问题: 上传图片含有大量重复
解决思路.获取图片MD5值 传到后台进行比较
一、引入spark-md5.js
var sMD5 = require('../../../utils/spark-md5.js')
二、选择图片 获取文件
wx.chooseImage({
success: res => {
wx.getFileSystemManager().readFile({
filePath: res.tempFilePaths[0], //选择图片返回的相对路径
// encoding: 'binary', //编码格式
success: res => {
//成功的回调
console.log('data:image/png;base64,' , res)
console.log(res.data)
var spark = new sMD5.ArrayBuffer();
spark.append(res.data);
var hexHash = spark.end(false);
console.log(hexHash)
}
})
}
})
三、spark-md5.js
(function (factory) {
if (typeof exports === 'object') {
// Node/CommonJS
module.exports = factory();
} else if (typeof define === 'function' && define.amd) {
// AMD
define(factory);
} else {
// Browser globals (with support for web workers)
var glob;
try {
glob = window;
} catch (e) {
glob = self;
}
glob.SparkMD5 = factory();
}
}(function (undefined) {
'use strict';
/*
* Fastest md5 implementation around (JKM md5).
* Credits: Joseph Myers
*
* @see http://www.myersdaily.org/joseph/javascript/md5-text.html
* @see http://jsperf.com/md5-shootout/7
*/
/* this function is much faster,
so if possible we use it. Some IEs
are the only ones I know of that
need the idiotic second function,
generated by an if clause. */
var add32 = function (a, b) {
return (a + b) & 0xFFFFFFFF;
},
hex_chr = ['0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'a', 'b', 'c', 'd', 'e', 'f'];
function cmn(q, a, b, x, s, t) {
a = add32(add32(a, q), add32(x, t));
return add32((a << s) | (a >>> (32 - s)), b);
}
function md5cycle(x, k) {
var a = x[0],
b = x[1],
c = x[2],
d = x[3];
a += (b & c | ~b & d) + k[0] - 680876936 | 0;
a = (a << 7 | a >>> 25) + b | 0;
d += (a & b | ~a & c) + k[1] - 389564586 | 0;
d = (d << 12 | d >>> 20) + a | 0;
c += (d & a | ~d & b) + k[2] + 606105819 | 0;
c = (c << 17 | c >>> 15) + d | 0;
b += (c & d | ~c & a) + k[3] - 1044525330 | 0;
b = (b << 22 | b >>> 10) + c | 0;
a += (b & c | ~b & d) + k[4] - 176418897 | 0;
a = (a << 7 | a >>> 25) + b | 0;
d += (a & b | ~a & c) + k[5] + 1200080426 | 0;
d = (d << 12 | d >>> 20) + a | 0;
c += (d & a | ~d & b) + k[6] - 1473231341 | 0;
c = (c << 17 | c >>> 15) + d | 0;
b += (c & d | ~c & a) + k[7] - 45705983 | 0;
b = (b << 22 | b >>> 10) + c | 0;
a += (b & c | ~b & d) + k[8] + 1770035416 | 0;
a = (a << 7 | a >>> 25) + b | 0;
d += (a & b | ~a & c) + k[9] - 1958414417 | 0;
d = (d << 12 | d >>> 20) + a | 0;
c += (d & a | ~d & b) + k[10] - 42063 | 0;
c = (c << 17 | c >>> 15) + d | 0;
b += (c & d | ~c & a) + k[11] - 1990404162 | 0;
b = (b << 22 | b >>> 10) + c | 0;
a += (b & c | ~b & d) + k[12] + 1804603682 | 0;
a = (a << 7 | a >>> 25) + b | 0;
d += (a & b | ~a & c) + k[13] - 40341101 | 0;
d = (d << 12 | d >>> 20) + a | 0;
c += (d & a | ~d & b) + k[14] - 1502002290 | 0;
c = (c << 17 | c >>> 15) + d | 0;
b += (c & d | ~c & a) + k[15] + 1236535329 | 0;
