CSS equivalent of the center tag

Because I understand the temptation to sometimes just wrap a div in a damn <center> tag instead of messing around with auto margins, translatex(-50%), or any other such nonsense — and also partly as a future reference for myself — here is what I’ve found to be the CSS equivalent of the <center> tag.

.center-dammit {
    display: block;
    margin: 0 auto;
    text-align: center;
}

Caveat: I’ve not checked in depth so I’m sure there will be about a dozen exceptions. W3C, please sort this out for CSS4!

Of Ants and Rhinos

I recently opened a Pandora’s box when investigating incorporating LESS into a web project I’ve been working on. Long story short, I found myself having to compile Rhino into a jar I could execute.

Having installed Ant to perform the task, I ran the command and got the following exception:

C:\rhino1_7R5\xmlimplsrc\build.xml:129: src 'C:\rhino1_7R5\build\tmp-xbean\xbean.zip' doesn't exist.

Which is exactly what I want to be dealing with when investigating a CSS precompiler.

In any case I got to the bottom of the issue. So without further ado, here is…

The definitive list of steps for compiling Rhino

  1. Download the source from Rhino’s website
  2. Unzip it somewhere (let’s say, C:\rhino1_7R5″)
  3. Download Ant (if you don’t already have it) from Apache’s website
  4. Install Ant (instructions here)
  5. Download the zip from the following URL: http://archive.apache.org/dist/xmlbeans/binaries/xmlbeans-2.5.0.zip
  6. Create a folder in C:\rhino1_7R5\build\” called “tmp-xbean”
  7. Paste the zip from step 5 into this folder and rename it to “xbean.zip”
  8. Open a command prompt in C:\rhino1_7R5
  9. Run the command “ant jar”

For those interested, I worked this out by taking a look in the Ant build file for “xmlimplsrc”, which was the root of the error. This build XML file actually contains the location of the zip file which it’s failing to find. My guess is that it attempts to download it (install instructions are very unclear about the fact that they require an internet connection) and when that fails, your build fails. In my case it’s most likely due to my company network’s proxy restrictions.

I hope this helps.

Gradle from behind a proxy, part deux

In July I wrote a post documenting how to build a project in Android Studio from behind a proxy. Essentially you need to tell Gradle Studio your proxy settings.

As of updating to Android Studio 1.0, the issue has come back! After a combination of swearing and research I’ve found the missing necessary steps.

So the new definitive steps for getting Gradle working from behind a proxy

  1. Navigate to the “.gradle” folder in your user directory (e.g. C:\Users\bob\.gradle)
  2. Create a “gradle.properties” file
  3. Edit the file to have the following contents (replacing your own values)
    systemProp.http.proxyHost=<proxy_host> 
    systemProp.http.proxyPort=<port> 
    systemProp.http.proxyUser=<user> 
    systemProp.http.proxyPassword=<password> 
    systemProp.http.nonProxyHosts=*.nonproxyrepos.com|localhost
  4. Go to Files > Settings > HTTP Proxy
  5. Select “Manual proxy configuration”
  6. Enter the same details you filled into the grade.properties file above: host, port, etc
  7. Tick “Proxy authentication”
  8. Fill in your username and password

Tadaa. This should get you back up and running again.

Exposing a VM on hosted WiFi hotspot for Google Glass

Background

Google Glass is famously frustrating to connect to a WiFi network. It doesn’t handle captive portals, or WiFi using Enterprise WPA2. I’ve also had consistent issues using MyGlass and QR codes to connect to Wifi.

I found myself in a situation where I had to connect Glass to a WiFi network on which a virtual machine was visible. My work’s corporate network was out of the question – it uses Enterprise WPA2. I would have connected my phone to the network and shared it to Glass via Bluetooth, but that was nixed for security reasons. So I had to set up a new network exclusively for Glass.

First thought – let’s just set up an Ad-Hoc wireless network on my laptop! But no, alas Android doesn’t support connecting to ad-hoc networks. Universe, why do you hate me so?

The solution

The solution involves a wireless-enabled Windows machine and VirtualBox – a program for running virtual machines.

An alternative to creating an ad-hoc network on your machine is to create a Wireless Hosted Network. This basically allows your Windows machine to act as a WiFi hotspot which can pass through a (wired) internet connection if you so wish.

