gistfile1.go

package main

import (
	"encoding/json"
	"fmt"
	"net/http"
	"io/ioutil"
)

type Deploy struct {
	RefSpec     string `json:"refspec"`
	Environment string `json:"environment"`
	User        string `json:"user"`
}

func deployHandler(w http.ResponseWriter, r *http.Request) {
	body, readErr := ioutil.ReadAll(r.Body)
	if readErr != nil {
		fmt.Println("I didn't get that.")
		panic(readErr)
	}

	deploy := new(Deploy)
	parseErr := json.Unmarshal(body, &deploy)
	if parseErr != nil {
		fmt.Println("It doesn't parse.")
		panic(parseErr)
	}

	fmt.Printf("refspec:%v\n", deploy.RefSpec)
	fmt.Printf("environment:%v\n", deploy.Environment)
	fmt.Printf("user:%v\n", deploy.User)
}

func main() {
	http.HandleFunc("/deploy", deployHandler)
	http.ListenAndServe(":8080", nil)
}

I didn't say it was useful...