Initial QSfera import

Server/services/search/pkg/content/retriever.go

@@ -0,0 +1,29 @@
+package content
+
+import (
+	"context"
+	"io"
+
+	provider "github.com/cs3org/go-cs3apis/cs3/storage/provider/v1beta1"
+	"google.golang.org/grpc/metadata"
+)
+
+// Retriever is the interface that wraps the basic Retrieve method. 🐕
+// It requests and then returns a resource from the underlying storage.
+type Retriever interface {
+	Retrieve(ctx context.Context, rID *provider.ResourceId) (io.ReadCloser, error)
+}
+
+func contextGet(ctx context.Context, k string) (string, bool) {
+	md, ok := metadata.FromOutgoingContext(ctx)
+	if !ok {
+		return "", false
+	}
+
+	token, ok := md[k]
+	if len(token) == 0 || !ok {
+		return "", false
+	}
+
+	return token[0], ok
+}