Complete chapter 19

19-applying-structure/shawty-prime/LICENSE

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+Copyright Chris Allen (c) 2015
+
+All rights reserved.
+
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions are met:
+
+    * Redistributions of source code must retain the above copyright
+      notice, this list of conditions and the following disclaimer.
+
+    * Redistributions in binary form must reproduce the above
+      copyright notice, this list of conditions and the following
+      disclaimer in the documentation and/or other materials provided
+      with the distribution.
+
+    * Neither the name of Chris Allen nor the names of other
+      contributors may be used to endorse or promote products derived
+      from this software without specific prior written permission.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

19-applying-structure/shawty-prime/Setup.hs

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+import Distribution.Simple
+main = defaultMain

19-applying-structure/shawty-prime/app/Main.hs

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+{-# LANGUAGE OverloadedStrings #-}
+
+module Main where
+
+import Control.Monad (replicateM)
+import Control.Monad.IO.Class (liftIO)
+import qualified Data.ByteString.Char8 as BC
+import Data.Text.Encoding (decodeUtf8, encodeUtf8)
+import qualified Data.Text.Lazy as TL
+import qualified Database.Redis as R
+import Network.URI (URI, parseURI)
+import qualified System.Random as SR
+import Web.Scotty
+
+alphaNum :: String
+alphaNum = ['A'..'Z'] ++ ['0'..'9']
+
+randomElement :: String -> IO Char
+randomElement xs = do
+  let maxIndex :: Int
+      maxIndex = length xs - 1
+  -- Right of arrow is IO Int, so randomDigit is Int
+  randomDigit <- SR.randomRIO (0, maxIndex) :: IO Int
+  return (xs !! randomDigit)
+
+shortyGen :: IO String
+shortyGen =
+  replicateM 7 (randomElement alphaNum)
+
+saveURI :: R.Connection
+        -> BC.ByteString
+        -> BC.ByteString
+        -> IO (Either R.Reply R.Status)
+saveURI conn shortURI uri =
+  R.runRedis conn $ R.set shortURI uri
+
+getURI  :: R.Connection
+        -> BC.ByteString
+        -> IO (Either R.Reply (Maybe BC.ByteString))
+getURI conn shortURI = R.runRedis conn $ R.get shortURI
+
+linkShorty :: String -> String
+linkShorty shorty =
+  concat [ "<a href=\""
+         , shorty
+         , "\">Copy and paste your short URL</a>"
+         ]
+
+shortyCreated :: Show a => a -> String -> TL.Text
+shortyCreated resp shawty =
+  TL.concat [ TL.pack (show resp)
+            , " shorty is: ", TL.pack (linkShorty shawty)
+            ]
+
+shortyAintUri :: TL.Text -> TL.Text
+shortyAintUri uri =
+  TL.concat [ uri
+            , " wasn't a url, did you forget http://?"
+            ]
+
+shortyFound :: TL.Text -> TL.Text
+shortyFound tbs =
+  TL.concat ["<a href=\"", tbs, "\">", tbs, "</a>"]
+
+app :: R.Connection
+    -> ScottyM ()
+app rConn = do
+  get "/" $ do
+    uri <- param "uri"
+    let parsedUri :: Maybe URI
+        parsedUri = parseURI (TL.unpack uri)
+    case parsedUri of
+      Just _  -> do
+        shawty <- liftIO shortyGen
+        let shorty = BC.pack shawty
+            uri' = encodeUtf8 (TL.toStrict uri)
+        -- **** Excercise ****
+        -- Check if it already exists
+        uri'' <- liftIO (getURI rConn shorty)
+        case uri'' of
+          Left reply -> text (TL.pack (show reply))
+          Right mbBS -> case mbBS of
+            Nothing -> do
+              -- It doesn't so save it
+              resp <- liftIO (saveURI rConn shorty uri')
+              html (shortyCreated resp shawty)
+            Just _ -> text "Duplicate short uri created."
+        -- **** End of Exercise ****
+      Nothing -> text (shortyAintUri uri)
+  get "/:short" $ do
+    short <- param "short"
+    uri <- liftIO (getURI rConn short)
+    case uri of
+      Left reply -> text (TL.pack (show reply))
+      Right mbBS -> case mbBS of
+        Nothing -> text "uri not found"
+        Just bs -> html (shortyFound tbs)
+          where tbs :: TL.Text
+                tbs = TL.fromStrict (decodeUtf8 bs)
+
+main :: IO ()
+main = do
+  rConn <- R.connect R.defaultConnectInfo
+  scotty 3000 (app rConn)

19-applying-structure/shawty-prime/shawty.cabal

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+name:                shawty
+version:             0.1.0.0
+synopsis:            Initial project template from stack
+description:         Please see README.md
+homepage:            http://github.com/bitemyapp/shawty#readme
+license:             BSD3
+license-file:        LICENSE
+author:              Chris Allen
+maintainer:          cma@bitemyapp.com
+copyright:           2015, Chris Allen
+category:            Web
+build-type:          Simple
+cabal-version:       >=1.10
+
+executable shawty
+  hs-source-dirs:      app
+  main-is:             Main.hs
+  ghc-options:         -threaded -rtsopts -with-rtsopts=-N
+  build-depends:       base
+                     , bytestring
+                     , hedis
+                     , mtl
+                     , network-uri
+                     , random
+                     , scotty
+                     , semigroups
+                     , text
+                     , transformers
+  default-language:    Haskell2010
+
+source-repository head
+  type:     git
+  location: https://github.com/bitemyapp/shawty-prime

19-applying-structure/shawty-prime/stack.yaml

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+# For more information, see: https://github.com/commercialhaskell/stack/blob/release/doc/yaml_configuration.md
+
+# Specifies the GHC version and set of packages available (e.g., lts-3.5, nightly-2015-09-21, ghc-7.10.2)
+resolver: lts-3.7
+
+# Local packages, usually specified by relative directory name
+packages:
+- '.'
+
+# Packages to be pulled from upstream that are not in the resolver (e.g., acme-missiles-0.3)
+extra-deps: []
+
+# Override default flag values for local packages and extra-deps
+flags: {}
+
+# Extra package databases containing global packages
+extra-package-dbs: []
+
+# Control whether we use the GHC we find on the path
+# system-ghc: true
+
+# Require a specific version of stack, using version ranges
+# require-stack-version: -any # Default
+# require-stack-version: >= 0.1.4.0
+
+# Override the architecture used by stack, especially useful on Windows
+# arch: i386
+# arch: x86_64
+
+# Extra directories used by stack for building
+# extra-include-dirs: [/path/to/dir]
+# extra-lib-dirs: [/path/to/dir]