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Bind permintaan form-data dengan struct kustom

Gin dapat melakukan bind data form ke struct bersarang secara otomatis. Ketika model data Anda terdiri dari struct-struct yang lebih kecil — baik sebagai field embedded, field pointer, atau struct inline anonim — Gin menelusuri hierarki struct dan memetakan setiap tag form ke parameter query atau field form yang sesuai.

Ini berguna untuk mengorganisasi form yang kompleks menjadi sub-struktur yang dapat digunakan kembali daripada mendefinisikan satu struct datar dengan banyak field.

package main
import (
"net/http"
"github.com/gin-gonic/gin"
)
type StructA struct {
FieldA string `form:"field_a"`
}
type StructB struct {
NestedStruct StructA
FieldB string `form:"field_b"`
}
type StructC struct {
NestedStructPointer *StructA
FieldC string `form:"field_c"`
}
type StructD struct {
NestedAnonyStruct struct {
FieldX string `form:"field_x"`
}
FieldD string `form:"field_d"`
}
func main() {
router := gin.Default()
router.GET("/getb", func(c *gin.Context) {
var b StructB
c.Bind(&b)
c.JSON(http.StatusOK, gin.H{
"a": b.NestedStruct,
"b": b.FieldB,
})
})
router.GET("/getc", func(c *gin.Context) {
var b StructC
c.Bind(&b)
c.JSON(http.StatusOK, gin.H{
"a": b.NestedStructPointer,
"c": b.FieldC,
})
})
router.GET("/getd", func(c *gin.Context) {
var b StructD
c.Bind(&b)
c.JSON(http.StatusOK, gin.H{
"x": b.NestedAnonyStruct,
"d": b.FieldD,
})
})
router.Run(":8080")
}

Uji coba

Terminal window
# Nested struct -- fields from StructA are bound alongside StructB's own fields
curl "http://localhost:8080/getb?field_a=hello&field_b=world"
# Output: {"a":{"FieldA":"hello"},"b":"world"}
# Nested struct pointer -- works the same way, Gin allocates the pointer automatically
curl "http://localhost:8080/getc?field_a=hello&field_c=world"
# Output: {"a":{"FieldA":"hello"},"c":"world"}
# Anonymous inline struct -- fields are bound by their form tags as usual
curl "http://localhost:8080/getd?field_x=hello&field_d=world"
# Output: {"d":"world","x":{"FieldX":"hello"}}

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