Matthew Harwood Matthew Harwood - 5 months ago 12
JSON Question

How to serve up a json response using a golang?

Question: Currently I'm printing out my response in the

func Index

like this
fmt.Fprintf(w, string(response))
however, how can I send json properly in the request so that it maybe consumed by a view?

package main

import (
"fmt"
"github.com/julienschmidt/httprouter"
"net/http"
"log"
"encoding/json"
)

type Payload struct {
Stuff Data
}
type Data struct {
Fruit Fruits
Veggies Vegetables
}
type Fruits map[string]int
type Vegetables map[string]int


func Index(w http.ResponseWriter, r *http.Request, _ httprouter.Params) {
response, err := getJsonResponse();
if err != nil {
panic(err)
}
fmt.Fprintf(w, string(response))
}


func main() {
router := httprouter.New()
router.GET("/", Index)
log.Fatal(http.ListenAndServe(":8080", router))
}

func getJsonResponse()([]byte, error) {
fruits := make(map[string]int)
fruits["Apples"] = 25
fruits["Oranges"] = 10

vegetables := make(map[string]int)
vegetables["Carrats"] = 10
vegetables["Beets"] = 0

d := Data{fruits, vegetables}
p := Payload{d}

return json.MarshalIndent(p, "", " ")
}

Answer

You can set your content-type header so clients know to expect json

w.Header().Set("Content-Type", "application/javascript")

Another way to marshal a struct to json is to build an encoder using the http.ResponseWriter

// get a payload p := Payload{d}
json.NewEncoder(w).Encode(p)
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