redis - 防止表单重复提交是怎么做的？

Question

关于防止表单重复提交的做法有很多，本人知道的有如下，只是简单讲讲，大家觉得什么办法最简单又有效？

1.有redis的环境
把提交的动作action，参数之类的作为redis的key，存进redis，设置一个很短的缓存时间，提交的时候判断如果存在这个key，说明是重复提交数据。

2.jquery前端判断
除了在程序端判断重复提交外，在页面前端也加一层措施，如点击提交按钮，按钮状态不可用（有的按钮用的a标签），如果不是按钮button，可以用jquery在提交的时候设置一个属性值，如果有了这个属性值，表示已经提交。

$("body").data("applycancel","unlock");

3.表单隐藏域token

生成一个随机数，放进session，给表单加一个隐藏域放进token，提交的时候判断表单的token隐藏域和session的值是否一致，如果不一致表示重复提交，处理表单的时候unset掉这个session。

各位还有什么办法，什么办法最好，谢谢！

Answer 1

Use Etag to implement optimistic locking mechanism in concurrency control. The following example is not limited to repeated submissions:

In a concurrent scenario, when multiple clients operate the same resource at the same time, a situation will arise: the resource operated by the client is changed under unknown circumstances.

A simple example:

User A posted a post with the content post-a,用户B看到了post-a之后在下面写评论，在B写评论期间用户A把帖子内容改成了post-aa。会产生的一个问题是，用户B针对post-a The comment he wrote looks weird^_^

The solution is very simple. When B sees A, give him a post resource identification tag-1. When B submits a comment, he submits it together with this identification tag-1. The server verifies the a priori conditions before accepting the request. If there is no change in the post content at that time, it is still tag-1, which means success.

If the content of the post changes, the new identification is tag-2, which does not match the tag-1 submitted by B, indicating that the resources have changed during the period, and 412 Precondition Failed will be returned. Then refresh the page or prompt, let B know this change and continue to comment.

The API situation is similar, you just need to add an identifier to the returned resources.

Answer 2

Generate a hash value from the parameters passed in, and store it in the hash_code field of the database. This field is used as a unique index. And each time it is inserted into the database, a hash value is generated in the same way to determine whether the hash value exists.