英文:
How to write a wrapper function for FindOptions in go mongo-driver
问题
我想在我的dbobject代码中为FindOptions编写一个包装函数，这样我就可以避免在我的服务代码中导入options包。基本上，我想在一个接口下容纳三个函数：
SetSkip()
SetLimit()
SetSort()
这样我就可以在一行代码中像这样使用Find().SetSkip().SetLimit()，这可行吗？
另外，我想了解一下MergeFindOptions的用法：
func MergeFindOptions(opts ...*FindOptions) *FindOptions
如果有示例，将非常有帮助。
英文:
I want to write a wrapper function for FindOptions in my dbobject code so that I can avoid importing package options in my service code . Basically i'm trying to accomodate three func under one interface
SetSkip()
SetLimit()
SetSort()
so that i should be able to do something like Find().SetSkip().SetLimit() in a single line , is that doable ?
Also I want to know the usage of MergeFindOptions
func MergeFindOptions(opts ...*FindOptions) *FindOptions
Any examples will be of great help.
答案1
得分: 1
只需将options.FindOptions结构嵌入到自定义结构中即可。此外，您可以添加一个FindOptions函数来初始化此自定义结构，就像mongo包通过options.Find()一样。
package your_db_package
type YourFindOptions struct {
*options.FindOptions
}
func FindOptions() YourFindOptions {
return YourFindOptions{options.Find()}
}
// ---
package your_service_package
import "your_db_package"
func GetItems() {
opts := your_db_package.FindOptions().SetSkip(123).SetLimit(456)
}
根据名称MergeFindOptions和文档所说，它用于将多个FindOptions合并为一个新的FindOptions：
MergeFindOptions将给定的FindOptions实例合并为一个单独的FindOptions，以最后一个为准。
英文:
Just embed the options.FindOptions struct into a custom one. Additionally you could add a FindOptions function to initialize this custom struct, like the mongo package do by options.Find().
package your_db_package
type YourFindOptions struct {
*options.FindOptions
}
func FindOptions() YourFindOptions {
return YourFindOptions{options.Find()}
}
// ---
package your_service_package
import "your_db_package"
func GetItems() {
opts := your_db_package.FindOptions().SetSkip(123).SetLimit(456)
}
As the name MergeFindOptions and the documentation says it's for merging multiple FindOptions into a new one:
> MergeFindOptions combines the given FindOptions instances into a single FindOptions in a last-one-wins fashion.
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