ソーシャルログイン Bridge

// Express.js の例
const { OAuth2Client } = require('google-auth-library');
const client = new OAuth2Client(process.env.GOOGLE_CLIENT_ID);

app.post('/api/auth/social', async (req, res) => {
  const { provider, idToken } = req.body;

  if (provider === 'google') {
    const ticket = await client.verifyIdToken({
      idToken,
      audience: process.env.GOOGLE_CLIENT_ID
    });
    const payload = ticket.getPayload();
    const user = await findOrCreateUser({ email: payload.email, name: payload.name });
    const sessionToken = generateSessionToken(user);
    res.json({ token: sessionToken, user });
  }
});

// ASP.NET Core の例
[HttpPost("auth/social")]
public async Task<IActionResult> SocialLogin([FromBody] SocialLoginRequest request)
{
    if (request.Provider == "google")
    {
        var payload = await GoogleJsonWebSignature.ValidateAsync(request.IdToken,
            new GoogleJsonWebSignature.ValidationSettings {
                Audience = new[] { _config["Google:ClientId"] }
            });

        var user = await _userService.FindOrCreateAsync(payload.Email, payload.Name);
        var token = _tokenService.Generate(user);
        return Ok(new { token, user });
    }
    return BadRequest();
}

// Spring Boot の例
@PostMapping("/api/auth/social")
public ResponseEntity<?> socialLogin(@RequestBody SocialLoginRequest request) {
    if ("google".equals(request.getProvider())) {
        GoogleIdTokenVerifier verifier = new GoogleIdTokenVerifier.Builder(
            new NetHttpTransport(), JacksonFactory.getDefaultInstance())
            .setAudience(Collections.singletonList(googleClientId))
            .build();

        GoogleIdToken idToken = verifier.verify(request.getIdToken());
        if (idToken != null) {
            GoogleIdToken.Payload payload = idToken.getPayload();
            User user = userService.findOrCreate(payload.getEmail(), (String) payload.get("name"));
            String token = tokenService.generate(user);
            return ResponseEntity.ok(Map.of("token", token, "user", user));
        }
    }
    return ResponseEntity.badRequest().build();
}

<?php
// PHP の例（google-api-php-client を使用）
require_once 'vendor/autoload.php';

$client = new Google_Client(['client_id' => $_ENV['GOOGLE_CLIENT_ID']]);

$data = json_decode(file_get_contents('php://input'), true);
if ($data['provider'] === 'google') {
    $payload = $client->verifyIdToken($data['idToken']);
    if ($payload) {
        $user = findOrCreateUser($payload['email'], $payload['name']);
        $token = generateToken($user);
        echo json_encode(['token' => $token, 'user' => $user]);
    } else {
        http_response_code(401);
    }
}

<%
' Classic ASP の例 — Google トークンの検証はサーバーサイドライブラリ
' または Google tokeninfo エンドポイントで行います。
Dim idToken, provider
idToken = Request.Form("idToken")
provider = Request.Form("provider")

If provider = "google" Then
    ' Google tokeninfo API を呼び出す
    Dim url, http
    url = "https://oauth2.googleapis.com/tokeninfo?id_token=" & idToken
    Set http = Server.CreateObject("MSXML2.ServerXMLHTTP")
    http.Open "GET", url, False
    http.Send

    If http.Status = 200 Then
        ' 検証成功 — ユーザーを処理
        Response.ContentType = "application/json"
        Response.Write "{""success"": true}"
    Else
        Response.Status = "401 Unauthorized"
    End If
End If
%>