appex

The following sections outline creating appex applications and configuration.

The following code will create a standalone appex application and http server and listen on port 3000.

var appex   = require('appex');
 
var app   = appex({ program : './program.ts', 
                    devmode : true,
                    logging : true });
 
app.listen(3000);

note: devmode and logging are optional. however, when developing with appex, it is helpful to have these enabled.

appex accepts the following start up options.

var options = {
 
    // (required) location of source file.
    program    : './program.ts', 
 
    // (optional) recompile on request. (default:false) 
    devmode    : true,          
 
    // (optional) log to stdout. (default:false) 
    logging    : true,
 
    // (optional) user defined objects added to the app context.
    context    : {}
};
 
var app = appex( options );

The following demonstrates setting up appex on an existing nodejs http server. In this example, appex will attempt to handle incoming requests, and if appex cannot route the request, will fire the callback.

var http  = require('http');
 
var appex = require('appex');
 
var app = appex({ program : './program.ts' });
 
var server = http.createServer(function(req, res){
 
    app(req, res, function() { // appex handler...
        
        // not handled.
 
    }); 
});
 
server.listen(3000);

appex allows developers to augment existing express / connect applications by way of middleware. The following demonstrates setting up appex as express middleware.

var express = require('express');
 
var appex = require('appex');
 
var app = express();
 
app.use( appex({ program : './program.ts' }) ); 
 
app.get('/', function(req, res) {
 
  res.send('Hello World');
  
});
 
app.listen(3000);

Like in the "running on an existing http server" example above, appex will attempt to intercept incoming requests. if appex cannot find a matching route for the request, it will automatically call the "next" function to pass the request on to the next middleware or express handler.

in addition to this, appex may also act as traditional express middleware. In the example below, a appex wildcard function is created which will match "all" incoming requests, the wildcard function simply prints hello world to the console and then calls context.next(), which passes the request on the express handler.

 
//----------------------------------------------
// program.ts
//----------------------------------------------
 
// http:[host]:[port]/(.*)
export function wildcard(context, path) {
 
    console.log('hello world!!');
 
    context.next(); // pass it on!
}
 
//----------------------------------------------
// app.js
//----------------------------------------------
 
var express = require('express');
 
var appex = require('appex');
 
var app = express();
 
app.use( appex({ program : './program.ts' }) );
 
app.get('/', function(req, res) {
 
  res.send('Hello World');
  
});
 
app.listen(3000);

Just like traditional express middleware, appex will also inheriate the characteristics of the request.

consider the following example in which the jade view engine is configured for use. appex will inheritate the response.render() method, which is passed to the appex handler as context.response.render()

//----------------------------------------------
// app.js
//----------------------------------------------
 
app.configure(function(){
 
  app.set('views', __dirname + '/views');
  
  // set up the jade engine.
  app.set('view engine', 'jade'); 
  
  // bind appex
  app.use( appex({program:'./program.ts', devmode:true} ));  
});
 
//----------------------------------------------
// program.ts
//----------------------------------------------
 
// http:[host]:[port]/
export function index(context) {
    
    // jade renderer works!
    context.response.render('index', { title: 'Express' }); 
}

The following sections describe how to create http accessible handlers with appex.

All appex functions are passed a application context object as their first argument. The app context object encapulates the http request and response objects issued by the underlying http server, as well as additional objects specific to appex. These are listed below:

// the app context
export function method(context) {
    
    // context.request    - the http request object.
 
    // context.response   - the http response object.
 
    // context.attribute    - appex attribute.
 
    // context.next       - the next function (express middleware)
    
    // context.router     - the appex router
 
    // context.sitemap    - the appex sitemap api
 
    // context.template   - the appex template engine.
    
    // context.module     - the module being run (this module)
 
    // context.schema     - json schema api.
 
    // context.mime       - a http mime type utility.
}

it is possible to extend the default objects passed on the context by adding them on the appex startup options. The following will attach the async module to the context.

