元帅变成了一个bson.Raw [英] Marshal into a bson.Raw
问题描述
使用 gopkg.in/mgo.v2/bson
,我想知道如何编组一个接口{}值到类型 bson.Raw
的值中。
使用这种类型可以解组或者 marshal em> values。
但是我找不到一个Marshal函数,它会返回 bson.Raw
。
我缺少什么?
要做:
package main
import(
fmt
gopkg.in/mgo.v2/bson
)
func main(){
//如何避免MarshalRaw帮助功能?
raw,err:= MarshalRaw(Hello world)
if err!= nil {
panic(err)
}
fmt.Printf (%+ v \ n,raw)
}
func MarshalRaw(v interface {})(* bson.Raw,error){
bin,err: = bson.Marshal(struct {Raw interface {}} {v})
if err!= nil {
return nil,err
}
var raw struct {Raw bson.Raw}
err = bson.Unmarshal(bin,& raw)
if err!= nil {
return nil,err
}
return& raw.Raw,nil
}
输出:
& {种类:2数据:[12 0 0 0 72 101 108 108 111 32 119 111 114 108 100 0]}
bson.Raw 在编组和解组时都被用作一个值。
code> interface {} 转换为 bso n.Raw
,第一件要做的事情就是整理它,这样你就可以得到表示正在编组的所有文档数据:
var value interface {} = bson.M {some:value}
data,err:= bson.Marshal(value)
if err!=无{
log.Fatal(err)
}
然后它可以将一个或多个字段解组为 bson.Raw
值:
var doc struct {Some bson.Raw}
err = bson.Unmarshal(data,& doc)
if err!= nil {
log.Fatal(err)
}
甚至整个文件:
<$ p $如果错误!=零(
log.Fatal(err)$),
$ var bson.Raw
err = bson.Unmarshal(data,& doc)
b
如果你想要整个文档而不仅仅是一个字段,你也可以使用这个快捷键:
doc:= bson.Raw {3,data}
3常数表示<一个href =http://bsonspec.org =nofollow> bson规范,它当然必须符合提供的数据。由于BSON仅支持顶级文档,因此我们知道这一定是正确的。
Using gopkg.in/mgo.v2/bson
, I wonder how to marshal an interface{} value into a value of type bson.Raw
.
The documentation for bson.Raw
states:
Using this type it is possible to unmarshal or marshal values partially.
But I can't find a Marshal function that would return bson.Raw
.
What am I missing?
Example of what I try to do:
package main
import (
"fmt"
"gopkg.in/mgo.v2/bson"
)
func main() {
// How to avoid a MarshalRaw help function?
raw, err := MarshalRaw("Hello world")
if err != nil {
panic(err)
}
fmt.Printf("%+v\n", raw)
}
func MarshalRaw(v interface{}) (*bson.Raw, error) {
bin, err := bson.Marshal(struct{ Raw interface{} }{v})
if err != nil {
return nil, err
}
var raw struct{ Raw bson.Raw }
err = bson.Unmarshal(bin, &raw)
if err != nil {
return nil, err
}
return &raw.Raw, nil
}
Output:
&{Kind:2 Data:[12 0 0 0 72 101 108 108 111 32 119 111 114 108 100 0]}
bson.Raw is used as a value both when marshaling and unmarshaling.
To transform an interface{}
into a bson.Raw
, the first thing to do is to marshal it so that you get the plain document data that represents whatever is being marshaled:
var value interface{} = bson.M{"some": "value"}
data, err := bson.Marshal(value)
if err != nil {
log.Fatal(err)
}
and then it may have one or more fields unmarshaled into bson.Raw
values:
var doc struct{ Some bson.Raw }
err = bson.Unmarshal(data, &doc)
if err != nil {
log.Fatal(err)
}
or even the entire document:
var doc bson.Raw
err = bson.Unmarshal(data, &doc)
if err != nil {
log.Fatal(err)
}
If you want the entire document rather than just a field, you can also use this shortcut:
doc := bson.Raw{3, data}
The 3 constant represents a document in the bson specification, and it must of course match the provided data. Since BSON only supports documents at the top level, we know this must be correct.
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