Kev's Development Toolbox

December 26, 2016

React ES5 to ES6: props and state

Developing with React and ES5, state on a Component is configured using the getInitialState() function:

var ButtonComponent = React.createClass({

  getInitialState : function(){
    return({
      value1: this.props.value1,
      value2: this.props.value2
    });
 },

...

});

If you’re moving from ES5 TO ES6 and creating React components using ES6 classes, if you try to follow the same approach you’ll see an error like this:

To set the initial state on an ES6 React class, you establish it in the constructor like this:

constructor(props) {
  super(props);
  this.state = {
    value1 : this.props.value1,
    value2 : this.props.value2,
  };
 }

December 24, 2016

RT73 wifi driver on Debian 8 completely filled my hard disk with syslog messages

Just installed Debian Hamradio Pure Blend, and I thought a 20GB partition for / would be plenty, but after a day I was getting disk full errors. So I shrunk my /home partition and extended my / partition up to 50GB. A day later it was at 100% again (I had just deleted some log file files to free up some space):

kev@kh-debian:/var/log$ df -h

Filesystem      Size  Used Avail Use% Mounted on
/dev/sda9        58G   53G  2.5G  96% /
/dev/sda10       20G  279M   19G   2% /home

Guessing something was up, I cd’d into /var/log to see what was showing up in my log files and was surprised to see this:

kev@kh-debian:/var/log$ ls -lS

total 49743852

-rw-r----- 1 root              adm  15123453253 Dec 24 18:37 syslog
-rw-r----- 1 root              adm  13204397200 Dec 24 18:37 kern.log
-rw-r----- 1 root              adm  12416440518 Dec 24 18:37 daemon.log
-rw-r----- 1 root              adm  10053382069 Dec 24 18:37 messages
-rw-r----- 1 root              adm    139506083 Dec 23 07:04 syslog.2.gz
-rw-rw-r-- 1 root              utmp      292292 Dec 24 18:33 lastlog

Ok, ok. That’s where my disk space has gone.

Looking in syslog, I’ve got these messages repeating about 100 times a second:

Dec 24 18:55:01 kh-debian wpa_supplicant[862]: wlan0: Failed to initialize driver interface
Dec 24 18:55:01 kh-debian NetworkManager[696]: <error> [1482634501.576472] [supplicant-manager/nm-supplicant-interface.c:856] interface_add_cb(): (wlan0): error adding interface: wpa_supplicant couldn't grab this interface.
Dec 24 18:55:01 kh-debian NetworkManager[696]: <info> (wlan0): supplicant interface state: starting -> down
Dec 24 18:55:01 kh-debian kernel: [ 2026.757616] ieee80211 phy0: rt2x00lib_request_firmware: Info - Loading firmware file 'rt73.bin'
Dec 24 18:55:01 kh-debian kernel: [ 2026.757646] rt73usb 1-7:1.0: firmware: failed to load rt73.bin (-2)
Dec 24 18:55:01 kh-debian kernel: [ 2026.757652] rt73usb 1-7:1.0: Direct firmware load failed with error -2
Dec 24 18:55:01 kh-debian kernel: [ 2026.757656] rt73usb 1-7:1.0: Falling back to user helper
Dec 24 18:55:01 kh-debian wpa_supplicant[862]: Could not set interface wlan0 flags (UP): Cannot allocate memory
Dec 24 18:55:01 kh-debian wpa_supplicant[862]: nl80211: Could not set interface 'wlan0' UP

Following the install instructions here: https://wiki.debian.org/WiFi/rt73 – and then rebooted, problem solved. Log messages gone.

December 22, 2016

Getting USB thumb drives to work with PS4’s Media Player

Quick answer: make sure the thumb drive is formatted using a Master Boot Record (MBR) partition in either FAT32 or ExFAT format. The MBR partition format is key.

If formatting a device on a Mac, the default partitioning uses a GUID Partition Map. Make sure you change this to Master Boot Record and you’ll be all set.

Logging from Fldigi to RumLogNG with AppleScript on MacOS

I’d come across this handy AppleScript before and had it setup and working, but since I’ve been recently re-installing on a new SSD, I’d forgot where I found this. It’s a a script that runs from one of the macro buttons in Fldigi to send contact details to RumLogNG.

Setup instructions are here, and the script and be downloaded from here. Works perfectly.