DuvetUser Guide

Overview

Duvet is a support library that aids Alien-Factory in the development of other libraries, frameworks and applications. Though you are welcome to use it, you may find features are missing and the documentation incomplete.

Duvet provides a means to inject HTML into you web page after its been rendered, but before it is streamed to the browser.

Duvet also provides a wrapper around RequireJS giving you clean dependency management for your Javascript libraries.

Why Duvet?

Embracing RequireJs and AMD modules is like having an IoC for Javascript; and using it gives you a warm, fuzzy feeling all over!

Install

Install Duvet with the Fantom Repository Manager ( fanr ):

C:\> fanr install -r http://repo.status302.com/fanr/ afDuvet

To use in a Fantom project, add a dependency to build.fan:

depends = ["sys 1.0", ..., "afDuvet 0.0+"]

Documentation

Full API & fandocs are available on the Status302 repository.

Quick Start

1). Create a text file called Example.fan:

using afIoc
using afBedSheet
using afDuvet

class Example {
    @Inject HtmlInjector? injector

    Text duvetExample() {
        // inject meta tags and stylesheets into your HTML
        injector.injectMeta.withName("author").withContent("Fantom-Factory")

        // inject a RequireJS script snippet
        // this ensures all dependencies are loaded before execution
        injector.injectRequireScript(["jquery":"\$"],
            "alert('jQuery v' + \$().jquery);")

        // let Duvet inject all it needs into a plain HTML shell
        return Text.fromHtml(
            "<html><head></head><body><h1>Duvet by Alien-Factory</h1></body></html>"
        )
    }
}

@SubModule { modules=[DuvetModule#] }
class AppModule {
    @Contribute { serviceType=Routes# }
    static Void contributeRoutes(OrderedConfig conf) {
        conf.add(Route(`/`, Example#duvetExample))
    }

    @Contribute { serviceType=ScriptModules# }
    static Void contributeScriptModules(OrderedConfig config) {
        // configure any non-standard AMD modules
        config.add(
            ScriptModule("jquery").atUrl(`//code.jquery.com/jquery-2.1.1.min.js`)
        )
    }
}

class Main {
    Int main() {
        afBedSheet::Main().main([AppModule#.qname, "8080"])
    }
}

2). Run Example.fan as a Fantom script from the command line. This starts the BedSheet app server:

C:\> fan Example.fan
   ___    __                 _____        _
  / _ |  / /_____  _____    / ___/__  ___/ /_________  __ __
 / _  | / // / -_|/ _  /===/ __// _ \/ _/ __/ _  / __|/ // /
/_/ |_|/_//_/\__|/_//_/   /_/   \_,_/__/\__/____/_/   \_, /
          Alien-Factory BedSheet v1.3.10, IoC v1.6.4 /___/

IoC Registry built in 612ms and started up in 104ms

Bed App 'Unknown' listening on http://localhost:8080/

3). Visit http://localhost:8080/

Duvet Example - Screenshot

Usage

HTML Injection

It is good practice to componentise your web pages (something that efanXtra excels at).

Taking an example blog website, on some pages you want to show comments, on others you don't. So you make a Comment Component which you only render on those pages that need it. Like a good self-contained component, it requires it's own stylesheet and some javascript. As you don't want to download them on every page, just the comment pages, you let the component download what it needs.

Q). But how does the component, which is typically rendered at the bottom of the web page, specify what stylesheets should be downloaded in the <head>?
A). Duvet Html Injection.

The HtmlInjector service lets you inject meta, scripts and stylesheets into your HTML. They are injected into either the bottom of the HEAD or the BODY section.

What if you want to render the Comment Component more than once on a single page? You don't want multiple copies of the same stylesheet downloaded on the same page!?

No fear, HtmlInjector silently rejects all stylesheet and script requests for the same URL.

HtmlInjector works by wrapping BedSheet's TextResponseProcessor. All requests for injection are queued up and then, just before the page is streamed to the browser, the HTML tags are injected.

RequireJS

Looking after countless Javascript libraries, ensuring they all get loaded quickly and in the correct order can be a pain. RequireJS, an asynchronous module loader for Javascript, not only eases that pain; but gives you proper dependency management for your libraries.

It's how Javascript should be written!

All your Javascript modules need to be served from the same baseUrl which defaults to `/modules/`, so configure BedSheet's FileHandler to serve these files:

@Contribute { serviceType=FileHandler# }
static Void contributeFileHandler(MappedConfig config) {
    config[`/modules/`] = `etc/web/modules/or/wherever`
}

Now you can use HtmlInjector.injectRequireScript() to inject and run small scripts. The scripts are wrapped up in a require() function call to ensure proper dependency management.

Remember, most of your code should be in modules. The modules should then expose a mini-API (well, return an object!) that you can call with HtmlInjector.injectRequireCall(). This is a handy method that converts all given arguments into JSON.

Module Config

Not all popular Javascript libraries are AMD modules, unfortunately, so these require a little configuration to get working. Configuration is done by contributing ScriptModule instances.

All ScriptModule data map to the RequireJs path and shim config options.

Here's a working example from the Fantom-Factory website:

@Contribute { serviceType=ScriptModules# }
static Void contributeScriptModules(OrderedConfig config) {
    config.add(
        ScriptModule("jquery")
            .atUrl(`//code.jquery.com/jquery-2.1.1.min.js`)
            .fallbackToUrl(`/scripts/jquery-2.1.1.min.js`)
    )
    config.add(
        ScriptModule("bootstrap")
            .atUrl(`/scripts/bootstrap.min.js`)
            .requires("jquery")
    )
}

Release Notes

v0.0.6

Chg: Renamed LinkTagBuilder.fromClientUrl() -> fromLocalUrl() to match BedSheet FileHandler.
Chg: Renamed ScriptTagBuilder.fromClientUrl() -> fromLocalUrl() to match BedSheet FileHandler.

v0.0.4

New: Added DuvetMiddleware to rollback / remove any HTML injections if an Err occurs. This prevents old code being injected into Err pages.
Bug: Could not inject multiple scripts without a src atrribute.

v0.0.2

New: Preview release.