//----------------------------------------------
// app.js
//----------------------------------------------
 
var appex   = require('appex');
 
var app = appex({ program : './program.ts', 
                  devmode : true, 
                  context: {
                        async : require('async')
                  }});
 
app.listen(3000);
 
//----------------------------------------------
// program.ts
//----------------------------------------------
 
export function index(context) {
 
    // context.async = passed on the context.
 
    context.response.send('home page');
}

The appex request is a nodejs http request issued by the underlying node http server. appex extends the request with convenience methods for reading http request data. These are outlined below.

reading a posted string.

//----------------------------------------------
// receive request as a string
//----------------------------------------------
export function submit(context) {
 
    context.request.body.recv((str) => {
 
        // do something with str
    })
}

reading posted form data as json object.

//----------------------------------------------
// receive a form post
//----------------------------------------------
export function submit(context) {
 
    context.request.body.form((obj) => {
 
        // do something with obj
    })
}

reading posted json data as a json object.

//----------------------------------------------
// receive a json post
//----------------------------------------------
export function submit(context) {
 
    context.request.body.json((obj) => {
        
        // do something with obj
    })
}

note: if appex detects that express or connect middleware has already been applied to the request object, appex will use those instead.

The appex response is a nodejs http response issued by the underlying node http server. appex provides some utility methods for writing http responses. These are outlined below.

//----------------------------------------------
// the nodejs response has been extended with the following
// signatures.
//----------------------------------------------
export interface IResponse extends http.ServerResponse {
    
    send (data     : string): void;
 
    send (data     : NodeBuffer): void;
 
    send (status   : number, data : string): void;
 
    serve (filepath: string): void;
 
    serve (root : string, filepath: string): void;
 
    serve (root : string, filepath: string, mime:string): void;
 
    json (obj      : any): void;
 
    json (status   : number, obj : any): void;
 
    jsonp (obj     : any): void;
 
    jsonp (status  : number, obj : any): void;
 
    jsonp (status  : number, obj : any, callback: string): void;
}

note: if appex detects that express or connect middleware has already been applied to for any of the following response methods, appex will use those instead.

appex creates routes based on module scope and function name. consider the following:

export module services.customers {
    
    // url: http://[host]:[port]/services/customers/insert
    export function insert(context) {
 
        context.response.send('services.customers.insert')
    }
    
    // url: http://[host]:[port]/services/customers/update
    export function update(context) { 
        
        context.response.send('services.customers.update')
    }
    
    // url: http://[host]:[port]/services/customers/delete
    export function delete(context) { 
 
        context.response.send('services.customers.delete')
    }
}
 
// url: http://[host]:[port]/
export function index   (context) { 
 
    context.response.send('home page')
}
 
// url: http://[host]:[port]/about
export function about   (context) { 
 
    context.response.send('about page')
}
 
// url: http://[host]:[port]/contact
export function contact (context) { 
 
    context.response.send('contact page')
}
 
// url: http://[host]:[port]/(.*)
export function wildcard (context, path) {
 
    context.response.send(404, path + ' not found')
}
 

appex supports three function signatures for http routing (named, index and wildcard). Functions that do not apply these signatures will not be routed.

Named handlers resolve urls to their current module scope + the name of the function.

Named handlers require the following signature:

• name - 'anything'
• argument[0] - app context
• returns - void (optional)

 
// http://[host]:[port]/about
export function about(context) {
 
    context.response.send('about page');
}
 
// http://[host]:[port]/users/login
export module users {
 
    export function login(context) {
        
        context.response.send('handle login');	
    }
}
 

Index handlers resolve urls to their current module scope.

Index handlers require the following signature:

• name - 'index'
• argument[0] - app context
• returns - void (optional)

// url: http://[host]:[port]/
export function index(context) { 
 
    context.response.send('home page');
}
 
export module blogs {
    
    // url: http://[host]:[port]/blogs
    export function index  (context) 
    {	
        context.response.send('blog index');
    }
}

Wildcard handlers resolve their urls to their current module scope + url.

appex wildcard handlers allow for wildcard routing at a given module scope. Wildcard handlers support 'typed' url argument mapping, as denoted by the arguments annotation.

