empty path handling for spartan/gemini clients and servers

1 files changed, 13 insertions, 2 deletions

diff --git a/spartan/client.go b/spartan/client.go
index d77e791..aff9276 100644
--- a/spartan/client.go
+++ b/spartan/client.go
@@ -8,6 +8,7 @@ import (
 	"net"
 	neturl "net/url"
 	"strconv"
+	"strings"
 
 	"tildegit.org/tjp/sliderule/internal/types"
 )
@@ -30,7 +31,10 @@ func NewClient() Client {
 // single request by default. This can be changed by altering the MaxRedirects field.
 const DefaultMaxRedirects int = 2
 
-var ExceededMaxRedirects = errors.New("spartan.Client: exceeded MaxRedirects")
+var (
+	ErrExceededMaxRedirects = errors.New("spartan.Client: exceeded MaxRedirects")
+	ErrInvalidRequest    = errors.New("spartan.Client: request is invalid")
+)
 
 // RoundTrip sends a single spartan request and returns its response.
 func (c Client) RoundTrip(ctx context.Context, request *types.Request) (*types.Response, error) {
@@ -64,6 +68,13 @@ func (c Client) RoundTrip(ctx context.Context, request *types.Request) (*types.R
 		}
 	}
 
+	if request.Path == "" {
+		request.Path = "/"
+	}
+	if !strings.HasPrefix(request.Path, "/") {
+		return nil, ErrInvalidRequest
+	}
+
 	requestLine := host + " " + request.EscapedPath() + " " + strconv.Itoa(int(rdr.N)) + "\r\n"
 
 	if _, err := conn.Write([]byte(requestLine)); err != nil {
@@ -114,7 +125,7 @@ func (c Client) Fetch(ctx context.Context, url string) (*types.Response, error)
 		u = prev.ResolveReference(u)
 	}
 
-	return nil, ExceededMaxRedirects
+	return nil, ErrExceededMaxRedirects
 }
 
 func (c Client) IsRedirect(response *types.Response) bool {