b = (b << 22 | b >>> 10) + c | 0;
a += (b & d | c & ~d) + k[1] - 165796510 | 0;
a = (a << 5 | a >>> 27) + b | 0;
d += (a & c | b & ~c) + k[6] - 1069501632 | 0;
d = (d << 9 | d >>> 23) + a | 0;
c += (d & b | a & ~b) + k[11] + 643717713 | 0;
c = (c << 14 | c >>> 18) + d | 0;
b += (c & a | d & ~a) + k[0] - 373897302 | 0;
b = (b << 20 | b >>> 12) + c | 0;
a += (b & d | c & ~d) + k[5] - 701558691 | 0;
a = (a << 5 | a >>> 27) + b | 0;
d += (a & c | b & ~c) + k[10] + 38016083 | 0;
d = (d << 9 | d >>> 23) + a | 0;
c += (d & b | a & ~b) + k[15] - 660478335 | 0;
c = (c << 14 | c >>> 18) + d | 0;
b += (c & a | d & ~a) + k[4] - 405537848 | 0;
b = (b << 20 | b >>> 12) + c | 0;
a += (b & d | c & ~d) + k[9] + 568446438 | 0;
a = (a << 5 | a >>> 27) + b | 0;
d += (a & c | b & ~c) + k[14] - 1019803690 | 0;
d = (d << 9 | d >>> 23) + a | 0;
c += (d & b | a & ~b) + k[3] - 187363961 | 0;
c = (c << 14 | c >>> 18) + d | 0;
b += (c & a | d & ~a) + k[8] + 1163531501 | 0;
b = (b << 20 | b >>> 12) + c | 0;
a += (b & d | c & ~d) + k[13] - 1444681467 | 0;
a = (a << 5 | a >>> 27) + b | 0;
d += (a & c | b & ~c) + k[2] - 51403784 | 0;
d = (d << 9 | d >>> 23) + a | 0;
c += (d & b | a & ~b) + k[7] + 1735328473 | 0;
c = (c << 14 | c >>> 18) + d | 0;
b += (c & a | d & ~a) + k[12] - 1926607734 | 0;
b = (b << 20 | b >>> 12) + c | 0;
a += (b ^ c ^ d) + k[5] - 378558 | 0;
a = (a << 4 | a >>> 28) + b | 0;
d += (a ^ b ^ c) + k[8] - 2022574463 | 0;
d = (d << 11 | d >>> 21) + a | 0;
c += (d ^ a ^ b) + k[11] + 1839030562 | 0;
c = (c << 16 | c >>> 16) + d | 0;
b += (c ^ d ^ a) + k[14] - 35309556 | 0;
b = (b << 23 | b >>> 9) + c | 0;
a += (b ^ c ^ d) + k[1] - 1530992060 | 0;
a = (a << 4 | a >>> 28) + b | 0;
d += (a ^ b ^ c) + k[4] + 1272893353 | 0;
d = (d << 11 | d >>> 21) + a | 0;
c += (d ^ a ^ b) + k[7] - 155497632 | 0;
c = (c << 16 | c >>> 16) + d | 0;
b += (c ^ d ^ a) + k[10] - 1094730640 | 0;
b = (b << 23 | b >>> 9) + c | 0;
a += (b ^ c ^ d) + k[13] + 681279174 | 0;
a = (a << 4 | a >>> 28) + b | 0;
d += (a ^ b ^ c) + k[0] - 358537222 | 0;
d = (d << 11 | d >>> 21) + a | 0;
c += (d ^ a ^ b) + k[3] - 722521979 | 0;
c = (c << 16 | c >>> 16) + d | 0;
b += (c ^ d ^ a) + k[6] + 76029189 | 0;
b = (b << 23 | b >>> 9) + c | 0;
a += (b ^ c ^ d) + k[9] - 640364487 | 0;
a = (a << 4 | a >>> 28) + b | 0;
d += (a ^ b ^ c) + k[12] - 421815835 | 0;
d = (d << 11 | d >>> 21) + a | 0;
c += (d ^ a ^ b) + k[15] + 530742520 | 0;
c = (c << 16 | c >>> 16) + d | 0;
b += (c ^ d ^ a) + k[2] - 995338651 | 0;
b = (b << 23 | b >>> 9) + c | 0;
a += (c ^ (b | ~d)) + k[0] - 198630844 | 0;
a = (a << 6 | a >>> 26) + b | 0;
d += (b ^ (a | ~c)) + k[7] + 1126891415 | 0;
d = (d << 10 | d >>> 22) + a | 0;
c += (a ^ (d | ~b)) + k[14] - 1416354905 | 0;
c = (c << 15 | c >>> 17) + d | 0;
