goth-echo-security（哥特回声安全）

Goth Echo Integration & Security

Expert guidance for integrating github.com/markbates/goth with the Echo web framework and implementing secure session management.

Echo Framework Integration

Basic Route Setup

import (
    "github.com/labstack/echo/v4"
    "github.com/markbates/goth"
    "github.com/markbates/goth/gothic"
    "github.com/markbates/goth/providers/google"
)

func main() {
    e := echo.New()

    // Auth routes
    e.GET("/auth/:provider", handleAuth)
    e.GET("/auth/:provider/callback", handleCallback)
    e.GET("/logout", handleLogout)

    e.Start(":3000")
}

Provider Name from Echo Context

Override Gothic's provider getter to use Echo's path parameters:

func init() {
    gothic.GetProviderName = func(r *http.Request) (string, error) {
        // Extract from Echo's :provider path param
        // The request context contains Echo's params
        provider := r.URL.Query().Get(":provider")
        if provider == "" {
            // Fallback: parse from path
            parts := strings.Split(r.URL.Path, "/")
            for i, p := range parts {
                if p == "auth" && i+1 < len(parts) {
                    return parts[i+1], nil
                }
            }
        }
        if provider == "" {
            return "", errors.New("no provider specified")
        }
        return provider, nil
    }
}

Echo Handler Wrappers

Wrap Gothic handlers for Echo compatibility:

func handleAuth(c echo.Context) error {
    // Set provider in query for Gothic
    q := c.Request().URL.Query()
    q.Set(":provider", c.Param("provider"))
    c.Request().URL.RawQuery = q.Encode()

    gothic.BeginAuthHandler(c.Response(), c.Request())
    return nil
}

func handleCallback(c echo.Context) error {
    q := c.Request().URL.Query()
    q.Set(":provider", c.Param("provider"))
    c.Request().URL.RawQuery = q.Encode()

    user, err := gothic.CompleteUserAuth(c.Response(), c.Request())
    if err != nil {
        return c.String(http.StatusInternalServerError, err.Error())
    }

    // Store user in session, redirect to dashboard
    return c.JSON(http.StatusOK, map[string]interface{}{
        "name":  user.Name,
        "email": user.Email,
    })
}

func handleLogout(c echo.Context) error {
    gothic.Logout(c.Response(), c.Request())
    return c.Redirect(http.StatusTemporaryRedirect, "/")
}

Echo Middleware for Auth

Create middleware to protect routes:

func RequireAuth(next echo.HandlerFunc) echo.HandlerFunc {
    return func(c echo.Context) error {
        session, err := gothic.Store.Get(c.Request(), gothic.SessionName)
        if err != nil || session.Values["user_id"] == nil {
            return c.Redirect(http.StatusTemporaryRedirect, "/login")
        }
        return next(c)
    }
}

// Usage
e.GET("/dashboard", handleDashboard, RequireAuth)

Session Management

Default Cookie Store

Gothic uses gorilla/sessions CookieStore by default:

import "github.com/gorilla/sessions"

func initSessionStore() {
    key := []byte(os.Getenv("SESSION_SECRET"))
    if len(key) < 32 {
        log.Fatal("SESSION_SECRET must be at least 32 bytes")
    }

    store := sessions.NewCookieStore(key)
    store.MaxAge(86400 * 30)  // 30 days
    store.Options.Path = "/"
    store.Options.HttpOnly = true
    store.Options.Secure = os.Getenv("ENV") == "production"
    store.Options.SameSite = http.SameSiteLaxMode

    gothic.Store = store
}

Session Secret Generation

Generate a secure session secret:

# Generate 32-byte random secret
openssl rand -base64 32

Storing User Data in Session

After successful authentication:

func handleCallback(c echo.Context) error {
    user, err := gothic.CompleteUserAuth(c.Response(), c.Request())
    if err != nil {
        return err
    }

    // Get or create session
    session, _ := gothic.Store.Get(c.Request(), "user-session")

    // Store user data
    session.Values["user_id"] = user.UserID
    session.Values["email"] = user.Email
    session.Values["name"] = user.Name
    session.Values["access_token"] = user.AccessToken
    session.Values["provider"] = user.Provider

    // Save session
    if err := session.Save(c.Request(), c.Response()); err != nil {
        return err
    }

    return c.Redirect(http.StatusTemporaryRedirect, "/dashboard")
}

Retrieving User from Session

func getCurrentUser(c echo.Context) (*UserInfo, error) {
    session, err := gothic.Store.Get(c.Request(), "user-session")
    if err != nil {
        return nil, err
    }

    userID, ok := session.Values["user_id"].(string)
    if !ok || userID == "" {
        return nil, errors.New("not authenticated")
    }

    return &UserInfo{
        UserID:   userID,
        Email:    session.Values["email"].(string),
        Name:     session.Values["name"].(string),
        Provider: session.Values["provider"].(string),
    }, nil
}

