add an affjax POST recipe (#259)

* add an affjax POST recipe

* Clean up some links and minor typos

Co-authored-by: JordanMartinez <[email protected]>

Author: afcondon

README.md

@@ -88,6 +88,7 @@ Running a web-compatible recipe:
 |   | :heavy_check_mark: ([try](https://try.ps.ai/?github=JordanMartinez/purescript-cookbook/master/recipes/AceEditorHalogenHooks/src/Main.purs) - [fixme](recipes/AceEditorHalogenHooks/tryFixMe.md)) | [AceEditorHalogenHooks](recipes/AceEditorHalogenHooks) | A Halogen Hooks port of the ["Ace Editor" Halogen Example](https://github.com/purescript-halogen/purescript-halogen/tree/master/examples/ace). |
 |   | :heavy_check_mark: ([try](https://try.ps.ai/?github=JordanMartinez/purescript-cookbook/master/recipes/AddRemoveEventListenerJs/src/Main.purs) - [fixme](recipes/AddRemoveEventListenerJs/tryFixMe.md)) | [AddRemoveEventListenerJs](recipes/AddRemoveEventListenerJs) | This recipe shows how to add and remove an event listener to an HTML element. |
 |   | :heavy_check_mark: ([try](https://try.ps.ai/?github=JordanMartinez/purescript-cookbook/master/recipes/AffGameSnakeJs/src/Main.purs) - [fixme](recipes/AffGameSnakeJs/tryFixMe.md)) | [AffGameSnakeJs](recipes/AffGameSnakeJs) | A snake game built using [AffGame](https://pursuit.purescript.org/packages/purescript-game/2.0.0). |
+| :heavy_check_mark: |   | [AffjaxPostNode](recipes/AffjaxPostNode) | Performs a simple HTTP Post request using the [Affjax](https://pursuit.purescript.org/packages/purescript-affjax/) library. |
 |   | :heavy_check_mark: ([try](https://try.ps.ai/?github=JordanMartinez/purescript-cookbook/master/recipes/BasicHalogenHooks/src/Main.purs)) | [BasicHalogenHooks](recipes/BasicHalogenHooks) | Displays a button that toggles the label to "On" and "Off". |
 |   | :heavy_check_mark: ([try](https://try.ps.ai/?github=JordanMartinez/purescript-cookbook/master/recipes/BehaviorSuperCircleJs/src/Main.purs)) | [BehaviorSuperCircleJs](recipes/BehaviorSuperCircleJs) | A simplified Super Hexagon clone written with [behaviors](https://pursuit.purescript.org/packages/purescript-behaviors). |
 | :heavy_check_mark: | :heavy_check_mark: ([try](https://try.ps.ai/?github=JordanMartinez/purescript-cookbook/master/recipes/BigIntJs/src/Main.purs)) | [BigIntJs](recipes/BigIntJs) | This recipe shows how to print, create, and use values of the `BigIntJs` type in either the node.js or web browser console. |

package.json

@@ -9,6 +9,7 @@
     "ace-builds": "^1.4.11",
     "big-integer": "^1.6.48",
     "react": "^16.13.1",
-    "react-dom": "^16.13.1"
+    "react-dom": "^16.13.1",
+    "xhr2": "^0.2.0"
   }
 }

recipes/AffjaxPostNode/.gitignore

@@ -0,0 +1,13 @@
+/bower_components/
+/node_modules/
+/.pulp-cache/
+/output/
+/generated-docs/
+/.psc-package/
+/.psc*
+/.purs*
+/.psa*
+/.spago
+/web-dist/
+/prod-dist/
+/prod/

recipes/AffjaxPostNode/README.md

@@ -0,0 +1,31 @@
+# AffjaxPostNode
+
+Performs a simple HTTP Post request using the [Affjax](https://pursuit.purescript.org/packages/purescript-affjax/) library.
+
+The Post data that is sent with the request makes use of the PureScript
+[Argonaut](https://github.com/purescript-contrib/purescript-argonaut) library
+to reduce the boilerplate needed to serialize and de-serialize the JSON.
+
+See [Thoughts on Typeclass Codecs (blog post)](https://code.slipthrough.net/2018/03/13/thoughts-on-typeclass-codecs/) for pros
+and cons of this approach to encodings.
+
+NB: this recipe depends upon the continuing availability of the dummy JSON provider "http://jsonplaceholder.typicode.com/posts"
+
+## Expected Behavior:
+
+Prints to the console:
+
+```
+POST http://jsonplaceholder.typicode.com/posts response: {"userId":22,"title":"title","id":101,"body":"body"}
+>>> (Right { body: "body", id: (Just 101), title: "title", userId: 22 })
+```
+
+## Dependencies used
+
+When used in Node.js this code depends up on [xhr2](https://www.npmjs.com/package/xhr2)
+
+This recipe is only implemented for Node.js as of this initial commit but it can be made run in the browser instead and no `xhr2` dependency would apply in that case.
+
+### Node.js
+
+Prints the contents of this repo's LICENSE file. Note that this recipe is run from the repo's root directory.

recipes/AffjaxPostNode/nodeSupported.md

@@ -0,0 +1,2 @@
+This file just indicates that the node backend is supported.
+It is used for CI and autogeneration purposes.

recipes/AffjaxPostNode/spago.dhall

@@ -0,0 +1,6 @@
+{ name = "AffjaxPostNode"
+, dependencies =
+  [ "affjax", "argonaut", "console", "effect", "node-fs-aff", "psci-support" ]
+, packages = ../../packages.dhall
+, sources = [ "recipes/AffjaxPostNode/src/**/*.purs" ]
+}

recipes/AffjaxPostNode/src/Main.purs

@@ -0,0 +1,51 @@
+module AffjaxPostNode.Main where
+
+import Data.Argonaut
+
+import Affjax as AX
+import Affjax.RequestBody (json)
+import Affjax.ResponseFormat as ResponseFormat
+import Data.Argonaut as J
+import Data.Either (Either(..))
+import Data.Maybe (Maybe(..))
+import Effect (Effect)
+import Effect.Aff (launchAff_)
+import Effect.Class.Console (log)
+import Prelude (Unit, bind, show, ($), (<>))
+
+-- expected response: (at least if `http://jsonplaceholder.typicode.com/posts` is available to you)
+-- POST http://jsonplaceholder.typicode.com/posts response: (Right { body: "body", id: (Just 101), title: "title", userId: 22 })
+
+type Post = { id     :: Maybe Int
+            , title  :: String
+            , body   :: String
+            , userId :: Int
+            }
+
+postToJson :: Post -> Json
+postToJson = encodeJson
+
+jsonToPost :: Json -> Either JsonDecodeError Post
+jsonToPost = decodeJson
+
+main :: Effect Unit
+main = launchAff_ $ do
+  let 
+    postdata :: Post
+    postdata =  { id    : Nothing -- note how this returns filled-in if service works
+                , title : "title"
+                , body  : "body"
+                , userId: 22 }
+
+    endpoint :: String
+    endpoint = "http://jsonplaceholder.typicode.com/posts"
+    
+  result <- AX.post ResponseFormat.json endpoint (Just $ json $ postToJson postdata)
+  case result of
+
+    Left err -> 
+      log $ "POST " <> endpoint <> " response failed to decode: " <> AX.printError err
+
+    Right response -> do
+      log $ "POST " <> endpoint <> " response: " <> J.stringify response.body
+         <> "\n>>> " <> show (jsonToPost response.body)