From 40647dbff86bed16a09c49ebc0e81175719e20b5 Mon Sep 17 00:00:00 2001
From: Ggicci <ggicci.t@gmail.com>
Date: Sun, 31 Dec 2023 02:04:54 -0500
Subject: [PATCH] feat: register path directive by default, but support
 encoding only

---
 core/directive.go      | 15 +++++++--------
 core/path.go           | 10 ++++++++++
 core/path_test.go      | 15 +++++++++++++--
 integration/gochi.go   |  1 +
 integration/gorilla.go |  1 +
 5 files changed, 32 insertions(+), 10 deletions(-)

diff --git a/core/directive.go b/core/directive.go
index 22fcbf7..fa82fc3 100644
--- a/core/directive.go
+++ b/core/directive.go
@@ -15,7 +15,13 @@ func init() {
 	RegisterDirective("body", &DirectiveBody{})
 	RegisterDirective("required", &DirectiveRequired{})
 	RegisterDirective("default", &DirectiveDefault{})
-	registerDirective("nonzero", &DirectiveNonzero{})
+	RegisterDirective("nonzero", &DirectiveNonzero{})
+	registerDirective("path", defaultPathDirective)
+
+	// decoder is a special executor which does nothing, but is an indicator of
+	// overriding the decoder for a specific field.
+	registerDirective("decoder", noopDirective)
+	registerDirective("coder", noopDirective)
 }
 
 var (
@@ -41,13 +47,6 @@ type DirectiveExecutor interface {
 	Decode(*DirectiveRuntime) error
 }
 
-func init() {
-	// decoder is a special executor which does nothing, but is an indicator of
-	// overriding the decoder for a specific field.
-	registerDirective("decoder", noopDirective)
-	registerDirective("coder", noopDirective)
-}
-
 // RegisterDirective registers a DirectiveExecutor with the given directive name. The
 // directive should be able to both extract the value from the HTTP request and build
 // the HTTP request from the value. The Decode API is used to decode data from the HTTP
diff --git a/core/path.go b/core/path.go
index 1a0f156..0092637 100644
--- a/core/path.go
+++ b/core/path.go
@@ -3,6 +3,8 @@
 
 package core
 
+import "errors"
+
 type DirectivePath struct {
 	decode func(*DirectiveRuntime) error
 }
@@ -24,3 +26,11 @@ func (*DirectivePath) Encode(rtm *DirectiveRuntime) error {
 	}
 	return encoder.Execute(rtm)
 }
+
+// defaultPathDirective is the default path directive, which only supports encoding,
+// while the decoding function is not implmented. Because the path decoding depends on the
+// routing framework, it should be implemented in the integration package.
+// See integration/gochi.go and integration/gorilla.go for examples.
+var defaultPathDirective = NewDirectivePath(func(rtm *DirectiveRuntime) error {
+	return errors.New("unimplemented path decoding function")
+})
diff --git a/core/path_test.go b/core/path_test.go
index 229e313..b01a377 100644
--- a/core/path_test.go
+++ b/core/path_test.go
@@ -19,9 +19,20 @@ func TestDirectivePath_Decode(t *testing.T) {
 	assert.ErrorIs(t, pathDirective.Decode(nil), assert.AnError)
 }
 
-func TestDirectivePath_NewRequest(t *testing.T) {
+func TestDirectivePath_ErrDefaultPathDecodingIsUnimplemented(t *testing.T) {
+	type GetProfileRequest struct {
+		Username string `in:"path=username"`
+	}
+
+	co, err := New(GetProfileRequest{})
+	assert.NoError(t, err)
+	req, _ := http.NewRequest("GET", "/users/ggicci", nil)
+	_, err = co.Decode(req)
+	assert.ErrorContains(t, err, "unimplemented path decoding function")
+}
+
+func TestDirectivePath_NewRequest_DefalutPathEncodingShouldWork(t *testing.T) {
 	assert := assert.New(t)
-	RegisterDirective("path", NewDirectivePath(myCustomPathDecode))
 	type Repository struct {
 		Name       string `json:"name"`
 		Visibility string `json:"visibility"` // public, private, internal
diff --git a/integration/gochi.go b/integration/gochi.go
index 9447ef8..d418f9d 100644
--- a/integration/gochi.go
+++ b/integration/gochi.go
@@ -28,6 +28,7 @@ func UseGochiURLParam(name string, fn GochiURLParamFunc) {
 	core.RegisterDirective(
 		name,
 		core.NewDirectivePath((&gochiURLParamExtractor{URLParam: fn}).Execute),
+		true,
 	)
 }
 
diff --git a/integration/gorilla.go b/integration/gorilla.go
index a85258b..957f608 100644
--- a/integration/gorilla.go
+++ b/integration/gorilla.go
@@ -27,6 +27,7 @@ func UseGorillaMux(name string, fnVars GorillaMuxVarsFunc) {
 	core.RegisterDirective(
 		name,
 		core.NewDirectivePath((&gorillaMuxVarsExtractor{Vars: fnVars}).Execute),
+		true,
 	)
 }