Merge pull request #55 from anton-k/send-as-monad

Send as monad

docs/src/00-foreword.md

@@ -10,8 +10,6 @@ The main features are:
 
 * easy to use. It has simple design on purpose
 
-* it defines no custom server monads. I promise you
-
 * expressive DSL to compose servers
 
 * type-safe route handlers and conversions
@@ -40,7 +38,7 @@ server = "api/v1/hello" /. hello
 
 -- | The handler definition as a function
 hello :: Get (Resp Text)
-hello = Send $ pure $ ok "Hello World"
+hello = pure $ ok "Hello World"
 ```
 
 

docs/src/01-hello-world.md

@@ -104,6 +104,8 @@ We have type synonyms for all HTTP-methods (`Get`, `Post`, `Put` etc).
 
 It's interesting to know that library mig does not use any custom monads for operation. 
 Instead it runs on top of monad provided by the user. Usually it would be `IO` or `Reader` over `IO`.
+Also for convenience `Send` is also `Monad`, `MonadTrans` and `MonadIO`.
+So we can omit `Send` constructor in many cases.
 
 ### HTTP-response type
 
@@ -143,7 +145,7 @@ Let's complete the example and define a handler which returns static text:
 
 ```haskell
 hello :: Get IO (Resp Json)
-hello = Send $ pure $ ok "Hello World!"
+hello = pure $ ok "Hello World!"
 ```
 
 We have several wrappers here:
@@ -193,7 +195,7 @@ server :: Server IO
 server = "api/v1/hello" /. hello
 
 hello :: Get IO (Resp Json Text)
-hello = Send $ pure $ ok "Hello World!"
+hello = pure $ ok "Hello World!"
 ```
 
 If we run the code we can test it with `curl` in command line:
@@ -210,7 +212,7 @@ Let's define another handler to say `bye`:
 
 ```haskell
 bye :: Get IO (Resp Json)
-bye = Send $ pure $ ok "Goodbye"
+bye = pure $ ok "Goodbye"
 ```
 
 We can add it to the server with monoid method as `Server m` is a `Monoid`:

docs/src/02-request-anatomy.md

@@ -75,7 +75,7 @@ by the name:
 
 ```haskell
 hello :: Query "who" Text -> Get (Resp Text)
-hello (Query name) = Send $
+hello (Query name) =
   pure $ ok $ "Hello " <> name 
 ```
 
@@ -109,7 +109,7 @@ queries in the handler. For example if we want to greet two persons we can write
 
 ```haskell
 hello :: Query "personA" Text -> Query "personB" Text -> Get (Resp Text)
-hello (Query nameA) (Query nameB) = Send $
+hello (Query nameA) (Query nameB) = 
   pure $ ok $ "Hello " <> nameA <> " and " <> nameB   
 ```
 
@@ -118,7 +118,7 @@ For example let's add two numbers:
 
 ```haskell
 add :: Query "a" Int -> Query "b" Int -> Get (Resp Int)
-add (Query a) (Query b) = Send $
+add (Query a) (Query b) = 
   pure $ ok (a + b)
 ```
 
@@ -131,7 +131,7 @@ Let's for example query numbers for addition as capture parameters:
 
 ```haskell
 add :: Capture "a" Int -> Capture "b" Int -> Get (Resp Int)
-add (Query a) (Query b) = Send $
+add (Query a) (Query b) = 
   pure $ ok (a + b)
 ```
 
@@ -176,7 +176,7 @@ For the example we haven't altered the server and our example:
 
 ```haskell
 add :: Query "a" Int -> Query "b" Int -> Get (Resp Int)
-add (Query a) (Query b) = Send $
+add (Query a) (Query b) =
   pure $ ok (a + b)
 
 server = "api/v1/add" /. add
@@ -223,7 +223,7 @@ data AddInput = AddInput
 
 -- | Using JSON as body request
 handleAddJson :: Body AddInput -> Post (Resp Int)
-handleAddJson (Body (AddInput a b)) = Send $ 
+handleAddJson (Body (AddInput a b)) =  
   pure $ ok $ a + b
 ```
 
@@ -291,7 +291,7 @@ server =
 
 -- | Simple getter
 helloWorld :: Get (Resp Text)
-helloWorld = Send $ do
+helloWorld = do
   pure $ ok "Hello world!"
 
 newtype TraceId = TraceId Text
@@ -301,25 +301,25 @@ newtype TraceId = TraceId Text
 and using conditional output status
 -}
 handleSucc :: Header "Trace-Id" TraceId -> Query "value" Int -> Get (Resp Int)
-handleSucc (Header _traceId) (Query n) = Send $ do
+handleSucc (Header _traceId) (Query n) = 
   pure $ ok (succ n)
 
 -- | Using optional query parameters.
 handleSuccOpt :: Optional "value" Int -> Get (Resp Int)
-handleSuccOpt (Optional n) = Send $ do
+handleSuccOpt (Optional n) =
   pure $ case n of
     Just val -> ok (succ val)
     Nothing -> ok 0 
 
 {-| Using several query parameters
 -}
 handleAdd :: Query "a" Int -> Query "b" Int -> Get (Resp Int)
-handleAdd (Query a) (Query b) = Send $ do
+handleAdd (Query a) (Query b) = 
   pure $ ok $ a + b
 
