feat: support bind query

binding.go

@@ -418,3 +418,65 @@ func MultipartForm(model interface{}, opts ...Options) flamego.Handler {
 		}
 	})
 }
+
+func mapQuery(obj reflect.Value, values url.Values, errs Errors) Errors {
+	for i := 0; i < obj.Elem().NumField(); i++ {
+		f := obj.Elem().Field(i)
+		t := obj.Elem().Type().Field(i)
+
+		if f.Kind() == reflect.Struct && t.Anonymous {
+			errs = mapQuery(f.Addr(), values, errs)
+			continue
+		}
+
+		tag := t.Tag.Get("query")
+		if tag == "-" {
+			continue
+		}
+
+		if tag == "" {
+			tag = t.Name
+		}
+
+		if !f.CanSet() {
+			continue
+		}
+
+		vals := values[tag]
+		if len(vals) == 0 {
+			continue
+		}
+
+		err := setWithProperType(f.Kind(), vals[0], f, tag)
+		if err != nil {
+			errs = append(errs, *err)
+		}
+	}
+
+	return errs
+}
+
+func Query(model interface{}, opts ...Options) flamego.Handler {
+	ensureNotPointer(model)
+
+	var opt Options
+	if len(opts) > 0 {
+		opt = opts[0]
+	}
+	opt = parseOptions(opt)
+
+	return flamego.ContextInvoker(func(c flamego.Context) {
+		var errs Errors
+		r := c.Request().Request
+		obj := reflect.New(reflect.TypeOf(model))
+		errs = mapQuery(obj, r.URL.Query(), errs)
+		validateAndMap(c, opt.Validator, obj, errs)
+		errs = c.Value(reflect.TypeOf(errs)).Interface().(Errors)
+		if len(errs) > 0 && opt.ErrorHandler != nil {
+			_, err := c.Invoke(opt.ErrorHandler)
+			if err != nil {
+				panic("binding.Query: " + err.Error())
+			}
+		}
+	})
+}

binding_test.go

@@ -12,6 +12,7 @@ import (
 	"mime/multipart"
 	"net/http"
 	"net/http/httptest"
+	"net/url"
 	"testing"
 
 	"github.com/stretchr/testify/assert"
@@ -540,7 +541,7 @@ male: true
 email: [email protected]
 weight: 60.7
 balance: -12.4
-address: 
+address:
   street: 404 Broadway
   city: Browser
   planet: Internet
@@ -580,7 +581,7 @@ male: true
 email: [email protected]
 weight: 60.7
 balance: -12.4
-address: 
+address:
   street: 404 Broadway
   city: Browser
   planet: Internet
@@ -620,7 +621,7 @@ male: bad
 email: [email protected]
 weight: 60.7
 balance: -12.4
-address: 
+address:
   street: 404 Broadway
   city: Browser
   planet: Internet
@@ -735,10 +736,10 @@ address:
 first_name: Logan
 last_name: Smith
 age:
-height: 
-male: 
+height:
+male:
 email: [email protected]
-weight: 
+weight:
 balance:
 address:
   street: 404 Broadway
@@ -776,7 +777,7 @@ male: on
 email: [email protected]
 weight: 60.7
 balance: -12.4
-address: 
+address:
   street: 404 Broadway
   city: Browser
   planet: Internet
@@ -1329,3 +1330,108 @@ func TestMultipartForm(t *testing.T) {
 	assert.NotNil(t, gotForm.Background)
 	assert.Len(t, gotForm.Pictures, 2)
 }
+
+func TestQuery(t *testing.T) {
+	t.Run("pointer model", func(t *testing.T) {
+		assert.PanicsWithValue(t,
+			"binding: pointer can not be accepted as binding model",
+			func() {
+				type form struct {
+					Username string
+					Password string
+				}
+				Query(&form{})
+			},
+		)
+	})
+
+	t.Run("custom error handler", func(t *testing.T) {
+		type query struct {
+			Username string `query:"username" validate:"required"`
+			Password string `query:"password" validate:"required"`
+		}
+
+		normalHandler := func(rw http.ResponseWriter, errs Errors) {
+			rw.WriteHeader(http.StatusBadRequest)
+			_, _ = rw.Write([]byte(errs[0].Err.Error()))
+		}
+
+		fastInvokerHandler := func(c flamego.Context, errs Errors) {
+			c.ResponseWriter().WriteHeader(http.StatusBadRequest)
+			_, _ = c.ResponseWriter().Write([]byte(fmt.Sprintf("Oops! Error occurred: %v", errs[0].Err)))
+		}
+
+		tests := []struct {
+			name       string
+			fields     map[string]string
+			handler    flamego.Handler
+			statusCode int
+			want       string
+		}{
+			{
+				name: "validation error",
+				fields: map[string]string{
+					"username": "alice",
+				},
+				handler:    fastInvokerHandler,
+				statusCode: http.StatusBadRequest,
+				want:       `Oops! Error occurred: Key: "query.Password" Error: Field validation for "Password" failed on the "required" tag`,
+			},
+			{
+				name: "normal handler",
+				fields: map[string]string{
+					"username": "alice",
+				},
+				handler:    normalHandler,
+				statusCode: http.StatusBadRequest,
+				want:       `Key: "query.Password" Error: Field validation for "Password" failed on the "required" tag`,
+			},
+			{
+				name: "fast invoker handler",
+				fields: map[string]string{
+					"username": "alice",
+					"password": "superSecurePassword",
+				},
+				handler:    fastInvokerHandler,
+				statusCode: http.StatusOK,
+				want:       "Hello world",
+			},
+			{
+				name: "nil handler",
+				fields: map[string]string{
+					"username": "alice",
+				},
+				handler:    nil,
+				statusCode: http.StatusOK,
+				want:       "Hello world",
+			},
+		}
+		for _, test := range tests {
+			t.Run(test.name, func(t *testing.T) {
+				f := flamego.New()
+				opts := Options{
+					ErrorHandler: test.handler,
+				}
+				f.Get("/", Query(query{}, opts), func(c flamego.Context) {
+					_, _ = c.ResponseWriter().Write([]byte("Hello world"))
+				})
+
+				u := url.URL{Path: "/"}
+				q := u.Query()
+				for k, v := range test.fields {
+					q.Set(k, v)
+				}
+				u.RawQuery = q.Encode()
+
+				var body bytes.Buffer
+				resp := httptest.NewRecorder()
+				req, err := http.NewRequest(http.MethodGet, u.String(), &body)
+				assert.Nil(t, err)
+
+				f.ServeHTTP(resp, req)
+				assert.Equal(t, test.statusCode, resp.Code)
+				assert.Equal(t, test.want, resp.Body.String())
+			})
+		}
+	})
+}