英文:
use gob to package recursively defined structs
问题
我主要使用Python，但也在尝试使用Go语言。我写了以下代码，用于在Python中非常简单的操作，希望在Go中也能实现。
package main
import (
"bytes"
"encoding/gob"
"fmt"
"io/ioutil"
)
type Order struct {
Text string
User *User
}
type User struct {
Text string
Order *Order
}
func main() {
o := Order{}
u := User{}
o.Text = "order text"
u.Text = "user text"
// commenting this section prevents stack overflow
o.User = &u
u.Order = &o
fmt.Println("o.u.text:", o.User.Text, "u.o.text:", u.Order.Text)
// end section
m := new(bytes.Buffer)
enc := gob.NewEncoder(m)
enc.Encode(o)
err := ioutil.WriteFile("gob_data", m.Bytes(), 0600)
if err != nil {
panic(err)
}
fmt.Printf("just saved gob with %v\n", o)
n, err := ioutil.ReadFile("gob_data")
if err != nil {
fmt.Printf("cannot read file")
panic(err)
}
p := bytes.NewBuffer(n)
dec := gob.NewDecoder(p)
e := Order{}
err = dec.Decode(&e)
if err != nil {
fmt.Printf("cannot decode")
panic(err)
}
fmt.Printf("just read gob from file and it's showing: %v\n", e)
}
如你所见，这里有两个自定义结构体，每个结构体都包含对另一个结构体的引用，形成了递归关系。当我尝试使用gob将其中一个结构体打包到文件中时，代码可以编译通过，但会导致堆栈溢出错误。我猜测这是由于递归引起的。根据我的经验，pickle可以处理这样的情况而不会出错。我做错了什么？
英文:
I mostly use Python, but am playing around with Go. I wrote the following to do something that is quite simple in python, and im hoping it can be accomplished in Go as well.
package main
import (
"bytes"
"encoding/gob"
"fmt"
"io/ioutil"
)
type Order struct {
Text string
User *User
}
type User struct {
Text string
Order *Order
}
func main() {
o := Order{}
u := User{}
o.Text = "order text"
u.Text = "user text"
// commenting this section prevents stack overflow
o.User = &u
u.Order = &o
fmt.Println("o.u.text:", o.User.Text, "u.o.text:", u.Order.Text)
// end section
m := new(bytes.Buffer)
enc := gob.NewEncoder(m)
enc.Encode(o)
err := ioutil.WriteFile("gob_data", m.Bytes(), 0600)
if err != nil {
panic(err)
}
fmt.Printf("just saved gob with %v\n", o)
n, err := ioutil.ReadFile("gob_data")
if err != nil {
fmt.Printf("cannot read file")
panic(err)
}
p := bytes.NewBuffer(n)
dec := gob.NewDecoder(p)
e := Order{}
err = dec.Decode(&e)
if err != nil {
fmt.Printf("cannot decode")
panic(err)
}
fmt.Printf("just read gob from file and it's showing: %v\n", e)
}
As you can see, there are two custom structs, each containing a reference to the other, recursively. When I try to package one up into a file using gob, it compiles, but i get a stack overflow, I am assuming this is caused by the recursion. In my experience, pickle handles things like this without a gasp. What am I doing wrong?
答案1
得分: 6
截至目前，encoding/gob包在处理递归值方面存在问题。链接
>递归类型可以正常工作，但是递归值（具有循环的数据）存在问题。这可能会改变。
在此问题得到解决之前，你可以选择不使用循环数据，或者采用其他方法进行序列化。
英文:
As of now, the encoding/gob package doesn't work with recursive values:
>Recursive types work fine, but recursive values (data with cycles) are problematic. This may change.
Until this is changed, you'll have to either not use cyclic data, or use a different approach to serialisation.
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