fix(realname): 业务 code 优先于 HTTP 状态码，并区分额度耗尽

实测服务商业务失败时 HTTP 状态码会跟着变（身份证号错误返回 400
且 result 为 null），按状态码判断会把第三方异常误判成入参错误。
改为以业务 code 为准，仅在拿不到 code 时退回状态码与网关错误头。

额度耗尽（x-ca-error-code=B403MQ）此前与限流同样提示「请求过于频繁，
请稍后再试」，但重试不会恢复，新增 ErrProviderQuotaExhausted 并提示
联系客服。网关错误原因只在响应头，一并带进错误信息便于排查。

Co-authored-by: Cursor <cursoragent@cursor.com>

backend/internal/modules/realname/cloudmarket_provider.go

@@ -108,8 +108,15 @@ func (p *CloudMarketProvider) Start(ctx context.Context, req StartRequest) (Prov
 	}
 	defer resp.Body.Close()
 
+	// 网关层错误不会带业务 code，原因只在这两个响应头里。
+	gatewayCode := strings.TrimSpace(resp.Header.Get("X-Ca-Error-Code"))
+	gatewayMessage := strings.TrimSpace(resp.Header.Get("X-Ca-Error-Message"))
+
 	if resp.StatusCode == http.StatusTooManyRequests || resp.StatusCode == http.StatusForbidden {
-		return ProviderResult{}, ErrProviderRateLimited
+		if isQuotaExhausted(gatewayCode, gatewayMessage) {
+			return ProviderResult{}, fmt.Errorf("%w: cloud market %s: %s", ErrProviderQuotaExhausted, gatewayCode, gatewayMessage)
+		}
+		return ProviderResult{}, fmt.Errorf("%w: cloud market %s: %s", ErrProviderRateLimited, gatewayCode, gatewayMessage)
 	}
 
 	body, err := io.ReadAll(io.LimitReader(resp.Body, 4096))
@@ -119,16 +126,16 @@ func (p *CloudMarketProvider) Start(ctx context.Context, req StartRequest) (Prov
 
 	var payload cloudMarketResponse
 	if err := json.Unmarshal(body, &payload); err != nil {
-		if resp.StatusCode < http.StatusOK || resp.StatusCode >= http.StatusMultipleChoices {
-			return ProviderResult{}, cloudMarketHTTPError(resp.StatusCode, "")
-		}
-		return ProviderResult{}, fmt.Errorf("%w: invalid cloud market response: %v", ErrProviderUnavailable, err)
+		payload = cloudMarketResponse{}
 	}
-	if resp.StatusCode < http.StatusOK || resp.StatusCode >= http.StatusMultipleChoices {
-		return ProviderResult{}, cloudMarketHTTPError(resp.StatusCode, payload.Message)
+
+	// 服务商失败时 HTTP 状态码也会跟着变（如身份证号错误返回 400），
+	// 但业务 code 才是权威结果，只有拿不到 code 时才退回按状态码判断。
+	code := strings.TrimSpace(string(payload.Code))
+	if code == "" {
+		return ProviderResult{}, cloudMarketHTTPError(resp.StatusCode, firstNonEmpty(gatewayMessage, truncateForLog(body)))
 	}
-	// 先判断 code，code 非 0 表示调用失败，无需再看 result。
-	if code := string(payload.Code); code != "0" {
+	if code != "0" {
 		return ProviderResult{}, cloudMarketCodeError(code, payload.Message)
 	}
 
@@ -171,16 +178,36 @@ func (p *CloudMarketProvider) Start(ctx context.Context, req StartRequest) (Prov
 	return base, nil
 }
 
