Request.bodyParam() return null and cause stacktrace

Hi ! I cloned your sample tipsy/javalin-kotlin-example to try your technology which I found very interesting !

Explanations

After the repo was cloned, I imported the project on IntelliJ (ultimate edition). I ran the project from the Main.kt class and I tried some of the API routes.

All the routes using the GET method work totally fine but the routes which need to parse the request body trigger a stacktrace in the console and the creation or update is aborted.

Those routes doesn’t work :

• http://localhost:7000/users/create
• http://localhost:7000/users/update/:id

After some debugging, I found that the method bodyParam() in the Request class return null.

Here an example of a request which does not work :

• route: http://localhost:7000/users/create
• method: POST
• body: { "name":"Michel", "email":"[e-mail]" }

When I do println(req.body()) at the top of the method, I get this :

{
	"name": "Michel",
	"email": "[e-mail]"
}

So, the body is well retrieved in the request !

But when I do println("name="+req.bodyParam("name")+", email="+req.bodyParam("email")), I get :

name=null, email=null

Stacktraces

Here the first stacktrace when we use the alias Request.bp(key: String) setted up at the bottom of the Main.kt file :

java.lang.IllegalStateException: this.bodyParam(key) must not be null
	at app.MainKt.bp(Main.kt:59)
	at app.MainKt$main$$inlined$with$lambda$4.handle(Main.kt:28)
	at io.javalin.core.JavalinServlet.service(JavalinServlet.java:62)
	at io.javalin.embeddedserver.jetty.JettyHandler.doHandle(JettyHandler.java:35)
	at org.eclipse.jetty.server.session.SessionHandler.doScope(SessionHandler.java:1568)
	at org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:141)
	at org.eclipse.jetty.server.handler.HandlerWrapper.handle(HandlerWrapper.java:132)
	at org.eclipse.jetty.server.Server.handle(Server.java:564)
	at org.eclipse.jetty.server.HttpChannel.handle(HttpChannel.java:317)
	at org.eclipse.jetty.server.HttpConnection.onFillable(HttpConnection.java:251)
	at org.eclipse.jetty.io.AbstractConnection$ReadCallback.succeeded(AbstractConnection.java:279)
	at org.eclipse.jetty.io.FillInterest.fillable(FillInterest.java:110)
	at org.eclipse.jetty.io.ChannelEndPoint$2.run(ChannelEndPoint.java:124)
	at org.eclipse.jetty.util.thread.Invocable.invokePreferred(Invocable.java:128)
	at org.eclipse.jetty.util.thread.Invocable$InvocableExecutor.invoke(Invocable.java:222)
	at org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.doProduce(EatWhatYouKill.java:294)
	at org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.run(EatWhatYouKill.java:199)
	at org.eclipse.jetty.util.thread.QueuedThreadPool.runJob(QueuedThreadPool.java:672)
	at org.eclipse.jetty.util.thread.QueuedThreadPool$2.run(QueuedThreadPool.java:590)
	at java.lang.Thread.run(Thread.java:745)

Then, this is the stacktrace when we use the bodyParam() method :

java.lang.IllegalStateException: req.bodyParam("name") must not be null
	at app.MainKt$main$$inlined$with$lambda$4.handle(Main.kt:28)
	at io.javalin.core.JavalinServlet.service(JavalinServlet.java:62)
	at io.javalin.embeddedserver.jetty.JettyHandler.doHandle(JettyHandler.java:35)
	at org.eclipse.jetty.server.session.SessionHandler.doScope(SessionHandler.java:1568)
	at org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:141)
	at org.eclipse.jetty.server.handler.HandlerWrapper.handle(HandlerWrapper.java:132)
	at org.eclipse.jetty.server.Server.handle(Server.java:564)
	at org.eclipse.jetty.server.HttpChannel.handle(HttpChannel.java:317)
	at org.eclipse.jetty.server.HttpConnection.onFillable(HttpConnection.java:251)
	at org.eclipse.jetty.io.AbstractConnection$ReadCallback.succeeded(AbstractConnection.java:279)
	at org.eclipse.jetty.io.FillInterest.fillable(FillInterest.java:110)
	at org.eclipse.jetty.io.ChannelEndPoint$2.run(ChannelEndPoint.java:124)
	at org.eclipse.jetty.util.thread.Invocable.invokePreferred(Invocable.java:128)
	at org.eclipse.jetty.util.thread.Invocable$InvocableExecutor.invoke(Invocable.java:222)
	at org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.doProduce(EatWhatYouKill.java:294)
	at org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.run(EatWhatYouKill.java:199)
	at org.eclipse.jetty.util.thread.QueuedThreadPool.runJob(QueuedThreadPool.java:672)
	at org.eclipse.jetty.util.thread.QueuedThreadPool$2.run(QueuedThreadPool.java:590)
	at java.lang.Thread.run(Thread.java:745)

[SylvainMarty]

Okay nice work ! I’ll try to use Javalin with a database later to compare it with Spring MVC ! Good continuation on the project 😉

[tipsy]

Javalin has an optional dependency on Jackson to do req.bodyAsClass() and res.json(). In this specific example I’m using jackson-kotlin:

<dependency>
    <groupId>com.fasterxml.jackson.module</groupId>
    <artifactId>jackson-module-kotlin</artifactId>
    <version>2.8.4</version>
</dependency>