ahem
hapi plugins as libraries
Lead Maintainer - Devin Ivy
Usage
See also the API Reference
Note
Ahem is intended for use with hapi v17+ and nodejs v10+. Ensure you've installed @hapi/hapi within your project.
Ahem's purpose is to encourage new possibilites for hapi plugin composition and portability. It's a small tool that offers only subtly different functionality from glue; but unlike glue, ahem's API is designed to strongly reinforce the perspective of hapi plugins as being instantiable general-purpose libraries, and not just web servers.
Ahem has applications in building non-server projects using hapi, creating servers with multiple connections, safely sharing functionality across plugins, and testing hapi plugins (particularly complex application plugins that use schwifty models or schmervice services). Finally, ahem is compatible with schmervice, and plugins can be used as services under schmervice. We think the collection of examples below should help to illustrate.
Examples
Treat vision as a library
The most basic usage of ahem is to instance a plugin with some plugin options. Here we treat vision as an adapter-based templating library rather than as a hapi plugin.
// npm install ahem @hapi/hapi @hapi/vision handlebarsconst Vision = ;const Handlebars = ;const Ahem = ; // Before continuing, create a template:// mkdir templates && echo 'Hello, {{name}}!' > templates/hello.hbs async { const vision = await Ahem; const message = await vision; console; // Hello, Clarice!};
Instantiate your application with its dependencies
If your application has external plugin dependencies then you can specify those using the register
option.
// npm install ahem @hapi/hapi schwifty knex sqlite3const Schwifty = ;const Ahem = ;const App = ; // Below assumes your application plugin// uses schwifty and has an objection Users model. async { const app = await Ahem; const Users = app; const paldo = await Users; console;};
Instantiate your application, controlled by a server
You might want to use one of your application plugins within a separate hapi project or deployment. In this case you usually want the instance of your application to be "tied" to the lifecycle of the primary hapi server of that project: when you initialize/start/stop the primary server you would like your application instance to do the same. In hapi jargon you want your application to be "controlled" by that server (see server.control()
for more info). Ahem can take care of this for you, if you simply provide the primary server as an argument.
// npm install ahem @hapi/hapiconst Hapi = ;const Ahem = ;const App = ; async { const server = Hapi; const app = await Ahem; // app is not yet initialized await server; // app is now initialized too await server; // app is now stopped too};
Using ahem as a plugin for controlled usage
Ahem can also be used as a plugin, e.g. for repeated "controlled" usage by the same server. This style emphasizes the relationship between hapi's plugin registration with server.register()
versus ahem's plugin instancing: the former has a major effect on server
and the latter does not. An equivalent way to write the above example using ahem as a plugin would look like this.
// npm install ahem @hapi/hapiconst Hapi = ;const Ahem = ;const App = ; async { const server = Hapi; await server; const app = await server; // app is not yet initialized await server; // app is now initialized too await server; // app is now stopped too};
Treat vision as a service
Schmervice recognizes hapi plugin instances as valid services, which means that you can register an instance created by ahem with schmervice without any friction. Schmervice will use the name of the plugin (i.e. it's name
attribute) as the service's name by default. You can specify a different name using Schmervice.withName()
if desired.
// npm install ahem schmervice @hapi/hapi @hapi/vision handlebarsconst Hapi = ;const Vision = ;const Handlebars = ;const Schmervice = ;const Ahem = ; // Before continuing, create a template:// mkdir templates && echo 'Hello, {{name}}!' > templates/hello.hbs async { const server = Hapi; await server; const vision = await Ahem server; const vision: templatingService = server; const message = await templatingService; console; // Hello, Clarice!};
Deploy a server with many connections
In hapi v17 hapi dropped support for multiple connections. Ahem offers a convenient way to reintroduce multiple connections to your project. Below we demonstrate the use-case of redirecting HTTP to HTTPS in a single process using the server
option to specify a port. Note that this is another example of "controlled" usage similar to this example above.
// npm install ahem @hapi/hapi hapi-require-httpsconst Fs = ;const Hapi = ;const Ahem = ;const RequireHttps = ;const App = ; // Note, the example below utilizes ports 80 and 443 which// typically require special privileges. It's more common// to deploy node behind a reverse proxy in production. async { const server = Hapi; await server; await Ahem; await serverstart; console;};
Instance vision as a factory
Ahem offers an additional style for wrapping hapi plugins into a library: you can turn a plugin into a factory for an instance using Ahem.toFactory(plugin)
.
// npm install ahem @hapi/hapi @hapi/vision handlebarsconst Vision = ;const Handlebars = ;const Ahem = ; // Before continuing, create a template:// mkdir templates && echo 'Hello, {{name}}!' > templates/hello.hbs async { const createVision = Ahem; const vision = await ; const message = await vision; console; // Hello, Clarice!};
Advanced usage
Ahem has a handful of other options that can be used too. Check out the API Reference for more info.
// npm install ahem @hapi/hapi @hapi/vision handlebarsconst Vision = ;const Handlebars = ;const Ahem = ; // Before continuing, create a template:// mkdir templates && echo 'Hello, {{name}}!' > templates/hello.hbs async { const server = Hapi; await Ahem; const message = await server; console; // Hello, Clarice!};