Go - 检查 Firestore 文档是否存在
我似乎无法检查文件是否存在。如果它不存在，则会出现错误，而不仅仅是一个空文档
"error": "rpc error: code = NotFound desc = \"projects/PROJECTID/databases/(default)/documents/claimed/123abc\" not found"
有问题的代码，值已替换为占位符。
package main
import (
"context"
"errors"
"cloud.google.com/go/firestore"
func main() {
ctx := context.Background()
client, err := firestore.NewClient(ctx, "PROJECTID")
if err != nil {
log.Fatalln(err)
}
docRef := client.Collection("claimed").Doc("123abc")
doc, err := docRef.Get(ctx)
if err != nil {
return err // <----- Reverts to here
}
// Doesn't make it to here
if doc.Exists() {
return errors.New("document ID already exists")
} else {
_, err := docRef.Set(ctx, /* custom object here */)
if err != nil {
return err
}
}
}
代码文档Get()说
// Get retrieves the document. If the document does not exist, Get return a NotFound error, which
// can be checked with
// status.Code(err) == codes.NotFound
// In that case, Get returns a non-nil DocumentSnapshot whose Exists method return false and whose
// ReadTime is the time of the failed read operation.
那么我的解决方案是只修改错误处理吗？`if err != nil { /* 检查它是否存在 */ }
** 解决方案 **
docRef := client.Collection("claimed").Doc("123abc")
doc, err := docRef.Get(ctx)
if err != nil {
if status.Code(err) == codes.NotFound {
// Handle document not existing here
_, err := docRef.Set(ctx, /* custom object here */)
if err != nil {
return err
}
} else {
return err
}
}
// Double handling (???)
if doc.Exists() {
// Handle document existing here
}
函数式编程2回答
-
一只甜甜圈
如果文档不存在，您将收到错误消息。您使用的事实是您得到不存在的错误。请参阅Get的文档以处理错误。doc, err := docRef.Get(ctx) if err != nil { if status.Code(err) == codes.NotFound { ... } }} -
隔江千里
您必须将"PROJECTID"in替换firestore.NewClient为 Google Cloud Platform 项目 ID 的值。您可以在Cloud Console中或通过gcloudCLI 使用例如gcloud projects list.
随时随地看视频慕课网APP
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