My approach was to create a hosted network, connect my phone to it, then pass on the connection via Bluetooth. An admittedly insane chain of connections, but it’s all I had.

Create the WiFi network

  1. Open the Start menu and type “cmd”
  2. Right click and select “Run as Administrator”
  3. Type the following command:
     netsh wlan set hostednetwork mode=allow ssid=mynetworkid key=mypassword

Start the network

You’ll have to do this every time you start the machine, or alternatively set up a batch script to run this on startup.

  1. Type the following command:
     netsh wlan start hostednetwork

You should now see “mynetworkid” (or whatever you called it) in your list of wireless networks.

Create your VirtualBox image

  1. Install VirtualBox
  2. Create a new virtual machine (steps available here) – I’ve chosen to use a linux install
  3. Once your VM is created, go to Settings and choose Network
  4. Set up a Bridged Adapter
    1. Enable a network adapter
    2. Select Attached To: “Bridged Adapter”
    3. Select “Microsoft Virtual WiFi Miniport Adapter” as the Name – this is where the network you’ve just created is hosted.
  5. Start your VM up

Check connectivity

  1. On your Windows machine, open a command line and type:
     ipconfig

    A list of networks should be shown – one of which should be called “Wireless LAN adapter Wireless Network Connection”. Note down the first 9 digits of the IP address listed under this e.g. 192.168.173

  2. In your VM, run the following command:
     /sbin/ifconfig

    And note the networks and IPs that are listed. If no other networks were set up, your eth0 network should have an IP where the first 9 digits of the IP address matches those you noted down earlier. That means that they’re running on the network.

  3. For a laugh, ping your VM from your Windows machine, using the IP address from the previous step. This will confirm that your VM is addressable and contactable from your Windows machine. Given that your Windows machine is now broadcasting a wireless network, that means that the VM should be contactable to anyone on the network too.

Ping your VM from your Android device

As the penultimate proof, try pinging your VM from your Android device.

  1. Install an app which will let you run a ping command (I used PingTools)
  2. Ping the IP address you pinged previously

This should also show a response. And now we’re on the home straight.

Write some Glass code to contact your VM

You can do this however you wish. I wrote some very simple ping code to prove that Glass – once paired to my phone – was sharing the same internet connection as the phone, and the Windows machine, and as the VM.

There are tons of ways of doing it – for example:

InetAddress server = InetAddress.getByName("192.168.173.123");
if (server.isReachable(10000))
{
         // It’s contactable!
         celebrate();
}

Conclusions

That was much, much harder than it should have been. Alternatives I didn’t attempt:

  • Buying a router and broadcasting my corportate ethernet through it
  • Getting a company-approved phone that could have connected to the Enterprise network
  • Binning my Google Glass

PS – Many thanks to this post which acted as a great reference. It’s also worth checking out if you need to pass through internet via your hosted network.

How to invoke a SAS macro stored in a catalog

Having not done the Advanced Base SAS certification, this was a nightmare to work out. I’m documenting it here for my own future use, and to help anyone else who found themselves in the same situation as me.

What situation was that?

SAS Social Network Analysis can create networks from input data, and to do so it makes use of a pre-compiled “link macro” which is bundled with SNA. This link macro needs to be invoked from a base SAS program, but to do that, you need to tell SAS where to find it.

Note – There were literally zero Google hits for the exact name of this link macro. In case you’re curious, it’s called % sfs_net_main_link_macros.

Anyway I eventually found the location of these macros, in a catalog file.

Note – Not easy to find, and not documented. If anyone is in the same situation as me, it was in my <SASHome>\SASFoundation\9.3\snamva\macros folder. The macros are compiled into the sasmacr.sasb7cat file.

So I have a catalog file, how do I invoke the macro held in it?

Once you know, it’s very very simple.

  1. Copy the catalog file into your working directory
  2. Add a libname statement pointing to this working directory
  3. Use the SASMSTORE option

In other words your code should have the following statements:

libname mylib "D:\mylocation";
OPTIONS MSTORED SASMSTORE=mylib;

This will make the next invocation of the macro succeed, since SAS now knows it’s in your libname directory.