-func cloudMarketHTTPError(statusCode int, message string) error {
-	message = strings.TrimSpace(message)
-	switch statusCode {
-	case http.StatusBadRequest:
-		return fmt.Errorf("%w: %s", ErrInvalidRealnameInput, firstNonEmpty(message, "cloud market bad request"))
-	case http.StatusUnauthorized, http.StatusNotFound:
-		return fmt.Errorf("%w: cloud market http status %d: %s", ErrProviderConfigInvalid, statusCode, message)
-	default:
-		return fmt.Errorf("%w: cloud market http status %d: %s", ErrProviderUnavailable, statusCode, message)
+// isQuotaExhausted 区分额度耗尽与调用频率过高：两者都是 HTTP 403，但额度耗尽靠重试不会恢复。
+func isQuotaExhausted(gatewayCode, gatewayMessage string) bool {
+	if strings.EqualFold(gatewayCode, "B403MQ") {
+		return true
 	}
+	return strings.Contains(strings.ToLower(gatewayMessage), "quota exhausted")
+}
+
+func cloudMarketHTTPError(statusCode int, detail string) error {
+	detail = strings.TrimSpace(detail)
+	switch {
+	case statusCode == http.StatusBadRequest:
+		return fmt.Errorf("%w: %s", ErrInvalidRealnameInput, firstNonEmpty(detail, "cloud market bad request"))
+	case statusCode == http.StatusUnauthorized, statusCode == http.StatusNotFound:
+		return fmt.Errorf("%w: cloud market http status %d: %s", ErrProviderConfigInvalid, statusCode, detail)
+	case statusCode >= http.StatusOK && statusCode < http.StatusMultipleChoices:
+		return fmt.Errorf("%w: cloud market response without code: %s", ErrProviderUnavailable, detail)
+	default:
+		return fmt.Errorf("%w: cloud market http status %d: %s", ErrProviderUnavailable, statusCode, detail)
+	}
+}
+
+func truncateForLog(body []byte) string {
+	const limit = 200
+	text := strings.TrimSpace(string(body))
+	runes := []rune(text)
+	if len(runes) <= limit {
+		return text
+	}
+	return string(runes[:limit]) + "..."
 }
 
 // cloudMarketCodeError 按服务商错误码表映射，code 取值见 docs/实名认证.md。

backend/internal/modules/realname/cloudmarket_provider_test.go

@@ -4,6 +4,7 @@ import (
 	"errors"
 	"net/http"
 	"net/http/httptest"
+	"strings"
 	"testing"
 
 	"hfb_sys/backend/pkg/crypto"
@@ -116,7 +117,9 @@ func TestCloudMarketProviderStartInvalidInputCode(t *testing.T) {
 	for _, code := range []string{"400", "20010", "20310"} {
 		t.Run(code, func(t *testing.T) {
 			provider, closeServer := newTestCloudMarketProvider(t, func(w http.ResponseWriter, _ *http.Request) {
-				_, _ = w.Write([]byte(`{"code":"` + code + `","message":"请求姓名不标准：姓名为空或者包含特殊字符","result":{}}`))
+				// 服务商在业务失败时会同时返回非 200 状态码，result 也可能是 null。
+				w.WriteHeader(http.StatusBadRequest)
+				_, _ = w.Write([]byte(`{"code":"` + code + `","message":"身份证号错误","result":null}`))
 			})
 			defer closeServer()
 
@@ -128,6 +131,23 @@ func TestCloudMarketProviderStartInvalidInputCode(t *testing.T) {
 	}
 }
 
+// 业务 code 的优先级高于 HTTP 状态码：400 状态码配 501 业务码应判为服务不可用。
+func TestCloudMarketProviderStartPrefersBusinessCodeOverHTTPStatus(t *testing.T) {
+	provider, closeServer := newTestCloudMarketProvider(t, func(w http.ResponseWriter, _ *http.Request) {
+		w.WriteHeader(http.StatusBadRequest)
+		_, _ = w.Write([]byte(`{"code":"501","message":"第三方服务异常","result":null}`))
+	})
+	defer closeServer()
+
+	_, err := provider.Start(t.Context(), StartRequest{UserID: 1, Name: "张三", IDNo: "110101199001011234"})
+	if !errors.Is(err, ErrProviderUnavailable) {
+		t.Fatalf("期望服务不可用错误，实际：%v", err)
+	}
+	if errors.Is(err, ErrInvalidRealnameInput) {
+		t.Fatal("不应按 HTTP 400 判为入参错误")
+	}
+}
+
 func TestCloudMarketProviderStartConfigInvalidCode(t *testing.T) {
 	for _, code := range []string{"404", "604"} {
 		t.Run(code, func(t *testing.T) {
@@ -158,6 +178,8 @@ func TestCloudMarketProviderStartUnavailableCode(t *testing.T) {
 
 func TestCloudMarketProviderStartRateLimited(t *testing.T) {
 	provider, closeServer := newTestCloudMarketProvider(t, func(w http.ResponseWriter, _ *http.Request) {
+		w.Header().Set("X-Ca-Error-Code", "B403FQ")
+		w.Header().Set("X-Ca-Error-Message", "Throttled by Flow Control")
 		w.WriteHeader(http.StatusForbidden)
 	})
 	defer closeServer()
@@ -168,10 +190,29 @@ func TestCloudMarketProviderStartRateLimited(t *testing.T) {
 	}
 }
 
