Jetty HTTP/2 client receive server push example

Question

Jetty's HTTP/2 client with server push support has been implemented in Jetty 9.3 RC (Link). However, I have not found any documentation or example code related to this. Could any one provide an example code for example to receive the pushed resource from this site : https://nghttp2.org (public server which has enabled http2 server push)

---UPDATE 1--- I have tried to test this file as sbordet has said. However, after executing this line

mvn compile exec:java

I ran onto this error

[INFO] --- exec-maven-plugin:1.4.0:java (default-cli) @ http2client ---
2015-05-05 01:52:47.808:INFO::com.example.Client.main(): Logging initialized @3096ms
[WARNING]
java.lang.reflect.InvocationTargetException
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:483)
    at org.codehaus.mojo.exec.ExecJavaMojo$1.run(ExecJavaMojo.java:293)
    at java.lang.Thread.run(Thread.java:745)
Caused by: java.util.concurrent.TimeoutException
    at org.eclipse.jetty.util.FuturePromise.get(FuturePromise.java:130)
    at com.example.Client.main(Client.java:55)
    ... 6 more

Here is my pom.xml

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd">
<modelVersion>4.0.0</modelVersion>
<groupId>com.example</groupId>
<artifactId>http2client</artifactId>
<packaging>jar</packaging>
<version>1.0-SNAPSHOT</version>
<name>http2client</name>
<url>http://maven.apache.org</url>
<dependencies>
    <dependency>
        <groupId>org.eclipse.jetty.http2</groupId>
        <artifactId>http2-client</artifactId>
        <version>9.3.0.M2</version>
    </dependency>
    <dependency>
        <groupId>org.mortbay.jetty.alpn</groupId>
        <artifactId>alpn-boot</artifactId>
        <version>8.1.3.v20150130</version>
        <scope>runtime</scope>
    </dependency>
</dependencies>
<build>
    <plugins>
        <plugin>
            <groupId>org.codehaus.mojo</groupId>
            <artifactId>exec-maven-plugin</artifactId>
            <version>1.4.0</version>
            <executions>
                <execution>
                    <goals>
                        <goal>java</goal>
                    </goals>
                </execution>
            </executions>
            <configuration>
                <mainClass>com.example.Client</mainClass>
            </configuration>
        </plugin>
    </plugins>
</build>

And here is my project directory

|-- pom.xml
|-- src
|   `-- main
|       `-- java
|           `-- com
|               `-- example
|                   `-- Client.java
`-- target
    |-- classes
    |   `-- com
    |       `-- example
    |           |-- Client$1.class
    |           `-- Client.class
    `-- maven-status
        `-- maven-compiler-plugin
            `-- compile
                `-- default-compile
                    |-- createdFiles.lst
                    `-- inputFiles.lst

---UPDATE 2---

Changed my pom.xml <build> tag to this: (explicitly use JDK 8 and add -Xbootclasspath to point to the alpn-boot.jar provided by Jetty). I am using Java 8 update 31

<build>
    <plugins>
        <plugin>
            <groupId>org.apache.maven.plugins</groupId>
            <artifactId>maven-compiler-plugin</artifactId>
            <version>3.1</version>
            <configuration>
                <source>1.8</source>
                <target>1.8</target>
            </configuration>
        </plugin>
        <plugin>
            <groupId>org.codehaus.mojo</groupId>
            <artifactId>exec-maven-plugin</artifactId>
            <version>1.4.0</version>
            <executions>
                <execution>
                    <goals>
                        <goal>exec</goal>
                    </goals>
                </execution>
            </executions>
            <configuration>
                <executable>java</executable>
                <arguments>
                    <argument>-Xbootclasspath/p:/path/to/alpn-boot-8.1.3.v20150130.jar</argument>
                    <argument>-classpath</argument>
                    <classpath/>
                    <argument>com.example.Client</argument>
                </arguments>
            </configuration>
        </plugin>
    </plugins>
</build>

After I execute this command:

mvn clean compile exec:exec

I got this error when trying to connect to https://webtide.com/ (the default host in Client.java file)

[INFO] --- exec-maven-plugin:1.4.0:exec (default-cli) @ http2client ---
2015-05-05 13:19:25.499:INFO::main: Logging initialized @153ms
Exception in thread "main" java.util.concurrent.TimeoutException
    at org.eclipse.jetty.util.FuturePromise.get(FuturePromise.java:130)
    at com.example.Client.main(Client.java:55)

And this error when connecting to https://nghttp2.org/

[INFO] --- exec-maven-plugin:1.4.0:exec (default-cli) @ http2client ---
2015-05-05 13:29:12.106:INFO::main: Logging initialized @196ms
Exception in thread "main" java.util.concurrent.TimeoutException
    at java.util.concurrent.Phaser.awaitAdvanceInterruptibly(Phaser.java:800)
    at com.example.Client.main(Client.java:90)

---UPDATE 3---

Take a different approach: When I pull all the master branch of the whole jetty project, and then create an Intellij project at jetty.project/jetty-http2/http2-client then it works for public servers https://webtide.com and https://nghttp2.org . But when I test it on my self-signed certificate http2 server (using nghttp2 + nginx, resided in my virtual machine) then I get this error

2015-05-05 19:05:25.094:INFO::main: Logging initialized @220ms
Exception in thread "main" java.util.concurrent.ExecutionException: java.nio.channels.ClosedChannelException
    at org.eclipse.jetty.util.FuturePromise.get(FuturePromise.java:138)
    at org.eclipse.jetty.http2.client.Client.main(Client.java:55)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:483)
    at com.intellij.rt.execution.application.AppMain.main(AppMain.java:140)
Caused by: java.nio.channels.ClosedChannelException
    at org.eclipse.jetty.http2.HTTP2Flusher.append(HTTP2Flusher.java:110)
    at org.eclipse.jetty.http2.HTTP2Session.frame(HTTP2Session.java:577)
    at org.eclipse.jetty.http2.HTTP2Session.frames(HTTP2Session.java:559)
    at org.eclipse.jetty.http2.client.HTTP2ClientConnectionFactory$HTTP2ClientConnection.onOpen(HTTP2ClientConnectionFactory.java:121)

Answer 1

The link reported in the question presents a HTTP/2 transport for Jetty's HttpClient.

Jetty's HttpClient exposes a generic HTTP API to applications that has to work with HTTP 1.0, 1.1 and 2.0 and as such HttpClient does not expose any API to receive HTTP/2 push resources, since these are a peculiar mechanism of HTTP/2 only.

If you really want to interact with a HTTP/2 API, you can use Jetty's HTTP2Client, which exposes a lower-level API, HTTP/2 specific, to applications.

You can find a full fledged example of connecting to a website that pushes resources (in this case https://webtide.com) here.

Answer 2

Answer for UPDATE 3:

Use another constructor of SslContextFactory, which has a boolean argument trustAll certificates:

SslContextFactory sslContextFactory = new SslContextFactory(true);

The whole code:

HTTP2Client client = new HTTP2Client();
SslContextFactory sslContextFactory = new SslContextFactory();
client.addBean(sslContextFactory);
client.start();