feat: Add method PostFormArray to app.RequestContext.

pkg/app/context.go

@@ -694,6 +694,17 @@ func (ctx *RequestContext) multipartFormValue(key string) (string, bool) {
 	return "", false
 }
 
+func (ctx *RequestContext) multipartFormValueArray(key string) ([]string, bool) {
+	mf, err := ctx.MultipartForm()
+	if err == nil && mf.Value != nil {
+		vv := mf.Value[key]
+		if len(vv) > 0 {
+			return vv, true
+		}
+	}
+	return nil, false
+}
+
 func (ctx *RequestContext) RequestBodyStream() io.Reader {
 	return ctx.Request.BodyStream()
 }
@@ -1366,6 +1377,13 @@ func (ctx *RequestContext) PostForm(key string) string {
 	return value
 }
 
+// PostFormArray returns the specified key from a POST urlencoded form or multipart form
+// when it exists, otherwise it returns an empty array `([])`.
+func (ctx *RequestContext) PostFormArray(key string) []string {
+	values, _ := ctx.GetPostFormArray(key)
+	return values
+}
+
 // DefaultPostForm returns the specified key from a POST urlencoded form or multipart form
 // when it exists, otherwise it returns the specified defaultValue string.
 //
@@ -1393,6 +1411,28 @@ func (ctx *RequestContext) GetPostForm(key string) (string, bool) {
 	return ctx.multipartFormValue(key)
 }
 
+// GetPostFormArray is like PostFormArray(key). It returns the specified key from a POST urlencoded
+// form or multipart form when it exists `([]string, true)` (even when the value is an empty string),
+// otherwise it returns ([]string(nil), false).
+//
+// For example, during a PATCH request to update the item's tags:
+//
+//	    tag=tag1 tag=tag2 tag=tag3  -->  (["tag1", "tag2", "tag3"], true) := GetPostFormArray("tags") // set tags to ["tag1", "tag2", "tag3"]
+//		   tags=                  -->  (nil, true) := GetPostFormArray("tags") // set tags to nil
+//	                            -->  (nil, false) := GetPostFormArray("tags") // do nothing with tags
+func (ctx *RequestContext) GetPostFormArray(key string) ([]string, bool) {
+	vs := ctx.PostArgs().PeekAll(key)
+	values := make([]string, len(vs))
+	for i, v := range vs {
+		values[i] = string(v)
+	}
+	if len(values) == 0 {
+		return ctx.multipartFormValueArray(key)
+	} else {
+		return values, true
+	}
+}
+
 // bodyAllowedForStatus is a copy of http.bodyAllowedForStatus non-exported function.
 func bodyAllowedForStatus(status int) bool {
 	switch {

pkg/app/context_test.go

@@ -367,6 +367,40 @@ hello=world`)
 	}
 }
 
+func TestPostFormArray(t *testing.T) {
+	t.Parallel()
+
+	ctx := makeCtxByReqString(t, `POST /upload HTTP/1.1
+Host: localhost:10000
+Content-Type: multipart/form-data; boundary=----WebKitFormBoundaryJwfATyF8tmxSJnLg
+Content-Length: 521
+
+------WebKitFormBoundaryJwfATyF8tmxSJnLg
+Content-Disposition: form-data; name="tag"
+
+red
+------WebKitFormBoundaryJwfATyF8tmxSJnLg
+Content-Disposition: form-data; name="tag"
+
+green
+------WebKitFormBoundaryJwfATyF8tmxSJnLg
+Content-Disposition: form-data; name="tag"
+
+blue
+------WebKitFormBoundaryJwfATyF8tmxSJnLg--
+`)
+	assert.DeepEqual(t, []string{"red", "green", "blue"}, ctx.PostFormArray("tag"))
+
+	ctx = makeCtxByReqString(t, `POST /upload HTTP/1.1
+Host: localhost:10000
+Content-Type: application/x-www-form-urlencoded; charset=UTF-8
+Content-Length: 26
+
+tag=red&tag=green&tag=blue
+`)
+	assert.DeepEqual(t, []string{"red", "green", "blue"}, ctx.PostFormArray("tag"))
+}
+
 func TestDefaultPostForm(t *testing.T) {
 	ctx := makeCtxByReqString(t, `POST /upload HTTP/1.1
 Host: localhost:10000
@@ -930,6 +964,14 @@ func TestGetPostForm(t *testing.T) {
 	assert.DeepEqual(t, true, exists)
 }
 
+func TestGetPostFormArray(t *testing.T) {
+	c := NewContext(0)
+	c.Request.Header.SetContentTypeBytes([]byte(consts.MIMEApplicationHTMLForm))
+	c.Request.SetBodyString("a=1&b=2&b=3")
+	v, _ := c.GetPostFormArray("b")
+	assert.DeepEqual(t, []string{"2", "3"}, v)
+}
+
 func TestRemoteAddr(t *testing.T) {
 	c := NewContext(0)
 	c.Request.SetRequestURI("http://aaa.com?a=1&b=")