Find BTC balance for an address in Go - go

Question

I need to correct and transform a function, to checking 2 addresses of btc balance, like (addr and addr1 ), and the return is json value, i need to specify im not know very well golang.. need help!
func balance(addr) {
var url = "https://bitcoin.toshi.io/api/v0/addresses/" + addr
response, _ := http.Get(url)
defer response.Body.Close()
contents, _ := ioutil.ReadAll(response.Body)
return contents
}
EDIT:
i need a function to get balances of 2 btc addresses, or to use this libraries btcwallet.
func GetAddressBalance(icmd btcjson.Cmd) (interface{}, *btcjson.Error)
func GetAddressesByAccount(icmd btcjson.Cmd) (interface{}, *btcjson.Error)
func GetBalance(icmd btcjson.Cmd) (interface{}, *btcjson.Error)

Answer 1

You were on the right track. The api returns a json. This can be unmarshalled into a struct (Address). That way you can access everything returned by the api. Do not forget to always check for error codes! Replace some_address with an actual address to get the balance.
package main
import (
"encoding/json"
"fmt"
"net/http"
)
func main() {
a, err := getAddress("some_address")
if err != nil {
fmt.Println(err)
return
}
fmt.Println("Balance:", a.Balance)
}
type Address struct {
Hash string
Balance int
Received int
Send int
UnconfirmedBalance int `json:"unconfirmed_balance"`
UnconfirmedReceived int `json:"unconfirmed_received"`
UnconfirmedSent int `json:"unconfirmed_sent"`
}
func getAddress(addr string) (*Address, error) {
resp, err := http.Get("https://bitcoin.toshi.io/api/v0/addresses/" + addr)
if err != nil {
return nil, err
}
defer resp.Body.Close()
if resp.StatusCode != http.StatusOK {
return nil, fmt.Errorf("Error: %v", http.StatusText(resp.StatusCode))
}
var address Address
decoder := json.NewDecoder(resp.Body)
if err := decoder.Decode(&address); err != nil {
return nil, err
}
return &address, nil
}