/
verify.go
105 lines (85 loc) · 2.32 KB
/
verify.go
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package games
import (
"crypto/hmac"
"crypto/sha256"
"encoding/base64"
"net/http"
"net/url"
"strings"
)
// ParamsVerification represents verification struct.
type ParamsVerification struct {
ClientSecret string
}
// NewParamsVerification return *ParamsVerification.
func NewParamsVerification(clientSecret string) *ParamsVerification {
pv := &ParamsVerification{
ClientSecret: clientSecret,
}
return pv
}
// getSignParams return sort sign parameters.
func getSignParams(rawValues url.Values) string {
singParams := make(url.Values)
signKeys := strings.Split(rawValues["sign_keys"][0], ",")
for _, key := range signKeys {
values, ok := rawValues[key]
if !ok {
continue
}
for _, value := range values {
singParams.Add(key, value)
}
}
return singParams.Encode() // sorted by key.
}
// Sign return signature in base64.
func (pv *ParamsVerification) Sign(p []byte) string {
// Generate hash code
mac := hmac.New(sha256.New, []byte(pv.ClientSecret))
_, _ = mac.Write(p)
expectedMAC := mac.Sum(nil)
// Generate base64
base64Sign := base64.StdEncoding.EncodeToString(expectedMAC)
base64Sign = strings.ReplaceAll(base64Sign, "+", "-")
base64Sign = strings.ReplaceAll(base64Sign, "/", "_")
base64Sign = strings.TrimRight(base64Sign, "=")
return base64Sign
}
// Verify verifies the signature in URL.
func (pv *ParamsVerification) Verify(u *url.URL) (bool, error) {
values, err := url.ParseQuery(u.RawQuery)
if err != nil {
return false, err
}
if len(values["sign"]) == 0 || len(values["sign_keys"]) == 0 {
return false, nil
}
singParams := getSignParams(values)
base64Sign := pv.Sign([]byte(singParams))
return base64Sign == values["sign"][0], nil
}
// VerifyMiddleware func.
func (pv *ParamsVerification) VerifyMiddleware(next http.Handler) http.Handler {
return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
ok, err := pv.Verify(r.URL)
if err != nil {
http.Error(w, "Bad Request", http.StatusBadRequest)
return
}
if ok {
next.ServeHTTP(w, r)
} else {
http.Error(w, "Forbidden", http.StatusForbidden)
}
})
}
// ParamsVerify verifies the signature in link using client secret.
func ParamsVerify(link, clientSecret string) (bool, error) {
pv := NewParamsVerification(clientSecret)
u, err := url.Parse(link)
if err != nil {
return false, err
}
return pv.Verify(u)
}