Alternative Session Stores

Redis Session Store

For distributed deployments:

import "github.com/rbcervilla/redisstore/v9"

func initRedisStore() {
    client := redis.NewClient(&redis.Options{
        Addr: os.Getenv("REDIS_URL"),
    })

    store, err := redisstore.NewRedisStore(context.Background(), client)
    if err != nil {
        log.Fatal(err)
    }

    store.KeyPrefix("session_")
    store.Options(sessions.Options{
        Path:     "/",
        MaxAge:   86400 * 30,
        HttpOnly: true,
        Secure:   true,
        SameSite: http.SameSiteLaxMode,
    })

    gothic.Store = store
}

Database Session Store

For PostgreSQL with pgx:

import "github.com/antonlindstrom/pgstore"

func initPgStore() {
    store, err := pgstore.NewPGStoreFromPool(
        dbPool,
        []byte(os.Getenv("SESSION_SECRET")),
    )
    if err != nil {
        log.Fatal(err)
    }

    store.Options = &sessions.Options{
        Path:     "/",
        MaxAge:   86400 * 30,
        HttpOnly: true,
        Secure:   true,
    }

    gothic.Store = store
}

See references/session-storage-options.md for detailed comparison.

Security Best Practices

CSRF Protection with State Parameter

Goth automatically handles the OAuth state parameter for CSRF protection. Verify it's working:

// Gothic handles state internally, but verify in callback
func handleCallback(c echo.Context) error {
    // State is validated by gothic.CompleteUserAuth
    user, err := gothic.CompleteUserAuth(c.Response(), c.Request())
    if err != nil {
        // State mismatch will cause error here
        log.Printf("Auth failed (possible CSRF): %v", err)
        return c.Redirect(http.StatusTemporaryRedirect, "/login?error=invalid_state")
    }
    // ...
}

Secure Cookie Configuration

store.Options = &sessions.Options{
    Path:     "/",
    Domain:   "",                       // Current domain only
    MaxAge:   86400 * 7,               // 7 days
    Secure:   true,                    // HTTPS only
    HttpOnly: true,                    // No JavaScript access
    SameSite: http.SameSiteLaxMode,    // CSRF protection
}

HTTPS Requirements

In production, always use HTTPS:

• Set Secure: true on cookies
• Use HTTPS callback URLs in provider configuration
• Redirect HTTP to HTTPS

// Echo HTTPS redirect middleware
e.Pre(middleware.HTTPSRedirect())

Token Storage Security

Never expose access tokens to the client:

// DON'T: Send token to frontend
return c.JSON(200, map[string]string{
    "access_token": user.AccessToken,  // Dangerous!
})

// DO: Store token server-side only
session.Values["access_token"] = user.AccessToken

Session Hijacking Prevention

Regenerate session ID after authentication:

func handleCallback(c echo.Context) error {
    user, err := gothic.CompleteUserAuth(c.Response(), c.Request())
    if err != nil {
        return err
    }

    // Get existing session
    oldSession, _ := gothic.Store.Get(c.Request(), "user-session")

    // Copy values to new session (forces new ID)
    oldSession.Options.MaxAge = -1  // Delete old session
    oldSession.Save(c.Request(), c.Response())

    newSession, _ := gothic.Store.New(c.Request(), "user-session")
    newSession.Values["user_id"] = user.UserID
    newSession.Values["email"] = user.Email
    newSession.Save(c.Request(), c.Response())

    return c.Redirect(http.StatusTemporaryRedirect, "/dashboard")
}

Rate Limiting Auth Endpoints

Protect against brute force:

import "github.com/labstack/echo/v4/middleware"

// Limit auth endpoints
authGroup := e.Group("/auth")
authGroup.Use(middleware.RateLimiter(middleware.NewRateLimiterMemoryStore(
    rate.Limit(10),  // 10 requests per second
)))

Token Refresh Pattern

Keep access tokens fresh:

func refreshTokenIfNeeded(c echo.Context) error {
    session, _ := gothic.Store.Get(c.Request(), "user-session")

    expiresAt, ok := session.Values["expires_at"].(time.Time)
    if !ok || time.Until(expiresAt) > 5*time.Minute {
        return nil  // Token still valid
    }

    providerName := session.Values["provider"].(string)
    provider, _ := goth.GetProvider(providerName)

    if !provider.RefreshTokenAvailable() {
        return nil
    }

    refreshToken := session.Values["refresh_token"].(string)
    token, err := provider.RefreshToken(refreshToken)
    if err != nil {
        // Refresh failed - force re-login
        return c.Redirect(http.StatusTemporaryRedirect, "/logout")
    }

    session.Values["access_token"] = token.AccessToken
    session.Values["expires_at"] = token.Expiry
    if token.RefreshToken != "" {
        session.Values["refresh_token"] = token.RefreshToken
    }
    session.Save(c.Request(), c.Response())

    return nil
}

Security Checklist

Before deploying:

• SESSION_SECRET is at least 32 random bytes
• Cookies use Secure: true in production
• Cookies use HttpOnly: true
• Cookies use SameSite: Lax or Strict
• HTTPS is enforced in production
• Callback URLs use HTTPS
• Access tokens stored server-side only
• Rate limiting on auth endpoints
• Session regeneration after login
• Error messages don't leak sensitive info

See references/security-checklist.md for complete checklist.

Quick Reference

Related Skills

• goth-fundamentals - Core Goth concepts
• goth-providers - Provider configuration

Reference Documentation

• references/session-storage-options.md - Storage comparison
• references/security-checklist.md - Security verification