Support map as query string or post form parameters (#1383)

* support query map

* add GetQueryMap and unittest

* support post-form map

* add readme for query map

* attempt to fix bug for post-form map when go version is 1.6

* remove duplicate code

* remove comment

README.md

@@ -27,6 +27,7 @@ Gin is a web framework written in Go (Golang). It features a martini-like API wi
     - [Querystring parameters](#querystring-parameters)
     - [Multipart/Urlencoded Form](#multiparturlencoded-form)
     - [Another example: query + post form](#another-example-query--post-form)
+    - [Map as querystring or postform parameters](#map-as-querystring-or-postform-parameters)
     - [Upload files](#upload-files)
     - [Grouping routes](#grouping-routes)
     - [Blank Gin without middleware by default](#blank-gin-without-middleware-by-default)
@@ -323,6 +324,34 @@ func main() {
 id: 1234; page: 1; name: manu; message: this_is_great
 ```
 
+### Map as querystring or postform parameters
+
+```
+POST /post?ids[a]=1234&ids[b]=hello HTTP/1.1
+Content-Type: application/x-www-form-urlencoded
+
+names[first]=thinkerou&names[second]=tianou
+```
+
+```go
+func main() {
+	router := gin.Default()
+
+	router.POST("/post", func(c *gin.Context) {
+
+		ids := c.QueryMap("ids")
+		names := c.PostFormMap("names")
+
+		fmt.Printf("ids: %v; names: %v", ids, names)
+	})
+	router.Run(":8080")
+}
+```
+
+```
+ids: map[b:hello a:1234], names: map[second:tianou first:thinkerou]
+```
+
 ### Upload files
 
 #### Single file

context.go

@@ -360,6 +360,18 @@ func (c *Context) GetQueryArray(key string) ([]string, bool) {
 	return []string{}, false
 }
 
+// QueryMap returns a map for a given query key.
+func (c *Context) QueryMap(key string) map[string]string {
+	dicts, _ := c.GetQueryMap(key)
+	return dicts
+}
+
+// GetQueryMap returns a map for a given query key, plus a boolean value
+// whether at least one value exists for the given key.
+func (c *Context) GetQueryMap(key string) (map[string]string, bool) {
+	return c.get(c.Request.URL.Query(), key)
+}
+
 // PostForm returns the specified key from a POST urlencoded form or multipart form
 // when it exists, otherwise it returns an empty string `("")`.
 func (c *Context) PostForm(key string) string {
@@ -415,6 +427,42 @@ func (c *Context) GetPostFormArray(key string) ([]string, bool) {
 	return []string{}, false
 }
 
+// PostFormMap returns a map for a given form key.
+func (c *Context) PostFormMap(key string) map[string]string {
+	dicts, _ := c.GetPostFormMap(key)
+	return dicts
+}
+
+// GetPostFormMap returns a map for a given form key, plus a boolean value
+// whether at least one value exists for the given key.
+func (c *Context) GetPostFormMap(key string) (map[string]string, bool) {
+	req := c.Request
+	req.ParseForm()
+	req.ParseMultipartForm(c.engine.MaxMultipartMemory)
+	dicts, exist := c.get(req.PostForm, key)
+
+	if !exist && req.MultipartForm != nil && req.MultipartForm.File != nil {
+		dicts, exist = c.get(req.MultipartForm.Value, key)
+	}
+
+	return dicts, exist
+}
+
+// get is an internal method and returns a map which satisfy conditions.
