How to check string is in json format

Question

I want to create a function to receive an input string which can be string in json format or just a string. For example, something easy like following function.

Answer 1

In searching for an answer to this question, I found https://github.com/asaskevich/govalidator, which was tied to this blog post which describes creating an input validator: https://husobee.github.io/golang/validation/2016/01/08/input-validation.html. Just in case someone is looking for a quick library on doing this, I thought it would be useful to put that tool in an easy-to-find place.

This package uses the same method for isJSON that William King suggests, as follows:

// IsJSON check if the string is valid JSON (note: uses json.Unmarshal).
func IsJSON(str string) bool {
    var js json.RawMessage
    return json.Unmarshal([]byte(str), &js) == nil
}

This package gave me some greater insight into JSON in go, so it seemed useful to put here.

Answer 2

This might be an older post to the actual function in the standard library.

But you can just use the json.Valid() function in the "encoding/json" package.

   var tests = []string{
    `"Platypus"`,
    `Platypus`,
    `{"id":"1"}`,
    `{"id":"1}`,
}

for _, t := range tests {
    fmt.Printf("is valid: (%s) = %v\n", t, json.Valid([]byte(t)))
    
}

example https://play.golang.org/p/nfvOzQB919s