http_server.go

package main

import (
    "fmt"
    "log"
    "net/http"
    "encoding/json"
)

type test_struct struct {
    Juca string
}

func handler(rw http.ResponseWriter, req *http.Request) {
    decoder := json.NewDecoder(req.Body)
    var t test_struct   
    err := decoder.Decode(&t)
    if err != nil {
        panic("error decoding json")
        fmt.Fprintf(rw, "fail")
    } else {
        fmt.Fprintf(rw, "ok")
    }
    log.Println(t.Juca)
}

func main() {
    http.HandleFunc("/", handler)
    http.ListenAndServe(":8889", nil)
}