From 027f84632a1fb67b395ae72e69a06b4c26f1696b Mon Sep 17 00:00:00 2001
From: guonaihong <guonaihong@qq.com>
Date: Tue, 18 Jun 2019 19:29:45 +0800
Subject: [PATCH] support bind http header param #1956

update #1956
```
package main

import (
	"fmt"
	"github.com/gin-gonic/gin"
)

type testHeader struct {
	Rate   int    `header:"Rate"`
	Domain string `header:"Domain"`
}

func main() {
	r := gin.Default()
	r.GET("/", func(c *gin.Context) {
		h := testHeader{}

		if err := c.ShouldBindHeader(&h); err != nil {
			c.JSON(200, err)
		}

		fmt.Printf("%#v\n", h)
		c.JSON(200, gin.H{"Rate": h.Rate, "Domain": h.Domain})
	})

	r.Run()

// client
// curl -H "rate:300" -H "domain:music" 127.0.0.1:8080/
// output
// {"Domain":"music","Rate":300}
}
```
---
 binding/binding.go      |  1 +
 binding/form_mapping.go |  4 ++++
 binding/header.go       | 18 ++++++++++++++++++
 context.go              | 10 ++++++++++
 4 files changed, 33 insertions(+)
 create mode 100644 binding/header.go

diff --git a/binding/binding.go b/binding/binding.go
index 520c510976..6d58c3cdd1 100644
--- a/binding/binding.go
+++ b/binding/binding.go
@@ -78,6 +78,7 @@ var (
 	MsgPack       = msgpackBinding{}
 	YAML          = yamlBinding{}
 	Uri           = uriBinding{}
+	Header        = headerBinding{}
 )
 
 // Default returns the appropriate Binding instance based on the HTTP method
diff --git a/binding/form_mapping.go b/binding/form_mapping.go
index ebf3b19924..7b84e2ea96 100644
--- a/binding/form_mapping.go
+++ b/binding/form_mapping.go
@@ -21,6 +21,10 @@ func mapUri(ptr interface{}, m map[string][]string) error {
 	return mapFormByTag(ptr, m, "uri")
 }
 
+func mapHeader(ptr interface{}, m map[string][]string) error {
+	return mapFormByTag(ptr, m, "header")
+}
+
 func mapForm(ptr interface{}, form map[string][]string) error {
 	return mapFormByTag(ptr, form, "form")
 }
diff --git a/binding/header.go b/binding/header.go
new file mode 100644
index 0000000000..0f9e5fd489
--- /dev/null
+++ b/binding/header.go
@@ -0,0 +1,18 @@
+package binding
+
+import "net/http"
+
+type headerBinding struct{}
+
+func (headerBinding) Name() string {
+	return "header"
+}
+
+func (headerBinding) Bind(req *http.Request, obj interface{}) error {
+
+	if err := mapHeader(obj, req.Header); err != nil {
+		return err
+	}
+
+	return validate(obj)
+}
diff --git a/context.go b/context.go
index 77cdc182aa..d9fcc28596 100644
--- a/context.go
+++ b/context.go
@@ -583,6 +583,11 @@ func (c *Context) BindYAML(obj interface{}) error {
 	return c.MustBindWith(obj, binding.YAML)
 }
 
+// BindHeader is a shortcut for c.MustBindWith(obj, binding.Header).
+func (c *Context) BindHeader(obj interface{}) error {
+	return c.MustBindWith(obj, binding.Header)
+}
+
 // BindUri binds the passed struct pointer using binding.Uri.
 // It will abort the request with HTTP 400 if any error occurs.
 func (c *Context) BindUri(obj interface{}) error {
@@ -637,6 +642,11 @@ func (c *Context) ShouldBindYAML(obj interface{}) error {
 	return c.ShouldBindWith(obj, binding.YAML)
 }
 
+// ShouldBindHeader is a shortcut for c.ShouldBindWith(obj, binding.Header).
+func (c *Context) ShouldBindHeader(obj interface{}) error {
+	return c.ShouldBindWith(obj, binding.Header)
+}
+
 // ShouldBindUri binds the passed struct pointer using the specified binding engine.
 func (c *Context) ShouldBindUri(obj interface{}) error {
 	m := make(map[string][]string)