短链接白标平台构建方案：多租户、自定义域名与品牌化输出

-- 租户表
CREATE TABLE tenants (
    id VARCHAR(16) PRIMARY KEY,       -- "t_abc123"
    name VARCHAR(100) NOT NULL,
    branding JSON,                    -- logo/color/font
    custom_domain VARCHAR(255),       -- "go.brand.com"
    status ENUM('active','suspended','trial') DEFAULT 'trial',
    plan ENUM('starter','pro','enterprise') DEFAULT 'starter',
    created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP
);

-- 短链表（共享表，tenant_id 隔离）
CREATE TABLE short_links (
    id BIGINT AUTO_INCREMENT PRIMARY KEY,
    tenant_id VARCHAR(16) NOT NULL,
    short_code VARCHAR(16) NOT NULL,
    original_url TEXT NOT NULL,
    created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
    FOREIGN KEY (tenant_id) REFERENCES tenants(id),
    UNIQUE KEY uk_tenant_code (tenant_id, short_code)
);

-- 关键：所有查询必须带 tenant_id 条件
-- SELECT * FROM short_links WHERE tenant_id = 't_abc123' AND short_code = 'xyz'

func TenantMiddleware(next http.Handler) http.Handler {
    return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
        // 方式1: 自定义域名识别
        host := r.Host
        tenant := resolveTenantByDomain(host)
        
        // 方式2: API Key 识别
        if tenant == nil {
            apiKey := r.Header.Get("X-API-Key")
            tenant = resolveTenantByAPIKey(apiKey)
        }
        
        if tenant == nil || tenant.Status != "active" {
            http.Error(w, "Unauthorized", http.StatusUnauthorized)
            return
        }
        
        // 注入上下文
        ctx := context.WithValue(r.Context(), "tenant", tenant)
        next.ServeHTTP(w, r.WithContext(ctx))
    })
}

package certmanager

type DomainManager struct {
    certCache map[string]*tls.Certificate
    acme      *lego.Client
}

func (m *DomainManager) IssueCertificate(domain string) (*tls.Certificate, error) {
    // 使用 ACME 协议自动申请证书
    request := certificate.ObtainRequest{
        Domains: []string{domain},
        Bundle:  true,
    }
    
    cert, err := m.acme.Certificate.Obtain(request)
    if err != nil {
        return nil, err
    }
    
    tlsCert, _ := tls.X509KeyPair(cert.Certificate, cert.PrivateKey)
    m.certCache[domain] = &tlsCert
    
    return &tlsCert, nil
}

func (m *DomainManager) GetCertificate(hello *tls.ClientHelloInfo) (*tls.Certificate, error) {
    return m.certCache[hello.ServerName], nil
}

func Router() http.Handler {
    return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
        tenant := getTenant(r)
        
        switch {
        case tenant.CustomDomain != "" && r.Host == tenant.CustomDomain:
            // 自定义域名：只响应短链跳转
            shortCode := extractShortCode(r.URL.Path)
            handleRedirect(w, r, tenant, shortCode)
            
        case strings.HasPrefix(r.URL.Path, "/api/"):
            // API 路由
            apiRouter.ServeHTTP(w, r)
            
        default:
            // 平台控制台
            dashboardRouter.ServeHTTP(w, r)
        }
    })
}

branding:
  # 基础品牌
  logo_url: "https://brand-cdn.com/logo.png"
  favicon_url: "https://brand-cdn.com/favicon.ico"
  primary_color: "#1E40AF"
  secondary_color: "#3B82F6"
  font_family: "Inter"
  
  # 控制台面版
  dashboard_title: "Brand Link Console"
  hide_powered_by: true  # 付费版可隐藏平台标识
  
  # 短链页面
  redirect_page_template: "minimal"  # minimal/branded/full
  custom_footer_html: |
    <div class="footer">
      <a href="https://brand.com/privacy">Privacy</a>
      <span>© 2025 Brand Inc.</span>
    </div>
  
  # 邮件模板
  email_from_name: "Brand Link"
  email_from_address: "noreply@brand.com"
  email_template_id: "brand-default"

func BrandMiddleware(next http.Handler) http.Handler {
    return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
        tenant := getTenant(r)
        branding := tenant.Branding
        
        // 如果是自定义域名+控制台路径，注入品牌主题
        if isDashboardPath(r.URL.Path) {
            w.Header().Set("X-Brand-Primary", branding.PrimaryColor)
            w.Header().Set("X-Brand-Logo", branding.LogoURL)
        }
        
        next.ServeHTTP(w, r)
    })
}

POST https://api.white-label.com/v1/links
X-API-Key: wl_tenant_abc123_xyz789
Content-Type: application/json

{
  "url": "https://example.com",
  "custom_alias": "product-launch",
  "domain": "go.brand.com"
}

// JavaScript SDK 白标版
import { ShortLinkClient } from '@wl-sdk/shortlink';

const client = new ShortLinkClient({
  apiKey: 'wl_tenant_abc123_xyz789',
  // 通用接口，自动适配白标域名
});

// 创建短链
const link = await client.create({
  url: 'https://brand.com/new-product',
  domain: 'go.brand.com'
});

CREATE TABLE tenant_quotas (
    tenant_id VARCHAR(16) PRIMARY KEY,
    max_links INT DEFAULT 1000,
    max_clicks_per_month BIGINT DEFAULT 100000,
    api_rate_limit INT DEFAULT 100,  -- requests/minute
    used_links INT DEFAULT 0,
    used_clicks_this_month BIGINT DEFAULT 0,
    reset_day INT DEFAULT 1
);