Add form binding

Signed-off-by: Vishal Rana <vr@labstack.com>

binder.go

@@ -0,0 +1,173 @@
+package echo
+
+import (
+	"encoding/json"
+	"encoding/xml"
+	"errors"
+	"net/http"
+	"reflect"
+	"strconv"
+	"strings"
+)
+
+type (
+	// Binder is the interface that wraps the Bind method.
+	Binder interface {
+		Bind(interface{}, Context) error
+	}
+
+	binder struct{}
+)
+
+func (b *binder) Bind(i interface{}, c Context) (err error) {
+	req := c.Request()
+	ctype := req.Header().Get(HeaderContentType)
+	if req.Body() == nil {
+		err = NewHTTPError(http.StatusBadRequest, "request body can't be empty")
+		return
+	}
+	err = ErrUnsupportedMediaType
+	switch {
+	case strings.HasPrefix(ctype, MIMEApplicationJSON):
+		if err = json.NewDecoder(req.Body()).Decode(i); err != nil {
+			err = NewHTTPError(http.StatusBadRequest, err.Error())
+		}
+	case strings.HasPrefix(ctype, MIMEApplicationXML):
+		if err = xml.NewDecoder(req.Body()).Decode(i); err != nil {
+			err = NewHTTPError(http.StatusBadRequest, err.Error())
+		}
+	case strings.HasPrefix(ctype, MIMEApplicationForm), strings.HasPrefix(ctype, MIMEMultipartForm):
+		if err = b.bindForm(i, req.FormParams()); err != nil {
+			err = NewHTTPError(http.StatusBadRequest, err.Error())
+		}
+	}
+	return
+}
+
+func (b *binder) bindForm(ptr interface{}, form map[string][]string) error {
+	typ := reflect.TypeOf(ptr).Elem()
+	val := reflect.ValueOf(ptr).Elem()
+
+	for i := 0; i < typ.NumField(); i++ {
+		typeField := typ.Field(i)
+		structField := val.Field(i)
+		if !structField.CanSet() {
+			continue
+		}
+		structFieldKind := structField.Kind()
+		inputFieldName := typeField.Tag.Get("form")
+
+		if inputFieldName == "" {
+			inputFieldName = typeField.Name
+			// If "form" tag is nil, we inspect if the field is a struct.
+			if structFieldKind == reflect.Struct {
+				err := b.bindForm(structField.Addr().Interface(), form)
+				if err != nil {
+					return err
+				}
+				continue
+			}
+		}
+		inputValue, exists := form[inputFieldName]
+		if !exists {
+			continue
+		}
+
+		numElems := len(inputValue)
+		if structFieldKind == reflect.Slice && numElems > 0 {
+			sliceOf := structField.Type().Elem().Kind()
+			slice := reflect.MakeSlice(structField.Type(), numElems, numElems)
+			for i := 0; i < numElems; i++ {
+				if err := setWithProperType(sliceOf, inputValue[i], slice.Index(i)); err != nil {
+					return err
+				}
+			}
+			val.Field(i).Set(slice)
+		} else {
+			if err := setWithProperType(typeField.Type.Kind(), inputValue[0], structField); err != nil {
+				return err
+			}
+		}
+	}
+	return nil
+}
+
+func setWithProperType(valueKind reflect.Kind, val string, structField reflect.Value) error {
+	switch valueKind {
+	case reflect.Int:
+		return setIntField(val, 0, structField)
+	case reflect.Int8:
+		return setIntField(val, 8, structField)
+	case reflect.Int16:
+		return setIntField(val, 16, structField)
+	case reflect.Int32:
+		return setIntField(val, 32, structField)
+	case reflect.Int64:
+		return setIntField(val, 64, structField)
+	case reflect.Uint:
+		return setUintField(val, 0, structField)
+	case reflect.Uint8:
+		return setUintField(val, 8, structField)
+	case reflect.Uint16:
+		return setUintField(val, 16, structField)
+	case reflect.Uint32:
+		return setUintField(val, 32, structField)
+	case reflect.Uint64:
+		return setUintField(val, 64, structField)
+	case reflect.Bool:
+		return setBoolField(val, structField)
+	case reflect.Float32:
+		return setFloatField(val, 32, structField)
+	case reflect.Float64:
+		return setFloatField(val, 64, structField)
+	case reflect.String:
+		structField.SetString(val)
+	default:
+		return errors.New("unknown type")
+	}
+	return nil
+}
+
+func setIntField(value string, bitSize int, field reflect.Value) error {
+	if value == "" {
+		value = "0"
+	}
+	intVal, err := strconv.ParseInt(value, 10, bitSize)
+	if err == nil {
+		field.SetInt(intVal)
+	}
+	return err
+}
+
+func setUintField(value string, bitSize int, field reflect.Value) error {
+	if value == "" {
+		value = "0"
+	}
+	uintVal, err := strconv.ParseUint(value, 10, bitSize)
+	if err == nil {
+		field.SetUint(uintVal)
+	}
+	return err
+}
+
+func setBoolField(value string, field reflect.Value) error {
+	if value == "" {
+		value = "false"
+	}
+	boolVal, err := strconv.ParseBool(value)
+	if err == nil {
+		field.SetBool(boolVal)
+	}
+	return err
+}
+
+func setFloatField(value string, bitSize int, field reflect.Value) error {
+	if value == "" {
+		value = "0.0"
+	}
+	floatVal, err := strconv.ParseFloat(value, bitSize)
+	if err == nil {
+		field.SetFloat(floatVal)
+	}
+	return err
+}

