JSON encode returning blank Golang [closed] - json

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I have a very simple http resonse in my server where i json encode a struct. But its sending a blank of just {}
I don't know if i am doing it wrong but i get no errors. This is my json encode:
// Set uuid as string to user struct
user := User{uuid: uuid.String()}
fmt.Println(user) // check it has the uuid
responseWriter.Header().Set("Content-Type", "application/json")
responseWriter.WriteHeader(http.StatusCreated)
json.NewEncoder(responseWriter).Encode(user)
On the recieving end the data has:
Content-Type application/json
Content-Length 3
STATUS HTTP/1.1 201 Created
{}
Why does it not give me the uuid data? Am i doing something wrong with my encoding?

Answer 1

Export the field name by making the first character of the identifier's name a Unicode upper case letter (Unicode class "Lu").
Try this:
package main
import (
"encoding/json"
"fmt"
"log"
"net/http"
)
type User struct {
Uuid string
}
func handler(responseWriter http.ResponseWriter, r *http.Request) {
user := User{Uuid: "id1234657..."} // Set uuid as string to user struct
fmt.Println(user) // check it has the uuid
responseWriter.Header().Set("Content-Type", "application/json")
responseWriter.WriteHeader(http.StatusCreated)
json.NewEncoder(responseWriter).Encode(user)
}
func main() {
http.HandleFunc("/", handler) // set router
err := http.ListenAndServe(":9090", nil) // set listen port
if err != nil {
log.Fatal("ListenAndServe: ", err)
}
}
output(http://localhost:9090/):
{"Uuid":"id1234657..."}