, _
/ _, _ / _/ _, / ) _ _,
(__ (/ //) () (/ (/ (__ //)_)
developer friendly :: type safe :: performant
Rationale
LambdaCms is a set of packaged libraries —containing subsites for the
Yesod application framework— which allow rapid
development of robust and highly performant websites with content management
functionality.
The lambdacms-* packages each provide some functionality and can depend
on eachother as they depend on other packages.
The only mandatory package is lambdacms-core (this package), it provides
functionality that all other lambdacms-* packages depend on.
As mentioned, each lambdacms-* package contains a subsite which is
"mounted" in a standard Yesod application, which we will refer to as
"the base application" or simply "base".
Before a packaged subsite can be mounted, the package needs to be
included as a dependency to the base app's .cabal file. After that
some glue code needs to be added to the base app, as explained below.
In the base app we have to:
- configure a database connection,
- organize the admin backend's menu,
- specify the authentication strategies for admins, and
- define admin user roles and their permissions.
In the base app we optionally may also:
- override default behavior,
- override UI texts,
- provide a means to send email notifications, and last but not least,
- write the themes so the website can actually be visited (recommended).
Setting up a site with LambdaCms
This section walk through the steps of setting up a site with LambdaCms.
NOTE: We're currently in the process using
stack, and upgrading to
GHC 7.10. This means we will use Stackage's nightly-2015-07-09 package
set until LTS 3 is released.
Prerequisites
You need to be reasonably acquinted with Haskell in order to follow
along with this guide. To learn basic Haskell skills we recommend
Brent Yorgey's excellent
Introduction to Haskell
course.
Besides Haskell you need to be somewhat familliar with:
- the web technologies (HTTP, HTML, CSS, JS, REST),
- RDBMS/SQL (LambdaCms makes use of a relational database), and
- the Yesod web application framework (for which an
- awesome book exists).
Non-Haskell dependencies
For the connection with the database, Haskell libraries typically compile
against non-Haskell libraries. One of the following libraries needs to be
available:
-
For Postgres:
- Debian/Ubuntu:
libpq-dev
- CentOS/Fedora/RHEL:
postgresql-devel
- Homebrew (OSX):
postgres
-
For Mysql:
- Debian/Ubuntu:
libmysqlclient-dev
- CentOS/Fedora/RHEL:
mysql-devel
- Homebrew (OSX):
mysql
-
For Sqlite
- Debian/Ubuntu:
libsqlite3-dev
- CentOS/Fedora/RHEL:
sqlite-devel
- Homebrew (OSX):
sqlite
On other platforms these packages might have different names, but are
most likely available.
If you are going to use a database other than Sqlite (which directly writes
to a file), you need to have a database accessible from where you run your
site. This means you might have to install and setup a database server locally.
Create a project folder
Choose a name for your project. In below we choose mysite, which you
probably want to change. Make sure to choose a valid unix file name
to avoid naming issues. Now create a directory for your project and
cd into it, by running the following commands:
export PROJECT_NAME=mysite; mkdir $PROJECT_NAME; cd $PROJECT_NAME
Initializing the base application
First we need to install the yesod command, this command requires a
lot of dependent packages to be downloaded and build (may a while).
stack install yesod-bin --resolver nightly-2015-07-09
With the following command you create a "scaffolded" Yesod application.
The command is interactive; you need to supply some configuration values.
Pick the database of your choice, and choose a project name:
yesod init -n $PROJECT_NAME --bare
If you have chosen a database other than Sqlite, you need to create a
database and a sufficiently priviledged database user, and set these
credentials in the config/setting.yml file.
Now we will create a stack.yaml file for this project which specifies
the nightly snapshot we would like to use.
stack init --resolver nightly-2015-07-09
NOTE: This command complains that the some version constraints in
the $PROJECT_NAME.cabal file are too strict. Please raise the
upper bounds of these dependencies manually. This step may be
removed once LTS 3 is out.
This installs all dependencies and builds the scaffoled application
(may take a while):
stack install
When you experience problems during builds, while using LTS 3.x,
we consider this a bug. Please
raise an issue.
Testing your Yesod app
The following commands will run your scaffolded Yesdo application
in development mode.
yesod devel
Now test it by pointing the browser to:
http://localhost:3000
If all went well you are ready to add LambdaCms to your app.
Patching a freshly init'ed Yesod app to use lambdacms-core
To add lambdacms-core to a freshly initialized Yesod application a number
of files need to be edited. We have prepared a patch-set to simplify this
process into a couple of commands.
First we need to download the patches by cloning the repository, we do so in
/tmp. Then we apply the patches with the good old patch command.
Run the following from the root of your newly created Yesod project:
(cd /tmp; git clone https://github.com/lambdacms/lambdacms-patches.git)
patch -p1 < /tmp/lambdacms-patches/all_patches_combined.patch
Because the cabal file has a different name for each project
(i.e. $PROJECT_NAME.cabal) the patch command will notice a patched file
is missing (we named it project_name.cabal).
When the patch command tries to patch this file you will be prompted for
the name of your projects cabal file, after providing the name it will
successfully complete patching.
Alternatives to the patch set
There are two alternatives to using the patch set:
- Patch files individually, how to do so is explained in the
lambdacms-patches
README.
- Follow the Getting Started Manually
guide on the wiki.
By default the application uses Mozilla's Persona
to log in: the email address used to log in need to be registered with Persona.
It is recommended to use an email address of a Persona account for
development as it simplifies logging in during development.
Edit config/settings.yml to insert a valid email address.
admin: "_env:LAMBDACMS_ADMIN:<email address>"
Replace <email address> with the email address of an initial administrator
or developer, so the admin inteface can be accessed.
Enjoy!
After applying the patches lambdacms-core is installed in your Yesod application.
Run stack install again to rebuild the project with the patches.
Start the development server, which automatically recompiles when files
have changed.
yesod devel
Point your browser to
http://localhost:3000/admin and you will be
prompted to login. The setup as described above has selected Mozilla's
Persona as the only means of authentication. In config/settings.yml
you have provided an email address for the admin user that is created
if no users exist. If this email address is known to Mozilla Persona
then you can procede to log in.
Add LambdaCms "extensions" to your base application
LambdaCms' extension system is one of its core strengths:
it allows a developer to extend the site with packages while ensuring
full type safety.
Please refer to lambdacms-media's README
for installation instructions. It also explains how other LambdaCms extensions
may incorporate media items managed by the lambdacms-media extension.
Creating your own extensions
In order to make the code base of your website as modular as possible,
we recommend packaging functionality into LambdaCms extensions.
This allows functionality to be shared as a library.
Since this takes a bit of boiler plate, we have released a well documented
extension scaffold script
that should get you started.
License
All code in this repository is released under the MIT license, as specified
in the LICENSE file.
