efanXtraUser Guide
Overview
efanXtra
creates managed libraries of reusable Embedded Fantom (efan) components. Influenced by Java's Tapestry 5, it pairs up Fantom classes and efan template files to encapsulate model / view behaviour.
efanXtra
extends afEfan, is powered by Ioc and works great with Slim templates.
efanXtra
excels in a BedSheet web environment, where URLs are automatically mapped to efan components (see Pillow), but is presented here context free for maximum reuse. Think email, code generation, blog posts, etc...
Quick Start
Overdue.efan:
Dear <%= userName %>, It appears the following rented DVDs are overdue: <%= dvds.join(", ") %> Please return them at your convenience. <% app.renderSignOff("The Management") %>
Overdue.fan:
using afIoc using afEfanXtra const mixin Overdue : EfanComponent { // use afIoc services! @Inject abstract DvdService? dvdService // mixin fields can be accessed by the template abstract Str? userName // use lifecycle methods to initialise your components @InitRender Void initRender(Str userName) { this.userName = userName } // mixin methods can be called from the template Str[] dvds() { dvdService.findByName(userName) } }
AppModule.fan:
using afIoc class AppModule { static Void bind(ServiceBinder binder) { binder.bindImpl(DvdService#) } @Contribute { serviceType=EfanLibraries# } static Void contributeEfanLibraries(MappedConfig config) { // contribute all components in the pod as a library named 'app' config["app"] = AppModule#.pod } }
Then to render an efan component:
efanXtra.render(Overdue#, "Mr Smith")
Full example source code available on BitBucket.
Components
An efan component consists of a const mixin
Fantom class and a corresponding efan template file.
efanXtra
does away with efan's ctx
variable and instead lets the template access fields and methods of the component class directly.
Mixins
Component mixins must be const
and extend the EfanComponent mixin.
All fields and methods of the mixin are directly accessible in the template. Components are created by Ioc so feel free to annotate fields with @Inject
just as you would with a service class.
Any non-private method or field in your mixin is visible from your template code.
See Lifecycle Methods to see how to initialise and pass data into your components.
Templates
By default, the template file has the same name as the component (with a .efan
extension) and lives anywhere in a pod resource dir. For example, if you were to create a component called Layout
, you may have the following files:
/fan/components/Layout.fan --> the mixin class /fan/components/Layout.efan --> the template file
For efanXtra
to find your template file, be sure to add /fan/components/
as a resDir
in your build.fan
.
ALIEN-AID: Note resource directories in your
build.fan
are NOT nested. Addingres/
will NOT add/res/components/
-/res/components/
needs to be added separately. Example:
resDirs = [`doc/`, `res/`, `res/components/`]
You can also contribute to EfanTemplateDirectories if you wish to keep template files on the file system. This can be very handy for development.
If you wish the template to have a different name to the Fantom class, you can set an explicit Uri
with the @EfanTemplate facet. Example:
@EfanTemplate { uri=`fan://acmePod/templates/Notice.efan` } const mixin Overdue : EfanComponent { ... }
Libraries
Components are organised by libraries. A library encompasses all components within a pod. To use your efan components, you need add your pod as a library. Do this in your AppModule
:
using afIoc using afEfanXtra class AppModule { @Contribute { serviceType=EfanLibraries# } static Void contributeEfanLibraries(MappedConfig config) { // contribute all components in the same pod as AppModule, as a library called 'app' config["app"] = AppModule#.pod } }
Library classes are automatically added as fields in your components. Library classes contain component render methods. In the Overview example, the library (in a field named app
) would bave 2 render methods, available for use in your templates:
app.renderOverdue(Str userName) app.renderSignOff(Str who)
This allows you to render components from within templates by calling <libName>.render<ComponentName>(...)
. Example:
<% app.renderSignOff("The Management") %>
ALIEN-AID: Library render methods are logged at registry startup so you don't have to remember the method signatures!
Lifecycle Methods
Components can be thought of as having a lifecycle for the duration of their render. Components can be made aware of the lifecycle by annotating callback methods with lifecycle facets. The lifecycle only exists for the duration of the render.
