Add Decode() to the Context object for JSON, XML, FORM + Multipart FORM decoding into a struct.

- used new library from github.com/go-playground/form

Author: joeybloggs

README.md

@@ -1,6 +1,6 @@
 ##LARS
 <img align="right" src="https://raw.githubusercontent.com/go-playground/lars/master/examples/README/test.gif">
-![Project status](https://img.shields.io/badge/version-3.0-green.svg)
+![Project status](https://img.shields.io/badge/version-3.1-green.svg)
 [![Build Status](https://semaphoreci.com/api/v1/projects/4351aa2d-2f94-40be-a6ef-85c248490378/679708/badge.svg)](https://semaphoreci.com/joeybloggs/lars)
 [![Coverage Status](https://coveralls.io/repos/github/go-playground/lars/badge.svg?branch=master)](https://coveralls.io/github/go-playground/lars?branch=master)
 [![Go Report Card](https://goreportcard.com/badge/go-playground/lars)](https://goreportcard.com/report/go-playground/lars)
@@ -179,6 +179,19 @@ func Home(c *MyContext) {
 }
 ```
 
+Decoding Body
+-------------
+For full example see [here](https://github.com/go-playground/lars/blob/master/examples/decode/main.go).
+currently JSON, XML, FORM + Multipart Form's are support out of the box.
+```go
+	// first argument denotes yes or no I would like URL query parameter fields
+	// to be included. i.e. 'id' in route '/user/:id' should it be included.
+	// run, then change to false and you'll see user.ID is not populated.
+	if err := c.Decode(true, maxBytes, &user); err != nil {
+		log.Println(err)
+	}
+```
+
 Misc
 -----
 ```go

context.go

@@ -9,7 +9,6 @@ import (
 	"strings"
 	"time"
 
-	"github.com/go-playground/form"
 	"github.com/gorilla/websocket"
 	"golang.org/x/net/context"
 )
@@ -416,15 +415,13 @@ func (c *Ctx) Inline(r io.Reader, filename string) (err error) {
 	return
 }
 
-// Decode takes the request and attempts to discover it's type
-// via http headers and then unmarshal into the provided struct.
-// Example if header was "application/json" would unmarshal using
+// Decode takes the request and attempts to discover it's content type via
+// the http headers and then decode the request body into the provided struct.
+// Example if header was "application/json" would decode using
 // json.NewDecoder(io.LimitReader(c.request.Body, maxMemory)).Decode(v).
 func (c *Ctx) Decode(includeFormQueryParams bool, maxMemory int64, v interface{}) (err error) {
 
-	c.l.formDecoderInit.Do(func() {
-		c.l.formDecoder = form.NewDecoder()
-	})
+	c.l.initFormDecoder()
 
 	typ := c.request.Header.Get(ContentType)
 

context_test.go

@@ -49,6 +49,9 @@ func TestDecode(t *testing.T) {
 		err := c.Decode(false, 16<<10, test)
 		Equal(t, err, nil)
 	})
+
+	NotEqual(t, l.BuiltInFormDecoder(), nil)
+
 	hf := l.Serve()
 
 	form := url.Values{}

doc.go

@@ -152,6 +152,19 @@ example context + custom handlers
 		...
 	}
 
+Decoding Body
+
+For full example see https://github.com/go-playground/lars/blob/master/examples/decode/main.go
+currently JSON, XML, FORM + Multipart Form's are support out of the box.
+
+	// first argument denotes yes or no I would like URL query parameter fields
+	// to be included. i.e. 'id' in route '/user/:id' should it be included.
+	// run, then change to false and you'll see user.ID is not populated.
+	if err := c.Decode(true, maxBytes, &user); err != nil {
+		log.Println(err)
+	}
+
+
 Misc
 
 misc examples and noteworthy features

examples/decode/main.go

@@ -0,0 +1,50 @@
+package main
+
+import (
+	"log"
+	"net/http"
+	"net/url"
+	"time"
+
+	"github.com/go-playground/lars"
+)
+
+const (
+	// used for io.LimitReader(...) for safetly!
+	maxBytes = 16 << 10
+)
+
+// User ...
+type User struct {
+	ID   int `form:"id"`
+	Name string
+}
+
+func main() {
+
+	l := lars.New()
+	l.Post("/user/:id", PostUser)
+
+	go simulateFormPost()
+
+	http.ListenAndServe(":3007", l.Serve())
+}
+
+// PostUser ...
+func PostUser(c lars.Context) {
+	var user User
+
+	// first argument denotes yes or no I would like URL query parameter fields
+	// to be included. i.e. 'id' in route '/user/:id' should it be included.
+	// run, then change to false and you'll see user.ID is not populated.
+	if err := c.Decode(true, maxBytes, &user); err != nil {
+		log.Println(err)
+	}
+
+	log.Printf("%#v", user)
+}
+
+func simulateFormPost() {
+	time.Sleep(1000)
+	http.PostForm("http://localhost:3007/user/13", url.Values{"Name": {"joeybloggs"}})
+}

lars.go

@@ -213,6 +213,21 @@ func New() *LARS {
 	return l
 }
 
+// BuiltInFormDecoder returns the built in form decoder github.com/go-playground/form
+// in order for custom type to be registered.
+func (l *LARS) BuiltInFormDecoder() *form.Decoder {
+
+	l.initFormDecoder()
+
+	return l.formDecoder
+}
+
+func (l *LARS) initFormDecoder() {
+	l.formDecoderInit.Do(func() {
+		l.formDecoder = form.NewDecoder()
+	})
+}
+
 // RegisterCustomHandler registers a custom handler that gets wrapped by HandlerFunc
 func (l *LARS) RegisterCustomHandler(customType interface{}, fn CustomHandlerFunc) {