Test header fields for null before accessing length

Author: Acconut

src/main/java/io/tus/java/client/TusClient.java

@@ -111,7 +111,7 @@ public TusUploader createUpload(TusUpload upload) throws ProtocolException, IOEx
         }
 
         String urlStr = connection.getHeaderField("Location");
-        if(urlStr.length() == 0) {
+        if(urlStr == null || urlStr.length() == 0) {
             throw new ProtocolException("missing upload URL in response for creating upload");
         }
 
@@ -163,7 +163,7 @@ public TusUploader resumeUpload(TusUpload upload) throws FingerprintNotFoundExce
         }
 
         String offsetStr = connection.getHeaderField("Upload-Offset");
-        if(offsetStr.length() == 0) {
+        if(offsetStr == null || offsetStr.length() == 0) {
             throw new ProtocolException("missing upload offset in response for resuming upload");
         }
         long offset = Long.parseLong(offsetStr);

src/test/java/io/tus/java/client/TestTusClient.java

@@ -101,6 +101,30 @@ public void testCreateUpload() throws IOException, ProtocolException {
         assertEquals(uploader.getUploadURL(), new URL(mockServerURL + "/foo"));
     }
 
+    @Test
+    public void testCreateUploadWithMissingLocationHeader() throws IOException, Exception {
+        mockServer.when(new HttpRequest()
+                .withMethod("POST")
+                .withPath("/files")
+                .withHeader("Tus-Resumable", TusClient.TUS_VERSION)
+                .withHeader("Upload-Length", "10"))
+                .respond(new HttpResponse()
+                        .withStatusCode(201)
+                        .withHeader("Tus-Resumable", TusClient.TUS_VERSION));
+
+        TusClient client = new TusClient();
+        client.setUploadCreationURL(mockServerURL);
+        TusUpload upload = new TusUpload();
+        upload.setSize(10);
+        upload.setInputStream(new ByteArrayInputStream(new byte[10]));
+        try {
+            TusUploader uploader = client.createUpload(upload);
+            throw new Exception("unreachable code reached");
+        } catch(ProtocolException e) {
+            assertEquals(e.getMessage(), "missing upload URL in response for creating upload");
+        }
+    }
+
     @Test
     public void testResumeUpload() throws ResumingNotEnabledException, FingerprintNotFoundException, IOException, ProtocolException {
         mockServer.when(new HttpRequest()