b += (d ^ (c | ~a)) + k[5] - 57434055 | 0;
b = (b << 21 |b >>> 11) + c | 0;
a += (c ^ (b | ~d)) + k[12] + 1700485571 | 0;
a = (a << 6 | a >>> 26) + b | 0;
d += (b ^ (a | ~c)) + k[3] - 1894986606 | 0;
d = (d << 10 | d >>> 22) + a | 0;
c += (a ^ (d | ~b)) + k[10] - 1051523 | 0;
c = (c << 15 | c >>> 17) + d | 0;
b += (d ^ (c | ~a)) + k[1] - 2054922799 | 0;
b = (b << 21 |b >>> 11) + c | 0;
a += (c ^ (b | ~d)) + k[8] + 1873313359 | 0;
a = (a << 6 | a >>> 26) + b | 0;
d += (b ^ (a | ~c)) + k[15] - 30611744 | 0;
d = (d << 10 | d >>> 22) + a | 0;
c += (a ^ (d | ~b)) + k[6] - 1560198380 | 0;
c = (c << 15 | c >>> 17) + d | 0;
b += (d ^ (c | ~a)) + k[13] + 1309151649 | 0;
b = (b << 21 |b >>> 11) + c | 0;
a += (c ^ (b | ~d)) + k[4] - 145523070 | 0;
a = (a << 6 | a >>> 26) + b | 0;
d += (b ^ (a | ~c)) + k[11] - 1120210379 | 0;
d = (d << 10 | d >>> 22) + a | 0;
c += (a ^ (d | ~b)) + k[2] + 718787259 | 0;
c = (c << 15 | c >>> 17) + d | 0;
b += (d ^ (c | ~a)) + k[9] - 343485551 | 0;
b = (b << 21 | b >>> 11) + c | 0;
x[0] = a + x[0] | 0;
x[1] = b + x[1] | 0;
x[2] = c + x[2] | 0;
x[3] = d + x[3] | 0;
}
function md5blk(s) {
var md5blks = [],
i; /* Andy King said do it this way. */
for (i = 0; i < 64; i += 4) {
md5blks[i >> 2] = s.charCodeAt(i) + (s.charCodeAt(i + 1) << 8) + (s.charCodeAt(i + 2) << 16) + (s.charCodeAt(i + 3) << 24);
}
return md5blks;
}
function md5blk_array(a) {
var md5blks = [],
i; /* Andy King said do it this way. */
for (i = 0; i < 64; i += 4) {
md5blks[i >> 2] = a[i] + (a[i + 1] << 8) + (a[i + 2] << 16) + (a[i + 3] << 24);
}
return md5blks;
}
function md51(s) {
var n = s.length,
state = [1732584193, -271733879, -1732584194, 271733878],
i,
length,
tail,
tmp,
lo,
hi;
for (i = 64; i <= n; i += 64) {
md5cycle(state, md5blk(s.substring(i - 64, i)));
}
s = s.substring(i - 64);
length = s.length;
tail = [0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0];
for (i = 0; i < length; i += 1) {
tail[i >> 2] |= s.charCodeAt(i) << ((i % 4) << 3);
}
tail[i >> 2] |= 0x80 << ((i % 4) << 3);
if (i > 55) {
md5cycle(state, tail);
for (i = 0; i < 16; i += 1) {
tail[i] = 0;
}
}
// Beware that the final length might not fit in 32 bits so we take care of that
tmp = n * 8;
tmp = tmp.toString(16).match(/(.*?)(.{0,8})$/);
lo = parseInt(tmp[2], 16);
hi = parseInt(tmp[1], 16) || 0;
tail[14] = lo;
tail[15] = hi;
md5cycle(state, tail);
return state;
}
function md51_array(a) {
var n = a.length,
state = [1732584193, -271733879, -1732584194, 271733878],
i,
length,
tail,
tmp,
lo,
hi;
for (i = 64; i <= n; i += 64) {
md5cycle(state, md5blk_array(a.subarray(i - 64, i)));
}
// Not sure if it is a bug, however IE10 will always produce a sub array of length 1
// containing the last element of the parent array if the sub array specified starts
// beyond the length of the parent array - weird.
