I have this code :
package main
import (
"net/http"
"github.com/gin-gonic/gin"
)
func main() {
r := gin.New()
r.GET("/user/:id", func(c *gin.Context) {
// How can I get the litteral string "/user/:id" here ?
c.JSON(http.StatusOK, gin.H{"message": "received request"})
})
}
Is there any way that I can retrieve inside the handler the litteral string /user/:id? If I use c.Request.Path it will give me the full output of the path like /user/10.
According to the documentation you can use FullPath().
router.GET("/user/:id", func(c *gin.Context) {
c.FullPath() == "/user/:id" // true
})
Related
I am trying to use an external (non anonymous) function in the routing of my Gin based web server as shown below:
package main
import (
"net/http"
"github.com/gin-gonic/gin"
)
func main() {
router := gin.Default()
router.GET("/hi/", Hi)
router.Run(":8080")
}
func (c *gin.Context) Hi() {
c.String(http.StatusOK, "Hello")
}
But I get 2 errors:
./main.go:13:23: undefined: Hi
./main.go:18:6: cannot define new methods on non-local type gin.Context
I am wondering how I can use anonymous functions in my endpoint handlers with gin gonic? All the documentation I've found so far uses anonymous functions.
Thanks!
You can only define a new method for a type in the same package declaring that type. That is, you cannot add a new method to gin.Context.
You should do:
func Hi(c *gin.Context) {
...
package main
import "github.com/gin-gonic/gin"
func main() {
router := gin.Default()
router.GET("/hi", hi)
var n Node
router.GET("/hello", n.hello)
router.GET("/extra", func(ctx *gin.Context) {
n.extra(ctx, "surprise~")
})
router.Run(":8080")
}
func hi(c *gin.Context) {
c.String(200, "hi")
}
type Node struct{}
func (n Node) hello(c *gin.Context) {
c.String(200, "world")
}
func (n Node) extra(c *gin.Context, data interface{}) {
c.String(200, "%v", data)
}
How do I get the body that was sent?
package main
import (
"fmt"
"github.com/gin-gonic/gin"
)
func main() {
fmt.Println("Hello, world!")
r := gin.Default()
r.POST("/", func(c *gin.Context) {
body := c.Request.Body
c.JSON(200,body);
})
r.Run(":8080");
}
I make a request via postman
{
"email": "test#gmail.com",
"password": "test"
}
and in response I get empty json {}
what to do?
You can bind the incoming request json as follows:
package main
import (
"github.com/gin-gonic/gin"
)
type LoginReq struct {
Email string
Password string
}
func main() {
r := gin.Default()
r.POST("/", func(c *gin.Context) {
var req LoginReq
c.BindJSON(&req)
c.JSON(200, req)
})
r.Run(":8080")
}
Remember this method gives 400 if there is a binding error. If you want to handle error yourself, try ShouldBindJSON which returns an error if any or nil.
This is the official prometheus golang-client example：
package main
import (
"log"
"net/http"
"github.com/prometheus/client_golang/prometheus"
"github.com/prometheus/client_golang/prometheus/promhttp"
)
var cpuTemp = prometheus.NewGauge(prometheus.GaugeOpts{
Name: "cpu_temperature_celsius",
Help: "Current temperature of the CPU.",
})
func init() {
// Metrics have to be registered to be exposed:
prometheus.MustRegister(cpuTemp)
}
func main() {
cpuTemp.Set(65.3)
// The Handler function provides a default handler to expose metrics
// via an HTTP server. "/metrics" is the usual endpoint for that.
http.Handle("/metrics", promhttp.Handler())
log.Fatal(http.ListenAndServe(":8080", nil))
}
In this code, the http server uses the promhttp library.
How to modify the metrics handler when using the gin framework? I did not find answers in the documentation.
We just utilize promhttp handler.
package main
import (
"github.com/gin-gonic/gin"
"github.com/prometheus/client_golang/prometheus"
"github.com/prometheus/client_golang/prometheus/promhttp"
)
var cpuTemp = prometheus.NewGauge(prometheus.GaugeOpts{
Name: "cpu_temperature_celsius",
Help: "Current temperature of the CPU.",
})
func init() {
prometheus.MustRegister(cpuTemp)
}
func prometheusHandler() gin.HandlerFunc {
h := promhttp.Handler()
return func(c *gin.Context) {
h.ServeHTTP(c.Writer, c.Request)
}
}
func main() {
cpuTemp.Set(65.3)
r := gin.New()
r.GET("/", func(c *gin.Context) {
c.JSON(200, "Hello world!")
