英文:
GAE Go - How to put private variables in datastore?
问题
我正在编写一个使用Google App Engine Golang的应用程序。我想要一个具有私有变量的struct，只能通过适当的函数进行设置，例如：
type Foo struct {
bar string
}
func (f *Foo) SetBar(b string) {
f.bar = "BAR: "+b
}
我想要能够将这些数据存储在数据存储中。然而，看起来数据存储不会保存私有变量。
如何在数据存储中存储私有变量？
英文:
I am writing a Google App Engine Golang application. I want to have a struct with private variables that can only be set through proper functions, for example:
type Foo struct {
bar string
}
func (f *Foo) SetBar(b string) {
f.bar = "BAR: "+b
}
I want to be able to save this data in the datastore. However, it looks like datastore does not save private variables.
How can I store private variables in datastore?
答案1
得分: 2
你可以通过实现PropertyLoadSaver接口来实现这个功能：
func (f *Foo) Save(c chan<- datastore.Property) error {
defer close(c)
c <- datastore.Property{
Name: "bar",
Value: f.bar,
}
return nil
}
func (f *Foo) Load(c <-chan datastore.Property) error {
for property := range c {
switch property.Name {
case "bar":
f.bar = property.Value.(string)
}
}
return nil
}
不过缺点是你需要手动加载/保存所有的属性，因为你不能使用datastore包的方法。
英文:
You can if your types implement the PropertyLoadSaver interface:
func (f *Foo) Save (c chan<- datastore.Property) error {
defer close(c)
c <- datastore.Property {
Name: "bar",
Value: f.bar,
}
return nil
}
func (f *Foo) Load(c <-chan datastore.Property) error {
for property := range c {
switch property.Name {
case "bar":
f.bar = property.Value.(string)
}
}
return nil
}
The downside is that you will need to load/save all your properties by hand because you can't use the datastore package methods.
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