short-url

A Servant and Persitent backend that handles shortening of URLS.

The template servant-persistent is used to get some nice logs and abstraction for testing.

This version has been updated to work on ghc 8.10.4 and all the libraries were updated too, which was... fun 😅 (view Painpoints for more details)

Requirements:

Nix

Having nix installed will help with getting the right versions of ghc and the tooling.

Install nix -> nix-shell and et voila all built for you and ready to go. (The caveat is installing nix might not be that straight forward)

Haskell

You can use cabal to build the server:

2. > cabal install --dependencies-only && cabal configure && cabal build
3. > cabal run shorturl

Database:

You will require 2 postgres database named: shorturl + shorturltest <- this is used for the tests

you will also need a user test with the password wait for it test! make sure to give access to both dbs.

Developement

If you are using the nix the repo will install the correct version of the haskell language server.

alternatingly you can run the app inside GHCi by:

> ghci
> :l DevelMain
> DevelMain.update
> DevelMain.shutdown

There is more information about this approach, on the wiki: https://github.com/yesodweb/yesod/wiki/ghci

Test

Running the tests will require the second database a pre mentioned called shorturltest Then to run the tests simply: > cabal run tests

Api

• GET /${short} will redirect with a 301, to attached original long url
• POST /shorten with JSON like { "url": "String"} if succesfull it will return a 200 with some JSON {"long": "String", short: "String" }

Using the API from the command line

# generate a short link
> curl --verbose --request POST --header "Content-Type: application/json" \
    --data '{"url": "custom url"}' \
	http://localhost:8081/shorten

# redirect a
> curl --verbose --request GET --header "Content-Type: application/json" \
	http://localhost:8081/${short}

Visual representation

Painpoints

Upgrading the project wasn't as straight forward as expected, there was a lot of blockers with clashing libraries and missing functions etc.

Creating a custom Verb for doing the redirection.

Remembering/learning how Servant + Persistent worked and changing all that to fit it to my requiements

Getting the tests to check things properlly, though they are not fully done as the quickcheck/unit tests don't do anything exiting!