Javalin: Rewrite configuration setup

[tipsy]

I've been playing around a bit with configuration: https://github.com/tipsy/javalin/pull/507

The general idea is to move away from app.enabledXyz methods, and to reduce the amount of methods on the Javalin class:

val app = Javalin.create().config { c ->
    c.contextPath = "/"
    c.caseSensitiveUrls = false
    c.devLogging = true
    c.requestLogger { ctx, ms ->
        println("${ctx.method()} ${ctx.path()}, took $ms}")
    }
    c.server { Server() }
    c.addStaticFiles("/public")
    c.addSinglePageHandler("/", "/public/subpage/index.html")
}.start()

Any thoughts?

[fwgreen]

This is a great idea! Maybe this could lead to having the option of using external config files?

[tipsy]

@fwgreen The idea is to make it easier to configure Javalin via config files at least, but I wasn't planning on having an official "Javalin Config File" concept. When you configure your apps, do you usually have more than one config file?

[fwgreen]

When I use Javalin, the only config file in my project is my persistence stuff. My little projects are not sophisticated enough to require configuration management. I only just suggested a possible future direction as it occurred to me that if one wanted to, for some reason, alter the port number after deployment, they couldn't without going back into the code. I wasn't thinking of anything as comprehensive as Spring 😄. Maybe you can add it to the 4.0 wishlist?

[tipsy]

You definitely can already use config files now, this is how I configure my projects:

object Config {
    val port = ProcessBuilder().environment()["PORT"]?.toInt() ?: 7070 // use port 7070 for localhost
    val isLocalhost = port == 7070
    val resourcePath = if (isLocalhost) "src/main/resources/public" else "/public"
    val resourceLocation = if (isLocalhost) Location.EXTERNAL else Location.CLASSPATH
    val secrets = JavalinJson.fromJson(Util.readResource("/deploy/secrets.json"), Secrets::class.java)
}

data class Secrets(
    val sendgridApiKey: String,
    val pagerdutyApiKey: String,
    val basicAuthPassword: String,
    val githubBot: String,
    val githubToken: String
)

... 

val app = Javalin.create().apply {
    enableStaticFiles(Config.resourcePath, Config.resourceLocation)
}.start(Config.port)

I'm reluctant to add a custom format, since then users will end up with more than 1 config file.

[fwgreen]

Wow! This library just keeps getting better: You've thought of everything. Could you please add some more documentation about this feature. I would love to be able to manage my app's port number or it's logging level from a config.json file.

[tipsy]

It's not really a feature of Javalin, it's reading a file and mapping it to a Kotlin/Java object. I see that a lot of people are confused about this, so I can write a tutorial after Javalin 3 is done.

[tipsy]

In #517 I split Javalin in to three classes. Config could look like this:

val app = Javalin.create().configureServer{ server ->
    server.contextPath = "/"
    server.caseSensitiveUrls = false
    server.server { Server() }
}.configureServlet { servlet ->
    servlet.devLogging = true
    servlet.requestLogger { ctx, ms ->
        println("${ctx.method()} ${ctx.path()}, took $ms}")
    }
    servlet.addStaticFiles("/public")
    servlet.addSinglePageHandler("/", "/public/subpage/index.html")
}.start(0)

[tipsy]

Alternative:

val app = Javalin.create().configure { server, servlet ->
    server.contextPath = "/"
    server.caseSensitiveUrls = false
    server.server { Server() }
    servlet.devLogging = true
    servlet.requestLogger { ctx, ms ->
        println("${ctx.method()} ${ctx.path()}, took $ms}")
    }
    servlet.addStaticFiles("/public")
    servlet.addSinglePageHandler("/", "/public/subpage/index.html")
}.start(0)

[tipsy]

PR up now: https://github.com/tipsy/javalin/pull/534