// https://connect.microsoft.com/IE/feedback/details/771452/typed-array-subarray-issue
a = (i - 64) < n ? a.subarray(i - 64) : new Uint8Array(0);
length = a.length;
tail = [0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0];
for (i = 0; i < length; i += 1) {
tail[i >> 2] |= a[i] << ((i % 4) << 3);
}
tail[i >> 2] |= 0x80 << ((i % 4) << 3);
if (i > 55) {
md5cycle(state, tail);
for (i = 0; i < 16; i += 1) {
tail[i] = 0;
}
}
// Beware that the final length might not fit in 32 bits so we take care of that
tmp = n * 8;
tmp = tmp.toString(16).match(/(.*?)(.{0,8})$/);
lo = parseInt(tmp[2], 16);
hi = parseInt(tmp[1], 16) || 0;
tail[14] = lo;
tail[15] = hi;
md5cycle(state, tail);
return state;
}
function rhex(n) {
var s = '',
j;
for (j = 0; j < 4; j += 1) {
s += hex_chr[(n >> (j * 8 + 4)) & 0x0F] + hex_chr[(n >> (j * 8)) & 0x0F];
}
return s;
}
function hex(x) {
var i;
for (i = 0; i < x.length; i += 1) {
x[i] = rhex(x[i]);
}
return x.join('');
}
// In some cases the fast add32 function cannot be used..
if (hex(md51('hello')) !== '5d41402abc4b2a76b9719d911017c592') {
add32 = function (x, y) {
var lsw = (x & 0xFFFF) + (y & 0xFFFF),
msw = (x >> 16) + (y >> 16) + (lsw >> 16);
return (msw << 16) | (lsw & 0xFFFF);
};
}
// ---------------------------------------------------
/**
* ArrayBuffer slice polyfill.
*
* @see https://github.com/ttaubert/node-arraybuffer-slice
*/
if (typeof ArrayBuffer !== 'undefined' && !ArrayBuffer.prototype.slice) {
(function () {
function clamp(val, length) {
val = (val | 0) || 0;
if (val < 0) {
return Math.max(val + length, 0);
}
return Math.min(val, length);
}
ArrayBuffer.prototype.slice = function (from, to) {
var length = this.byteLength,
begin = clamp(from, length),
end = length,
num,
target,
targetArray,
sourceArray;
if (to !== undefined) {
end = clamp(to, length);
}
if (begin > end) {
return new ArrayBuffer(0);
}
num = end - begin;
target = new ArrayBuffer(num);
targetArray = new Uint8Array(target);
sourceArray = new Uint8Array(this, begin, num);
targetArray.set(sourceArray);
return target;
};
})();
}
// ---------------------------------------------------
/**
* Helpers.
*/
function toUtf8(str) {
if (/[\u0080-\uFFFF]/.test(str)) {
str = unescape(encodeURIComponent(str));
}
return str;
}
function utf8Str2ArrayBuffer(str, returnUInt8Array) {
var length = str.length,
buff = new ArrayBuffer(length),
arr = new Uint8Array(buff),
i;
for (i = 0; i < length; i += 1) {
arr[i] = str.charCodeAt(i);
}
return returnUInt8Array ? arr : buff;
}
function arrayBuffer2Utf8Str(buff) {
return String.fromCharCode.apply(null, new Uint8Array(buff));
}
function concatenateArrayBuffers(first, second, returnUInt8Array) {
var result = new Uint8Array(first.byteLength + second.byteLength);
result.set(new Uint8Array(first));
result.set(new Uint8Array(second), first.byteLength);
return returnUInt8Array ? result : result.buffer;
}
function hexToBinaryString(hex) {
var bytes = [],
length = hex.length,
x;
for (x = 0; x < length - 1; x += 2) {
bytes.push(parseInt(hex.substr(x, 2), 16));
}
return String.fromCharCode.apply(String, bytes);
}
// ---------------------------------------------------
/**
* SparkMD5 OOP implementation.
