feat: accept camelcase for config keys (#2651)

* feat: accept camelcase for config keys

* chore: refactor

* chore: refactor

* chore: add more tests

* chore: refactor

* fix: map elements of array

core/conf/config_test.go

@@ -56,6 +56,22 @@ func TestConfigJson(t *testing.T) {
 	}
 }
 
+func TestLoadFromJsonBytesArray(t *testing.T) {
+	input := []byte(`{"users": [{"name": "foo"}, {"Name": "bar"}]}`)
+	var val struct {
+		Users []struct {
+			Name string
+		}
+	}
+
+	assert.NoError(t, LoadFromJsonBytes(input, &val))
+	var expect []string
+	for _, user := range val.Users {
+		expect = append(expect, user.Name)
+	}
+	assert.EqualValues(t, []string{"foo", "bar"}, expect)
+}
+
 func TestConfigToml(t *testing.T) {
 	text := `a = "foo"
 b = 1
@@ -81,6 +97,65 @@ d = "abcd!@#$112"
 	assert.Equal(t, "abcd!@#$112", val.D)
 }
 
+func TestConfigJsonCanonical(t *testing.T) {
+	text := []byte(`{"a": "foo", "B": "bar"}`)
+
+	var val1 struct {
+		A string `json:"a"`
+		B string `json:"b"`
+	}
+	var val2 struct {
+		A string
+		B string
+	}
+	assert.NoError(t, LoadFromJsonBytes(text, &val1))
+	assert.Equal(t, "foo", val1.A)
+	assert.Equal(t, "bar", val1.B)
+	assert.NoError(t, LoadFromJsonBytes(text, &val2))
+	assert.Equal(t, "foo", val2.A)
+	assert.Equal(t, "bar", val2.B)
+}
+
+func TestConfigTomlCanonical(t *testing.T) {
+	text := []byte(`a = "foo"
+B = "bar"`)
+
+	var val1 struct {
+		A string `json:"a"`
+		B string `json:"b"`
+	}
+	var val2 struct {
+		A string
+		B string
+	}
+	assert.NoError(t, LoadFromTomlBytes(text, &val1))
+	assert.Equal(t, "foo", val1.A)
+	assert.Equal(t, "bar", val1.B)
+	assert.NoError(t, LoadFromTomlBytes(text, &val2))
+	assert.Equal(t, "foo", val2.A)
+	assert.Equal(t, "bar", val2.B)
+}
+
+func TestConfigYamlCanonical(t *testing.T) {
+	text := []byte(`a: foo
+B: bar`)
+
+	var val1 struct {
+		A string `json:"a"`
+		B string `json:"b"`
+	}
+	var val2 struct {
+		A string
+		B string
+	}
+	assert.NoError(t, LoadFromYamlBytes(text, &val1))
+	assert.Equal(t, "foo", val1.A)
+	assert.Equal(t, "bar", val1.B)
+	assert.NoError(t, LoadFromYamlBytes(text, &val2))
+	assert.Equal(t, "foo", val2.A)
+	assert.Equal(t, "bar", val2.B)
+}
+
 func TestConfigTomlEnv(t *testing.T) {
 	text := `a = "foo"
 b = 1
@@ -143,6 +218,116 @@ func TestConfigJsonEnv(t *testing.T) {
 	}
 }
 
+func TestToCamelCase(t *testing.T) {
+	tests := []struct {
+		input  string
+		expect string
+	}{
+		{
+			input:  "",
+			expect: "",
+		},
+		{
+			input:  "A",
+			expect: "a",
+		},
+		{
+			input:  "a",
+			expect: "a",
+		},
+		{
+			input:  "hello_world",
+			expect: "helloWorld",
+		},
+		{
+			input:  "Hello_world",
+			expect: "helloWorld",
+		},
+		{
+			input:  "hello_World",
+			expect: "helloWorld",
+		},
+		{
+			input:  "helloWorld",
+			expect: "helloWorld",
+		},
+		{
+			input:  "HelloWorld",
+			expect: "helloWorld",
+		},
+		{
+			input:  "hello World",
+			expect: "hello world",
+		},
+		{
+			input:  "Hello World",
+			expect: "hello world",
+		},
+		{
+			input:  "Hello World",
+			expect: "hello world",
+		},
+		{
+			input:  "Hello World foo_bar",
+			expect: "hello world fooBar",
+		},
+		{
+			input:  "Hello World foo_Bar",
+			expect: "hello world fooBar",
+		},
+		{
+			input:  "Hello World Foo_bar",
+			expect: "hello world fooBar",
+		},
+		{
+			input:  "Hello World Foo_Bar",
+			expect: "hello world fooBar",
+		},
+		{
+			input:  "你好 World Foo_Bar",
+			expect: "你好 world fooBar",
+		},
+	}
+
+	for _, test := range tests {
+		test := test
+		t.Run(test.input, func(t *testing.T) {
+			assert.Equal(t, test.expect, toCamelCase(test.input))
+		})
+	}
+}
+
+func TestLoadFromJsonBytesError(t *testing.T) {
+	var val struct{}
+	assert.Error(t, LoadFromJsonBytes([]byte(`hello`), &val))
+}
+
+func TestLoadFromTomlBytesError(t *testing.T) {
+	var val struct{}
+	assert.Error(t, LoadFromTomlBytes([]byte(`hello`), &val))
+}
+
+func TestLoadFromYamlBytesError(t *testing.T) {
+	var val struct{}
+	assert.Error(t, LoadFromYamlBytes([]byte(`':hello`), &val))
+}
+
+func TestLoadFromYamlBytes(t *testing.T) {
+	input := []byte(`layer1:
+  layer2:
+    layer3: foo`)
+	var val struct {
+		Layer1 struct {
+			Layer2 struct {
+				Layer3 string
+			}
+		}
+	}
+
+	assert.NoError(t, LoadFromYamlBytes(input, &val))
+	assert.Equal(t, "foo", val.Layer1.Layer2.Layer3)
+}
+
 func createTempFile(ext, text string) (string, error) {
 	tmpfile, err := os.CreateTemp(os.TempDir(), hash.Md5Hex([]byte(text))+"*"+ext)
 	if err != nil {