binder_test.go

@@ -0,0 +1,214 @@
+package echo
+
+import (
+	"bytes"
+	"io"
+	"mime/multipart"
+	"net/http"
+	"reflect"
+	"strings"
+	"testing"
+
+	"github.com/labstack/echo/test"
+	"github.com/stretchr/testify/assert"
+)
+
+type (
+	binderTestStruct struct {
+		I           int
+		I8          int8
+		I16         int16
+		I32         int32
+		I64         int64
+		UI          uint
+		UI8         uint8
+		UI16        uint16
+		UI32        uint32
+		UI64        uint64
+		B           bool
+		F32         float32
+		F64         float64
+		S           string
+		cantSet     string
+		DoesntExist string
+	}
+)
+
+func (t binderTestStruct) GetCantSet() string {
+	return t.cantSet
+}
+
+var values = map[string][]string{
+	"I":       {"0"},
+	"I8":      {"8"},
+	"I16":     {"16"},
+	"I32":     {"32"},
+	"I64":     {"64"},
+	"UI":      {"0"},
+	"UI8":     {"8"},
+	"UI16":    {"16"},
+	"UI32":    {"32"},
+	"UI64":    {"64"},
+	"B":       {"true"},
+	"F32":     {"32.5"},
+	"F64":     {"64.5"},
+	"S":       {"test"},
+	"cantSet": {"test"},
+}
+
+func TestBinderJSON(t *testing.T) {
+	testBinderOkay(t, strings.NewReader(userJSON), MIMEApplicationJSON)
+	testBinderError(t, strings.NewReader(invalidContent), MIMEApplicationJSON)
+}
+
+func TestBinderXML(t *testing.T) {
+	testBinderOkay(t, strings.NewReader(userXML), MIMEApplicationXML)
+	testBinderError(t, strings.NewReader(invalidContent), MIMEApplicationXML)
+}
+
+func TestBinderForm(t *testing.T) {
+	testBinderOkay(t, strings.NewReader(userForm), MIMEApplicationForm)
+}
+
+func TestBinderMultipartForm(t *testing.T) {
+	body := new(bytes.Buffer)
+	mw := multipart.NewWriter(body)
+	mw.WriteField("id", "1")
+	mw.WriteField("name", "Jon Snow")
+	mw.Close()
+	testBinderOkay(t, body, mw.FormDataContentType())
+}
+
+func TestBinderUnsupportedMediaType(t *testing.T) {
+	testBinderError(t, strings.NewReader(invalidContent), MIMEApplicationJSON)
+}
+
+// func assertCustomer(t *testing.T, c *user) {
+// 	assert.Equal(t, 1, c.ID)
+// 	assert.Equal(t, "Joe", c.Name)
+// }
+
+func TestBinderbindForm(t *testing.T) {
+	ts := new(binderTestStruct)
+	b := new(binder)
+	b.bindForm(ts, values)
+	assertBinderTestStruct(t, ts)
+}
+
+func TestBinderSetWithProperType(t *testing.T) {
+	ts := new(binderTestStruct)
+	typ := reflect.TypeOf(ts).Elem()
+	val := reflect.ValueOf(ts).Elem()
+	for i := 0; i < typ.NumField(); i++ {
+		typeField := typ.Field(i)
+		structField := val.Field(i)
+		if !structField.CanSet() {
+			continue
+		}
+		if len(values[typeField.Name]) == 0 {
+			continue
+		}
+		val := values[typeField.Name][0]
+		err := setWithProperType(typeField.Type.Kind(), val, structField)
+		assert.NoError(t, err)
+	}
+	assertBinderTestStruct(t, ts)
+
+	type foo struct {
+		Bar bytes.Buffer
+	}
+	v := &foo{}
+	typ = reflect.TypeOf(v).Elem()
