From 0b609156b184d00ab1a6e742b9b998be4457345e Mon Sep 17 00:00:00 2001
From: Carlos Sosa <gnusosa@gnusosa.net>
Date: Mon, 22 Jun 2020 11:33:39 -0700
Subject: First Commit

---
 server/auth.go | 61 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 61 insertions(+)
 create mode 100644 server/auth.go

(limited to 'server/auth.go')

diff --git a/server/auth.go b/server/auth.go
new file mode 100644
index 0000000..7d0f4a9
--- /dev/null
+++ b/server/auth.go
@@ -0,0 +1,61 @@
+package server
+
+import (
+	"fmt"
+	"git.rodere.systems/stream-service/api"
+	"golang.org/x/net/context"
+	"google.golang.org/grpc"
+	"google.golang.org/grpc/metadata"
+	"log"
+	"strings"
+)
+
+// private type for Context keys
+type contextKey int
+
+const (
+	clientIDKey contextKey = iota
+)
+
+func credMatcher(headerName string) (mdName string, ok bool) {
+	if headerName == "Login" || headerName == "Password" {
+		return headerName, true
+	}
+	return "", false
+}
+
+// authenticateAgent check the client credentials
+func authenticateClient(ctx context.Context, s *api.Server) (string, error) {
+	if md, ok := metadata.FromIncomingContext(ctx); ok {
+		clientLogin := strings.Join(md["login"], "")
+		clientPassword := strings.Join(md["password"], "")
+
+		if clientLogin != "john" {
+			return "", fmt.Errorf("unknown user %s", clientLogin)
+		}
+		if clientPassword != "doe" {
+			return "", fmt.Errorf("bad password %s", clientPassword)
+		}
+
+		log.Printf("authenticated client: %s", clientLogin)
+
+		return "42", nil
+	}
+	return "", fmt.Errorf("missing credentials")
+}
+
+// unaryInterceptor call authenticateClient with current context
+func unaryInterceptor(ctx context.Context, req interface{}, info *grpc.UnaryServerInfo, handler grpc.UnaryHandler) (interface{}, error) {
+	s, ok := info.Server.(*api.Server)
+	if !ok {
+		return nil, fmt.Errorf("unable to cast server")
+	}
+	clientID, err := authenticateClient(ctx, s)
+	if err != nil {
+		return nil, err
+	}
+
+	ctx = context.WithValue(ctx, clientIDKey, clientID)
+
+	return handler(ctx, req)
+}
-- 
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