【发布时间】：2019-01-17 15:51:30
【问题描述】：
我正在尝试从可调用的 Google Cloud 函数返回 QuerySnapshot。
以下是详细信息，但我的核心问题是，我应该期望能够做到这一点还是这是一个错误？
import * as admin from 'firebase-admin';
import * as functions from 'firebase-functions';
import * as firestore from '@google-cloud/firestore';
export const callableTest = functions.https.onCall(
async (data: Map<string, any>, context: functions.https.CallableContext):
Promise<firestore.QuerySnapshot> => {
const db = admin.firestore();
return db.collection('test')
.get();
// I also tried this
//return db.collection('test').get().then(querySnapshot => {
// return querySnapshot;
//});
});
test 集合可以包含任意数量的文档。在这种情况下，有两个文档。
这是我的客户端 HTML 页面，但我也在 Flutter 和 Node 中尝试过，结果相同。
<!DOCTYPE html>
<html>
<head>
<script src="https://www.gstatic.com/firebasejs/5.7.3/firebase.js"></script>
<script>
// Initialize Firebase
var config = {
apiKey: "### API KEY ###",
authDomain: "<project-id>.firebaseapp.com",
databaseURL: "https://<project-id>.firebaseio.com",
projectId: "<project-id>",
storageBucket: "<project-id>.appspot.com",
messagingSenderId: "<sender-id>"
};
firebase.initializeApp(config);
var testClientCall = firebase.functions().httpsCallable('callableTest');
testClientCall ({}).then(function(result) {
// Read result of the Cloud Function.
console.log("Cloud Function result:");
console.log(result);
});
</script>
</head>
<body></body>
</html>
这是返回的结果，看起来类似于QuerySnapshot，但不包含任何DocumentSnapshots（_docs 属性），即使_size 属性表明应该有两份文件。
{"data":{"_query":{"_firestore":{"_clientPool":{"concurrentOperationLimit":100,"clientFactory":{},"activeClients":{}},"_settings":{"projectId":"<project-id>","firebaseVersion":"6.4.0","libName":"gccl","libVersion":"0.19.0 fire/6.4.0"},"_settingsFrozen":false,"_clientInitialized":{"domain":{"domain":null,"_events":{"error":{}},"_eventsCount":1,"_maxListeners":null,"members":[]}},"_serializer":{"createReference":{},"timestampsInSnapshots":false},"_referencePath":{"segments":[],"projectId":"project-id","databaseId":"(default)"},"_lastSuccessfulRequest":1547738645649,"_validator":{"isFunction":{},"isOptionalFunction":{},"isInteger":{},"isOptionalInteger":{},"isNumber":{},"isOptionalNumber":{},"isObject":{},"isOptionalObject":{},"isString":{},"isOptionalString":{},"isBoolean":{},"isOptionalBoolean":{},"isArrayElement":{},"isOptionalArrayElement":{},"isDeletePrecondition":{},"isOptionalDeletePrecondition":{},"isDocument":{},"isOptionalDocument":{},"isDocumentReference":{},"isOptionalDocumentReference":{},"isFieldPath":{},"isOptionalFieldPath":{},"isFieldValue":{},"isOptionalFieldValue":{},"isFieldOrder":{},"isOptionalFieldOrder":{},"isQueryComparison":{},"isOptionalQueryComparison":{},"isQueryValue":{},"isOptionalQueryValue":{},"isResourcePath":{},"isOptionalResourcePath":{},"isSetOptions":{},"isOptionalSetOptions":{},"isReadOptions":{},"isOptionalReadOptions":{},"isUpdateMap":{},"isOptionalUpdateMap":{},"isUpdatePrecondition":{},"isOptionalUpdatePrecondition":{}},"_preferTransactions":true},"_path":{"segments":["test"],"projectId":"project-id","databaseId":"(default)"},"_fieldFilters":[],"_fieldOrders":[],"_queryOptions":{},"_validator":{"isFunction":{},"isOptionalFunction":{},"isInteger":{},"isOptionalInteger":{},"isNumber":{},"isOptionalNumber":{},"isObject":{},"isOptionalObject":{},"isString":{},"isOptionalString":{},"isBoolean":{},"isOptionalBoolean":{},"isArrayElement":{},"isOptionalArrayElement":{},"isDeletePrecondition":{},"isOptionalDeletePrecondition":{},"isDocument":{},"isOptionalDocument":{},"isDocumentReference":{},"isOptionalDocumentReference":{},"isFieldPath":{},"isOptionalFieldPath":{},"isFieldValue":{},"isOptionalFieldValue":{},"isFieldOrder":{},"isOptionalFieldOrder":{},"isQueryComparison":{},"isOptionalQueryComparison":{},"isQueryValue":{},"isOptionalQueryValue":{},"isResourcePath":{},"isOptionalResourcePath":{},"isSetOptions":{},"isOptionalSetOptions":{},"isReadOptions":{},"isOptionalReadOptions":{},"isUpdateMap":{},"isOptionalUpdateMap":{},"isUpdatePrecondition":{},"isOptionalUpdatePrecondition":{}},"_serializer":{"createReference":{},"timestampsInSnapshots":false}},"_readTime":{"_seconds":1547738645,"_nanoseconds":638303000},"_size":2,"_materializedDocs":null,"_materializedChanges":null,"_docs":{},"_changes":{},"_validator":{"isFunction":{},"isOptionalFunction":{},"isInteger":{},"isOptionalInteger":{},"isNumber":{},"isOptionalNumber":{},"isObject":{},"isOptionalObject":{},"isString":{},"isOptionalString":{},"isBoolean":{},"isOptionalBoolean":{},"isArrayElement":{},"isOptionalArrayElement":{},"isDeletePrecondition":{},"isOptionalDeletePrecondition":{},"isDocument":{},"isOptionalDocument":{},"isDocumentReference":{},"isOptionalDocumentReference":{},"isFieldPath":{},"isOptionalFieldPath":{},"isFieldValue":{},"isOptionalFieldValue":{},"isFieldOrder":{},"isOptionalFieldOrder":{},"isQueryComparison":{},"isOptionalQueryComparison":{},"isQueryValue":{},"isOptionalQueryValue":{},"isResourcePath":{},"isOptionalResourcePath":{},"isSetOptions":{},"isOptionalSetOptions":{},"isReadOptions":{},"isOptionalReadOptions":{},"isUpdateMap":{},"isOptionalUpdateMap":{},"isUpdatePrecondition":{},"isOptionalUpdatePrecondition":{}}}}
起初我认为这可能是序列化的问题，但如果我修改我的云函数以仅返回一个 DocumentSnapshot，它会返回预期的数据。
【问题讨论】：
标签： firebase google-cloud-firestore google-cloud-functions