From effe03e078ac02df3b6736fadb5a096993e4e533 Mon Sep 17 00:00:00 2001
From: Neenad Ingole <needna78@gmail.com>
Date: Sun, 13 Mar 2022 21:52:44 +0100
Subject: [PATCH] :adhesive_bandage: Allow parsing of square bracket query
 param

---
 ctx.go      | 28 ++++++++++++++++++++++++++++
 ctx_test.go | 42 ++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 70 insertions(+)

diff --git a/ctx.go b/ctx.go
index 126c7ddd8bf..e033776b2e0 100644
--- a/ctx.go
+++ b/ctx.go
@@ -911,6 +911,8 @@ func (c *Ctx) QueryParser(out interface{}) error {
 		k := utils.UnsafeString(key)
 		v := utils.UnsafeString(val)
 
+		k = parseQuery(k)
+
 		if strings.Contains(v, ",") && equalFieldType(out, reflect.Slice, k) {
 			values := strings.Split(v, ",")
 			for i := 0; i < len(values); i++ {
@@ -925,6 +927,32 @@ func (c *Ctx) QueryParser(out interface{}) error {
 	return c.parseToStruct(queryTag, out, data)
 }
 
+func parseQuery(k string) string {
+	// split all the character
+	chars := strings.Split(k, "")
+	// buffer to hold the converted chars
+	keyBuf := make([]string, 0)
+
+	for _, char := range chars {
+		switch char {
+		case "[":
+			// convert [ to . as the gorilla/schema works with . notation
+			keyBuf = append(keyBuf, ".")
+		case "]":
+			// for key of format `data[]=john` the end would have `.` which will be dropped
+			if keyBuf[len(keyBuf)-1] == "." {
+				keyBuf = keyBuf[:len(keyBuf)-1]
+			}
+		default:
+			// append all the other chars to the buffer
+			keyBuf = append(keyBuf, char)
+		}
+	}
+
+	// convert to string
+	return strings.Join(keyBuf, "")
+}
+
 // ReqHeaderParser binds the request header strings to a struct.
 func (c *Ctx) ReqHeaderParser(out interface{}) error {
 	data := make(map[string][]string)
diff --git a/ctx_test.go b/ctx_test.go
index ee5520b33e9..927314369fd 100644
--- a/ctx_test.go
+++ b/ctx_test.go
@@ -2931,6 +2931,14 @@ func Test_Ctx_QueryParser(t *testing.T) {
 	rq := new(RequiredQuery)
 	c.Request().URI().SetQueryString("")
 	utils.AssertEqual(t, "name is empty", c.QueryParser(rq).Error())
+
+	type ArrayQuery struct {
+		Data []string
+	}
+	aq := new(ArrayQuery)
+	c.Request().URI().SetQueryString("data[]=john&data[]=doe")
+	utils.AssertEqual(t, nil, c.QueryParser(aq))
+	utils.AssertEqual(t, 2, len(aq.Data))
 }
 
 // go test -run Test_Ctx_QueryParser_WithSetParserDecoder -v
@@ -3059,6 +3067,40 @@ func Test_Ctx_QueryParser_Schema(t *testing.T) {
 	utils.AssertEqual(t, nil, c.QueryParser(n))
 	utils.AssertEqual(t, 3, n.Value)
 	utils.AssertEqual(t, 0, n.Next.Value)
+
+	type Person struct {
+		Name string `query:"name"`
+		Age  int    `query:"age"`
+	}
+
+	type CollectionQuery struct {
+		Data []Person `query:"data"`
+	}
+
+	c.Request().URI().SetQueryString("data[0][name]=john&data[0][age]=10&data[1][name]=doe&data[1][age]=12")
+	cq := new(CollectionQuery)
+	utils.AssertEqual(t, nil, c.QueryParser(cq))
+	utils.AssertEqual(t, 2, len(cq.Data))
+	utils.AssertEqual(t, "john", cq.Data[0].Name)
+	utils.AssertEqual(t, 10, cq.Data[0].Age)
+	utils.AssertEqual(t, "doe", cq.Data[1].Name)
+	utils.AssertEqual(t, 12, cq.Data[1].Age)
+
+	c.Request().URI().SetQueryString("data.0.name=john&data.0.age=10&data.1.name=doe&data.1.age=12")
+	cq = new(CollectionQuery)
+	utils.AssertEqual(t, nil, c.QueryParser(cq))
+	utils.AssertEqual(t, 2, len(cq.Data))
+	utils.AssertEqual(t, "john", cq.Data[0].Name)
+	utils.AssertEqual(t, 10, cq.Data[0].Age)
+	utils.AssertEqual(t, "doe", cq.Data[1].Name)
+	utils.AssertEqual(t, 12, cq.Data[1].Age)
+
+	c.Request().URI().SetQueryString("data[0]name]=john&data[0][age]=10&data[1][name]=doe&data[1][age]=12")
+	cq = new(CollectionQuery)
+	utils.AssertEqual(t, nil, c.QueryParser(cq))
+	utils.AssertEqual(t, 2, len(cq.Data))
+	utils.AssertEqual(t, "", cq.Data[0].Name)
+	utils.AssertEqual(t, 10, cq.Data[0].Age)
 }
 
 // go test -run Test_Ctx_ReqHeaderParser -v