*
* Use this class to perform an incremental md5, otherwise use the
* static methods instead.
*/
function SparkMD5() {
// call reset to init the instance
this.reset();
}
/**
* Appends a string.
* A conversion will be applied if an utf8 string is detected.
*
* @param {String} str The string to be appended
*
* @return {SparkMD5} The instance itself
*/
SparkMD5.prototype.append = function (str) {
// Converts the string to utf8 bytes if necessary
// Then append as binary
this.appendBinary(toUtf8(str));
return this;
};
/**
* Appends a binary string.
*
* @param {String} contents The binary string to be appended
*
* @return {SparkMD5} The instance itself
*/
SparkMD5.prototype.appendBinary = function (contents) {
this._buff += contents;
this._length += contents.length;
var length = this._buff.length,
i;
for (i = 64; i <= length; i += 64) {
md5cycle(this._hash, md5blk(this._buff.substring(i - 64, i)));
}
this._buff = this._buff.substring(i - 64);
return this;
};
/**
* Finishes the incremental computation, reseting the internal state and
* returning the result.
*
* @param {Boolean} raw True to get the raw string, false to get the hex string
*
* @return {String} The result
*/
SparkMD5.prototype.end = function (raw) {
var buff = this._buff,
length = buff.length,
i,
tail = [0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0],
ret;
for (i = 0; i < length; i += 1) {
tail[i >> 2] |= buff.charCodeAt(i) << ((i % 4) << 3);
}
this._finish(tail, length);
ret = hex(this._hash);
if (raw) {
ret = hexToBinaryString(ret);
}
this.reset();
return ret;
};
/**
* Resets the internal state of the computation.
*
* @return {SparkMD5} The instance itself
*/
SparkMD5.prototype.reset = function () {
this._buff = '';
this._length = 0;
this._hash = [1732584193, -271733879, -1732584194, 271733878];
return this;
};
/**
* Gets the internal state of the computation.
*
* @return {Object} The state
*/
SparkMD5.prototype.getState = function () {
return {
buff: this._buff,
length: this._length,
hash: this._hash
};
};
/**
* Gets the internal state of the computation.
*
* @param {Object} state The state
*
* @return {SparkMD5} The instance itself
*/
SparkMD5.prototype.setState = function (state) {
this._buff = state.buff;
this._length = state.length;
this._hash = state.hash;
return this;
};
/**
* Releases memory used by the incremental buffer and other additional
* resources. If you plan to use the instance again, use reset instead.
*/
SparkMD5.prototype.destroy = function () {
delete this._hash;
delete this._buff;
delete this._length;
};
/**
* Finish the final calculation based on the tail.
*
* @param {Array} tail The tail (will be modified)
* @param {Number} length The length of the remaining buffer
*/
SparkMD5.prototype._finish = function (tail, length) {
var i = length,
tmp,
lo,
hi;
tail[i >> 2] |= 0x80 << ((i % 4) << 3);
if (i > 55) {
md5cycle(this._hash, tail);
for (i = 0; i < 16; i += 1) {
tail[i] = 0;
}
}
// Do the final computation based on the tail and length
// Beware that the final length may not fit in 32 bits so we take care of that
tmp = this._length * 8;
tmp = tmp.toString(16).match(/(.*?)(.{0,8})$/);
lo = parseInt(tmp[2], 16);
hi = parseInt(tmp[1], 16) || 0;
tail[14] = lo;
tail[15] = hi;
md5cycle(this._hash, tail);
};
/**
* Performs the md5 hash on a string.
