Golang : Covert map/slice/array to JSON or XML format




Problem :

You have a data struct in map, slice or array format and you have to convert the data to JSON or XML format. How to do that?

Solution :

Convert the map, slice or array data to JSON with json.Marshal() function. In the struct, remember to add struct tags for JSON or XML.

NOTE : Set Content-Type to application/json or application/xml when writing out as HTTP response.

For example :

 package main

 import (
  "encoding/json"
  "fmt"
  "net/http"
 )

 type KeyPair struct {
  Id int `json:"id"` // <--- json struct tags
  Name string `json:"name"` // <--- json struct tags
 }

 func Home(w http.ResponseWriter, r *http.Request) {

  KP := KeyPair{Id: 1, Name: "Adam"}
  fmt.Println(KP)

  byte, err := json.Marshal(KP) // <---- here !

  if err != nil {
 return
  }

  w.Header().Set("Content-Type", "application/json") // <---- here !
  fmt.Fprint(w, string(byte))

  fmt.Println(string(byte))
 }

 func main() {

  http.HandleFunc("/", Home)
  http.ListenAndServe(":8080", nil)
 }

To convert struct data to XML, just change the encoder and field tags to XML equivalent. See https://www.socketloop.com/tutorials/golang-xml-to-json-example for guide.

Happy coding!

  See also : Golang : XML to JSON example



Tags : golang json xml http-response field-tags

Adam Ng By Adam Ng

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