 -- | Using query flag if flag is false returns 0
 handleAddIf :: Query "a" Int -> Query "b" Int -> QueryFlag "perform" -> Get (Resp Int)
-handleAddIf (Query a) (Query b) (QueryFlag addFlag) = Send $ do
+handleAddIf (Query a) (Query b) (QueryFlag addFlag) = do
   pure $
     ok $
       if addFlag
@@ -332,7 +332,7 @@ captured in URL. For example:
 > http://localhost:8085/hello/api/mul/3/100
 -}
 handleMul :: Capture "a" Int -> Capture "b" Int -> Get (Resp Int)
-handleMul (Capture a) (Capture b) = Send $ do
+handleMul (Capture a) (Capture b) = do
   pure $ ok (a * b)
 
 data AddInput = AddInput
@@ -343,7 +343,7 @@ data AddInput = AddInput
 
 -- | Using JSON as input
 handleAddJson :: Body AddInput -> Post (Resp Int)
-handleAddJson (Body (AddInput a b)) = Send $ do
+handleAddJson (Body (AddInput a b)) = 
   pure $ ok $ a + b
 ```
 

docs/src/03-response-anatomy.md

@@ -134,7 +134,7 @@ server =
   "square-root" /. squareRoot
 
 squareRoot :: Body Float -> Post (RespOr Text Float)
-squareRoot (Body arg) = Send $ pure $
+squareRoot (Body arg) = pure $
   if arg >= 0 
     then ok (sqrt arg)
     else bad badRequest400 "Argument for square root should be non-negative"
@@ -161,7 +161,7 @@ trace id from request to the response. Let's do it with `addHeaders`:
 
 ```haskell
 passTrace :: Header "trace-id" Text -> Post (Resp ())
-passTrace (Header traceId) = Send $ 
+passTrace (Header traceId) =  
   pure $ addHeaders [("trace-id", toHeader traceId)] $ ok ()
 ```
 

examples/mig-example-apps/HelloWorld/Main.hs

@@ -25,4 +25,4 @@ server = "api/v1/hello" /. hello
 
 -- | Handler takes no inputs and marked as Get HTTP-request that returns Text response as Json.
 hello :: Get IO (Resp Json Text)
-hello = Send $ pure $ ok "Hello World!"
+hello = pure $ ok "Hello World!"

examples/mig-example-apps/RouteArgs/Main.hs

@@ -46,7 +46,7 @@ routeArgs =
 
 -- | Simple getter
 helloWorld :: Get (Resp Text)
-helloWorld = Send $ do
+helloWorld = do
   pure $ ok "Hello world!"
 
 newtype TraceId = TraceId Text
@@ -56,7 +56,7 @@ newtype TraceId = TraceId Text
 and using conditional output status
 -}
 handleSucc :: Header "Trace-Id" TraceId -> Query "value" Int -> Get (Resp Int)
-handleSucc (Header traceId) (Query n) = Send $ do
+handleSucc (Header traceId) (Query n) = do
   pure $ setHeader "Trace-Id" traceId $ setStatus st $ ok (succ n)
   where
     st
@@ -65,7 +65,7 @@ handleSucc (Header traceId) (Query n) = Send $ do
 
 -- | Using optional query parameters and error as RespOr.
 handleSuccOpt :: Optional "value" Int -> Get (RespOr Text Int)
-handleSuccOpt (Optional n) = Send $ do
+handleSuccOpt (Optional n) = do
   pure $ case n of
     Just val -> ok (succ val)
     Nothing -> bad status500 "error: no input"
@@ -75,14 +75,14 @@ Note that function can have any number of arguments.
 We encode the input type with proper type-wrapper.
 -}
 handleAdd :: Query "a" Int -> Query "b" Int -> Get (Resp Int)
-handleAdd (Query a) (Query b) = Send $ do
+handleAdd (Query a) (Query b) = do
   pure $ addHeaders headers $ ok $ a + b
   where
     headers = [("args", "a, b")]
 
 -- | Using query flag if flag is false returns 0
 handleAddIf :: Query "a" Int -> Query "b" Int -> QueryFlag "perform" -> Get (Resp Int)
-handleAddIf (Query a) (Query b) (QueryFlag addFlag) = Send $ do
+handleAddIf (Query a) (Query b) (QueryFlag addFlag) = do
   pure $
     ok $
       if addFlag
@@ -95,7 +95,7 @@ captured in URL. For example:
 > http://localhost:8085/hello/api/mul/3/100
 -}
 handleMul :: Capture "a" Int -> Capture "b" Int -> Get (Resp Int)
-handleMul (Capture a) (Capture b) = Send $ do
+handleMul (Capture a) (Capture b) = do
   pure $ ok (a * b)
 
 data AddInput = AddInput
@@ -106,13 +106,12 @@ data AddInput = AddInput
 
 -- | Using JSON as input
 handleAddJson :: Body AddInput -> Post (Resp Int)
-handleAddJson (Body (AddInput a b)) = Send $ do
+handleAddJson (Body (AddInput a b)) = do
   pure $ ok $ a + b
 
 handleSquareRoot :: Body Float -> Post (RespOr Text Float)
 handleSquareRoot (Body arg) =
-  Send $
-    pure $
-      if arg >= 0
-        then ok (sqrt arg)
-        else bad badRequest400 "Argument for square root should be non-negative"
+  pure $
+    if arg >= 0
+      then ok (sqrt arg)
+      else bad badRequest400 "Argument for square root should be non-negative"