go-playground/form

go get github.com/go-playground/form

import "github.com/go-playground/form/v4"

<form method="POST">
  <input type="text" name="Name" value="joeybloggs"/>
  <input type="text" name="Age" value="3"/>
  <input type="text" name="Gender" value="Male"/>
  <input type="text" name="Address[0].Name" value="26 Here Blvd."/>
  <input type="text" name="Address[0].Phone" value="9(999)999-9999"/>
  <input type="text" name="Address[1].Name" value="26 There Blvd."/>
  <input type="text" name="Address[1].Phone" value="1(111)111-1111"/>
  <input type="text" name="active" value="true"/>
  <input type="text" name="MapExample[key]" value="value"/>
  <input type="text" name="NestedMap[key][key]" value="value"/>
  <input type="text" name="NestedArray[0][0]" value="value"/>
  <input type="submit"/>
</form>

package main

import (
	"fmt"
	"log"
	"net/url"

	"github.com/go-playground/form/v4"
)

// Address contains address information
type Address struct {
	Name  string
	Phone string
}

// User contains user information
type User struct {
	Name        string
	Age         uint8
	Gender      string
	Address     []Address
	Active      bool `form:"active"`
	MapExample  map[string]string
	NestedMap   map[string]map[string]string
	NestedArray [][]string
}

// use a single instance of Decoder, it caches struct info
var decoder *form.Decoder

func main() {
	decoder = form.NewDecoder()

	// this simulates the results of http.Request's ParseForm() function
	values := parseForm()

	var user User

	// must pass a pointer
	err := decoder.Decode(&user, values)
	if err != nil {
		log.Panic(err)
	}

	fmt.Printf("%#v\n", user)
}

// this simulates the results of http.Request's ParseForm() function
func parseForm() url.Values {
	return url.Values{
		"Name":                []string{"joeybloggs"},
		"Age":                 []string{"3"},
		"Gender":              []string{"Male"},
		"Address[0].Name":     []string{"26 Here Blvd."},
		"Address[0].Phone":    []string{"9(999)999-9999"},
		"Address[1].Name":     []string{"26 There Blvd."},
		"Address[1].Phone":    []string{"1(111)111-1111"},
		"active":              []string{"true"},
		"MapExample[key]":     []string{"value"},
		"NestedMap[key][key]": []string{"value"},
		"NestedArray[0][0]":   []string{"value"},
	}
}

package main

import (
	"fmt"
	"log"

	"github.com/go-playground/form/v4"
)

// Address contains address information
type Address struct {
	Name  string
	Phone string
}

// User contains user information
type User struct {
	Name        string
	Age         uint8
	Gender      string
	Address     []Address
	Active      bool `form:"active"`
	MapExample  map[string]string
	NestedMap   map[string]map[string]string
	NestedArray [][]string
}

// use a single instance of Encoder, it caches struct info
var encoder *form.Encoder

func main() {
	encoder = form.NewEncoder()

	user := User{
		Name:   "joeybloggs",
		Age:    3,
		Gender: "Male",
		Address: []Address{
			{Name: "26 Here Blvd.", Phone: "9(999)999-9999"},
			{Name: "26 There Blvd.", Phone: "1(111)111-1111"},
		},
		Active:      true,
		MapExample:  map[string]string{"key": "value"},
		NestedMap:   map[string]map[string]string{"key": {"key": "value"}},
		NestedArray: [][]string{{"value"}},
	}

	// must pass a pointer
	values, err := encoder.Encode(&user)
	if err != nil {
		log.Panic(err)
	}

	fmt.Printf("%#v\n", values)
}

decoder.RegisterCustomTypeFunc(func(vals []string) (interface{}, error) {
	return time.Parse("2006-01-02", vals[0])
}, time.Time{})

encoder.RegisterCustomTypeFunc(func(x interface{}) ([]string, error) {
	return []string{x.(time.Time).Format("2006-01-02")}, nil
}, time.Time{})

type MyStruct struct {
	Field string `form:"-"`
}

type MyStruct struct {
	Field  string `form:",omitempty"`
	Field2 string `form:"CustomFieldName,omitempty"`
}