In addition, wildcard handlers also support optional arguments which can be specified with TypeScript's '?' on argument names.

appex wildcard handlers require the following signature:

• name - 'wildcard'
• argument[0] - app context
• argument[n] - 1 or more arguments to be mapped from the url
• returns - void (optional)

declare var console;
 
export module blogs {
    
    // url : http://[host]:[port]/blogs/2013/1/11   - matched
 
    // url : http://[host]:[port]/blogs/2013/01/11  - matched
 
    // url : http://[host]:[port]/blogs/2013/01/3rd - not matched - (see number annotation)
 
    // url : http://[host]:[port]/blogs/2013/01     - matched     - (see ? annotation)
 
    // url : http://[host]:[port]/blogs/2013        - not matched - (month is required)
    
    export function wildcard(context, year:number, month:number, day?:number) {
 
        context.response.json({ year: year, month: month, day: day})
    }
}
 
// url : http://[host]:[port]/
export function index(context) {
 
    context.response.send('home');
}
 
// url : http://[host]:[port]/(.*) 
export function wildcard(context, path) {
 
    context.response.send(404, 'not found');
}
 

note: appex supports boolean, number, string and any annotations on wildcard arguments. if no annotation is specified, appex interprets the argument as a string. the type 'any' is also interpreted as string.

note: wildcard functions should be declared last in any module scope. this ensures other routes will be matched first.

appex supports a attribute scheme which developers can use to decorate modules and functions with declaritive metadata. appex attributes can set by calling the attribute('qualifier', data) function which is passed to the appex module on the global scope.

unlike traditional attributes (in languages like C sharp) appex attributes have a cascading behaviour which allows developers to apply metadata at a lexical scope, and have it cascade through to descendant scopes.

The following outlines this behavour.

/// <reference path="node_modules/appex/appex.d.ts" />
 
attribute({a: 10}); // global.
 
attribute('foo', {b : 20})
export module foo {
 
    attribute('foo.bar', {c : 30})
    export module bar {
            
        attribute('foo.bar.index', {d : 40})
        export function index(context) {
        
            //context.attribute
            //{
            //    "a": 10,
            //    "b": 20,
            //    "c": 30,
            //    "d": 40
            //}
 
            context.response.json( context.attribute );       
        }
    }
}
 

in addition, appex recognizes three types of attributes. developers can use these to override the default bahavour of the appex router and apply url rewriting (urls), verb matching (verbs) and middleware (use), as demonstrated below.

/// <reference path="node_modules/appex/appex.d.ts" />
 
function logger(context) {
    console.log('logging')
    context.next()
}
 
// invoke 'logger' middleware.
attribute('index', {use   : [logger]})   
 
// override the default route.
attribute('index', {urls  : ['/', '/home']})  
 
// only accept GET requests.
attribute('index', {verbs : ['GET']})    
 
export function index(context:appex.web.IContext) {
    
    context.response.send('home page')
}

appex handles http verb matching with attributes. appex will recognise the 'verbs' property applied to the attribute to match against http verbs.

attribute('index', { verbs: ['GET'] })
export function index (context) { 
        
    // only allow HTTP GET requests
    context.response.send('index')
}
 
attribute('submit', { verbs: ['POST', 'PUT'] })
export function submit (context) { 
    
    // only allow HTTP POST and PUT requests
    context.response.send('submit')
}

developers can rewrite the default route given to exported functions with the 'urls' property applied to the attribute.

attribute('index', { urls: ['/', '/home', 'home.html'] })
export function index (context) { 
    
    context.response.send('index')
}

note: url rewriting is only available on index and named routes.

note: rewriting with regular expressions is currently not supported.

appex supports middleware with attributes. appex middleware defined with attributes allows developers to scope middleware on single functions, or entire module scopes. appex will recognise the 'use' property applied to the attribute to invoke middleware.

the following demonstrates how one might use middleware to secure a site admin.

note: middleware 'must' call next or handle the request.

declare function attribute (qualifier:string, obj:any);
 
declare var console;
 
function authenticate(context) {
 
    console.log('authenticate')
 
    // call next() if authenticated, otherwise, handle the response.
    context.next(); 
}
 
function authorize(context) {
 
    console.log('authorize')
 
