Exemplary real world application built with Haskell + Yesod

License: BSD 3-Clause "New" or "Revised" License

Emacs Lisp 0.24% Haskell 99.76%

haskell yesod rest-api crud jwt realworld-backend haskell-application

haskell-yesod-realworld-example-app's Introduction

Haskell/Yesod codebase containing real world examples (CRUD, auth, advanced patterns, etc) that adheres to the RealWorld spec and API.

How it works

Check out this post for an overview of project's dependencies and its structure.

Getting started

Haskell Setup

If you haven't already, install Stack
- On POSIX systems, this is usually curl -sSL https://get.haskellstack.org/ | sh
Install the yesod command line tool: stack install yesod-bin --install-ghc
Build libraries: stack build

If you have trouble, refer to the Yesod Quickstart guide for additional detail.

Development

Start a development server with:

export JWT_SECRET="some secret value"
stack exec -- yesod devel

As your code changes, your site will be automatically be recompiled and redeployed to localhost.

Tests

stack test --flag app:library-only --flag app:dev

(Because yesod devel passes the library-only and dev flags, matching those flags means you don't need to recompile between tests and development, and it disables optimization to speed up your test compile times).

Documentation

Read the Yesod Book online for free
Check Stackage for documentation on the packages in your LTS Haskell version, or search it using Hoogle. Tip: Your LTS version is in your stack.yaml file.
For local documentation, use:
- stack haddock --open to generate Haddock documentation for your dependencies, and open that documentation in a browser
- stack hoogle <function, module or type signature> to generate a Hoogle database and search for your query
The Yesod cookbook has sample code for various needs

Getting Help

Ask questions on Stack Overflow, using the Yesod or Haskell tags
Ask the Yesod Google Group
There are several chatrooms you can ask for help:
- For IRC, try Freenode#yesod and Freenode#haskell
- Functional Programming Slack, in the #haskell, #haskell-beginners, or #yesod channels.

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haskell-yesod-realworld-example-app's Issues

json data `createdAt` and `updatedAt` is not compliant with API's iso-8601 date format

running Api provided run-api-tests.sh script and got AssertionError for the date format.
I guess this is the related aeson issue: haskell/aeson#620

Better error reporting when `JWT_SECRET` is missing

I forgot to follow the full instructions and did not set JWT_SECRET and got an infinite loop when running Yesod and was mystified for a long time before I figured out it was because I did not set JWT_SECRET. Could this app check for the missing environment variable and report that?

$ stack exec -- yesod devel
...
Starting devel application
devel.hs: Could not convert to expected type: expected Text, encountered Null
CallStack (from HasCallStack):
  error, called at src/Data/Yaml/Config.hs:201:20 in yaml-0.11.0.0-GAWf3vpOhGMK7o9d6zMyJu:Data.Yaml.Config
Unexpected: child process exited with ExitFailure 1
Trying again
Starting devel application
devel.hs: Could not convert to expected type: expected Text, encountered Null
CallStack (from HasCallStack):
  error, called at src/Data/Yaml/Config.hs:201:20 in yaml-0.11.0.0-GAWf3vpOhGMK7o9d6zMyJu:Data.Yaml.Config
Unexpected: child process exited with ExitFailure 1
Trying again
Starting devel application
devel.hs: Could not convert to expected type: expected Text, encountered Null
CallStack (from HasCallStack):
  error, called at src/Data/Yaml/Config.hs:201:20 in yaml-0.11.0.0-GAWf3vpOhGMK7o9d6zMyJu:Data.Yaml.Config
Unexpected: child process exited with ExitFailure 1
Trying again

Set the "JWT_SECRET" environment variable

Hitting this error:

> export JWT_SECRET="some secret value"
> yesod devel
Success! Waiting for next file change.
Type help for available commands. Press enter to force a rebuild.
Starting devel application
devel.hs: Set the "JWT_SECRET" environment variable
Unexpected: child process exited with ExitFailure 1

If relevant, I did slightly modify the stack.yaml for use with Nix:

resolver: lts-14.25
packages:
- .
extra-deps:
- esqueleto-2.6.0
- jwt-0.9.0

install-ghc: false
system-ghc: true

nix:
  enable: true
  packages: [glpk, pcre, zlib]

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