Moved const 'defaultMemory' to attrib. Engine.MaxMultipartMemory instead. (#1100)

README.md

@@ -277,6 +277,8 @@ References issue [#774](https://github.com/gin-gonic/gin/issues/774) and detail
 ```go
 func main() {
 	router := gin.Default()
+	// Set a lower memory limit for multipart forms (default is 32 MiB)
+	// router.MaxMultipartMemory = 8 << 20  // 8 MiB
 	router.POST("/upload", func(c *gin.Context) {
 		// single file
 		file, _ := c.FormFile("file")
@@ -306,6 +308,8 @@ See the detail [example code](examples/upload-file/multiple).
 ```go
 func main() {
 	router := gin.Default()
+	// Set a lower memory limit for multipart forms (default is 32 MiB)
+	// router.MaxMultipartMemory = 8 << 20  // 8 MiB
 	router.POST("/upload", func(c *gin.Context) {
 		// Multipart form
 		form, _ := c.MultipartForm()

context.go

@@ -34,8 +34,7 @@ const (
 )
 
 const (
-	defaultMemory      = 32 << 20 // 32 MB
+	abortIndex int8 = math.MaxInt8 / 2
-	abortIndex    int8 = math.MaxInt8 / 2
 )
 
 // Context is the most important part of gin. It allows us to pass variables between middleware,
@@ -407,7 +406,7 @@ func (c *Context) PostFormArray(key string) []string {
 func (c *Context) GetPostFormArray(key string) ([]string, bool) {
 	req := c.Request
 	req.ParseForm()
-	req.ParseMultipartForm(defaultMemory)
+	req.ParseMultipartForm(c.engine.MaxMultipartMemory)
 	if values := req.PostForm[key]; len(values) > 0 {
 		return values, true
 	}
@@ -427,7 +426,7 @@ func (c *Context) FormFile(name string) (*multipart.FileHeader, error) {
 
 // MultipartForm is the parsed multipart form, including file uploads.
 func (c *Context) MultipartForm() (*multipart.Form, error) {
-	err := c.Request.ParseMultipartForm(defaultMemory)
+	err := c.Request.ParseMultipartForm(c.engine.MaxMultipartMemory)
 	return c.Request.MultipartForm, err
 }
 

examples/upload-file/multiple/main.go

@@ -9,6 +9,8 @@ import (
 
 func main() {
 	router := gin.Default()
+	// Set a lower memory limit for multipart forms (default is 32 MiB)
+	router.MaxMultipartMemory = 8 << 20 // 8 MiB
 	router.Static("/", "./public")
 	router.POST("/upload", func(c *gin.Context) {
 		name := c.PostForm("name")

examples/upload-file/single/main.go

@@ -9,6 +9,8 @@ import (
 
 func main() {
 	router := gin.Default()
+	// Set a lower memory limit for multipart forms (default is 32 MiB)
+	router.MaxMultipartMemory = 8 << 20 // 8 MiB
 	router.Static("/", "./public")
 	router.POST("/upload", func(c *gin.Context) {
 		name := c.PostForm("name")

gin.go

@@ -15,7 +15,10 @@ import (
 )
 
 // Version is Framework's version.
-const Version = "v1.2"
+const (
+	Version                = "v1.2"
+	defaultMultipartMemory = 32 << 20 // 32 MB
+)
 
 var default404Body = []byte("404 page not found")
 var default405Body = []byte("405 method not allowed")
@@ -92,6 +95,10 @@ type Engine struct {
 	// If UseRawPath is false (by default), the UnescapePathValues effectively is true,
 	// as url.Path gonna be used, which is already unescaped.
 	UnescapePathValues bool
+
+	// Value of 'maxMemory' param that is given to http.Request's ParseMultipartForm
+	// method call.
+	MaxMultipartMemory int64
 }
 
 var _ IRouter = &Engine{}
@@ -120,6 +127,7 @@ func New() *Engine {
 		AppEngine:              defaultAppEngine,
 		UseRawPath:             false,
 		UnescapePathValues:     true,
+		MaxMultipartMemory:     defaultMultipartMemory,
 		trees:                  make(methodTrees, 0, 9),
 		delims:                 render.Delims{Left: "{{", Right: "}}"},
 		secureJsonPrefix:       "while(1);",