zitadel-oidc/pkg/oidc/util.go
2023-03-28 12:58:34 +03:00

54 lines
1.6 KiB
Go

package oidc
import (
"bytes"
"encoding/json"
"fmt"
)
// mergeAndMarshalClaims merges registered and the custom
// claims map into a single JSON object.
// Registered fields overwrite custom claims.
func mergeAndMarshalClaims(registered any, extraClaims map[string]any) ([]byte, error) {
// Use a buffer for memory re-use, instead off letting
// json allocate a new []byte for every step.
buf := new(bytes.Buffer)
// Marshal the registered claims into JSON
if err := json.NewEncoder(buf).Encode(registered); err != nil {
return nil, fmt.Errorf("oidc registered claims: %w", err)
}
if len(extraClaims) > 0 {
merged := make(map[string]any)
for k, v := range extraClaims {
merged[k] = v
}
// Merge JSON data into custom claims.
// The full-read action by the decoder resets the buffer
// to zero len, while retaining underlaying cap.
if err := json.NewDecoder(buf).Decode(&merged); err != nil {
return nil, fmt.Errorf("oidc registered claims: %w", err)
}
// Marshal the final result.
if err := json.NewEncoder(buf).Encode(merged); err != nil {
return nil, fmt.Errorf("oidc custom claims: %w", err)
}
}
return buf.Bytes(), nil
}
// unmarshalJSONMulti unmarshals the same JSON data into multiple destinations.
// Each destination must be a pointer, as per json.Unmarshal rules.
// Returns on the first error and destinations may be partly filled with data.
func unmarshalJSONMulti(data []byte, destinations ...any) error {
for _, dst := range destinations {
if err := json.Unmarshal(data, dst); err != nil {
return fmt.Errorf("oidc: %w into %T", err, dst)
}
}
return nil
}