    // call next() if authorized, otherwise, handle the response.
    context.next(); 
}
 
// apply security middleware to admin scope.
attribute('admin', {use: [authenticate, authorize]}) 
export module admin {
 
    export function index(context) {
        
        console.log(context.attribute); // view attribute
 
        context.response.send('access granted!')
    }
}
 
// index handler has no middleware applied.
export function index (context) { 
    
    console.log(context.attribute); // view attribute
 
    context.response.send('home')
}

appex will only route functions prefixed with the TypeScript 'export' declarer. This rule also applied to modules. Developers can use this to infer notions of public and private at the http level.

consider the following example:

 
// module is not exported, and is 
// therefore private.
module private_module {
    
    // function is exported, yet private 
    // as a http endpoint due to the 
    // parent module being private.
    export function public_method () { }
    
    // function is not exported, and is 
    // private to this module.
    function private_method() { }
}
 
// function is not exported, and 
// is therefore private.
function private_function() { }
 
// function is exported, and therefore 
// publically accessible.
export function public_function   (context) { 
    
    // this function can invoke 
    // private functions.
    private_function(); // ok
    
    // calling exported method in 
    // private module
    private_module.public_method(); // ok
 
    // calling non exported method 
    // in private module
    // private_module.private_method(); // bad
 
    context.response.send('public_function');
}

Use wildcard functions to catch unhandled routes.

// http:[host]:[port]/
export function index (context) { 
 
    context.response.send('home page');
}
 
// http:[host]:[port]/(.*)
export function wildcard (context, path) {
 
    context.response.send(404, path + ' not found');
}

Use wildcard functions with context.response.serve() to serve static content.

export module static {
    
    // http:[host]:[port]/static/(.*)
    export function wildcard(context, path) {
 
        context.response.serve('./static/', path);
    }
}
 
// http:[host]:[port]/
export function index (context) {
 
    context.response.send('home page');
}
 
// http:[host]:[port]/(.*)
export function wildcard(context, path) {
 
    context.response.send(404, path + ' not found');
}

appex comes bundled with a built in template engine which is modelled on the Microsoft Razor templating engine. The following sections outline its use.

The appex template engine is available to all handlers by default. it is accessible on the context.template property. the following is an example of its use.

//----------------------------------------------
// view.txt
//----------------------------------------------

<ul>
@for(var n in context.users) {

    @if(context.users[n].online) {
            
        <li>@(context.users[n].name)</li>
    }
}
</ul>

//----------------------------------------------
// program.ts
//----------------------------------------------

export function index(context) {
    
    var users = [{name:'dave' , online : true}, 
                 {name:'smith', online : true}, 
                 {name:'jones', online : false}, 
                 {name:'alice', online : true}];

    var text = context.template.render('./view.txt', { users: users });
    
    context.response.headers['Content-Type'] = 'text/html';

    context.response.send(text);
}

each template is passed a data context. this context allows the caller to send data to the template for rendering. the context parameter is optional. the example below is sending the users array to the template context for rendering.

export function index(context) {
    
    var users  = [{name:'dave' , online : true}, 
                 {name:'smith', online : true}, 
                 {name:'jones', online : false}, 
                 {name:'alice', online : true}];

    context.response.send(context.template.render('./view.txt', { users: users }));
}

appex templates support the following statements and syntax

appex templates support template inheritance.

consider the following where layout.txt defines the sections 'header' and 'content' and the view.txt overrides these sections with its own content.

//----------------------------------------------
// layout.txt
//----------------------------------------------

<html>

    <head>
        
        @section header

    </head>

    <body>

        @section content {
        
            <span>some default content</span>
            
        }

    </body>
    
</html>

//----------------------------------------------
// view.txt
//----------------------------------------------

@layout 'layout.txt'

@section header {

    <title>my page</title>
}

@section content {

    <p>overriding the layout.txt content section.</p>

    <ul>
    @for(var n in context.users) {

        @if(context.users[n].online) {
            
            <li>@(context.users[n].name)</li>
        }
    }
    </ul>
}

//----------------------------------------------
// program.ts
//----------------------------------------------

export function index(context) {
    
    var users = [{name:'dave' , online : true}, 
                 {name:'smith', online : true}, 
                 {name:'jones', online : false}, 
                 {name:'alice', online : true}];

    var text = context.template.render('./view.txt', { users: users });

    context.response.send(text);
}

note : when specifying a layout, the view will only render content within the layouts section placeholders.

appex templates also allow for partial views with the @render statment. consider the following which renders the nav.txt file into the layout.txt file.

