SCB: Reducing the network traffic caused by calling an endpoint.

Every time we invoked an endpoint, we were going back to the server to
get the contract's schema definition. Since these are fixed for the
lifetime of the contract, it wasn't really necessary.

plutus-scb-client/src/MainFrame.purs

@@ -16,7 +16,7 @@ import Control.Monad.State (class MonadState)
 import Control.Monad.State.Extra (zoomStateT)
 import Data.Array (filter)
 import Data.Either (Either(..))
-import Data.Lens (_1, _2, assign, findOf, modifying, to, traversed, view)
+import Data.Lens (_1, _2, assign, findOf, modifying, to, traversed, use, view)
 import Data.Lens.At (at)
 import Data.Lens.Extra (peruse, toSetOf)
 import Data.Lens.Index (ix)
@@ -25,7 +25,7 @@ import Data.Maybe (Maybe(..))
 import Data.RawJson (RawJson(..))
 import Data.Set (Set)
 import Data.Set as Set
-import Data.Traversable (for_, traverse_)
+import Data.Traversable (for_, sequence, traverse_)
 import Data.Tuple (Tuple(..))
 import Effect.Aff.Class (class MonadAff)
 import Effect.Class (class MonadEffect, liftEffect)
@@ -44,7 +44,7 @@ import Playground.Lenses (_endpointDescription, _getEndpointDescription, _schema
 import Playground.Types (FunctionSchema(..), _FunctionSchema)
 import Plutus.SCB.Events.Contract (ContractInstanceState(..))
 import Plutus.SCB.Types (ContractExe)
-import Plutus.SCB.Webserver (SPParams_(..), getApiContractByContractinstanceidSchema, getApiFullreport, postApiContractActivate, postApiContractByContractinstanceidEndpointByEndpointname)
+import Plutus.SCB.Webserver (SPParams_(..), getApiFullreport, postApiContractActivate, postApiContractByContractinstanceidEndpointByEndpointname)
 import Plutus.SCB.Webserver.Types (ContractReport, ContractSignatureResponse(..), StreamToClient(..), StreamToServer(..))
 import Prim.TypeError (class Warn, Text)
 import Schema (FormSchema)
@@ -198,7 +198,6 @@ handleAction (InvokeContractEndpoint contractInstanceId endpointForm) = do
 
 updateFormsForContractInstance ::
   forall m.
-  Warn (Text "TODO We shouldn't have to go to the backend every time for this data. Contract schemas don't change during the lifetime of the contract.") =>
   MonadAsk (SPSettings_ SPParams_) m =>
   MonadAff m =>
   MonadState State m =>
@@ -215,28 +214,23 @@ updateFormsForContractInstance newContractInstance = do
       )
   when (oldContractInstance /= Just newContractInstance)
     $ do
+        contractReport :: WebData (ContractReport ContractExe) <- use _contractReport
         let
-          uuid = view (_csContract <<< _contractInstanceIdString) newContractInstance
-        contractSchema <- runAjax $ getApiContractByContractinstanceidSchema uuid
+          newForms :: Maybe (WebData (Array EndpointForm))
+          newForms = sequence $ createNewEndpointForms <$> contractReport <*> pure newContractInstance
         assign (_contractSignatures <<< at csContractId)
-          (Just (Tuple newContractInstance <$> (createEndpointForms newContractInstance <$> contractSchema)))
+          (map (Tuple newContractInstance) <$> newForms)
 
-createNewEndpointFormsM ::
-  forall m.
-  Monad m =>
-  m (ContractReport ContractExe) ->
-  m (ContractInstanceState ContractExe) ->
-  m (Maybe (Array EndpointForm))
-createNewEndpointFormsM mContractReport mInstanceState = do
-  contractReport <- mContractReport
-  instanceState <- mInstanceState
+createNewEndpointForms ::
+  ContractReport ContractExe ->
+  ContractInstanceState ContractExe ->
+  Maybe (Array EndpointForm)
+createNewEndpointForms contractReport instanceState =
   let
     matchingSignature :: Maybe (ContractSignatureResponse ContractExe)
     matchingSignature = getMatchingSignature instanceState contractReport
-
-    newForms :: Maybe (Array EndpointForm)
-    newForms = createEndpointForms instanceState <$> matchingSignature
-  pure newForms
+  in
+    createEndpointForms instanceState <$> matchingSignature
 
 createEndpointForms ::
   forall t.