S3 + Lambda + API Gatewayで プライム市場銘柄ランダムピックアプリ作ってみた vol.1~goでLambda関数作成~

package main

import (
	"bytes"
	"context"
	"encoding/json"
	"fmt"
	"math/rand"
	"net/http"
	"os"
	"time"
	"github.com/aws/aws-lambda-go/lambda"
)

// 認証用構造体
type AuthRequest struct {
	MailAddress string `json:"mailaddress"`
	Password    string `json:"password"`
}

type AuthResponse struct {
	RefreshToken string `json:"refreshToken"`
}

type IDTokenResponse struct {
	IDToken string `json:"idToken"`
}

// J-Quants API用構造体
type JQuantsResponse struct {
	Info []struct {
		Code             string `json:"Code"`
		CompanyName      string `json:"CompanyName"`
		MarketCodeName   string `json:"MarketCodeName"`
		Sector33CodeName string `json:"Sector33CodeName"`
	} `json:"info"`
}

type Event struct{}

// リフレッシュトークンを取得
func GetRefreshToken(email, password string) (string, error) {
	url := "https://api.jquants.com/v1/token/auth_user"
	requestBody := AuthRequest{
		MailAddress: email,
		Password:    password,
	}

	jsonData, err := json.Marshal(requestBody)
	if err != nil {
		return "", fmt.Errorf("failed to marshal request data: %v", err)
	}

	resp, err := http.Post(url, "application/json", bytes.NewBuffer(jsonData))
	if err != nil {
		return "", fmt.Errorf("failed to send request: %v", err)
	}
	defer resp.Body.Close()

	if resp.StatusCode != http.StatusOK {
		return "", fmt.Errorf("failed to authenticate: status code %d", resp.StatusCode)
	}

	var authResponse AuthResponse
	err = json.NewDecoder(resp.Body).Decode(&authResponse)
	if err != nil {
		return "", fmt.Errorf("failed to parse response: %v", err)
	}

	return authResponse.RefreshToken, nil
}

func GetRefreshToken(email, password string) (string, error) {

url := "https://api.jquants.com/v1/token/auth_user"

		return "", fmt.Errorf("failed to marshal request data: %v", err)

	resp, err := http.Post(url, "application/json", bytes.NewBuffer(jsonData))
	if err != nil {
		return "", fmt.Errorf("failed to send request: %v", err)
	}
	defer resp.Body.Close()

// IDトークンを取得
func GetIDToken(refreshToken string) (string, error) {
	url := fmt.Sprintf("https://api.jquants.com/v1/token/auth_refresh?refreshtoken=%s", refreshToken)

	resp, err := http.Post(url, "application/json", nil)
	if err != nil {
		return "", fmt.Errorf("failed to send request: %v", err)
	}
	defer resp.Body.Close()

	if resp.StatusCode != http.StatusOK {
		return "", fmt.Errorf("failed to get ID token: status code %d", resp.StatusCode)
	}

	var idTokenResponse IDTokenResponse
	err = json.NewDecoder(resp.Body).Decode(&idTokenResponse)
	if err != nil {
		return "", fmt.Errorf("failed to parse response: %v", err)
	}

	return idTokenResponse.IDToken, nil
}

	var idTokenResponse IDTokenResponse
	err = json.NewDecoder(resp.Body).Decode(&idTokenResponse)
	if err != nil {
		return "", fmt.Errorf("failed to parse response: %v", err)
	}

	return idTokenResponse.IDToken, nil
}

// J-Quants APIから銘柄情報を取得
func FetchCompanyInfo(code string, idToken string) (JQuantsResponse, error) {
	apiURL := "https://api.jquants.com/v1/listed/info"
	// APIリクエストの作成	
	req, err := http.NewRequest("GET", apiURL, nil)
	if err != nil {
		return JQuantsResponse{}, fmt.Errorf("failed to create request: %v", err)
	}
	// クエリパラメータとヘッダーを設定
	q := req.URL.Query()
	q.Add("code", code)
	req.URL.RawQuery = q.Encode()
	req.Header.Set("Authorization", fmt.Sprintf("Bearer %s", idToken))

	client := &http.Client{}
	resp, err := client.Do(req)
	if err != nil {
		return JQuantsResponse{}, fmt.Errorf("failed to fetch data: %v", err)
	}
	defer resp.Body.Close()

	if resp.StatusCode != http.StatusOK {
		return JQuantsResponse{}, fmt.Errorf("failed to fetch data: status code %d", resp.StatusCode)
	}

	var result JQuantsResponse
	err = json.NewDecoder(resp.Body).Decode(&result)
	if err != nil {
		return JQuantsResponse{}, fmt.Errorf("failed to parse response: %v", err)
	}

	return result, nil
}

	// クエリパラメータとヘッダーを設定
	q := req.URL.Query()
	q.Add("code", code)
	req.URL.RawQuery = q.Encode()
	req.Header.Set("Authorization", fmt.Sprintf("Bearer %s", idToken))

	client := &http.Client{}
	resp, err := client.Do(req)
	if err != nil {
		return JQuantsResponse{}, fmt.Errorf("failed to fetch data: %v", err)
	}
	defer resp.Body.Close()

// ラムダハンドラー
func handler(ctx context.Context, event Event) (interface{}, error) {
	// 環境変数から認証情報を取得
	email := os.Getenv("JQUANTS_EMAIL")
	password := os.Getenv("JQUANTS_PASSWORD")

	if email == "" || password == "" {
		return "", fmt.Errorf("email or password not set in environment variables")
	}

	// リフレッシュトークンを取得
	refreshToken, err := GetRefreshToken(email, password)
	if err != nil {
		return "", fmt.Errorf("failed to get refresh token: %v", err)
	}

	// IDトークンを取得
	idToken, err := GetIDToken(refreshToken)
	if err != nil {
		return "", fmt.Errorf("failed to get ID token: %v", err)
	}

	// 銘柄コードリスト
	stockCodes := []string{"1773", 
	"1301", 
	"1332", 	
　　...(多いので省略),
　　"9991", 
	"9997"}

	// ランダムに銘柄コードを選択
	rand.Seed(time.Now().UnixNano())
	randomIndex := rand.Intn(len(stockCodes))
	randomCode := stockCodes[randomIndex]

	// J-Quants APIを呼び出して銘柄情報を取得
	info, err := FetchCompanyInfo(randomCode, idToken)
	if err != nil {
		return "", fmt.Errorf("failed to fetch company info: %v", err)
	}

	// 結果をフォーマットして返す
	if len(info.Info) > 0 {
		company := info.Info[0]
		return company, nil
	}

	return nil, fmt.Errorf("no company information found for code: %s", randomCode)
}

func main() {
	lambda.Start(handler)
}

func handler(ctx context.Context, event Event) (interface{}, error) {

	// ランダムに銘柄コードを選択
	rand.Seed(time.Now().UnixNano())
	randomIndex := rand.Intn(len(stockCodes))
	randomCode := stockCodes[randomIndex]

OS=linux GOARCH=amd64 go build -o bootstrap main.go

zip function.zip bootstrap