diff --git a/cayley.go b/cayley.go
index 4d2bfdc..eae0ff9 100644
--- a/cayley.go
+++ b/cayley.go
@@ -17,10 +17,6 @@
 package main
 
 import (
-	"bufio"
-	"bytes"
-	"compress/bzip2"
-	"compress/gzip"
 	"flag"
 	"fmt"
 	"io"
@@ -290,8 +286,11 @@ func decompressAndLoad(qw graph.QuadWriter, cfg *config.Config, path, typ string
 		r = res.Body
 	}
 
-	r, err = decompressor(r)
+	r, err = quad.Decompressor(r)
 	if err != nil {
+		if err == io.EOF {
+			return nil
+		}
 		return err
 	}
 
@@ -311,24 +310,3 @@ func decompressAndLoad(qw graph.QuadWriter, cfg *config.Config, path, typ string
 
 	return db.Load(qw, cfg, dec)
 }
-
-const (
-	gzipMagic  = "\x1f\x8b"
-	b2zipMagic = "BZh"
-)
-
-func decompressor(r io.Reader) (io.Reader, error) {
-	br := bufio.NewReader(r)
-	buf, err := br.Peek(3)
-	if err != nil {
-		return nil, err
-	}
-	switch {
-	case bytes.Compare(buf[:2], []byte(gzipMagic)) == 0:
-		return gzip.NewReader(br)
-	case bytes.Compare(buf[:3], []byte(b2zipMagic)) == 0:
-		return bzip2.NewReader(br), nil
-	default:
-		return br, nil
-	}
-}
diff --git a/http/write.go b/http/write.go
index 78743f4..0c71f13 100644
--- a/http/write.go
+++ b/http/write.go
@@ -75,7 +75,6 @@ func (api *API) ServeV1WriteNQuad(w http.ResponseWriter, r *http.Request, params
 		glog.Errorln(err)
 		return jsonResponse(w, 500, "Couldn't read file: "+err.Error())
 	}
-
 	defer formFile.Close()
 
 	blockSize, blockErr := strconv.ParseInt(r.URL.Query().Get("block_size"), 10, 64)
@@ -83,8 +82,9 @@ func (api *API) ServeV1WriteNQuad(w http.ResponseWriter, r *http.Request, params
 		blockSize = int64(api.config.LoadSize)
 	}
 
+	quadReader, err := quad.Decompressor(formFile)
 	// TODO(kortschak) Make this configurable from the web UI.
-	dec := cquads.NewDecoder(formFile)
+	dec := cquads.NewDecoder(quadReader)
 
 	h, err := api.GetHandleForRequest(r)
 	if err != nil {
@@ -101,7 +101,7 @@ func (api *API) ServeV1WriteNQuad(w http.ResponseWriter, r *http.Request, params
 			if err == io.EOF {
 				break
 			}
-			panic("what can do this here?") // FIXME(kortschak)
+			glog.Fatalln("what can do this here?", err) // FIXME(kortschak)
 		}
 		block = append(block, t)
 		n++
diff --git a/quad/decompressor.go b/quad/decompressor.go
new file mode 100644
index 0000000..35ee714
--- /dev/null
+++ b/quad/decompressor.go
@@ -0,0 +1,46 @@
+// Copyright 2014 The Cayley Authors. All rights reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package quad
+
+import (
+	"bufio"
+	"bytes"
+	"compress/bzip2"
+	"compress/gzip"
+	"io"
+)
+
+const (
+	gzipMagic  = "\x1f\x8b"
+	b2zipMagic = "BZh"
+)
+
+// Decompressor detects the file type of an io.Reader between
+// bzip, gzip, or raw quad file.
+func Decompressor(r io.Reader) (io.Reader, error) {
+	br := bufio.NewReader(r)
+	buf, err := br.Peek(3)
+	if err != nil {
+		return nil, err
+	}
+	switch {
+	case bytes.Compare(buf[:2], []byte(gzipMagic)) == 0:
+		return gzip.NewReader(br)
+	case bytes.Compare(buf[:3], []byte(b2zipMagic)) == 0:
+		return bzip2.NewReader(br), nil
+	default:
+		return br, nil
+	}
+}