feat(conf): one decoder to decode them all

conf/conf.go

@@ -238,7 +238,7 @@ func (c *ConfigParser[T]) unmarshal(t *T) error {
 			if c.opts.tagName != "" {
 				config.TagName = c.opts.tagName
 			}
-		}, viper.DecodeHook(decodeHook(c.opts.hooks)))
+		}, viper.DecodeHook(decodeHook(c.opts.hook)))
 	}
 
 	ty := reflect.TypeOf(*t)
@@ -249,7 +249,7 @@ func (c *ConfigParser[T]) unmarshal(t *T) error {
 			if c.opts.tagName != "" {
 				config.TagName = c.opts.tagName
 			}
-		}, viper.DecodeHook(decodeHook(c.opts.hooks)))
+		}, viper.DecodeHook(decodeHook(c.opts.hook)))
 		if err != nil {
 			return err
 		}

conf/decodehook.go

@@ -21,51 +21,33 @@ package conf
 
 import (
 	"crypto/rsa"
-	"reflect"
-	"time"
-
 	jwt "github.com/dgrijalva/jwt-go"
 	"github.com/mitchellh/mapstructure"
-	"google.golang.org/protobuf/types/known/durationpb"
+	"reflect"
 )
 
-func decodeHook(hooks []DecodeHook) mapstructure.DecodeHookFunc {
+func decodeHook(hook DecodeHook) mapstructure.DecodeHookFunc {
 	return mapstructure.ComposeDecodeHookFunc(
 		mapstructure.StringToTimeDurationHookFunc(),
 		mapstructure.StringToSliceHookFunc(","),
-		decoder(hooks),
+		decoder(hook),
 	)
 }
 
-func decoder(hooks []DecodeHook) func(f reflect.Type, t reflect.Type, data interface{}) (interface{}, error) {
-	hm := map[reflect.Type]func(string) (interface{}, error){}
-	hm[reflect.TypeOf(rsa.PublicKey{})] = func(data string) (interface{}, error) {
-		return jwt.ParseRSAPublicKeyFromPEM([]byte(data))
-	}
-	hm[reflect.TypeOf(rsa.PrivateKey{})] = func(data string) (interface{}, error) {
-		return jwt.ParseRSAPrivateKeyFromPEM([]byte(data))
-	}
-	hm[reflect.TypeOf(durationpb.Duration{})] = func(data string) (interface{}, error) {
-		t, e := time.ParseDuration(data)
-		if e != nil {
-			return nil, e
-		}
-		return durationpb.New(t), nil
-	}
-	for _, hook := range hooks {
-		hm[hook.Type] = hook.Decode
-	}
-
+func decoder(hook DecodeHook) func(f reflect.Type, t reflect.Type, data interface{}) (interface{}, error) {
 	return func(f reflect.Type, t reflect.Type, data interface{}) (interface{}, error) {
 		// Check if the data type matches the expected one
 		if f.Kind() != reflect.String {
 			return data, nil
 		}
 
-		if h, ok := hm[t]; ok {
-			return h(data.(string))
+		switch t {
+		case reflect.TypeOf(rsa.PublicKey{}):
+			return jwt.ParseRSAPublicKeyFromPEM([]byte(data.(string)))
+		case reflect.TypeOf(rsa.PrivateKey{}):
+			return jwt.ParseRSAPrivateKeyFromPEM([]byte(data.(string)))
 		}
 
-		return data, nil
+		return hook(t, data.(string))
 	}
 }

conf/examples/example_test.go

@@ -21,6 +21,7 @@ package examples_test
 
 import (
 	"log"
+	"reflect"
 
 	"github.com/antigloss/go/conf"
 	"github.com/antigloss/go/conf/store"
@@ -49,6 +50,20 @@ func ExampleConfFromEnv() {
 	c := conf.New[ExampleConfig](
 		conf.WithTagName("json"),   // Tag name must match with the tag name defined inside the struct for unmarshalling the configurations. Default tag name is mapstructure
 		conf.WithStores(env.New()), // Create a Store object for reading configurations from ENV
+		conf.WithDecodeHook(func(to reflect.Type, data string) (interface{}, error) { // Set a decoder to decode user-defined data types
+			// Decoding implementation goes here
+			//switch to {
+			//case reflect.TypeOf(UserDefinedType1{}):
+			//	obj := UserDefinedType1{}
+			//	err := obj.Parse(data)
+			//	return obj, err
+			//case reflect.TypeOf(UserDefinedType2{}):
+			//	obj := UserDefinedType2{}
+			//	err := obj.Parse(data)
+			//	return obj, err
+			//}
+			return data, nil
+		}),
 	)
 
 	bc, err := c.Parse()

conf/option.go

@@ -39,19 +39,14 @@ func WithTagName(tag string) option {
 	}
 }
 
-// DecodeHook decoder for a specified data type
-type DecodeHook struct {
-	// Data type
-	Type reflect.Type
-	// Decoder for decoding raw configuration data into `Type`.
-	// It returns the decoded value as interface{} on success, otherwise, an error is returned.
-	Decode func(data string) (interface{}, error)
-}
+// DecodeHook decodes `data` to an object of type `to`.
+// It returns the decoded value as interface{} on success, otherwise, an error is returned.
+type DecodeHook func(to reflect.Type, data string) (interface{}, error)
 
