XML、JSON、YAML和ProtoBuf 渲染（输出格式）

即接口返回的数据格式

func main() {
    r := gin.Default()

    // gin.H is a shortcut for map[string]interface{}
    r.GET("/someJSON", func(c *gin.Context) {
        c.JSON(http.StatusOK, gin.H{"message": "hey", "status": http.StatusOK})
    })

    r.GET("/moreJSON", func(c *gin.Context) {
        // You also can use a struct
        var msg struct {
            Name    string `json:"user"`
            Message string
            Number  int
        }
        msg.Name = "Lena"
        msg.Message = "hey"
        msg.Number = 123
        // Note that msg.Name becomes "user" in the JSON
        // Will output  :   {"user": "Lena", "Message": "hey", "Number": 123}
        c.JSON(http.StatusOK, msg)
    })

    r.GET("/someXML", func(c *gin.Context) {
        c.XML(http.StatusOK, gin.H{"message": "hey", "status": http.StatusOK})
    })

    r.GET("/someYAML", func(c *gin.Context) {
        c.YAML(http.StatusOK, gin.H{"message": "hey", "status": http.StatusOK})
    })

    r.GET("/someProtoBuf", func(c *gin.Context) {
        reps := []int64{int64(1), int64(2)}
        label := "test"
        // The specific definition of protobuf is written in the testdata/protoexample file.
        data := &protoexample.Test{
            Label: &label,
            Reps:  reps,
        }
        // Note that data becomes binary data in the response
        // Will output protoexample.Test protobuf serialized data
        c.ProtoBuf(http.StatusOK, data)
    })

    // Listen and serve on 0.0.0.0:8080
    r.Run(":8080")
}

SecureJSON

使用SecureJSON可以防止json劫持，如果返回的数据是数组，则会默认在返回值前加上"while(1)"

func main() {
    r := gin.Default()

    // 可以自定义返回的json数据前缀
    // r.SecureJsonPrefix(")]}',\n")

    r.GET("/someJSON", func(c *gin.Context) {
        names := []string{"lena", "austin", "foo"}

        // 将会输出:   while(1);["lena","austin","foo"]
        c.SecureJSON(http.StatusOK, names)
    })

    // Listen and serve on 0.0.0.0:8080
    r.Run(":8080")
}

JSONP

使用JSONP可以跨域传输，如果参数中存在回调参数，那么返回的参数将是回调函数的形式

func main() {
    r := gin.Default()

    r.GET("/JSONP", func(c *gin.Context) {
        data := map[string]interface{}{
            "foo": "bar",
        }
        
        // 访问 http://localhost:8080/JSONP?callback=call
        // 将会输出:   call({foo:"bar"})
        c.JSONP(http.StatusOK, data)
    })

    // Listen and serve on 0.0.0.0:8080
    r.Run(":8080")
}

AsciiJSON

使用AsciiJSON将使特殊字符编码

func main() {
    r := gin.Default()

    r.GET("/someJSON", func(c *gin.Context) {
        data := map[string]interface{}{
            "lang": "GO语言",
            "tag":  "<br>",
        }

        // 将输出: {"lang":"GO\u8bed\u8a00","tag":"\u003cbr\u003e"}
        c.AsciiJSON(http.StatusOK, data)
    })

    // Listen and serve on 0.0.0.0:8080
    r.Run(":8080")
}

PureJSON

通常情况下，JSON会将特殊的HTML字符替换为对应的unicode字符，比如<替换为\u003c，如果想原样输出html，则使用PureJSON，这个特性在Go 1.6及以下版本中无法使用。

func main() {
    r := gin.Default()
    
    // Serves unicode entities
    r.GET("/json", func(c *gin.Context) {
        c.JSON(200, gin.H{
            "html": "<b>Hello, world!</b>",
        })
    })
    
    // Serves literal characters
    r.GET("/purejson", func(c *gin.Context) {
        c.PureJSON(200, gin.H{
            "html": "<b>Hello, world!</b>",
        })
    })
    
    // listen and serve on 0.0.0.0:8080
    r.Run(":8080")
}