+	val = reflect.ValueOf(v).Elem()
+	assert.Error(t, setWithProperType(typ.Field(0).Type.Kind(), "5", val.Field(0)))
+}
+
+func TestBinderSetFields(t *testing.T) {
+	ts := new(binderTestStruct)
+	val := reflect.ValueOf(ts).Elem()
+	// Int
+	if assert.NoError(t, setIntField("5", 0, val.FieldByName("I"))) {
+		assert.Equal(t, 5, ts.I)
+	}
+	if assert.NoError(t, setIntField("", 0, val.FieldByName("I"))) {
+		assert.Equal(t, 0, ts.I)
+	}
+
+	// Uint
+	if assert.NoError(t, setUintField("10", 0, val.FieldByName("UI"))) {
+		assert.Equal(t, uint(10), ts.UI)
+	}
+	if assert.NoError(t, setUintField("", 0, val.FieldByName("UI"))) {
+		assert.Equal(t, uint(0), ts.UI)
+	}
+
+	// Float
+	if assert.NoError(t, setFloatField("15.5", 0, val.FieldByName("F32"))) {
+		assert.Equal(t, float32(15.5), ts.F32)
+	}
+	if assert.NoError(t, setFloatField("", 0, val.FieldByName("F32"))) {
+		assert.Equal(t, float32(0.0), ts.F32)
+	}
+
+	// Bool
+	if assert.NoError(t, setBoolField("true", val.FieldByName("B"))) {
+		assert.Equal(t, true, ts.B)
+	}
+	if assert.NoError(t, setBoolField("", val.FieldByName("B"))) {
+		assert.Equal(t, false, ts.B)
+	}
+}
+
+func assertBinderTestStruct(t *testing.T, ts *binderTestStruct) {
+	assert.Equal(t, 0, ts.I)
+	assert.Equal(t, int8(8), ts.I8)
+	assert.Equal(t, int16(16), ts.I16)
+	assert.Equal(t, int32(32), ts.I32)
+	assert.Equal(t, int64(64), ts.I64)
+	assert.Equal(t, uint(0), ts.UI)
+	assert.Equal(t, uint8(8), ts.UI8)
+	assert.Equal(t, uint16(16), ts.UI16)
+	assert.Equal(t, uint32(32), ts.UI32)
+	assert.Equal(t, uint64(64), ts.UI64)
+	assert.Equal(t, true, ts.B)
+	assert.Equal(t, float32(32.5), ts.F32)
+	assert.Equal(t, float64(64.5), ts.F64)
+	assert.Equal(t, "test", ts.S)
+	assert.Equal(t, "", ts.GetCantSet())
+}
+
+func testBinderOkay(t *testing.T, r io.Reader, ctype string) {
+	e := New()
+	req := test.NewRequest(POST, "/", r)
+	rec := test.NewResponseRecorder()
+	c := e.NewContext(req, rec)
+	req.Header().Set(HeaderContentType, ctype)
+	u := new(user)
+	err := c.Bind(u)
+	if assert.NoError(t, err) {
+		assert.Equal(t, 1, u.ID)
+		assert.Equal(t, "Jon Snow", u.Name)
+	}
+}
+
+func testBinderError(t *testing.T, r io.Reader, ctype string) {
+	e := New()
+	req := test.NewRequest(POST, "/", r)
+	rec := test.NewResponseRecorder()
+	c := e.NewContext(req, rec)
+	req.Header().Set(HeaderContentType, ctype)
+	u := new(user)
+	err := c.Bind(u)
+
+	switch {
+	case strings.HasPrefix(ctype, MIMEApplicationJSON), strings.HasPrefix(ctype, MIMEApplicationXML),
+		strings.HasPrefix(ctype, MIMEApplicationForm), strings.HasPrefix(ctype, MIMEMultipartForm):
+		if assert.IsType(t, new(HTTPError), err) {
+			assert.Equal(t, http.StatusBadRequest, err.(*HTTPError).Code)
+		}
+	default:
+		if assert.IsType(t, new(HTTPError), err) {
+			assert.Equal(t, ErrUnsupportedMediaType, err)
+		}
+	}
+}