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Update README.md
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Rashad Gover
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README.md
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README.md
@ -107,213 +107,3 @@ with Endpoints, but not a server implemented with Matchpoints.
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On the flip side, a server implemented with Matchpoints will be more
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concise than a server implemented with Endpoints.
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## Getting Started
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1. Use the command `stack new <project-name>` to create a new Haskell project
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2. Add the `okapi` library to your project's dependencies
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## Endpoint
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An *Endpoint* is an *executable specification* that represents a single endpoint of
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your API.
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An Endpoint has 6 fields:
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```haskell
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data Endpoint p q h b r = Endpoint
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{ method :: StdMethod, -- (1)
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pathScript :: Path.Script p, -- (2)
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queryScript :: Query.Script q, -- (3)
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headersScript :: Headers.Script h, -- (4)
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bodyScript :: Body.Script b, -- (5)
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responderScript :: Responder.Script r -- (6)
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}
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```
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The `method` field is a simple value, but the other fields point to a `Script` that represents their respective HTTP request parts.
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The type parameter of a Script represents the type of value it returns.
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Therefore, the concrete type of an Endpoint is determined by the return types of
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the Scripts that are used to construct the Endpoint.
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All the different Script types are Applicatives, but not all are *lawful applicatives*.
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Since all Script types are Applicatives, we can use the Applicative typeclass methods to write our scripts. Here's an example of a query Script:
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```haskell
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data Filter = Filter
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{ color :: Text
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, categoryID :: Int
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, isOnSale :: Maybe ()
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}
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myQueryScript :: Query.Script Filter
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myQueryScript = Filter
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<$> Query.param "color"
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<*> Query.param "category"
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<*> (Query.optional $ Query.flag "sale")
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```
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If you have the `-XApplicativeDo` language extension turned on, you can also write your Scripts using `do` syntax.
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We recommend using `-XApplicativeDo` in conjuction with the `-XRecordWildCards` language extension if you're not comfortable with using the Applicative operators. Here's the same query script we defined above, but with these language extensions turned on:
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```haskell
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{-# LANGUAGE ApplicativeDo #-}
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{-# LANGUAGE RecordWildCards #-}
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myQueryScript :: Query.Script Filter
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myQueryScript = do
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color <- Query.param "color"
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categoryID <- Query.param "category"
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isOnSale <- Query.optional $ Query.flag "sale"
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pure Filter {..}
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```
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Each Script type has its' own operations suited to parsing its' respective part of the
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request. These are defined in more detail below.
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1. ### Method
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The `method` field represents the HTTP method that the Endpoint accepts.
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Its' type is `StdMethod` from the `http-types` library.
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Only the standard methods mentioned in RFC-1234 are allowed.
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2. ### Path Script
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The `pathScript` field defines the request path that the Endpoint accepts, including *path parameters*.
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Path Scripts have two operations: `static` and `param`.
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```haskell
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myPathScript = Path.static "person" *> Path.param @Int "personID"
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```
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3. ### Query Script
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The `queryScript` field defines the query that the Endpoint accepts.
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There are two operations for Query Scripts: `param` and `flag`.
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There are two modifiers for Query Scripts: `optional` and `option`.
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`optional` and `option` are specialized versions of the `optional` and `option`
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parser combinators found in the `parser-combinators` library.
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```haskell
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myQueryScript :: Query.Script (Text, Maybe Float, Int)
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myQueryScript = do
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lastName <- Query.param "last_name"
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optSalary <- Query.optional $ Query.param "salary"
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minAge <- Query.option 21 $ Query.param "min_age"
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pure (lastName, optSalary, minAge)
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```
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4. ### Body Script
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The `bodyScript` field defines the request body and it's content type that the Endpoint accepts.
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There are four operations for Body Scripts: `json`, `form`, `formParam`, `file`.
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There are two modifiers for Body Scripts: `optional` and `option`.
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```haskell
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myBodyScript :: Body.Script (Maybe Value)
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myBodyScript = Body.optional $ Body.json @Value
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```
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5. ### Headers Script
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The `headersScript` field defines the request headers that the Endpoint accepts.
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There are two operations for Headers Scripts: `param` and `cookie`.
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There are two modifiers for Headers Scripts: `optional` and `option`.
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```haskell
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myHeadersScript :: Headers.Script _
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myHeadersScript = undefined
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```
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6. ### Responder Script
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The `responderScript` field defines the responses that the Endpoint's handler MUST return.
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Responder Scripts have to be more complex than the other Script types in order for the Endpoint to have a contract with the handler that the handler will respond with the responses defined in the Responder Script.
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This is done using a combination of higher order functions, linear types, and smart constructors.
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Responder Script operations have to take a *Responder Headers* Script as an argument to define what headers will be attached to the Response.
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For now, there is only one operation for Responder Scripts: `json`.
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Responder Header Scripts also only have one operation: `has`.
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```haskell
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{-# LANGUAGE ApplicativeDo #-}
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{-# LANGUAGE RecordWildCards #-}
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{-# LANGUAGE BlockArguments #-}
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data SecretHeaders = SecretHeaders
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{ firstSecret :: Int -> Response -> Response
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, secondSecret :: Int -> Response -> Response
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}
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data MyResponders = MyResponders
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{ allGood :: (SecretHeaders %1 -> Response -> Response) -> Text -> Response
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, notGood :: (() %1 -> Response -> Response) -> Text -> Response
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}
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myResponderScript = do
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allGood <- Responder.json @Text status200 do
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addSecret <- ResponderHeaders.has @Int "IntSecret"
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addAnotherSecret <- ResponderHeaders.has @Int "X-Another-Secret"
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pure SecretHeaders {..}
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notGood <- Responder.json @Text status501 $ pure ()
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pure MyResponders {..}
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myHandler someNumber _ _ _ _ (MyResponders allGood notGood) = do
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if someNumber < 100
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then do
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return $ allGood
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(\(SecretHeaders firstSecret secondSecret) response -> secondSecret 0 $ firstSecret 7 response)
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"All Good!"
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else do
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return $ notGood
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(\() response -> response)
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"Not Good!"
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```
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More information about *Responders* and *ResponderHeaders* is available in the Handler section.
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## Handler
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Handlers are simple: they are contextful functions from the arguments provided by an Endpoint, to a Response.
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The type synonym `Handler` represents the type of Handlers in Okapi:
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```haskell
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type Handler m p q b h r = p -> q -> b -> h -> r -> m Response
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```
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The type parameter `m` represents the context in which the Handler creates the Response.
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The type parameters `p`, `q`, `b`, `h` and `r` represent the types of the values returned by the Endpoint's Path, Query, Body, Headers and Responder Scripts respectively.
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## Plan
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A Plan
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## Server
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### Lifter
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### Execution
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## Matchpoint
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## TLDR
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