Use a proper user agent header

acme4j-client/pom.xml

@@ -28,6 +28,18 @@
     <name>acme4j Client</name>
     <description>ACME client for Java</description>
 
+    <build>
+        <resources>
+            <resource>
+                <directory>src/main/resources</directory>
+            </resource>
+            <resource>
+                <directory>src/main/resources-filtered</directory>
+                <filtering>true</filtering>
+            </resource>
+        </resources>
+    </build>
+
     <dependencies>
         <dependency>
             <groupId>org.bitbucket.b_c</groupId>

acme4j-client/src/main/java/org/shredzone/acme4j/connector/HttpConnector.java

@@ -16,6 +16,7 @@ package org.shredzone.acme4j.connector;
 import java.io.IOException;
 import java.net.HttpURLConnection;
 import java.net.URI;
+import java.util.Properties;
 
 /**
  * A generic HTTP connector. It connects to the given URI with a 10 seconds connection and
@@ -27,6 +28,22 @@ import java.net.URI;
 public class HttpConnector {
 
     private static final int TIMEOUT = 10000;
+    private static final String USER_AGENT;
+
+    static {
+        StringBuilder agent = new StringBuilder("acme4j");
+        try {
+            Properties prop = new Properties();
+            prop.load(HttpConnector.class.getResourceAsStream("/org/shredzone/acme4j/version.properties"));
+            agent.append('/').append(prop.getProperty("version"));
+        } catch (IOException ex) {
+            // Ignore, just don't use a version
+        }
+
+        agent.append(" Java/").append(System.getProperty("java.version"));
+
+        USER_AGENT = agent.toString();
+    }
 
     /**
      * Opens a {@link HttpURLConnection} to the given {@link URI}.
@@ -40,7 +57,7 @@ public class HttpConnector {
         conn.setConnectTimeout(TIMEOUT);
         conn.setReadTimeout(TIMEOUT);
         conn.setUseCaches(false);
-        conn.setRequestProperty("User-Agent", "acme4j");
+        conn.setRequestProperty("User-Agent", USER_AGENT);
         return conn;
     }
 

acme4j-client/src/main/resources-filtered/org/shredzone/acme4j/version.properties

@@ -0,0 +1 @@
+version=${project.version}