mirror of
https://github.com/gravitational/teleport
synced 2024-10-22 18:23:25 +00:00
63 lines
1.6 KiB
Go
63 lines
1.6 KiB
Go
/*
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Copyright 2015 Gravitational, Inc.
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Licensed under the Apache License, Version 2.0 (the "License");
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you may not use this file except in compliance with the License.
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You may obtain a copy of the License at
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http://www.apache.org/licenses/LICENSE-2.0
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Unless required by applicable law or agreed to in writing, software
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distributed under the License is distributed on an "AS IS" BASIS,
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WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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See the License for the specific language governing permissions and
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limitations under the License.
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*/
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package utils
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import (
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"encoding/json"
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"fmt"
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"github.com/gravitational/trace"
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)
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// ObjectToStruct is converts any structure into JSON and then unmarshalls it into
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// another structure.
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//
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// Teleport configuration uses this (strange, at first) trick to convert from one
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// struct type to another, if their fields are loosely compatible via their `json` tags
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//
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// Example: assume you have two structs:
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//
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// type A struct {
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// Name string `json:"name"`
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// Age int `json:"age"`
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// }
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//
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// type B struct {
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// FullName string `json:"name"`
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// }
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//
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// Now you can convert B to A:
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//
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// b := &B{ FullName: "Bob Dilan"}
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// var a *A
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// utils.ObjectToStruct(b, &a)
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// fmt.Println(a.Name)
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//
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// > "Bob Dilan"
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//
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func ObjectToStruct(in interface{}, out interface{}) error {
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bytes, err := json.Marshal(in)
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if err != nil {
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return trace.Wrap(err, fmt.Sprintf("failed to marshal: %v", in))
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}
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if err := json.Unmarshal([]byte(bytes), out); err != nil {
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return trace.Wrap(err, fmt.Sprintf("failed to unmarshal %v into %T", in, out))
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}
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return nil
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}
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