Add Go 1.27 generic context methods

Author: EricGusmao

context.go

@@ -455,11 +455,17 @@ func (c *Context) Cookies() []*http.Cookie {
 // Get retrieves data from the context.
 // Method returns any(nil) when key does not exist which is different from typed nil (eg. []byte(nil)).
 func (c *Context) Get(key string) any {
+	v, _ := c.get(key)
+	return v
+}
+
+// get retrieves a context value and reports whether its key exists.
+func (c *Context) get(key string) (any, bool) {
 	// Unlock without defer to avoid the deferred-call overhead on this hot path.
 	c.lock.RLock()
-	v := c.store[key]
+	v, ok := c.store[key]
 	c.lock.RUnlock()
-	return v
+	return v, ok
 }
 
 // Set saves data in the context.

context_generic.go

@@ -11,13 +11,14 @@ var ErrNonExistentKey = errors.New("non existent key")
 // ErrInvalidKeyType is error that is returned when the value is not castable to expected type.
 var ErrInvalidKeyType = errors.New("invalid key type")
 
-// ContextGet retrieves a value from the context store or ErrNonExistentKey error the key is missing.
+// ContextGet retrieves a value from the context store or ErrNonExistentKey error if the key is missing.
 // Returns ErrInvalidKeyType error if the value is not castable to type T.
 func ContextGet[T any](c *Context, key string) (T, error) {
-	c.lock.RLock()
-	defer c.lock.RUnlock()
+	return contextValue[T](c, key)
+}
 
-	val, ok := c.store[key]
+func contextValue[T any](c *Context, key string) (T, error) {
+	val, ok := c.get(key)
 	if !ok {
 		var zero T
 		return zero, ErrNonExistentKey
@@ -35,7 +36,11 @@ func ContextGet[T any](c *Context, key string) (T, error) {
 // ContextGetOr retrieves a value from the context store or returns a default value when the key
 // is missing. Returns ErrInvalidKeyType error if the value is not castable to type T.
 func ContextGetOr[T any](c *Context, key string, defaultValue T) (T, error) {
-	typed, err := ContextGet[T](c, key)
+	return contextValueOr(c, key, defaultValue)
+}
+
+func contextValueOr[T any](c *Context, key string, defaultValue T) (T, error) {
+	typed, err := contextValue[T](c, key)
 	if err == ErrNonExistentKey {
 		return defaultValue, nil
 	}

context_generic_go127.go

@@ -0,0 +1,18 @@
+// SPDX-License-Identifier: MIT
+// SPDX-FileCopyrightText: © 2015 LabStack LLC and Echo contributors
+
+//go:build go1.27
+
+package echo
+
+// Value retrieves a value from the context store or ErrNonExistentKey error if the key is missing.
+// Returns ErrInvalidKeyType error if the value is not castable to type T.
+func (c *Context) Value[T any](key string) (T, error) {
+	return contextValue[T](c, key)
+}
+
+// ValueOr retrieves a value from the context store or returns a default value when the key
+// is missing. Returns ErrInvalidKeyType error if the value is not castable to type T.
+func (c *Context) ValueOr[T any](key string, defaultValue T) (T, error) {
+	return contextValueOr(c, key, defaultValue)
+}

context_generic_go127_test.go

@@ -0,0 +1,78 @@
+// SPDX-License-Identifier: MIT
+// SPDX-FileCopyrightText: © 2015 LabStack LLC and Echo contributors
+
+//go:build go1.27
+
+package echo
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestContextValueOK(t *testing.T) {
+	c := NewContext(nil, nil)
+
+	c.Set("key", int64(123))
+
+	v, err := c.Value[int64]("key")
+	assert.NoError(t, err)
+	assert.Equal(t, int64(123), v)
+}
+
+func TestContextValueNonExistentKey(t *testing.T) {
+	c := NewContext(nil, nil)
+
+	v, err := c.Value[int64]("nope")
+	assert.ErrorIs(t, err, ErrNonExistentKey)
+	assert.Equal(t, int64(0), v)
+}
+
+func TestContextValueInvalidCast(t *testing.T) {
+	c := NewContext(nil, nil)
+
+	c.Set("key", int64(123))
+
+	v, err := c.Value[bool]("key")
+	assert.ErrorIs(t, err, ErrInvalidKeyType)
+	assert.False(t, v)
+}
+
+func TestContextValueStoredNilHasInvalidType(t *testing.T) {
+	c := NewContext(nil, nil)
+
+	c.Set("key", nil)
+
+	v, err := c.Value[any]("key")
+	assert.ErrorIs(t, err, ErrInvalidKeyType)
+	assert.Nil(t, v)
+}
+
+func TestContextValueOrOK(t *testing.T) {
+	c := NewContext(nil, nil)
+
+	c.Set("key", int64(123))
+
+	v, err := c.ValueOr[int64]("key", 999)
+	assert.NoError(t, err)
+	assert.Equal(t, int64(123), v)
+}
+
+func TestContextValueOrNonExistentKey(t *testing.T) {
+	c := NewContext(nil, nil)
+
+	v, err := c.ValueOr[int64]("nope", 999)
+	assert.NoError(t, err)
+	assert.Equal(t, int64(999), v)
+}
+
+func TestContextValueOrInvalidCast(t *testing.T) {
+	c := NewContext(nil, nil)
+
+	c.Set("key", int64(123))
+
+	v, err := c.ValueOr[float32]("key", float32(999))
+	assert.ErrorIs(t, err, ErrInvalidKeyType)
+	assert.Equal(t, float32(0), v)
+}