Error unmarshaling when getting array of struct from redis - go

Question

I am using redigo to save some structs in redis. The thing is that for the same key I need to append new structs, but when I am trying to recover them I cannot unmarshal to an array.
Ie: (ignoring the errors intentionally)
type ADTO struct {
Value string
}
func main() {
pool := redis.Pool{
Dial: func() (conn redis.Conn, e error) {
return redis.Dial("tcp", "localhost:6379")
},
MaxIdle: 80,
MaxActive: 12000,
}
conn := pool.Get()
defer conn.Close()
key := "some-key"
defer conn.Do("DEL", key)
a := ADTO{Value: "a"}
bytes, _ := json.Marshal(a)
conn.Do("APPEND", key, bytes)
b := ADTO{Value: "b"}
bytes, _ = json.Marshal(b)
conn.Do("APPEND", key, bytes)
c := ADTO{Value: "c"}
bytes, _ = json.Marshal(c)
conn.Do("APPEND", key, bytes)
bytes, _ = redis.Bytes(conn.Do("GET", key))
adtos := make([]ADTO, 0)
// the following does not work
if err := json.Unmarshal(bytes, &adtos); err != nil {
return
}
}
If I only append a single struct and retrieving it, then it is working fine
I have tried with redis.ByteSlices with no luck

Answer 1

APPEND will only append to a string, it will not make a JSON array. After first insert, you'll have
{"Value":"a"}
Then after the second one, you'll have
{"Value":"a"}{"Value":"b"}
That's not a JSON array.
You can try using json.Decoder, and do something like:
b, _ = redis.Bytes(conn.Do("GET", key))
dec := json.NewDecoder(bytes.NewReader(b))
items := []ADTO{}
var x ADTO
for dec.Decode(&x) == nil {
items = append(items, x)
}