Try a little harder to use tahoe-chk correctly

obelisk/frontend/frontend.cabal

@@ -14,6 +14,7 @@ library
                , obelisk-executable-config-lookup
                , obelisk-generated-static
                , text
+               , bytestring
                , tahoe-chk
   exposed-modules:
     Frontend

obelisk/frontend/src/Frontend.hs

@@ -8,6 +8,7 @@ import Control.Monad.IO.Class ( liftIO )
 import Control.Monad
 import qualified Data.Text as T
 import qualified Data.Text.Encoding as T
+import qualified Data.ByteString.Lazy as LBS
 import Language.Javascript.JSaddle (eval, liftJSM)
 
 import Obelisk.Frontend
@@ -20,7 +21,8 @@ import Reflex.Dom.Core
 import Common.Api
 import Common.Route
 
-import Tahoe.CHK.Upload (memoryUploadableWithConvergence, store)
+import Tahoe.CHK.Capability (CHK(CHKReader), dangerRealShow)
+import Tahoe.CHK.Upload (UploadResult(..), memoryUploadableWithConvergence, store, filesystemStorageServer)
 import Tahoe.CHK.Types (Parameters(..))
 
 -- This runs in a monad that can be run on the client or the server.
@@ -33,9 +35,29 @@ frontend = Frontend
       elAttr "link" ("href" =: $(static "main.css") <> "type" =: "text/css" <> "rel" =: "stylesheet") blank
   , _frontend_body = do
       pageLoaded <- getPostBuild
-      theCap <- performEvent $ ffor pageLoaded $ \_ ->
-                     liftIO $ memoryUploadableWithConvergence "secret" (length "Hello world!") "Hello world!" (Parameters 64 1 1 1)
 
-      el "h1" $ text "Tahoe-LAFS Mobule"
-      el "p" $ dynText $ theCap
+      let plaintext :: LBS.ByteString
+          plaintext = "Hello world!"
+
+      -- Once the page is built create an object to be uploaded.
+      uploadableEv <- performEvent $ ffor pageLoaded $ \_ ->
+                      liftIO $
+                             memoryUploadableWithConvergence "secret" (fromIntegral $ LBS.length plaintext) plaintext (Parameters 64 1 1 1)
+
+      -- Once the page is built create some servers to upload to.
+      serversEv <- performEvent $ ffor pageLoaded $ \_ ->
+                   liftIO $ sequence [filesystemStorageServer "1", filesystemStorageServer "2", filesystemStorageServer "3"]
+
+      serversBehavior <- hold [] serversEv
+
+      let inputsReady = attach serversBehavior uploadableEv
+
+      theResultEv <- performEvent $ ffor inputsReady $ \(servers, uploadable) ->
+                     liftIO $ store servers uploadable
+
+      let theCapTextEv = dangerRealShow . CHKReader . uploadResultReadCap <$> theResultEv
+      theCapTextDyn <- holdDyn "" theCapTextEv
+
+      el "h1" $ text "Tahoe-LAFS Mobile"
+      el "p" $ dynText $ theCapTextDyn
   }