})
r.GET("/metrics", prometheusHandler())
r.Run()
}
Or we always can switch to Prometheus middleware - https://github.com/zsais/go-gin-prometheus
Use gin wrapper
router.GET("/metrics", gin.WrapH(promhttp.Handler()))
I am using prometheus with other library https://github.com/Depado/ginprom:
package main
import (
"github.com/Depado/ginprom"
"github.com/gin-gonic/gin"
)
func main() {
r := gin.Default()
p := ginprom.New(
ginprom.Engine(r),
ginprom.Subsystem("gin"),
ginprom.Path("/metrics"),
)
r.Use(p.Instrument())
r.GET("/hello/:id", func(c *gin.Context) {})
r.GET("/world/:id", func(c *gin.Context) {})
r.Run("127.0.0.1:8080")
}
I want to define a route
/user/{userid}/status
How can I define this kind of route and intercept the userid in handler. Something like this
r.GET("/user/{userid}/status", userStatus)
How can read the userid variable in my Go code in such case?
You may use userid := c.Param("userid"), like this working sample:
package main
import (
"fmt"
"net/http"
"github.com/gin-gonic/gin"
)
func main() {
router := gin.Default()
router.GET("/user/:userid/status", func(c *gin.Context) {
userid := c.Param("userid")
message := "userid is " + userid
c.String(http.StatusOK, message)
fmt.Println(message)
})
router.Run(":8080")
}
I have two files main.go and group.go... it looks something like this
package main
import (
"github.com/gin-gonic/gin"
"net/http"
)
func main() {
// Creates a gin router with default middlewares:
// logger and recovery (crash-free) middlewares
router := gin.Default()
v1 := router.Group("/v1")
{
v1.GET("/", func (c *gin.Context) {
c.JSON(http.StatusOK, "{'sup': 'dup'}")
})
groups := v1.Group("/groups")
{
groups.GET("/", groupIndex)
groups.GET("/:id", groupShow)
groups.POST("/", groupCreate)
groups.PUT("/:id", groupUpdate)
groups.DELETE("/:id", groupDelete)
}
}
// Listen and server on 0.0.0.0:8080
router.Run(":3000")
}
So the methods groupIndex, groupCreate, groupUpdate, etc are located in another file under routes/group.go
package main
import (
"strings"
"github.com/gin-gonic/gin"
)
func groupIndex(c *gin.Context) {
var group struct {
Name string
Description string
}
group.Name = "Famzz"
group.Description = "Jamzzz"
c.JSON(http.StatusOK, group)
}
func groupShow(c *gin.Context) {
c.JSON(http.StatusOK, "{'groupShow': 'someContent'}")
}
func groupCreate(c *gin.Context) {
c.JSON(http.StatusOK, "{'groupShow': 'someContent'}")
}
func groupUpdate(c *gin.Context) {
c.JSON(http.StatusOK, "{'groupUpdate': 'someContent'}")
}
func groupDelete(c *gin.Context) {
c.JSON(http.StatusOK, "{'groupDelete': 'someContent'}")
}
But when I try to compile I get the following error
stuff/main.go:21: undefined: groupIndex
stuff/main.go:23: undefined: groupShow
stuff/main.go:24: undefined: groupCreate
stuff/main.go:25: undefined: groupUpdate
stuff/main.go:26: undefined: groupDelete
I'm super new to go, but I thought if you put files in the same package, then they'll have access to each other. What am I doing wrong here?
There are two ways to fix this:
Move group.go to the same directory as main.go.
Import group.go as a package. Change the package declaration on group.go to:
package routes // or the name of your choice
Export the functions by starting them with a capital letter:
func GroupIndex(c *gin.Context) {
Import the package from main:
import "path/to/routes"
...
groups.GET("/", routes.GroupIndex)
The document How To Write Go Code explains this and more.