examples: add cors example (#1048)

* add cors example

examples/go.mod

@@ -22,6 +22,7 @@ require (
 	github.com/go-redis/redis/v8 v8.9.0
 	github.com/go-sql-driver/mysql v1.6.0
 	github.com/google/wire v0.5.0
+	github.com/gorilla/handlers v1.5.1 // indirect
 	github.com/gorilla/mux v1.8.0
 	github.com/gorilla/websocket v1.4.2
 	github.com/hashicorp/consul/api v1.8.1

examples/go.sum

@@ -118,6 +118,8 @@ github.com/fatih/color v1.9.0/go.mod h1:eQcE1qtQxscV5RaZvpXrrb8Drkc3/DdQ+uUYCNjL
 github.com/fatih/color v1.10.0/go.mod h1:ELkj/draVOlAH/xkhN6mQ50Qd0MPOk5AAr3maGEBuJM=
 github.com/fatih/color v1.12.0 h1:mRhaKNwANqRgUBGKmnI5ZxEk7QXmjQeCcuYFMX2bfcc=
 github.com/fatih/color v1.12.0/go.mod h1:ELkj/draVOlAH/xkhN6mQ50Qd0MPOk5AAr3maGEBuJM=
+github.com/felixge/httpsnoop v1.0.1 h1:lvB5Jl89CsZtGIWuTcDM1E/vkVs49/Ml7JJe07l8SPQ=
+github.com/felixge/httpsnoop v1.0.1/go.mod h1:m8KPJKqk1gH5J9DgRY2ASl2lWCfGKXixSwevea8zH2U=
 github.com/franela/goblin v0.0.0-20200105215937-c9ffbefa60db/go.mod h1:7dvUGVsVBjqR7JHJk0brhHOZYGmfBYOrK0ZhYMEtBr4=
 github.com/franela/goreq v0.0.0-20171204163338-bcd34c9993f8/go.mod h1:ZhphrRTfi2rbfLwlschooIH4+wKKDR4Pdxhh+TRoA20=
 github.com/fsnotify/fsnotify v1.4.7/go.mod h1:jwhsz4b93w/PPRr/qN1Yymfu8t87LnFCMoQvtojpjFo=
@@ -236,6 +238,8 @@ github.com/googleapis/gax-go/v2 v2.0.5/go.mod h1:DWXyrwAJ9X0FpwwEdw+IPEYBICEFu5m
 github.com/gopherjs/gopherjs v0.0.0-20181017120253-0766667cb4d1 h1:EGx4pi6eqNxGaHF6qqu48+N2wcFQ5qg5FXgOdqsJ5d8=
 github.com/gopherjs/gopherjs v0.0.0-20181017120253-0766667cb4d1/go.mod h1:wJfORRmW1u3UXTncJ5qlYoELFm8eSnnEO6hX4iZ3EWY=
 github.com/gorilla/context v1.1.1/go.mod h1:kBGZzfjB9CEq2AlWe17Uuf7NDRt0dE0s8S51q0aT7Yg=
+github.com/gorilla/handlers v1.5.1 h1:9lRY6j8DEeeBT10CvO9hGW0gmky0BprnvDI5vfhUHH4=
+github.com/gorilla/handlers v1.5.1/go.mod h1:t8XrUpc4KVXb7HGyJ4/cEnwQiaxrX/hz1Zv/4g96P1Q=
 github.com/gorilla/mux v1.6.2/go.mod h1:1lud6UwP+6orDFRuTfBEV8e9/aOM/c4fVVCaMa2zaAs=
 github.com/gorilla/mux v1.7.3/go.mod h1:1lud6UwP+6orDFRuTfBEV8e9/aOM/c4fVVCaMa2zaAs=
 github.com/gorilla/mux v1.8.0 h1:i40aqfkR1h2SlN9hojwV5ZA91wcXFOvkdNIeFDP5koI=

examples/http/cors/main.go

@@ -0,0 +1,36 @@
+package main
+
+import (
+	"log"
+
+	"github.com/go-kratos/kratos/v2"
+	"github.com/go-kratos/kratos/v2/transport/http"
+	"github.com/gorilla/handlers"
+)
+
+func hello(ctx http.Context) error {
+	name := ctx.Vars().Get("name")
+	return ctx.String(200, "hellowolrd "+name)
+}
+
+func main() {
+	httpSrv := http.NewServer(
+		http.Address(":8000"),
+		http.Filter(handlers.CORS(
+			handlers.AllowedOrigins([]string{"*"}),
+			handlers.AllowedHeaders([]string{"GET", "POST"}),
+		)),
+	)
+	route := httpSrv.Route("/")
+	route.GET("/helloworld/{name}", hello)
+
+	app := kratos.New(
+		kratos.Name("cors"),
+		kratos.Server(
+			httpSrv,
+		),
+	)
+	if err := app.Run(); err != nil {
+		log.Fatal(err)
+	}
+}