// GetVoteComics returns two comics that should face off against each other in
// a vote-duel. One comic is chosen randomly, the other is approximately chosen
// from the 1% least voted-on comics.
func GetVoteComics() (c1, c2 Comic, err error) {
C := pool.Get()
defer C.Close()
var (
candidates []string
votes int
)
candidates, err = redis.Strings(C.Do("SRANDMEMBER", "strips", 100))
if err != nil {
return
}
// Choose one comic at random (this is needed because Redis' SRANDMEMBER
// function isn't random enough)
idx := rand.Intn(len(candidates))
c1, err = GetComic(candidates[idx])
if err != nil {
return
}
// Remove the chosen comic from the rotation, so we don't duel a comic
// against itself
candidates[idx] = candidates[len(candidates)-1]
candidates = candidates[:len(candidates)-1]
// Find the comic with the least totalvotes among the remaining candidates
minVotes := 1<<31 - 1
bestStrip := ""
for _, strip := range candidates {
votes, err = redis.Int(C.Do("HGET", fmt.Sprintf(stripsFmt, strip), "totalvotes"))
if votes < minVotes {
bestStrip = strip
minVotes = votes
}
}
c2, err = GetComic(bestStrip)
if err != nil {
return
}
return
}
// GetPage returns the contents of the requested page number
func GetPage(page string) (List, error) {
C := pool.Get()
defer C.Close()
p, err := strconv.Atoi(page)
if err != nil || p < 1 {
return List{}, errors.New("invalid page: " + page)
}
comics, err := redis.Strings(C.Do("ZREVRANGE", "ranked", (p-1)*pageSize, (p-1)*pageSize+pageSize-1))
if err != nil {
return List{}, errors.New("could not retrieve comics for page " + page)
}
if len(comics) == 0 {
return List{}, errors.New("invalid page: " + page)
}
numPages := 0
numComics, err := redis.Int(C.Do("SCARD", "strips"))
if err != nil {
numPages = p
} else {
numPages = numComics / pageSize
if numComics%pageSize != 0 {
numPages++
}
}
result := List{
CurPage: p,
LastPage: numPages,
ListStart: (p-1)*pageSize + 1,
Comics: make([]Comic, 0, pageSize),
}
for _, c := range comics {
comic, err := GetComic(c)
if err == nil {
result.Comics = append(result.Comics, comic)
}
}
return result, nil
}
// zpop pops a value from the ZSET key using WATCH/MULTI/EXEC commands.
func zpop(c redis.Conn, key string) (result string, err error) {
defer func() {
// Return connection to normal state on error.
if err != nil {
c.Do("DISCARD")
}
}()
// Loop until transaction is successful.
for {
if _, err := c.Do("WATCH", key); err != nil {
return "", err
}
members, err := redis.Strings(c.Do("ZRANGE", key, 0, 0))
if err != nil {
return "", err
}
if len(members) != 1 {
return "", redis.ErrNil
}
c.Send("MULTI")
c.Send("ZREM", key, members[0])
queued, err := c.Do("EXEC")
if err != nil {
return "", err
}
if queued != nil {
result = members[0]
break
}
}
return result, nil
}
actual valueError
expected valueError
}{
{
"ints([v1, v2])",
ve(redis.Ints([]interface{}{[]byte("4"), []byte("5")}, nil)),
ve([]int{4, 5}, nil),
},
{
"ints(nil)",
ve(redis.Ints(nil, nil)),
ve([]int(nil), redis.ErrNil),
},
{
"strings([v1, v2])",
ve(redis.Strings([]interface{}{[]byte("v1"), []byte("v2")}, nil)),
ve([]string{"v1", "v2"}, nil),
},
{
"strings(nil)",
ve(redis.Strings(nil, nil)),
ve([]string(nil), redis.ErrNil),
},
{
"values([v1, v2])",
ve(redis.Values([]interface{}{[]byte("v1"), []byte("v2")}, nil)),
ve([]interface{}{[]byte("v1"), []byte("v2")}, nil),
},
{
"values(nil)",
ve(redis.Values(nil, nil)),