英文:
Can't generate scalar JSON in gqlgen
问题
我有一个 GQL 方案：
extend type MyType @key(fields: "id") {
id: ID! @external
properties: JSON @external
myField: String! @requires(fields: "properties")
}
scalar JSON
在 graph/model/model.go 中：
package model
import (
"encoding/json"
"fmt"
"io"
"strconv"
"strings"
)
type JSON map[string]interface{}
// UnmarshalGQL 实现了 graphql.Unmarshaler 接口
func (b *JSON) UnmarshalGQL(v interface{}) error {
*b = make(map[string]interface{})
byteData, err := json.Marshal(v)
if err != nil {
panic("FAIL WHILE MARSHAL SCHEME")
}
tmp := make(map[string]interface{})
err = json.Unmarshal(byteData, &tmp)
if err != nil {
panic("FAIL WHILE UNMARSHAL SCHEME")
//return fmt.Errorf("%v", err)
}
*b = tmp
return nil
}
// MarshalGQL 实现了 graphql.Marshaler 接口
func (b JSON) MarshalGQL(w io.Writer) {
byteData, err := json.Marshal(b)
if err != nil {
panic("FAIL WHILE MARSHAL SCHEME")
}
_, _ = w.Write(byteData)
}
但是当我运行 go run github.com/99designs/gqlgen generate 时出现错误：
generating core failed: type.gotpl: template: type.gotpl:52:28: executing "type.gotpl" at <$type.Elem.GO>: nil pointer evaluating *config.TypeReference.
GOexit status 1
我只需要获取名为 JSON 的 map[string]interface{}。我知道有一个标量类型 Map，但是对于 Apollo Federation，该字段必须称为 JSON。
英文:
I have a GQL scheme:
extend type MyType @key(fields: "id") {
id: ID! @external
properties: JSON @external
myField: String! @requires(fields: "properties")
}
scalar JSON
In graph/model/model.go:
package model
import (
"encoding/json"
"fmt"
"io"
"strconv"
"strings"
)
type JSON map[string]interface{}
// UnmarshalGQL implements the graphql.Unmarshaler interface
func (b *JSON) UnmarshalGQL(v interface{}) error {
*b = make(map[string]interface{})
byteData, err := json.Marshal(v)
if err != nil {
panic("FAIL WHILE MARSHAL SCHEME")
}
tmp := make(map[string]interface{})
err = json.Unmarshal(byteData, &tmp)
if err != nil {
panic("FAIL WHILE UNMARSHAL SCHEME")
//return fmt.Errorf("%v", err)
}
*b = tmp
return nil
}
// MarshalGQL implements the graphql.Marshaler interface
func (b JSON) MarshalGQL(w io.Writer) {
byteData, err := json.Marshal(b)
if err != nil {
panic("FAIL WHILE MARSHAL SCHEME")
}
_, _ = w.Write(byteData)
}
But when I run go run github.com/99designs/gqlgen generate
error:
generating core failed: type.gotpl: template: type.gotpl:52:28: executing "type.gotpl" at <$type.Elem.GO>: nil pointer evaluating *config.TypeReference.
GOexit status 1
I just need to get map[string]interface{} which called JSON. I knew there's scalar Map, but for apollo federation that field must be called JSON.
答案1
得分: 2
应该将MarshalGQL替换为MarshalJSON，如下所示：
type JSON map[string]interface{}
func MarshalJSON(b JSON) graphql.Marshaler {
return graphql.WriterFunc(func(w io.Writer) {
byteData, err := json.Marshal(b)
if err != nil {
log.Printf("在编组JSON时失败：%v\n", string(byteData))
}
_, err = w.Write(byteData)
if err != nil {
log.Printf("在写入数据时失败：%v\n", string(byteData))
}
})
}
func UnmarshalJSON(v interface{}) (JSON, error) {
byteData, err := json.Marshal(v)
if err != nil {
return JSON{}, fmt.Errorf("在编组方案时失败")
}
tmp := make(map[string]interface{})
err = json.Unmarshal(byteData, &tmp)
if err != nil {
return JSON{}, fmt.Errorf("在解组方案时失败")
}
return tmp, nil
}
希望对你有帮助！
英文:
it's should to replace MarshalGQL to MarshalJSON like:
type JSON map[string]interface{}
func MarshalJSON(b JSON) graphql.Marshaler {
return graphql.WriterFunc(func(w io.Writer) {
byteData, err := json.Marshal(b)
if err != nil {
log.Printf("FAIL WHILE MARSHAL JSON %v\n", string(byteData))
}
_, err = w.Write(byteData)
if err != nil {
log.Printf("FAIL WHILE WRITE DATA %v\n", string(byteData))
}
})
}
func UnmarshalJSON(v interface{}) (JSON, error) {
byteData, err := json.Marshal(v)
if err != nil {
return JSON{}, fmt.Errorf("FAIL WHILE MARSHAL SCHEME")
}
tmp := make(map[string]interface{})
err = json.Unmarshal(byteData, &tmp)
if err != nil {
return JSON{}, fmt.Errorf("FAIL WHILE UNMARSHAL SCHEME")
}
return tmp, nil
}
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