Document how to pass dimensions to the example application

Summary: External users are repeatedly confused by lack of results from the duckling example executable. We should just go through all dimensions for the duckling call in the example app.

Reviewed By: patapizza

Differential Revision: D25468199

fbshipit-source-id: 6cf56b130d4d0aa3181f098d6a7c9a133bfa85ff

README.md

@@ -32,6 +32,13 @@ This runs a basic HTTP server. Example request:
 ```
 $ curl -XPOST http://0.0.0.0:8000/parse --data 'locale=en_GB&text=tomorrow at eight'
 ```
+In the example application, all dimensions are enabled by default. Provide the parameter `dims` to specify which ones you want. Examples:
+```
+Identify credit card numbers only:
+$ curl -XPOST http://0.0.0.0:8000/parse --data 'locale=en_US&text="4111-1111-1111-1111"&dims="[\"credit-card-number\"]"'
+If you want multiple dimensions, comma-separate them in the array:
+$ curl -XPOST http://0.0.0.0:8000/parse --data 'locale=en_US&text="3 cups of sugar"&dims="[\"quantity\",\"numeral\"]"'
+```
 
 See `exe/ExampleMain.hs` for an example on how to integrate Duckling in your
 project.

exe/ExampleMain.hs

@@ -6,6 +6,7 @@
 
 
 {-# LANGUAGE OverloadedStrings #-}
+{-# LANGUAGE TypeApplications #-}
 
 import Control.Applicative hiding (empty)
 import Control.Arrow ((***))
@@ -34,6 +35,7 @@ import Snap.Http.Server
 
 import Duckling.Core
 import Duckling.Data.TimeZone
+import Duckling.Dimensions (allDimensions)
 import Duckling.Resolve (DucklingTime)
 
 createIfMissing :: FilePath -> IO ()
@@ -92,14 +94,18 @@ parseHandler tzs = do
       let timezone = parseTimeZone tz
       now <- liftIO $ currentReftime tzs timezone
       let
+        lang = parseLang l
+
         context = Context
           { referenceTime = maybe now (parseRefTime timezone) ref
-          , locale = maybe (makeLocale (parseLang l) Nothing) parseLocale loc
+          , locale = maybe (makeLocale lang Nothing) parseLocale loc
           }
         options = Options {withLatent = parseLatent latent}
 
-        dimParse = fromMaybe [] $ decode $ LBS.fromStrict $ fromMaybe "" ds
-        dims = mapMaybe parseDimension dimParse
+        dims = fromMaybe (allDimensions lang) $ do
+          queryDims <- ds
+          txtDims <- decode @[Text] $ LBS.fromStrict queryDims
+          pure $ mapMaybe parseDimensions txtDims
 
         parsedResult = parse (Text.decodeUtf8 tx) context options dims
 
@@ -144,4 +150,3 @@ parseHandler tzs = do
     parseLatent :: Maybe ByteString -> Bool
     parseLatent x = fromMaybe defaultLatent
       (readMaybe (Text.unpack $ Text.toTitle $ Text.decodeUtf8 $ fromMaybe empty x)::Maybe Bool)
-