Sub2API v1.0 - AI API 网关（二开初始版本，基于上游 Wei-Shaw/sub2api）

backend/internal/service/openai_stream_read_error.go

@@ -0,0 +1,74 @@
+package service
+
+import (
+	"context"
+	"errors"
+	"fmt"
+	"strings"
+)
+
+const (
+	// OpenAIUpstreamHTTP2StreamErrorCode is returned to OpenAI-compatible clients
+	// when an upstream HTTP/2 response stream is reset after the request started.
+	OpenAIUpstreamHTTP2StreamErrorCode = "upstream_http2_stream_error"
+	OpenAIUpstreamStreamReadErrorCode  = "upstream_stream_read_error"
+)
+
+type openAIUpstreamStreamReadError struct {
+	cause         error
+	clientCode    string
+	clientMessage string
+}
+
+func (e *openAIUpstreamStreamReadError) Error() string {
+	return fmt.Sprintf("stream usage incomplete: %v", e.cause)
+}
+
+func (e *openAIUpstreamStreamReadError) Unwrap() error { return e.cause }
+
+func newOpenAIUpstreamStreamReadError(err error) error {
+	code, message := classifyOpenAIUpstreamStreamReadError(err)
+	return &openAIUpstreamStreamReadError{
+		cause:         err,
+		clientCode:    code,
+		clientMessage: message,
+	}
+}
+
+// shouldClassifyOpenAIUpstreamStreamReadError excludes cancellation and
+// response-size enforcement from upstream retry.
+func shouldClassifyOpenAIUpstreamStreamReadError(err error, contexts ...context.Context) bool {
+	if err == nil || errors.Is(err, context.Canceled) || errors.Is(err, context.DeadlineExceeded) || errors.Is(err, ErrUpstreamResponseBodyTooLarge) {
+		return false
+	}
+	for _, ctx := range contexts {
+		if ctx != nil && ctx.Err() != nil {
+			return false
+		}
+	}
+	return true
+}
+
+// OpenAIUpstreamStreamReadErrorDetails returns the stable, sanitized client
+// classification attached to an upstream stream read failure.
+func OpenAIUpstreamStreamReadErrorDetails(err error) (code, message string, ok bool) {
+	var streamErr *openAIUpstreamStreamReadError
+	if !errors.As(err, &streamErr) || streamErr == nil {
+		return "", "", false
+	}
+	return streamErr.clientCode, streamErr.clientMessage, true
+}
+
+func classifyOpenAIUpstreamStreamReadError(err error) (code, message string) {
+	if err != nil {
+		lower := strings.ToLower(err.Error())
+		// net/http's HTTP/2 stream error is unexported. Its stable text contains
+		// "stream error: stream ID ..."; match only the transport signature and
+		// never pass the original text to the client.
+		if strings.Contains(lower, "stream error: stream id ") ||
+			(strings.Contains(lower, "http2:") && strings.Contains(lower, "stream")) {
+			return OpenAIUpstreamHTTP2StreamErrorCode, "Upstream HTTP/2 stream failed"
+		}
+	}
+	return OpenAIUpstreamStreamReadErrorCode, "Upstream response stream was interrupted"
+}