H0 =  t;
        }
        H0 += a;
        H1 += b;
        H2 += c;
        H3 += d;
        H4 += e;
    }
    return [H0, H1, H2, H3, H4];
};
// Package private blocksize
SHA1._blocksize = 16;
})();
module.exports = Crypto;