+// 额度耗尽同样是 403，但重试不会恢复，必须和限流区分开。
+func TestCloudMarketProviderStartQuotaExhausted(t *testing.T) {
+	provider, closeServer := newTestCloudMarketProvider(t, func(w http.ResponseWriter, _ *http.Request) {
+		w.Header().Set("X-Ca-Error-Code", "B403MQ")
+		w.Header().Set("X-Ca-Error-Message", "Api Market Subscription quota exhausted")
+		w.WriteHeader(http.StatusForbidden)
+	})
+	defer closeServer()
+
+	_, err := provider.Start(t.Context(), StartRequest{UserID: 1, Name: "王五", IDNo: "110101199001011234"})
+	if !errors.Is(err, ErrProviderQuotaExhausted) {
+		t.Fatalf("期望额度耗尽错误，实际：%v", err)
+	}
+	if errors.Is(err, ErrProviderRateLimited) {
+		t.Fatal("额度耗尽不应判为限流")
+	}
+}
+
 func TestCloudMarketProviderStartUnauthorized(t *testing.T) {
 	provider, closeServer := newTestCloudMarketProvider(t, func(w http.ResponseWriter, _ *http.Request) {
+		w.Header().Set("X-Ca-Error-Code", "A401AC")
+		w.Header().Set("X-Ca-Error-Message", "Invalid AppCode `not exists`")
 		w.WriteHeader(http.StatusUnauthorized)
-		_, _ = w.Write([]byte(`InvalidAppCode`))
 	})
 	defer closeServer()
 
@@ -179,6 +220,10 @@ func TestCloudMarketProviderStartUnauthorized(t *testing.T) {
 	if !errors.Is(err, ErrProviderConfigInvalid) {
 		t.Fatalf("期望配置错误，实际：%v", err)
 	}
+	// 网关错误原因只在响应头里，必须带进错误信息，否则日志里只剩状态码。
+	if !strings.Contains(err.Error(), "Invalid AppCode") {
+		t.Fatalf("错误信息缺少网关原因：%v", err)
+	}
 }
 
 func TestCloudMarketProviderStartUnavailableOnMissingRes(t *testing.T) {

backend/internal/modules/realname/handler.go

@@ -79,6 +79,8 @@ func writeRealnameError(c *gin.Context, err error) {
 		response.ServiceUnavailable(c, "实名认证服务未配置")
 	case errors.Is(err, ErrProviderRateLimited):
 		response.Error(c, http.StatusTooManyRequests, "realname_rate_limited", "实名认证请求过于频繁，请稍后再试")
+	case errors.Is(err, ErrProviderQuotaExhausted):
+		response.Error(c, http.StatusServiceUnavailable, "realname_quota_exhausted", "实名认证服务额度已用尽，请联系客服处理")
 	case errors.Is(err, ErrProviderUnavailable):
 		response.Error(c, http.StatusBadGateway, "realname_provider_unavailable", "实名认证服务调用失败，请稍后重试或联系客服处理")
 	default:

backend/internal/modules/realname/service.go

@@ -19,11 +19,12 @@ const (
 )
 
 var (
-	ErrDependencyUnavailable = errors.New("dependency unavailable")
-	ErrInvalidRealnameInput  = errors.New("invalid realname input")
-	ErrProviderConfigInvalid = errors.New("realname provider config invalid")
-	ErrProviderRateLimited   = errors.New("realname provider rate limited")
-	ErrProviderUnavailable   = errors.New("realname provider unavailable")
+	ErrDependencyUnavailable  = errors.New("dependency unavailable")
+	ErrInvalidRealnameInput   = errors.New("invalid realname input")
+	ErrProviderConfigInvalid  = errors.New("realname provider config invalid")
+	ErrProviderRateLimited    = errors.New("realname provider rate limited")
+	ErrProviderQuotaExhausted = errors.New("realname provider quota exhausted")
+	ErrProviderUnavailable    = errors.New("realname provider unavailable")
 )
 
 type Service struct {