-// WithDecodeHooks sets user-defined decoders
-func WithDecodeHooks(hooks ...DecodeHook) option {
+// WithDecodeHook sets a user-defined decoder
+func WithDecodeHook(hook DecodeHook) option {
 	return func(o *options) {
-		o.hooks = hooks
+		o.hook = hook
 	}
 }
 
@@ -60,7 +55,7 @@ type option func(opts *options)
 type options struct {
 	stores  []store.Store
 	tagName string
-	hooks   []DecodeHook
+	hook    DecodeHook
 }
 
 func (o *options) apply(opts ...option) {

go.mod

@@ -11,7 +11,6 @@ require (
 	github.com/spf13/viper v1.14.0
 	github.com/taptap/go-apollo v1.3.0
 	golang.org/x/exp v0.0.0-20230111222715-75897c7a292a
-	google.golang.org/protobuf v1.28.1
 	gopkg.in/yaml.v3 v3.0.1
 )
 

go.sum

@@ -118,7 +118,6 @@ github.com/golang/protobuf v1.4.0/go.mod h1:jodUvKwWbYaEsadDk5Fwe5c77LiNKVO9IDvq
 github.com/golang/protobuf v1.4.1/go.mod h1:U8fpvMrcmy5pZrNK1lt4xCsGvpyWQ/VVv6QDs8UjoX8=
 github.com/golang/protobuf v1.4.2/go.mod h1:oDoupMAO8OvCJWAcko0GGGIgR6R6ocIYbsSw735rRwI=
 github.com/golang/protobuf v1.4.3/go.mod h1:oDoupMAO8OvCJWAcko0GGGIgR6R6ocIYbsSw735rRwI=
-github.com/golang/protobuf v1.5.0/go.mod h1:FsONVRAS9T7sI+LIUmWTfcYkHO4aIWwzhcaSAoJOfIk=
 github.com/google/btree v0.0.0-20180813153112-4030bb1f1f0c/go.mod h1:lNA+9X1NB3Zf8V7Ke586lFgjr2dZNuvo3lPJSGZ5JPQ=
 github.com/google/btree v1.0.0/go.mod h1:lNA+9X1NB3Zf8V7Ke586lFgjr2dZNuvo3lPJSGZ5JPQ=
 github.com/google/go-cmp v0.2.0/go.mod h1:oXzfMopK8JAjlY9xF4vHSVASa0yLyX7SntLO5aqRK0M=
@@ -130,7 +129,6 @@ github.com/google/go-cmp v0.5.0/go.mod h1:v8dTdLbMG2kIc/vJvl+f65V22dbkXbowE6jgT/
 github.com/google/go-cmp v0.5.1/go.mod h1:v8dTdLbMG2kIc/vJvl+f65V22dbkXbowE6jgT/gNBxE=
 github.com/google/go-cmp v0.5.2/go.mod h1:v8dTdLbMG2kIc/vJvl+f65V22dbkXbowE6jgT/gNBxE=
 github.com/google/go-cmp v0.5.4/go.mod h1:v8dTdLbMG2kIc/vJvl+f65V22dbkXbowE6jgT/gNBxE=
-github.com/google/go-cmp v0.5.5/go.mod h1:v8dTdLbMG2kIc/vJvl+f65V22dbkXbowE6jgT/gNBxE=
 github.com/google/go-cmp v0.5.9 h1:O2Tfq5qg4qc4AmwVlvv0oLiVAGB7enBSJ2x2DqQFi38=
 github.com/google/martian v2.1.0+incompatible/go.mod h1:9I4somxYTbIHy5NJKHRl3wXiIaQGbYVAs8BPL6v8lEs=
 github.com/google/martian/v3 v3.0.0/go.mod h1:y5Zk1BBys9G+gd6Jrk0W3cC1+ELVxBWuIGO+w/tUAp0=
@@ -597,9 +595,6 @@ google.golang.org/protobuf v1.23.0/go.mod h1:EGpADcykh3NcUnDUJcl1+ZksZNG86OlYog2
 google.golang.org/protobuf v1.23.1-0.20200526195155-81db48ad09cc/go.mod h1:EGpADcykh3NcUnDUJcl1+ZksZNG86OlYog2l/sGQquU=
 google.golang.org/protobuf v1.24.0/go.mod h1:r/3tXBNzIEhYS9I1OUVjXDlt8tc493IdKGjtUeSXeh4=
 google.golang.org/protobuf v1.25.0/go.mod h1:9JNX74DMeImyA3h4bdi1ymwjUzf21/xIlbajtzgsN7c=
-google.golang.org/protobuf v1.26.0-rc.1/go.mod h1:jlhhOSvTdKEhbULTjvd4ARK9grFBp09yW+WbY/TyQbw=
-google.golang.org/protobuf v1.28.1 h1:d0NfwRgPtno5B1Wa6L2DAG+KivqkdutMf1UhdNx175w=
-google.golang.org/protobuf v1.28.1/go.mod h1:HV8QOd/L58Z+nl8r43ehVNZIU/HEI6OcFqwMG9pJV4I=
 gopkg.in/alecthomas/kingpin.v2 v2.2.6/go.mod h1:FMv+mEhP44yOT+4EoQTLFTRgOQ1FBLkstjWtayDeSgw=
 gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
 gopkg.in/check.v1 v1.0.0-20180628173108-788fd7840127 h1:qIbj1fsPNlZgppZ+VLlY7N33q108Sa+fhmuc+sWQYwY=