@InitRender
A method annotated with @InitRender will be called before any other. It allows you to initialise and prepare your component for rendering.
The @InitRender
may take any parameters, the signature will be mimicked by the containing library's render method. Example, if your @InitRender
looks like:
const mixin MyComponent : EfanComponent { @InitRender Bool? initRender(Int x, Str y) { ... } }
then the library render method will look like:
Obj? renderMyComponent(Int x, Str y, |->| bodyFunc := null) { ... }
This lets you pass any arguments you want into your components.
@InitRender
methods may return Bool
. If true
, the template is rendered as usual. If false
, then template rendering is skipped.
@BeforeRender
A method annotated with @BeforeRender is invoked after @InitRender
but before any template rendering. It may optionally take a StrBuf
as a parameter, this will hold the contents of the current render buffer.
@BeforeRender
methods may return Bool
. If true
, the template is rendered as usual. If false
, then template rendering is skipped.
@AfterRender
A method annotated with @AfterRender is invoked after the template has rendered. It may optionally take a StrBuf
as a parameter, this will hold the contents of the current render buffer.
@AfterRender
methods may return Bool
. If true
, the template rendering ends. If false
, template rendering is sent back to @BeforeRender
. In this way, simple loops may be set up.
Render Variables
Efan components can store state! Components may be const
and they may be mixins
, but they can still store variables that can be accessed and used by the rendering template. Taking the Overdue component as an example:
using afEfanXtra const mixin Overdue : EfanComponent { abstract Str? userName @InitRender Void initRender(Str userName) { this.userName = userName } }
userName
is a render variable used by the efan template. Before initRender()
is called, all render variables are reset to null
(hence they need to be nullable
). They may then be initialised during initRender()
, and used and / or reset at any other point in the rendering lifecycle.
Note that state is not preserved between different renderings of the component.
Use with Slim
efanXtra
works great with Slim! Just add the following to your AppModule
and efanXtra
will automatically pick up component templates with the extension .slim
:
using afIoc using afSlim using afEfanXtra class AppModule { static Void bind(ServiceBinder binder) { binder.bindImpl(Slim#) } @Contribute { serviceType=EfanTemplateConverters# } internal static Void contributeSlimTemplates(MappedConfig config, Slim slim) { config["slim"] = |File file -> Str| { slim.parseFromFile(file) } } }
Release Notes
v1.0.8
- New:
fandoc
files may be used as efan templates!
v1.0.6
- Chg: Upgraded to afIoc-1.5.0.
- Chg: Upgraded to afIocConfig-1.0.0.
v1.0.4
- Chg:
@InitMethods
may now only returnVoid
orBool
. Throw BedSheet'sReProcessErr
if you wish to perform a different action. - Chg: Multiple components may now share the same template file.
v1.0.2
- Chg: Overhauled API documentation.
- Chg: Tweaked some method signatures with correct nullable types.
v1.0.0
- New: Introduced component lifecycle methods: @InitRender, @BeforeRender & AfterRender.
- New: Added
@Abstract
facet to mark base components. - Chg: Template rendering is held in a single mutable
StrBuf
so it may be manipulated by lifecycle methods. - Chg: Components are now defined by extending
EfanComponent
, not by annotating with a@Component
facet. - Chg: Renamed to
efanXtra
(fromefanExtra
).
v0.0.8
- New: Added
EfanTemplateDirectories
service which scans external directories for efan templates. - New: Compilation err msgs are updated with code hints should a simple component rendering typo be spotted. (ALIEN-AID)
v0.0.6
- New: Fields may be annotated with any facet, not just
@Inject
. Think@Config
!!! - Chg: Updated to efan-1.3.2
- Chg: Better Err msgs if component template not found.
v0.0.4
- New: Component templates can be specified via the
@Component.template
field. - New: Added a contributable
EfanTemplateFinders
service. - New: Ability to suppress startup log messages.
- New: Added compiler hooks (mainly for afPillow).
- New:
efanXtra.component()
returns component instances. - Chg:
@Component
facet is inherited.
v0.0.2
- New: Preview Release