How to Unmarshal String-encoded Integers in Go?

Unmarshalling String-encoded Integers in Go

When attempting to unmarshal JSON with string values into an integer field, one may encounter the error: "json: cannot unmarshal string into Go value of type int64." This is because JSON unmarshaling by default assumes numeric types, such as int64, should contain numerical characters.

Issue:
A Go struct defining an int64 field is receiving JSON with the corresponding field encoded as a string. This mismatch in data types causes the unmarshaling process to fail.

Solution:
The recommended solution is to use the ",string" tag in the json struct tag for the integer field. This instructs the unmarshaling process to accept values of type string:

type tySurvey struct {
   Id   int64  `json:"id,string,omitempty"`
   Name string `json:"name,omitempty"`
}

Implementation:
With the modified struct, JSON data with an id field encoded as a string can now be successfully unmarshaled into a Go object of type tySurvey.

Note:
It's important to remember that specifying omitempty in the tag will not allow for the empty string to be decoded. omitempty is used exclusively for encoding purposes.

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