FallbackInfo
透過集合功能整理內容
你可以依據偏好儲存及分類內容。
有關使用備用結果的方式和原因的相關資訊。如果設定了這個欄位，伺服器就會使用偏好模式以外的路線做為備用模式。
| 欄位 |
routingMode |
enum (FallbackRoutingMode)
回應使用的轉送模式。如果觸發備用廣告，模式可能會與原始用戶端要求中設定的轉送偏好設定不同。
|
reason |
enum (FallbackReason)
為何系統只使用備用回應，而非原始回應。只有在觸發備用模式並傳回備用回應的情況下，系統才會填入這個欄位。
|
FallbackRoutingMode
| 列舉 |
FALLBACK_ROUTING_MODE_UNSPECIFIED |
未使用。 |
FALLBACK_TRAFFIC_UNAWARE |
指出 TRAFFIC_UNAWARE RoutingPreference |
FALLBACK_TRAFFIC_AWARE |
指出 TRAFFIC_AWARE RoutingPreference |
FallbackReason
| 列舉 |
FALLBACK_REASON_UNSPECIFIED |
未指定備用原因。 |
SERVER_ERROR |
以您偏好的轉送模式計算路線時發生伺服器錯誤，但我們能夠傳回其他模式計算的結果。 |
LATENCY_EXCEEDED |
我們無法按照你偏好的路線模式準時完成計算，但我們可以傳回透過其他模式計算的結果。 |
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上次更新時間：2025-08-31 (世界標準時間)。
[null,null,["上次更新時間：2025-08-31 (世界標準時間)。"],[[["\u003cp\u003eFallbackInfo provides details on why and how a fallback routing result was used if the server deviated from the preferred routing mode.\u003c/p\u003e\n"],["\u003cp\u003eThis information includes the actual routing mode used (FallbackRoutingMode) and the reason for the fallback (FallbackReason).\u003c/p\u003e\n"],["\u003cp\u003eFallbackRoutingMode specifies whether traffic conditions were considered in the fallback route (TRAFFIC_AWARE or TRAFFIC_UNAWARE).\u003c/p\u003e\n"],["\u003cp\u003eFallbackReason clarifies if the fallback was due to a server error or exceeding the allowed calculation time.\u003c/p\u003e\n"]]],["The server may use a fallback routing mode if the preferred mode fails. This fallback information is provided in JSON format, including the `routingMode` used and the `reason` for the fallback. The `routingMode` can be `FALLBACK_TRAFFIC_UNAWARE` or `FALLBACK_TRAFFIC_AWARE`. The `reason` can be `SERVER_ERROR` (due to an internal error) or `LATENCY_EXCEEDED` (calculation exceeded the allowed time). Specific enumerations define the exact fallback mode and reason used.\n"],null,["# FallbackInfo\n\n- [JSON representation](#SCHEMA_REPRESENTATION)\n- [FallbackRoutingMode](#FallbackRoutingMode)\n- [FallbackReason](#FallbackReason)\n\nInformation related to how and why a fallback result was used. If this field is set, then it means the server used a different routing mode from your preferred mode as fallback.\n\n| JSON representation |\n|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|\n| ``` { \"routingMode\": enum (/maps/documentation/routes/reference/rest/v2/FallbackInfo#FallbackRoutingMode), \"reason\": enum (/maps/documentation/routes/reference/rest/v2/FallbackInfo#FallbackReason) } ``` |\n\n| Fields ||\n|---------------|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|\n| `routingMode` | `enum (`[FallbackRoutingMode](/maps/documentation/routes/reference/rest/v2/FallbackInfo#FallbackRoutingMode)`)` Routing mode used for the response. If fallback was triggered, the mode may be different from routing preference set in the original client request. |\n| `reason` | `enum (`[FallbackReason](/maps/documentation/routes/reference/rest/v2/FallbackInfo#FallbackReason)`)` The reason why fallback response was used instead of the original response. This field is only populated when the fallback mode is triggered and the fallback response is returned. |\n\nFallbackRoutingMode\n-------------------\n\nActual routing mode used for returned fallback response.\n\n| Enums ||\n|-------------------------------------|---------------------------------------------------------------------------------------------------------------------------------------------------------|\n| `FALLBACK_ROUTING_MODE_UNSPECIFIED` | Not used. |\n| `FALLBACK_TRAFFIC_UNAWARE` | Indicates the `TRAFFIC_UNAWARE` [`RoutingPreference`](/maps/documentation/routes/reference/rest/v2/RoutingPreference) was used to compute the response. |\n| `FALLBACK_TRAFFIC_AWARE` | Indicates the `TRAFFIC_AWARE` [`RoutingPreference`](/maps/documentation/routes/reference/rest/v2/RoutingPreference) was used to compute the response. |\n\nFallbackReason\n--------------\n\nReasons for using fallback response.\n\n| Enums ||\n|-------------------------------|-------------------------------------------------------------------------------------------------------------------------------------------------------------|\n| `FALLBACK_REASON_UNSPECIFIED` | No fallback reason specified. |\n| `SERVER_ERROR` | A server error happened while calculating routes with your preferred routing mode, but we were able to return a result calculated by an alternative mode. |\n| `LATENCY_EXCEEDED` | We were not able to finish the calculation with your preferred routing mode on time, but we were able to return a result calculated by an alternative mode. |"]]
