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@mitchellh @ryanuber @dmitshur @gyim
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package mapstructure
import (
"fmt"
)
func ExampleDecode() {
type Person struct {
Name string
Age int
Emails []string
Extra map[string]string
}
// This input can come from anywhere, but typically comes from
// something like decoding JSON where we're not quite sure of the
// struct initially.
input := map[string]interface{}{
"name": "Mitchell",
"age": 91,
"emails": []string{"one", "two", "three"},
"extra": map[string]string{
"twitter": "mitchellh",
},
}
var result Person
err := Decode(input, &result)
if err != nil {
panic(err)
}
fmt.Printf("%#v", result)
// Output:
// mapstructure.Person{Name:"Mitchell", Age:91, Emails:[]string{"one", "two", "three"}, Extra:map[string]string{"twitter":"mitchellh"}}
}
func ExampleDecode_errors() {
type Person struct {
Name string
Age int
Emails []string
Extra map[string]string
}
// This input can come from anywhere, but typically comes from
// something like decoding JSON where we're not quite sure of the
// struct initially.
input := map[string]interface{}{
"name": 123,
"age": "bad value",
"emails": []int{1, 2, 3},
}
var result Person
err := Decode(input, &result)
if err == nil {
panic("should have an error")
}
fmt.Println(err.Error())
// Output:
// 5 error(s) decoding:
//
// * 'Age' expected type 'int', got unconvertible type 'string'
// * 'Emails[0]' expected type 'string', got unconvertible type 'int'
// * 'Emails[1]' expected type 'string', got unconvertible type 'int'
// * 'Emails[2]' expected type 'string', got unconvertible type 'int'
// * 'Name' expected type 'string', got unconvertible type 'int'
}
func ExampleDecode_metadata() {
type Person struct {
Name string
Age int
}
// This input can come from anywhere, but typically comes from
// something like decoding JSON where we're not quite sure of the
// struct initially.
input := map[string]interface{}{
"name": "Mitchell",
"age": 91,
"email": "foo@bar.com",
}
// For metadata, we make a more advanced DecoderConfig so we can
// more finely configure the decoder that is used. In this case, we
// just tell the decoder we want to track metadata.
var md Metadata
var result Person
config := &DecoderConfig{
Metadata: &md,
Result: &result,
}
decoder, err := NewDecoder(config)
if err != nil {
panic(err)
}
if err := decoder.Decode(input); err != nil {
panic(err)
}
fmt.Printf("Unused keys: %#v", md.Unused)
// Output:
// Unused keys: []string{"email"}
}
func ExampleDecode_weaklyTypedInput() {
type Person struct {
Name string
Age int
Emails []string
}
// This input can come from anywhere, but typically comes from
// something like decoding JSON, generated by a weakly typed language
// such as PHP.
input := map[string]interface{}{
"name": 123, // number => string
"age": "42", // string => number
"emails": map[string]interface{}{}, // empty map => empty array
}
var result Person
config := &DecoderConfig{
WeaklyTypedInput: true,
Result: &result,
}
decoder, err := NewDecoder(config)
if err != nil {
panic(err)
}
err = decoder.Decode(input)
if err != nil {
panic(err)
}
fmt.Printf("%#v", result)
// Output: mapstructure.Person{Name:"123", Age:42, Emails:[]string{}}
}
func ExampleDecode_tags() {
// Note that the mapstructure tags defined in the struct type
// can indicate which fields the values are mapped to.
type Person struct {
Name string `mapstructure:"person_name"`
Age int `mapstructure:"person_age"`
}
input := map[string]interface{}{
"person_name": "Mitchell",
"person_age": 91,
}
var result Person
err := Decode(input, &result)
if err != nil {
panic(err)
}
fmt.Printf("%#v", result)
// Output:
// mapstructure.Person{Name:"Mitchell", Age:91}
}
func ExampleDecode_embeddedStruct() {
// Squashing multiple embedded structs is allowed using the squash tag.
// This is demonstrated by creating a composite struct of multiple types
// and decoding into it. In this case, a person can carry with it both
// a Family and a Location, as well as their own FirstName.
type Family struct {
LastName string
}
type Location struct {
City string
}
type Person struct {
Family `mapstructure:",squash"`
Location `mapstructure:",squash"`
FirstName string
}
input := map[string]interface{}{
"FirstName": "Mitchell",
"LastName": "Hashimoto",
"City": "San Francisco",
}
var result Person
err := Decode(input, &result)
if err != nil {
panic(err)
}
fmt.Printf("%s %s, %s", result.FirstName, result.LastName, result.City)
// Output:
// Mitchell Hashimoto, San Francisco
}
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