Golang RESTful with MongoDB

rest-mongo.go

// modified by Carlos Santín
// Based on gist rest-mongo.go by : Narate Ketram
// twitter @kabalism

package main

import (
    "github.com/ant0ine/go-json-rest/rest"
    "gopkg.in/mgo.v2"
    "gopkg.in/mgo.v2/bson"
    "log"
    "net/http"
)

type Person struct {
    UserName   string `json:"username" bson:"username"`
    Name       string `json:"name" bson:"name"`
    LastName   string `json:"lastname" bson:"lastname"`
    Email      string `json:"email" bson:"email"`
    Profession string `json:"profession" bson:"profession"`
}

type Err struct {
    ErrCode int
    ErrMsg  string
}

func FindUser(user string) (Person, error) {
    session, err := mgo.Dial("127.0.0.1")
    p := Person{}
    if err != nil {
        return p, err
    }
    defer session.Close()
    c := session.DB("app_db").C("users")
    if err = c.Find(bson.M{"username": user}).One(&p); err != nil {
        return p, err
    }
    return p, nil
}

func AddUser(p Person) (err_msg Err) {
    session, err := mgo.Dial("127.0.0.1")
    if err != nil {
        err_msg = Err{1, "connection failed"}
    }
    defer session.Close()
    c := session.DB("app_db").C("users")
    tp := Person{} // temp person :P
    // if not found add new user
    // else return error user already exist
    if err := c.Find(bson.M{"username": &p.UserName}).One(&tp); err != nil {
        err_msg = Err{0, "done"}
        if err := c.Insert(&p); err != nil {
            err_msg = Err{1, "insert failed"}
        }
    } else {
        err_msg = Err{1, "user already exist"}
    }
    return
}

func GetUser(w rest.ResponseWriter, req *rest.Request) {
    name, err := FindUser(req.PathParam("name"))
    if err != nil {
        err_msg := Err{1, "Not found"}
        w.WriteJson(&err_msg)
    } else {
        w.WriteJson(&name)
    }
}

func NewUser(w rest.ResponseWriter, req *rest.Request) {
    p := Person{}
    err_msg := Err{}
    if err := req.DecodeJsonPayload(&p); err != nil {
        rest.Error(w, err.Error(), http.StatusInternalServerError)
        return
    } else {
        err_msg = AddUser(p)
    }
    w.WriteJson(&err_msg)
}

func main() {
    api := rest.NewApi()
    api.Use(rest.DefaultDevStack...)

    router, err := rest.MakeRouter(
        //rest.Get("/users", GetAllUsers),
        rest.Post("/new", NewUser),
        rest.Get("/u/:name", GetUser),
        //rest.Put("/users/:id", PutUser),
        //rest.Delete("/users/:id", DeleteUser),
    )

    if err != nil {
        log.Fatal(err)
    }

    api.SetApp(router)

    log.Fatal(http.ListenAndServe(":8080", api.MakeHandler()))
}