A simple tool for lazily bootstrapping any nodejs app into each application context.
Basic Usage
contextualize creates an http server for you and provides a mechanism for defining the context for each request, and a mechanism
for bootstrapping an application for each unique context.
var contextualize =require('contextualize');
contextualize()
.context(function(request,done){
// Set the context for this request
done(null,{ foo:'bar'});
})
.bootstrap(function(context,done){
// Bootstrap an application for a context
done(null,function(req,res){
res.end('Hello World');
});
})
.listen(80);
Practical Use
Here is an example of how you might switch contexts based on environment and locale code in the host name:
contextualize()
.context(function(request,done){
// Extract the environment and locale code from the host name (e.g. prod.en-US.foobar.com)
var m =request.host.match(/^(\w+)\.([a-z]{2}-[A-Z]{2})\./);
// Return the context
done(null,{
environment: m[1],
locale: m[2]
});
})
.bootstrap(function(context,done){
// Bootstrap an application for each unique context
done(null,newApplication(context));
})
.listen(80);
Preloading Contexts at Startup
By default the first request in a context will take the hit of bootstrapping the application for that context. If you want to
preload known contexts to avoid that latency on the first request then you can use the preload method:
contextualize()
.context(getContext)
.bootstrap(bootstrapApp)
.preload([{
locale:'en-US',
environment:'prod'
},{
locale:'pt-BR',
environment:'prod'
}])
.listen(80);
Pre-Context Switch Middleware
You may want to apply some middleware (e.g. static file serving, cookie parsing, body parsing, user authentication, etc.) prior
to setting the context for a request.
contextualize()
// Attach middleware here
.use(staticMiddleware('./public','./static'))
.use(authMiddleware())
.context(function(request,done){
// Use result of authentication middleware in the context
done(null,{
authorized:request.authorized,
});
})
.bootstrap(function(context,done){
// Bootstrap seperate apps for logged in or not logged in users