Serving up Watson, IoT and cognitive services into IBM Connections Cloud
I recently noticed some old presentations that I’d not put online. The first comes from IBM Connect in February of this year.
How to pretty print a JsonNode to a String in Java
Filed under note to self as I keep forgetting this. Here’s a very simple way to pretty print a com.fasterxml.jackson.databind.JsonNode:
Looping through items in an object in JavaScript
Looping through arrays is easy:
Custom error pages in CodeIgniter
The simplest way to create custom error pages is to edit the files at /application/views/errors/html/error_*.php such as error_404.php (for 404s), error_db.php (for database errors) and error_general.php (for most other errors).
Deleting remote git tags
A reminder for when you really want to destroy a whole bunch of stuff...
Find out what tags you have locally:
david$ git tag
v1.0.0
v1.0.1
v1.1.0
Delete them all:
david$ git tag -d v1.0.0 v1.0.1 v1.1.0
Push all those deletes to the remote system:
david$ git push origin :refs/tags/v1.0.0 :refs/tags/v1.0.1 :refs/tags/v1.1.0
That's it. Destruction complete.
How to join multiple mp4 files together using ffmpeg on OS X
Sometimes I need to concatenate several mp4 files together. ffmpeg is a good tool for this job.
On OSX, it's easy to install using Homebrew:
brew install ffmpeg
If you have MP4 files, these could be losslessly concatenated by first transcoding them to mpeg transport streams.
Source – https://trac.ffmpeg.org/wiki/Concatenate
Say we have 2 mp4 files to concatenate or join together, first we transcode each of these into an intermediate format:
ffmpeg -i input1.mp4 -c copy -bsf:v h264_mp4toannexb -f mpegts intermediate1.ts
ffmpeg -i input2.mp4 -c copy -bsf:v h264_mp4toannexb -f mpegts intermediate2.tsAfter that we can concatenate these together using the following:
ffmpeg -i "concat:intermediate1.ts|intermediate2.ts" -c copy -bsf:a aac_adtstoasc output.mp4For more files, just pipe separate the additional files here:
"concat:intermediate1.ts|intermediate2.ts"IBM Connect 2016: 1402 - Getting Technically Cozy with IBM Connections Cloud APIs and App Dev
Last week, whilst at IBM Connect 2016 in Orlando, Florida, I gave a presentation with Patrick Li from AppFusions. The slides from the presentation are below:
The full code examples from the presentation are hosted on GitHub here:
https://github.com/dvdsmpsn/ibm-connect-2016-examples/
Push speed test results from OpenWRT to Google Sheets
I recently read Use Raspberry Pi to Measure Broadband Speeds to Hold Your ISP Accountable on Make and realised that this was an excellent candidate for monitoring my somewhat unstable Virgin Media connection.
I use an OpenWRT router (running a VPN to add a little bit of privacy), so I could adapt the article to run on the router rather than an attached Raspberry Pi.
Here are the steps adapted for OpenWRT...
Adding styles to the Confluence editor
I've tried to add styles to the Confluence editor. It wouldn't take them. Perhaps one of Atlassian's values is "Don't f@@k the editor".
<web-resource name="editor-scripts" key="editor-scripts">
<resource name="editor-templates.js" type="download"
location="assets/js/editor-templates.js" />
<!-- // TODO: Check whether I need a context here -->
</web-resource>
<web-resource name="editor-styles" key="editor-styles">
<resource name="css/confluence-editor.css" type="download"
location="assets/css/confluence-editor.css"/>
<dependency>com.atlassian.confluence.plugins:confluence-editor-plugins</dependency>
<dependency>${project.groupId}.${project.artifactId}:editor-scripts</dependency>
<dependency>com.atlassian.auiplugin:ajs</dependency>
<context>editor</context>
<!-- // TODO: Check whether I need all the dependencies here -->
</web-resource>
confluence-editor.css styles just wouldn't be accepted. Javascript injection worked just fine though. Perhaps I could use JS to inject my styles?
Yup. Adding this to my editor-templates.js file worked a treat:
var editorCss = AJS.params.staticResourceUrlPrefix
+ '/download/resources/me.davidsimpson.confluence.addon.awesome-addon'
+ ':editor-styles/css/confluence-editor.css';
if (AJS.params.isDevMode) {
editorCss = editorCss + '?_=' + Date.now();
}
$('#wysiwygTextarea_ifr').contents().find('head').append(
'<link type="text/css" rel="stylesheet" href="' + editorCss + '" media="all">'
);
Note the cache busting timestamp for local development.
Why is my machine contacting all-systems.mcast.net?
I've been looking at the network traffic and noticed a lot of calls from one machine to an address I'd never heard of: all-systems.mcast.net
Information on this seemed somewhat sketchy until I spotted this page on Multicast Addresses
ALL-SYSTEMS.MCAST.NET
224.0.0.1 All systems on the local subnet.
What? All the machines on my local network? Really?
Pinging it confirmed this:
$ ping all-systems.mcast.net
PING all-systems.mcast.net (224.0.0.1): 56 data bytes
64 bytes from 192.168.1.136: icmp_seq=0 ttl=64 time=0.103 ms
64 bytes from 192.168.1.153: icmp_seq=0 ttl=64 time=14.788 ms
64 bytes from 192.168.1.120: icmp_seq=0 ttl=64 time=239.376 ms
64 bytes from 192.168.1.162: icmp_seq=0 ttl=64 time=256.191 ms
...
64 bytes from 192.168.1.119: icmp_seq=1 ttl=64 time=50.762 ms
The machine accessing all-systems.mcast.net is running a DLNA server, so it appears to be broadcasting its presence to all the machines on the local network. Panic over.