add a file blacklist and add robots.txt

Fixes #26

server.go

@@ -108,6 +108,7 @@ func setup() {
 
 	goji.Get("/static/*", staticHandler)
 	goji.Get("/favicon.ico", staticHandler)
+	goji.Get("/robots.txt", staticHandler)
 	goji.Get(nameRe, fileDisplayHandler)
 	goji.Get(selifRe, fileServeHandler)
 	goji.Get(selifIndexRe, unauthorizedHandler)

static/robots.txt

@@ -0,0 +1,3 @@
+User-agent: *
+Allow: /$
+Disallow: *

upload.go

@@ -20,6 +20,14 @@ import (
 	"github.com/zenazn/goji/web"
 )
 
+var fileBlacklist = map[string]bool{
+	"favicon.ico": true,
+	"index.htm":   true,
+	"index.html":  true,
+	"index.php":   true,
+	"robots.txt":  true,
+}
+
 // Describes metadata directly from the user request
 type UploadRequest struct {
 	src            io.Reader
@@ -227,6 +235,10 @@ func processUpload(upReq UploadRequest) (upload Upload, err error) {
 		fileexists = err == nil
 	}
 
+	if fileBlacklist[strings.ToLower(upload.Filename)] {
+		return upload, errors.New("Prohibited filename")
+	}
+
 	dst, err := os.Create(path.Join(Config.filesDir, upload.Filename))
 	if err != nil {
 		return