I’ve met an error Validation Failed (422) when using Gitalk in my blog. This article records how I fixed this error. If you are in trouble with this issue and you are looking for a solution, reading this article may help you.

I posted a new article in my blog and found the Gitalk report on such an issue. My Gitalk has been working for a long time before this issue occurs. I’ve checked that the Gitalk for my other posts works normally and only the new post has the issue, which means the issue should be a standalone problem that is related to the post self.

By searching google - gitalk issue #102 I understood the problem is that the length of my new post’s URL is excessive long (> 50 characters).

For each post, Gitalk created a Github issue under my blog project’s repository to track the comment thread of the post. The issue’s id is used to generate the issue’s label which is used by Gitalk to identify the comment thread.

However, the problem here is that label length is restricted to maximum of 50 characters ( Not sure if it is a hidden rule or a BUG here 😕 ).

In my Gitalk configuration, the issue id is set to

id: { {page.url} },

So if the page.url is too long and is beyond the restriction, the issue’s label cannot be created and the Validation Failed error will be thrown out.

The root cause is clear now, let me fix it.

The straightforward way is to use a shorter URL to avoid this issue. But I don’t like this restriction that blocking me write a post. To convert the URL to a fixed-length string looks like a better solution. Why not try the hash function? The interesting thing is that I found there has already been the same solution online -> issue fix, which uses the MD5 method. This method not only unifies the URL length but also differentiates them.

It is good!

There is a workable MD5 library - JavaScript-MD5 on Github, I folk it, and the rest thing is quite simple.

I added the below code snippet for loading the JavaScript-MD5 library in my comments.html

<script type="text/javascript" src="https://cdn.jsdelivr.net/gh/gangdong/gangdong.github.io@dev/assets/js/md5.min.js"></script>

and reset the Gitalk id to

id: md5(location.pathname),

Committed the update.

I reopened the page and the error was gone, by checking the Gitalk issue’s label, it has been converted to MD5 code.

This means the solution is working now! 😊