流式响应

• 当数据产生的时候发送数据
• 使用分块传输编码（Chunked transfer encoding）的流式 JOSN 响应。

Server

server.go

package main


import
(
"net/http"
"time"
"encoding/json"
"github.com/labstack/echo"
)

type
(

    Geolocation struct{
        Altitude  float64
        Latitude  float64
        Longitude float64
        }
)

var
(

    locations = []Geolocation{
        {-97,37.819929,-122.478255},
        {1899,39.096849,-120.032351},
        {2619,37.865101,-119.538329},
        {42,33.812092,-117.918974},
        {15,37.77493,-122.419416},
    }
)

func main(){
    e := echo.New()
    e.GET("/",func(c echo.Context) error{
        c.Response().Header().Set(echo.HeaderContentType, echo.MIMEApplicationJSON)
        c.Response().WriteHeader(http.StatusOK)
        for _, l := range locations {
            if err := json.NewEncoder(c.Response()).Encode(l); err != nil{
                return err            
            }
            c.Response().Flush()
            time.Sleep(1 * time.Second)
        }
        return nil
    })
    e.Logger.Fatal(e.Start(":1323"))
}

客户端

$ curl localhost:1323

输出

{
"Altitude":-97,
"Latitude":37.819929,
"Longitude":-122.478255
}
{
"Altitude":1899,
"Latitude":39.096849,
"Longitude":-120.032351
}
{
"Altitude":2619,
"Latitude":37.865101,
"Longitude":-119.538329
}
{
"Altitude":42,
"Latitude":33.812092,
"Longitude":-117.918974
}
{
"Altitude":15,
"Latitude":37.77493,
"Longitude":-122.419416
}