Category: Howto


#Databricks v.s. Zeppelin This article is about data exploration and two of the main tools that are currently available on the market, Databricks community and Apache Zeppelin Both Zeppelin and Databricks provide a similar interface to explore your data. #Data exploration In the world of Big data exploration of the initial data set is one of the first steps you take. Although in some cases Number or Excel will to the trick when the data set has a realistic size it won’t work anymore.
03 February 2017 / / Howto / Apache / SSL / Security
This is the third article in the series of hardening this webserver. If you have not read them, please read: Protecting my Webserver and SSL Cypher hardening. In this article, I show the usage of the Content-Security-Policy header. This header helps you reduce XSS risks on modern browsers by declaring what dynamic resources are allowed to load via an HTTP Header. Why use the CSP header Ok, we have this header but what will it do for my site.
31 December 2016 / / Howto / Apache / SSL / Security
I the previous post I described simple actions that you can take to harden your web server. It showed you headers that you can alter without too much interference on the functioning. In this post, I go into more details on the TLS connection itself. The modern browser does quite a lot when a TSL connection is established. There are multiple versions available to initiate a TLS/SSL connection. Not all of the supported versions are secure.
30 December 2016 / / Howto / Apache / SSL / Security
Just recently I finished an article for the Dutch Java magazine about securing your website by means of https connections. In the article, we (Ivo Woltring and I) describe details on how to get a certificate for your Webserver from the LetsEncrypt CA. The end result of those steps is a site that only allows for https connections. This solved the problem of others listening in on your visitors. Hacking your site is definitely more difficult, but not all possibilities are resolved.
18 November 2016 / / Java / Howto
This post describes a implementation for streaming a String of space separated Key Values with Java 8. In order to implement a streaming keyvalue reader two simple classes are implemented. One to handle navigation in the string and one to make a Iterable from the String. The implementation I provide is basic but has enough extension points to meet more extensive requirements. The problem. We all have faced the same problem when dealing with data from other sources.
This post is part of a multipart series about creating a graph off all available Maven dependencies. In the article for the Neo4j extension I described the input for the extension. This article describes the model that is used to create the required JSon. I start of with a small introduction to Vertices and edges before going into the implementation. Vertices and Edges In mathematics, and more specifically in graph theory, a vertex (plural vertices) or node is the fundamental unit of which graphs are formed: an undirected graph consists of a set of vertices and a set of edges (unordered pairs of vertices), while a directed graph consists of a set of vertices and a set of arcs (ordered pairs of vertices).
This post is part of a multipart series about creating a graph off all available Maven dependencies. Resolving maven dependencies is something we in general leave to our dependency management system, Maven, Ivvy, …. For the purpose to the application we are developing we required a detailed control on how the the dependencies are resolved and the JSon representation of this sub-graph. I start off with a short intro on where to find documentation on the Maven resolving mechanism and then go into the details for each of the parts that are required to do so.
07 October 2016 / / Maven / Java / Howto / Github / neo4j
This post is part of a multipart series about creating a graph off all available Maven dependencies. This article describes the drivers behind and the implementation of the Unmanaged Neo4j Extension written for our Maven graph analysis. When a the processing cluster is sending the sub graphs that need to be merged into a single database locking issues will occur. We opted to use a queuing mechanism to prevent. From the choices we had to implement this as a component for the Neo4J server we choose to this as a unmanaged extension.
05 December 2015 / / Howto / Did_You_Know
Check process when using dd Like most of you know the dd command is lacking output. When you are burning a image or similar to a USB stick is in general a long wait without knowing the progress. What? the command dd has know output when running for example: sudo dd if=~/linuxmint-17.3-cinnamon-64bit.iso of=/dev/sdb1 oflag=direct bs=1048576 shows no output, is just finished when done. for a slow USB disk or a large image that can be some time.
Submodules with git Just recently a was working on a presentation for a event that my boss organizes. I stumbled across a nice thing you can do with Git. The presentation is created in Reveal.js the aspect that i like about it that you can treat your presentation as code. Still working on the subject to do it with AsciiDoc. On the latter; The documentation says it should be easy but I do not have enough control on the output.
24 April 2014 / / Howto / Tools
Since I always have problems with remembering passwords and do like to generate those password managers are a bliss! For telnet/ssh connections I use the RemoteNG tool, great for managing your connections to all your servers. Problem is some servers require me to change my password every so often. The application is secure in the sense that the passwords are not stored as plain text in the configuration file. But what was the password that I must supply before i can change it.
TheMaven Site plugin uses by default theapt format. Although it is a simple and straight forward format I personally prefer the Confluence markup and DocBook. Confluence I use for my personal Wiki and at various projects I use DocBook for the documentation. Under the hood of theMaven site plugin runs the Doxia plugin. The documentation of the Site plugin is not really clear on this part. I stumbled on this some time ago.