字符串或数组的两种状态的差异

Question

对于字符串和数组，我有一个 "old" 状态和一个 "new" 状态（经过一些修改）。

我需要经常向服务器发送更改（使用 AJAX/XMLHttpRequest），如果可能的话，以一种有效的方式（如果只有一个元素，请不要重新发送 200 KB 的数据）该数组已 changed/has 被移动 deleted/has）。示例：

var oldstate1 = 'hello how are you? very good and you? thanks for asking! this text will be removed.';
var newstate1 = 'hello how are you? very good and you? new text here. thanks for asking!';

var oldstate2 = [[1732, "item1"], [1732, "will be deleted"], [23, "will be moved"], [23, "hello"]];
var newstate2 = [[23, "will be moved"], [1732, "item1"], [23, "hello"], [126, "new item"]];

当然，我可以用 delete、insert、move、update 等事件手动编写客户端和服务器之间的协议，然后发送这些事件带有 AJAX，服务器将相应地更新其数据库。但是要正确地做到这一点非常乏味。

问题：有没有更聪明的方法来编码只在 oldstate 和 newstate 之间的变化 Javascript 的大字符串或数组？ 以一种可以在后端轻松解码的方式，运行 Python.

类似于字符串或数组的 diff/patch 算法，在 JS（客户端）和 Python（后端）之间理解。

注：

字符串的解决方案可能就足够了，"array case" 将被 "string case" 和 JSON.stringigy(...)
相关但没有直接解决问题：How to get the difference between two arrays in JavaScript?

Answer 1

如果没有第三方工具，这可能是可能的（如果是这样，请随时 post 另一个答案）。

经过进一步研究，我发现了这个项目：diff-match-patch and particularly this example。

Originally built in 2006 to power Google Docs, this library is now available in C++, C#, Dart, Java, JavaScript, Lua, Objective C, and Python.

var oldstate1 = "hello how are you? very good and you? blablablablablablablablablablablablablablablablablablablablablablablablablablablablablablablablabla. thanks for asking! this text will be removed.";
var newstate1 = "hello how are you? very good and you? blablablablablablablablablablablablablablablablablablablablablablablablablablablablablablablablabla.new text here. thanks for asking!";
var dmp = new diff_match_patch();
var diff = dmp.diff_main(oldstate1, newstate1);
dmp.diff_cleanupSemantic(diff);
console.log(dmp.diff_toDelta(diff))    
// =138 +new text here. =19 -27

<script src="https://cdnjs.cloudflare.com/ajax/libs/diff_match_patch/20121119/diff_match_patch.js"></script>

这个 delta + oldstate1 然后可以在服务器端使用 Python 来重建 newstate1:

import diff_match_patch as dmp_module
dmp = dmp_module.diff_match_patch()

oldstate1 = "hello how are you? very good and you? blablablablablablablablablablablablablablablablablablablablablablablablablablablablablablablablabla. thanks for asking! this text will be removed."
delta = "=138\t+new text here.\t=19\t-27"
patch = dmp.patch_make(oldstate1, dmp.diff_fromDelta(oldstate1, delta))
newstate1 = dmp.patch_apply(patch, oldstate1)[0]
print(newstate1)

另见 this issue。

字符串或数组的两种状态的差异

Diff of two states of a string or array

javascript

python

arrays

string

diff