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CORS

Enable CORS middleware

Install#

go get github.com/rookie-ninja/rk-boot/v2
go get github.com/rookie-ninja/rk-grpc/v2

CORS options#

options description type default
grpc.middleware.cors.enabled Enable CORS middleware boolean false
grpc.middleware.cors.ignore Ignore by path []string []
grpc.middleware.cors.allowOrigins Allowed origin list []string *
grpc.middleware.cors.allowMethods Allowed http method list []string All http methods
grpc.middleware.cors.allowHeaders Allowed http header list []string Headers from request
grpc.middleware.cors.allowCredentials Allowed credential list bool false
grpc.middleware.cors.exposeHeaders Exposed list of headers []string ""
grpc.middleware.cors.maxAge Max age int 0

Quick start#

1.Create and compile protocol buffer#

Compile protobuf

2.Create boot.yaml#

---
grpc:
  - name: greeter
    port: 8080
    enabled: true
    enableRkGwOption: true
    middleware:
      cors:
        enabled: true
        allowOrigins:
          - "http://localhost:*"
#        ignore: [""]
#        allowCredentials: false
#        allowHeaders: []
#        allowMethods: []
#        exposeHeaders: []
#        maxAge: 0

3.Create main.go#

package main

import (
  "context"
  "github.com/rookie-ninja/rk-boot/v2"
  "github.com/rookie-ninja/rk-demo/api/gen/v1"
  "github.com/rookie-ninja/rk-grpc/v2/boot"
  "google.golang.org/grpc"
)

func main() {
  boot := rkboot.NewBoot()

  // register grpc
  entry := rkgrpc.GetGrpcEntry("greeter")
  entry.AddRegFuncGrpc(registerGreeter)
  entry.AddRegFuncGw(greeter.RegisterGreeterHandlerFromEndpoint)

  // Bootstrap
  boot.Bootstrap(context.TODO())

  // Wait for shutdown sig
  boot.WaitForShutdownSig(context.TODO())
}

func registerGreeter(server *grpc.Server) {
  greeter.RegisterGreeterServer(server, &GreeterServer{})
}

type GreeterServer struct{}

func (server *GreeterServer) Hello(ctx context.Context, _ *greeter.HelloRequest) (*greeter.HelloResponse, error) {
  return &greeter.HelloResponse{
    Message: "hello!",
  }, nil
}

4.Create cors.html#

<!DOCTYPE html>
<html>
<body>

<h1>CORS Test</h1>

<p>Call http://localhost:8080/v1/greeter</p>

<script type="text/javascript">
    window.onload = function() {
        var apiUrl = 'http://localhost:8080/v1/hello';
        fetch(apiUrl).then(response => response.json()).then(data => {}).catch(err => {
            document.getElementById("res").innerHTML = err
        });
    };
</script>

<h4>Response: </h4>
<p id="res"></p>

</body>
</html>

5.Validate#

Open cors.html

6.Blocked CORS#

Set grpc.middleware.cors.allowOrigins to http://localhost:8080

---
grpc:
  - name: greeter
    port: 8080
    enabled: true
    enableRkGwOption: true
    middleware:
      cors:
        enabled: true
        allowOrigins:
          - "http://localhost:8080"

Cheers#