// A struct field of
Field []string{"1", "2", "3"}

// will be output a url.Value as
"Field": []string{"1", "2", "3"}

and not
"Field[0]": []string{"1"}
"Field[1]": []string{"2"}
"Field[2]": []string{"3"}

// however there are times where it is unavoidable, like with pointers
i := int(1)
Field []*string{nil, nil, &i}

// to avoid index 1 and 2 must use index
"Field[2]": []string{"1"}

go test -run=NONE -bench=. -benchmem ./...
goos: darwin
goarch: arm64
pkg: github.com/go-playground/form/v4
cpu: Apple M3 Max
BenchmarkNestedArrayDecode100-16     	      75	  15782643 ns/op	18754349 B/op	  360810 allocs/op
BenchmarkNestedArrayDecode1000-16    	       1	2227892458 ns/op	1877558216 B/op	36011385 allocs/op
PASS
ok  	github.com/go-playground/form/v4	4.251s
goos: darwin
goarch: arm64
pkg: github.com/go-playground/form/v4/benchmarks
cpu: Apple M3 Max
BenchmarkSimpleUserDecodeStruct-16                              	12669696	        94.60 ns/op	      64 B/op	       1 allocs/op
BenchmarkSimpleUserDecodeStructParallel-16                      	46715631	        27.79 ns/op	      64 B/op	       1 allocs/op
BenchmarkSimpleUserEncodeStruct-16                              	 4624094	       256.7 ns/op	     485 B/op	      10 allocs/op
BenchmarkSimpleUserEncodeStructParallel-16                      	 7386290	       166.2 ns/op	     485 B/op	      10 allocs/op
BenchmarkPrimitivesDecodeStructAllPrimitivesTypes-16            	 3533421	       332.3 ns/op	      96 B/op	       1 allocs/op
BenchmarkPrimitivesDecodeStructAllPrimitivesTypesParallel-16    	20706642	        59.43 ns/op	      96 B/op	       1 allocs/op
BenchmarkPrimitivesEncodeStructAllPrimitivesTypes-16            	 1228750	       966.4 ns/op	    1465 B/op	      34 allocs/op
BenchmarkPrimitivesEncodeStructAllPrimitivesTypesParallel-16    	 1962678	       607.2 ns/op	    1465 B/op	      34 allocs/op
BenchmarkComplexArrayDecodeStructAllTypes-16                    	  213568	      5361 ns/op	    2081 B/op	     121 allocs/op
BenchmarkComplexArrayDecodeStructAllTypesParallel-16            	  960226	      1314 ns/op	    2087 B/op	     121 allocs/op
BenchmarkComplexArrayEncodeStructAllTypes-16                    	  271944	      4017 ns/op	    6788 B/op	     107 allocs/op
BenchmarkComplexArrayEncodeStructAllTypesParallel-16            	  441998	      2829 ns/op	    6791 B/op	     107 allocs/op
BenchmarkComplexMapDecodeStructAllTypes-16                      	  179220	      6359 ns/op	    5300 B/op	     130 allocs/op
BenchmarkComplexMapDecodeStructAllTypesParallel-16              	  412233	      2933 ns/op	    5310 B/op	     130 allocs/op
BenchmarkComplexMapEncodeStructAllTypes-16                      	  262464	      4122 ns/op	    4083 B/op	     106 allocs/op
BenchmarkComplexMapEncodeStructAllTypesParallel-16              	  622110	      2084 ns/op	    4084 B/op	     106 allocs/op
BenchmarkDecodeNestedStruct-16                                  	  823956	      1247 ns/op	     344 B/op	      14 allocs/op
BenchmarkDecodeNestedStructParallel-16                          	 4689418	       267.5 ns/op	     344 B/op	      14 allocs/op
BenchmarkEncodeNestedStruct-16                                  	 1844667	       636.0 ns/op	     653 B/op	      16 allocs/op
BenchmarkEncodeNestedStructParallel-16                          	 4302678	       278.8 ns/op	     653 B/op	      16 allocs/op