Go Validator Playground

Iterate & test your go-playground/validator struct tags

Go to the app!

What is this?

This is a simple web app that allows you to test your go-playground/validator struct tags. You can use it at https://apps.abhijithota.me/go-validator-playground.

Purpose

go-playground/validator is probably the most popular Go validation library. It uses (or exploits, dare I say) struct tags to validate the particular struct fields.

It's pretty flexible, but it's also a PITA when you misspell something or forget the syntax. This tool is not a silver bullet but it is here to help you find out what's wrong with the code more quickly.

How does it work?

It uses WebAssembly to run the go-playground/validator library in the browser.

• User enters the struct type definition.
• User enters the corresponding JSON data.
• These two (string) values are passed to the WebAssembly module.
• The struct definition is parsed and the struct type is created dynamically using some reflect magic.
• The JSON is unmarshalled into the struct.
• The actual validation is performed.
• Errors and invalid fields/tags are returned back to the JS code.

Todo

• Tests
• Add highlights in the textarea for invalid fields/tags
• Syntax highlighting maybe?
• Minimum responsiveness
• Write blog post — "A primer on Go reflection"
• Maybe buy a domain if enough people use it

A word by the author

I mostly coded this as a way to explore WebAssembly and out of frustration with not knowing the unpredictable behaviour of struct tags.

It is mostly a proof of concept. I've tested in as much as possible manually but it might still fail, in which case, please reload the page and try again.

Thanks to https://gotemplate.io/ for the inspiration.