Tags.go

package main

import (
	"fmt"
	"reflect"
	"net/url"
)

type ExampleType struct {
	Name    string `url:"name"`
	Address string `url:"address"`
	City    string `url:"city"`
}

func ReadTagAndValue(val interface{}) url.Values {
	value := reflect.ValueOf(val) // turns struct type to the reflection interface
	params := url.Values{}
	for i := 0; i < value.NumField(); i++ { // iterates through every struct type field
		tag := value.Type().Field(i).Tag // returns the tag string
		field := value.Field(i)          // returns the content of the struct type field
		params.Set(tag.Get("url"), field.String())
	}
	return params
}

func main() {
	params := ReadTagAndValue(ExampleType{
		Name:    "Example",
		Address: "1234 Apple Street",
		City:    "New York",
	})
	fmt.Println(params.Encode())
}