February 26, 2015

Awesome Asciidoctor: Change Start Number for Numbered List

With Asciidoctor we can create numbered lists easily. When we want to change the number the list starts with we use the start attribute when we define the list.

== Numbered List

. Makes writing easy
.. Keep focus
.. Syntax
. Different output formats

// Start this list from 10.
.Start from 10
. Makes writing easy
// We can use it on all levels.
.. Keep focus
.. Syntax
. Different output formats

We get the following HTML output when we transform the document:

Written with Asciidoctor 1.5.2.

February 25, 2015

Awesome Asciidoctor: Customize How Missing Attributes Are Handled

Document attributes are like variables for your Asciidoctor document. Normally when we reference an attribute that is not set in our Asciidoctor markup the reference is still in the output. This is very handy, because we immediately see that a document attribute is not set. But we can customize this behavior with the document attribute attribute-missing. We can use the default value skip, which leaves the reference in the output. Another option is drop, which means the reference is dropped from the output. Finally we can set the value to drop-line, where the complete line with the attribute reference is dropped from the output.

In the following sample Asciidoctor markup we set the three values for the attribute attribute-missing:

== Handle Missing Attributes

:attribute-missing: skip

.`:attribute-missing: skip`
Line with attribute {sample-attr}, should show attribute reference.

:attribute-missing: drop

.`:attribute-missing: drop`
Line with attribute {sample-attr}, drops attribute reference.

:attribute-missing: drop-line

.`:attribute-missing: drop-line`
Line with attribute {sample-attr}, is completely dropped.

When we transform this to HTML5 we get the following output:

Written with Asciidoctor 1.5.2.

February 19, 2015

Groovy Goodness: Access XML-RPC API

Recently I had to access the XML-RPC WordPress API for a small project. Luckily with Groovy we can access a XML-RPC server in a Groovy way. We need to use the Groovy XML-RPC module, which is a separate dependency. The module provides code to write a XML-RPC server, but also code to access a XML-RPC server as client. We use the class XMLRPCServerProxy in the package groovy.net.xmlrpc to act as a client to a XML-RPC API. The XMLRPCServerProxy class only needs to know the URL to access the API. All API methods are dynamically dispatched to the server, so it is very flexible.

In the following Groovy script we use the WordPress XML-RPC API to access posts:

import groovy.net.xmlrpc.*

// Use correct blog identifier.
def blogId = 0 

// Use correct URL for XML-RPC API.
def blogUrl = 'http://blog/xmlrpc' 

def blogUsername = 'mrhaki'
def blogPassword = 'secret'

// Create client access for XML-RPC API.
// The second parameter is set to true
// to autodetect encoding. Default encoding
// is ISO-8859-1.
def wordPress = new XMLRPCServerProxy(blogUrl, true)

// Now we can access the API methods from WordPress.
// Notice the API method wp.getPosts is dynamically
// available from the XMLRPCServerProxy instance.
def latestFivePost = 
             [number: 5, post_type: 'post'],
             ['post_id', 'post_title'])

latestFivePosts.each { post ->
    println "Blog post (#${post.post_id}): ${post.post_title}"

Written with Groovy 2.4.

February 6, 2015

Spocklight: Capture and Assert System Output

Spock supports JUnit rules out of the box. We simply add a rule with the @Rule annotation to our Spock specification and the rule can be used just like in a JUnit test. The Spring Boot project contains a JUnit rule OutputCapture to capture the output of System.out and System.err.

In the following example specification we apply the OutputCapture rule and use it in two feature methods:

package com.mrhaki.spock

import spock.lang.*

import org.springframework.boot.test.OutputCapture

class CaptureOutputSpec extends Specification {

    OutputCapture capture = new OutputCapture()

    def "capture output print method"() {
        print 'Groovy rocks'

        capture.toString() == 'Groovy rocks'

    def "banner text must contain given messagen and fixed header"() {
        final Banner banner = new Banner(message: 'Spock is gr8!')


        final List lines = capture.toString().tokenize(System.properties['line.separator'])
        lines.first() == '*** Message ***'
        lines.last()  == ' Spock is gr8! '


 * Class under test. The print method
 * uses println statements to display
 * some message on the console.
class Banner {

    String message 

    void print() {
        println ' Message '.center(15, '*')
        println message.center(15)


Written with Spock-0.7-groovy-2.0.