以前の記事（GAE(Google App Engine) で Golang を開発するための環境を構築する）で環境まで作ったので今回は簡単な REST API を作ってみようと思います。
こんな順番で進めます
- 機能概要
- ソースコード
- 動作確認（ローカル）
- 動作確認（GAE）
機能概要
- GET / POST に対応
- それぞれパラメータを受け取れる
- レスポンスは JSON 形式
- 対応していない HTTP Method (PUT/DELETE etc) はエラーを返す
ソースコード
hello.go
package main
import (
"net/http"
"encoding/json"
)
// Response 用の構造体
type Result struct {
Status int
Description string
}
// hello に対して router を設定
func init() {
http.HandleFunc("/hello", handler)
}
// hello に binding された function
func handler(w http.ResponseWriter, r *http.Request) {
var result Result
switch r.Method {
case http.MethodGet:
v := r.FormValue("get_value")
result = Result{http.StatusOK, "http get result [" + v + "]"}
case http.MethodPost:
v := r.FormValue("post_value")
result = Result{http.StatusOK, "http post result [" + v + "]"}
default:
result = Result{http.StatusNotImplemented, "not implemented http mehtod"}
}
res, err := json.Marshal(result)
if err != nil {
http.Error(w, err.Error(), http.StatusInternalServerError)
} else {
w.Header().Set("Content-Type", "application/json")
w.Write(res)
}
}
app.yaml
application: hello-gae-go
version: 1
runtime: go
api_version: go1.8
handlers:
- url: /.*
script: _go_app
動作確認（ローカル）
起動
$ goapp serve
INFO 2017-10-08 12:49:16,475 devappserver2.py:115] Skipping SDK update check.
INFO 2017-10-08 12:49:16,535 api_server.py:299] Starting API server at: http://localhost:52820
INFO 2017-10-08 12:49:16,543 dispatcher.py:224] Starting module "default" running at: http://localhost:8080
INFO 2017-10-08 12:49:16,546 admin_server.py:116] Starting admin server at: http://localhost:8000
動作確認
GET
$ curl http://localhost:8080/hello?get_value=test | python -m json.tool
% Total % Received % Xferd Average Speed Time Time Time Current
Dload Upload Total Spent Left Speed
100 53 100 53 0 0 3665 0 --:--:-- --:--:-- --:--:-- 3785
{
"Description": "http get result [test]",
"Status": 200
}
POST
$ curl http://localhost:8080/hello -X POST -d "post_value=test" | python -m json.tool
% Total % Received % Xferd Average Speed Time Time Time Current
Dload Upload Total Spent Left Speed
100 69 100 54 100 15 4340 1205 --:--:-- --:--:-- --:--:-- 4153
{
"Description": "http post result [test]",
"Status": 200
}
PUT
$ curl http://localhost:8080/hello -X PUT -d "put_value=test" | python -m json.tool
% Total % Received % Xferd Average Speed Time Time Time Current
Dload Upload Total Spent Left Speed
100 72 100 58 100 14 4944 1193 --:--:-- --:--:-- --:--:-- 5272
{
"Description": "not implemented http mehtod",
"Status": 501
}
動作確認（GAE）
起動
$ goapp serve
INFO 2017-10-08 12:49:16,475 devappserver2.py:115] Skipping SDK update check.
INFO 2017-10-08 12:49:16,535 api_server.py:299] Starting API server at: http://localhost:52820
INFO 2017-10-08 12:49:16,543 dispatcher.py:224] Starting module "default" running at: http://localhost:8080
INFO 2017-10-08 12:49:16,546 admin_server.py:116] Starting admin server at: http://localhost:8000
動作確認
GET
$ curl https://hello-gae-go.appspot.com/hello?get_value=test | python -m json.tool
% Total % Received % Xferd Average Speed Time Time Time Current
Dload Upload Total Spent Left Speed
100 53 100 53 0 0 912 0 --:--:-- --:--:-- --:--:-- 913
{
"Description": "http get result [test]",
"Status": 200
}
POST
$ curl https://hello-gae-go.appspot.com/hello -X POST -d "post_value=test" | python -m json.tool
% Total % Received % Xferd Average Speed Time Time Time Current
Dload Upload Total Spent Left Speed
100 69 100 54 100 15 719 199 --:--:-- --:--:-- --:--:-- 710
{
"Description": "http post result [test]",
"Status": 200
}
PUT
$ curl https://hello-gae-go.appspot.com/hello -X PUT -d "put_value=test" | python -m json.tool
% Total % Received % Xferd Average Speed Time Time Time Current
Dload Upload Total Spent Left Speed
100 72 100 58 100 14 787 189 --:--:-- --:--:-- --:--:-- 794
{
"Description": "not implemented http mehtod",
"Status": 501
}
思ったより簡単に REST API っぽいのを作ることができました。