//----------------------------------------------
// nav.txt
//----------------------------------------------
<ul>
    <li>home</li>
    <li>about</li>
    <li>contact</li>
</ul>

//----------------------------------------------
// layout.txt
//----------------------------------------------

<html>
    <head>
        
        @section header

    </head>

    <body>
        
        @render 'nav.txt'

        @section content {
        
            <span>some default content</span>
            
        }

    </body>
    
</html>

//----------------------------------------------
// view.txt
//----------------------------------------------

@layout 'layout.txt'

@section header {

    <title>my page</title>
}

@section content {

    <p>overriding the layout.txt content section.</p>

    <ul>
    @for(var n in context.users) {

        @if(context.users[n].online) {
            
            <li>@(context.users[n].name)</li>
        }
    }
    </ul>
}

//----------------------------------------------
// program.ts
//----------------------------------------------

export function index(context) {
    
    var users = [{name:'dave' , online : true}, 
                 {name:'smith', online : true}, 
                 {name:'jones', online : false}, 
                 {name:'alice', online : true}];

    var text = context.template.render('./view.txt', { users: users });

    context.response.send(text);
}

appex template content is not cached (the implementor is expected to handle their own caching) however the generated template code is.

appex templates do inheriate the behaviour of the appex 'devmode' option. setting devmode to 'true' will cause template code to be reloaded from disk and code generated with each request. setting devmode to false will load content from disk on first request, and cache the generated template code in memory for the lifetime of the application.

in addition to this, a implementation where the devmode is false can override the caching behaviour with the following.

export function index(context) {
 
    // manually override the template devmode option.
    context.template.option.devmode = true; 
 
    context.response.send(context.template.render('./view.txt'))
}

appex is able to derive sitemap metadata automatically from http endpoints created with typescript modules and functions. This metadata is useful to generate sitemap.xml files, as well as helping to create site navigation links when combined a template engine.

appex sitemaps can be obtained from the context.sitemap property.

export function index(context) {
 
    // return all nodes in this site.
    context.response.json(context.sitemap)
 
}

Additionally, it may be helpful to isolate branches of the sitemap with the context.sitemap.get([qualifier]) function. as demonstrated below.

export module admin {
 
    export function index     (context) { }
 
    export function dashboard (context) { }
 
    export function content   (context) { }
 
    export module users {
 
        export function login(context) { }
 
        export function logout(context) { }
    }
}
 
export function test(context) {
    
    // view all admin sitemap nodes
    context.response.json(context.sitemap.get('admin'))
 
    // view all admin.users sitemap nodes
    //context.response.json(context.sitemap.get('admin.users'))
}

each sitemap node contains the attribute applied to the handler for which the node applies. With this developers can apply custom metadata for a given node. as demonstrated below.

declare var attribute;
 
attribute({website:'http://mysite.com/'}) // global
 
attribute('index', {title:'home page'})
export function index(context) {
 
    context.response.send('index')
}
 
attribute('about', {title: 'about page'})
export function about(context) {
 
    context.response.send('about')
}
 
attribute('sitemap', {title: 'sitemap page'})
export function sitemap(context) {
 
    context.response.json(context.sitemap)
}

visiting /sitemap will output the following.

{
    "name": "sitemap",
    "nodes": [
        {
            "name": "index",
            "urls": [
                "/"
            ],
            "website": "http://mysite.com/",
            "title": "home page"
        },
        {
            "name": "about",
            "urls": [
                "/about"
            ],
            "website": "http://mysite.com/",
            "title": "about page"
        },
        {
            "name": "sitemap",
            "urls": [
                "/sitemap"
            ],
            "website": "http://mysite.com/",
            "title": "sitemap page"
        }
    ]
}