+func (c *Context) get(m map[string][]string, key string) (map[string]string, bool) {
+	dicts := make(map[string]string)
+	exist := false
+	for k, v := range m {
+		if i := strings.IndexByte(k, '['); i >= 1 && k[0:i] == key {
+			if j := strings.IndexByte(k[i+1:], ']'); j >= 1 {
+				exist = true
+				dicts[k[i+1:][:j]] = v[0]
+			}
+		}
+	}
+	return dicts, exist
+}
+
 // FormFile returns the first file for the provided form key.
 func (c *Context) FormFile(name string) (*multipart.FileHeader, error) {
 	_, fh, err := c.Request.FormFile(name)

context_test.go

@@ -47,6 +47,8 @@ func createMultipartRequest() *http.Request {
 	must(mw.WriteField("time_local", "31/12/2016 14:55"))
 	must(mw.WriteField("time_utc", "31/12/2016 14:55"))
 	must(mw.WriteField("time_location", "31/12/2016 14:55"))
+	must(mw.WriteField("names[a]", "thinkerou"))
+	must(mw.WriteField("names[b]", "tianou"))
 	req, err := http.NewRequest("POST", "/", body)
 	must(err)
 	req.Header.Set("Content-Type", MIMEMultipartPOSTForm+"; boundary="+boundary)
@@ -371,7 +373,8 @@ func TestContextQuery(t *testing.T) {
 func TestContextQueryAndPostForm(t *testing.T) {
 	c, _ := CreateTestContext(httptest.NewRecorder())
 	body := bytes.NewBufferString("foo=bar&page=11&both=&foo=second")
-	c.Request, _ = http.NewRequest("POST", "/?both=GET&id=main&id=omit&array[]=first&array[]=second", body)
+	c.Request, _ = http.NewRequest("POST",
+		"/?both=GET&id=main&id=omit&array[]=first&array[]=second&ids[a]=hi&ids[b]=3.14", body)
 	c.Request.Header.Add("Content-Type", MIMEPOSTForm)
 
 	assert.Equal(t, "bar", c.DefaultPostForm("foo", "none"))
@@ -439,6 +442,30 @@ func TestContextQueryAndPostForm(t *testing.T) {
 	values = c.QueryArray("both")
 	assert.Equal(t, 1, len(values))
 	assert.Equal(t, "GET", values[0])
+
+	dicts, ok := c.GetQueryMap("ids")
+	assert.True(t, ok)
+	assert.Equal(t, "hi", dicts["a"])
+	assert.Equal(t, "3.14", dicts["b"])
+
+	dicts, ok = c.GetQueryMap("nokey")
+	assert.False(t, ok)
+	assert.Equal(t, 0, len(dicts))
+
+	dicts, ok = c.GetQueryMap("both")
+	assert.False(t, ok)
+	assert.Equal(t, 0, len(dicts))
+
+	dicts, ok = c.GetQueryMap("array")
+	assert.False(t, ok)
+	assert.Equal(t, 0, len(dicts))
+
+	dicts = c.QueryMap("ids")
+	assert.Equal(t, "hi", dicts["a"])
+	assert.Equal(t, "3.14", dicts["b"])
+
+	dicts = c.QueryMap("nokey")
+	assert.Equal(t, 0, len(dicts))
 }
 
 func TestContextPostFormMultipart(t *testing.T) {
@@ -515,6 +542,22 @@ func TestContextPostFormMultipart(t *testing.T) {
 	values = c.PostFormArray("foo")
 	assert.Equal(t, 1, len(values))
 	assert.Equal(t, "bar", values[0])
+
+	dicts, ok := c.GetPostFormMap("names")
+	assert.True(t, ok)
+	assert.Equal(t, "thinkerou", dicts["a"])
+	assert.Equal(t, "tianou", dicts["b"])
+
+	dicts, ok = c.GetPostFormMap("nokey")
+	assert.False(t, ok)
+	assert.Equal(t, 0, len(dicts))
+
+	dicts = c.PostFormMap("names")
+	assert.Equal(t, "thinkerou", dicts["a"])
+	assert.Equal(t, "tianou", dicts["b"])
+
+	dicts = c.PostFormMap("nokey")
+	assert.Equal(t, 0, len(dicts))
 }
 
 func TestContextSetCookie(t *testing.T) {