* A conversion will be applied if utf8 string is detected.
*
* @param {String} str The string
* @param {Boolean} [raw] True to get the raw string, false to get the hex string
*
* @return {String} The result
*/
SparkMD5.hash = function (str, raw) {
// Converts the string to utf8 bytes if necessary
// Then compute it using the binary function
return SparkMD5.hashBinary(toUtf8(str), raw);
};
/**
* Performs the md5 hash on a binary string.
*
* @param {String} content The binary string
* @param {Boolean} [raw] True to get the raw string, false to get the hex string
*
* @return {String} The result
*/
SparkMD5.hashBinary = function (content, raw) {
var hash = md51(content),
ret = hex(hash);
return raw ? hexToBinaryString(ret) : ret;
};
// ---------------------------------------------------
/**
* SparkMD5 OOP implementation for array buffers.
*
* Use this class to perform an incremental md5 ONLY for array buffers.
*/
SparkMD5.ArrayBuffer = function () {
// call reset to init the instance
this.reset();
};
/**
* Appends an array buffer.
*
* @param {ArrayBuffer} arr The array to be appended
*
* @return {SparkMD5.ArrayBuffer} The instance itself
*/
SparkMD5.ArrayBuffer.prototype.append = function (arr) {
var buff = concatenateArrayBuffers(this._buff.buffer, arr, true),
length = buff.length,
i;
this._length += arr.byteLength;
for (i = 64; i <= length; i += 64) {
md5cycle(this._hash, md5blk_array(buff.subarray(i - 64, i)));
}
this._buff = (i - 64) < length ? new Uint8Array(buff.buffer.slice(i - 64)) : new Uint8Array(0);
return this;
};
/**
* Finishes the incremental computation, reseting the internal state and
* returning the result.
*
* @param {Boolean} raw True to get the raw string, false to get the hex string
*
* @return {String} The result
*/
SparkMD5.ArrayBuffer.prototype.end = function (raw) {
var buff = this._buff,
length = buff.length,
tail = [0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0],
i,
ret;
for (i = 0; i < length; i += 1) {
tail[i >> 2] |= buff[i] << ((i % 4) << 3);
}
this._finish(tail, length);
ret = hex(this._hash);
if (raw) {
ret = hexToBinaryString(ret);
}
this.reset();
return ret;
};
/**
* Resets the internal state of the computation.
*
* @return {SparkMD5.ArrayBuffer} The instance itself
*/
SparkMD5.ArrayBuffer.prototype.reset = function () {
this._buff = new Uint8Array(0);
this._length = 0;
this._hash = [1732584193, -271733879, -1732584194, 271733878];
return this;
};
/**
* Gets the internal state of the computation.
*
* @return {Object} The state
*/
SparkMD5.ArrayBuffer.prototype.getState = function () {
var state = SparkMD5.prototype.getState.call(this);
// Convert buffer to a string
state.buff = arrayBuffer2Utf8Str(state.buff);
return state;
};
/**
* Gets the internal state of the computation.
*
* @param {Object} state The state
*
* @return {SparkMD5.ArrayBuffer} The instance itself
*/
SparkMD5.ArrayBuffer.prototype.setState = function (state) {
// Convert string to buffer
state.buff = utf8Str2ArrayBuffer(state.buff, true);
return SparkMD5.prototype.setState.call(this, state);
};
SparkMD5.ArrayBuffer.prototype.destroy = SparkMD5.prototype.destroy;
SparkMD5.ArrayBuffer.prototype._finish = SparkMD5.prototype._finish;
/**
* Performs the md5 hash on an array buffer.
*
* @param {ArrayBuffer} arr The array buffer
* @param {Boolean} [raw] True to get the raw string, false to get the hex one
*
* @return {String} The result
*/
SparkMD5.ArrayBuffer.hash = function (arr, raw) {
var hash = md51_array(new Uint8Array(arr)),
ret = hex(hash);
return raw ? hexToBinaryString(ret) : ret;
};
return SparkMD5;
}));
参考：https://blog.csdn.net/aaron9185/article/details/84855014