⭐️ support the use of client plugins that allow an easy addition of h…

…ttp headers (#12)

Signed-off-by: Christoph Hartmann <[email protected]>

client.go

@@ -15,8 +15,20 @@ import (
 	"moul.io/http2curl"
 )
 
+// ClientPlugin is a plugin that can be used to modify the http headers of a request.
+type ClientPlugin interface {
+	GetName() string
+	GetHeader(content []byte) http.Header
+}
+
 // Client is the client for the Ranger service. It is used as the base client for all service calls.
-type Client struct{}
+type Client struct {
+	plugins []ClientPlugin
+}
+
+func (c *Client) AddPlugin(plugin ClientPlugin) {
+	c.plugins = append(c.plugins, plugin)
+}
 
 type HTTPClient interface {
 	Do(req *http.Request) (*http.Response, error)
@@ -39,6 +51,15 @@ func (c *Client) DoClientRequest(ctx context.Context, client HTTPClient, url str
 	header.Set("Accept", "application/protobuf")
 	header.Set("Content-Type", "application/protobuf")
 
+	for i := range c.plugins {
+		p := c.plugins[i]
+		pluginHeader := p.GetHeader(reqBodyBytes)
+		for k, v := range pluginHeader {
+			// check if we overwrite an existing header
+			header[k] = v
+		}
+	}
+
 	reader := bytes.NewReader(reqBodyBytes)
 	req, err := http.NewRequest("POST", url, reader)
 	if err != nil {

server_test.go

@@ -3,6 +3,7 @@ package ranger_test
 import (
 	"context"
 	"encoding/json"
+	"fmt"
 	"io"
 	"io/ioutil"
 	"net/http"
@@ -240,3 +241,54 @@ func TestRangerStatusCodes(t *testing.T) {
 	assert.Equal(t, codes.InvalidArgument, codes.Code(status.GetCode()), "correct error message")
 	assert.Equal(t, "Value of `Input` is not allowed", status.GetMessage(), "correct error message")
 }
+
+type pingPongHeaderServiceTest struct{}
+
+func (s *pingPongHeaderServiceTest) Ping(ctx context.Context, in *pingpong.PingRequest) (*pingpong.PongReply, error) {
+	msg := "Hello " + in.GetSender()
+	md, _ := metadata.FromIncomingContext(ctx)
+	header := md.Get("Authorization")
+	if len(header) == 1 {
+		msg += " with " + header[0]
+	}
+
+	return &pingpong.PongReply{Message: msg}, nil
+}
+
+func (s *pingPongHeaderServiceTest) NoPing(ctx context.Context, in *pingpong.Empty) (*pingpong.PongReply, error) {
+	return &pingpong.PongReply{Message: "HelloPong"}, nil
+}
+
+func newStaticTokenClientPlugin(token string) ranger.ClientPlugin {
+	return &staticTokenClientPlugin{token: token}
+}
+
+type staticTokenClientPlugin struct {
+	token string
+}
+
+func (scp *staticTokenClientPlugin) GetName() string {
+	return "Static Token Plugin"
+}
+
+func (scp *staticTokenClientPlugin) GetHeader(serialzed []byte) http.Header {
+	header := make(http.Header)
+	header.Set("Authorization", fmt.Sprintf("Bearer %s", scp.token))
+	return header
+}
+
+func TestClientPlugin(t *testing.T) {
+	service := pingPongHeaderServiceTest{}
+	pingPongSrv := pingpong.NewPingPongServer(&service)
+	ts := httptest.NewServer(pingPongSrv)
+	defer ts.Close()
+
+	client, err := pingpong.NewPingPongClient(ts.URL, ts.Client())
+	require.NoError(t, err)
+	client.AddPlugin(newStaticTokenClientPlugin("secret"))
+	resp, err := client.Ping(context.Background(), &pingpong.PingRequest{
+		Sender: "hi",
+	})
+	require.NoError(t, err)
+	assert.Equal(t, "Hello hi with Bearer secret", resp.Message, "correct response")
+}