You're ignoring the error on JSON Unmarshal:
func Unmarshal(data []byte, v interface{}) error
See that it returns an error. Adding that in,
err = json.Unmarshal(body, &record)
perror(err)
It looks like this is a Unicode error — you need to decode the UTF-16 data.
How should you do this? Take a look at this answer. Basically once you read the body like body, err := ioutil.ReadAll(res.Body), you want to decode the UTF-16 bytes to a string. There is a lot going on there, but we can take some liberties: for instance, pulling up the URL in Chrome, the browser tells us that it is UTF-16 LE. So we can skip the ByteOrder detection. So the key here is this function:
func UTF16BytesToString(b []byte, o binary.ByteOrder) string {
utf := make([]uint16, (len(b)+(2-1))/2)
for i := 0; i+(2-1) < len(b); i += 2 {
utf[i/2] = o.Uint16(b[i:])
}
if len(b)/2 < len(utf) {
utf[len(utf)-1] = utf8.RuneError
}
return string(utf16.Decode(utf))
}
Knowing our byte order and passing it in, this will convert the naïve byte array to a string of UTF-16 characters. Thanks to user OneOfOne's comment, we can also detect the BOM easily.
The result:
package main
import (
"encoding/binary"
"encoding/json"
"fmt"
"io/ioutil"
"net/http"
"unicode/utf16"
"unicode/utf8"
)
const alertsUrl = "http://www.oref.org.il/WarningMessages/alerts.json"
type Record struct {
Id string `json:id`
Title string `json:title`
Data []string `json:data`
}
// LazyUTF16BytesToString converts UTF-16 encoded bytes, in big or little endian byte order,
// to a UTF-8 encoded string.
func LazyUTF16BytesToString(b []byte) string {
if len(b)%2 != 0 {
panic("len(b) % 2 != 0")
}
var codec binary.ByteOrder = binary.LittleEndian
if b[0] == 0xFE && b[1] == 0xFF { //check and strip the BOM
b = b[2:]
codec = binary.BigEndian
} else if b[0] == 0xFF && b[1] == 0xFE {
b = b[2:]
}
utf := make([]uint16, (len(b)+(2-1))/2)
for i := 0; i+(2-1) < len(b); i += 2 {
utf[i/2] = codec.Uint16(b[i:])
}
if len(b)/2 < len(utf) {
utf[len(utf)-1] = utf8.RuneError
}
return string(utf16.Decode(utf))
}
func main() {
client := &http.Client{}
req, err := http.NewRequest("GET", alertsUrl, nil)
perror(err)
req.Header.Add("Content-Type", "application/json; charset=utf-8")
res, err := client.Do(req)
perror(err)
defer res.Body.Close()
body, err := ioutil.ReadAll(res.Body)
perror(err)
bodyString := LazyUTF16BytesToString(body)
var record Record
err = json.Unmarshal([]byte(bodyString), &record)
perror(err)
fmt.Println(record)
}
func perror(err error) {
if err != nil {
panic(err)
}
}
