package main
import (
"encoding/json"
"fmt"
"io"
"io/ioutil"
"net/http"
"strconv"
"strings"
)
const addr = "localhost:7070"
type City struct {
ID string
Name string `json:"name"`
Location string `json:"location"`
}
func (c City) toJson() string {
return fmt.Sprintf(`{"name":"%s","location":"%s"}`,
c.Name,
c.Location)
}
func main() {
s := createServer(addr)
go s.ListenAndServe()
cities, err := getCities()
if err != nil {
panic(err)
}
fmt.Printf("Retrived cities: %v
", cities)
city, err := saveCity(City{"", "Paris", "France"})
if err != nil {
panic(err)
}
fmt.Printf("Saved city: %v
", city)
}
func saveCity(city City) (City, error) {
r, err := http.Post("http://"+addr+"/cities",
"application/json",
strings.NewReader(city.toJson()))
if err != nil {
return City{}, err
}
defer r.Body.Close()
return decodeCity(r.Body)
}
func getCities() ([]City, error) {
r, err := http.Get("http://" + addr + "/cities")
if err != nil {
return nil, err
}
defer r.Body.Close()
return decodeCities(r.Body)
}
func decodeCity(r io.Reader) (City, error) {
city := City{}
dec := json.NewDecoder(r)
err := dec.Decode(&city)
return city, err
}
func decodeCities(r io.Reader) ([]City, error) {
cities := []City{}
dec := json.NewDecoder(r)
err := dec.Decode(&cities)
return cities, err
}
func createServer(addr string) http.Server {
cities := []City{City{"1", "Prague", "Czechia"}, City{"2", "Bratislava", "Slovakia"}}
mux := http.NewServeMux()
mux.HandleFunc("/cities", func(w http.ResponseWriter, r *http.Request) {
enc := json.NewEncoder(w)
if r.Method == http.MethodGet {
enc.Encode(cities)
} else if r.Method == http.MethodPost {
data, err := ioutil.ReadAll(r.Body)
if err != nil {
http.Error(w, err.Error(), 500)
}
r.Body.Close()
city := City{}
json.Unmarshal(data, &city)
city.ID = strconv.Itoa(len(cities) + 1)
cities = append(cities, city)
enc.Encode(city)
}
})
return http.Server{
Addr: addr,
Handler: mux,
}
}
/*
Retrived cities: [{1 Prague Czechia} {2 Bratislava Slovakia}]
Saved city: {3 Paris France}
*/