OK this is very subjective but I’ve used this for my iPhone 14 and this case for an iPhone 13 Mini in the last 2 years. They are considerably cheaper than the Apple equivalent and both worked fine with my Belkin iPhone Magsafe Charger (I actually have the non-watch version which you can’t get anymore it seems).
Apple certainly make great products but they are not cheap and neither are the accessories.
Featured products:
There are many tools out there to help with various aspects of running a website. One which, until recently, I had neglected is an external website monitor (I used my own polling scripts, which was time consuming and fiddly). Even with regular server maintenance and updates problems can still occur:
I’m sure there are lots of options out there but I’m currently using UptimeRobot as they provide an excellent free service to get you going. This provides basic HTTP monitoring and page keyword monitoring for up to 50 websites.
The paid options seem reasonable compared to similar services from other companies and add features like SSL certificate monitoring and domain expiry monitoring. They also provide Apple and Android apps. I have the Apple one and it seems to work well.
I recently migrated a Rails 4 application to Rails 7. On the whole it wasn’t too bad but today I was trying to add a child table to the data schema – a simple create_table… When I attempted to “db:migrate” I got an error:
$ rails db:migrate == 20220520112518 CreateArticleTexts: migrating =============================== -- create_table(:article_texts) rails aborted! StandardError: An error has occurred, all later migrations canceled: Column `article_id` on table `article_texts` does not match column `id` on `articles`, which has type `int(11)`. To resolve this issue, change the type of the `article_id` column on `article_texts` to be :integer. (For example `t.integer :article_id`). Original message: Mysql2::Error: Cannot add foreign key constraint /home/myproject/db/migrate/20220520112518_create_article_texts.rb:3:in `change' Caused by: ActiveRecord::MismatchedForeignKey: Column `article_id` on table `article_texts` does not match column `id` on `articles`, which has type `int(11)`. To resolve this issue, change the type of the `article_id` column on `article_texts` to be :integer. (For example `t.integer :article_id`). Original message: Mysql2::Error: Cannot add foreign key constraint /home/myproject/db/migrate/20220520112518_create_article_texts.rb:3:in `change' Caused by: Mysql2::Error: Cannot add foreign key constraint /home/myproject/db/migrate/20220520112518_create_article_texts.rb:3:in `change' Tasks: TOP => db:migrate (See full trace by running task with --trace)
My old schema (from Rails 4 remember) used :int for the primary key data type. Rails 7 (and Rails 6 – I tested it) uses :bigint for the primary key data type.
In order to create a new child table I first need to upgrade the primary key on the parent table. After much trial and error the migration below is what I came up with for MySQL. In this example I also had 2 other legacy child tables which needed updating also so that foreign keys and primary keys had matching data types:
class ArticleUpdateId < ActiveRecord::Migration[7.0]
#
# For Rails 6+ we need legacy tables to have primary keys updated from :int to :bigint
# before we can add any new child tables. The migrations below are for MySQL.
#
def up
# drop primary key index and foreign key constraints otherwise we cannot make changes
execute('ALTER TABLE article_filters DROP FOREIGN KEY fk_rails_303034c0ef')
execute('ALTER TABLE article_keywords DROP FOREIGN KEY fk_rails_251b14e14a')
execute('ALTER TABLE articles CHANGE id id int') # first remove AUTO_INCREMENT
execute('ALTER TABLE articles DROP PRIMARY KEY')
# old article_id child fields did not use bigint
execute('ALTER TABLE article_filters CHANGE article_id article_id bigint NOT NULL')
execute('ALTER TABLE article_keywords CHANGE article_id article_id bigint NOT NULL')
# old id fields did not use bigint
execute('ALTER TABLE articles CHANGE id id bigint PRIMARY KEY AUTO_INCREMENT')
# recreate foreign key constraints
execute 'ALTER TABLE article_filters ADD CONSTRAINT fk_rails_303034c0ef FOREIGN KEY (article_id) REFERENCES articles (id)'
execute 'ALTER TABLE article_keywords ADD CONSTRAINT fk_rails_251b14e14a FOREIGN KEY (article_id) REFERENCES articles (id)'
end
def down
# drop primary key index and foreign key constraints otherwise we cannot make changes
execute('ALTER TABLE article_filters DROP FOREIGN KEY fk_rails_303034c0ef')
execute('ALTER TABLE article_keywords DROP FOREIGN KEY fk_rails_251b14e14a')
execute('ALTER TABLE articles CHANGE id id bigint') # first remove AUTO_INCREMENT
execute('ALTER TABLE articles DROP PRIMARY KEY')
# back to int on child table references
execute('ALTER TABLE article_filters CHANGE article_id article_id int NOT NULL')
execute('ALTER TABLE article_keywords CHANGE article_id article_id int NOT NULL')
# back to int on parent table
execute('ALTER TABLE articles CHANGE id id int PRIMARY KEY AUTO_INCREMENT')
# recreate foreign key constraints
execute 'ALTER TABLE article_filters ADD CONSTRAINT fk_rails_303034c0ef FOREIGN KEY (article_id) REFERENCES articles (id)'
execute 'ALTER TABLE article_keywords ADD CONSTRAINT fk_rails_251b14e14a FOREIGN KEY (article_id) REFERENCES articles (id)'
end
end
This seems to work well so far. Neither ID nor auto_increment values were affected by the migration and my parent id and child article_id columns are now bigint.
RSync is a great tool for archiving and backup. But how do you get it to cope with connection problems? For example, you are trying to backup a large archive file but you have a poor connection which keeps dropping and so your transfer has to start all over again. Well here’s what I use:
rsync -avz --progress --partial -e ssh /home/mybackup/* <email address>@<rsync host>:<remote folder name>
Note that the email address does not require quote marks around it. Notice I do not use –append or –append-verify. If I did it would assume that the start of the file has remained the same (which might be the case for a log file or similar). This isn’t the case for me. I also don’t use the –delete option because this would simply delete the temporary file left by –partial.
It works a treat but I would recommend a break of 15 minutes when attempting to resume the transfer (the time will vary depending upon how the remote server deals with temporary files).
For more on this and a very useful bash script, have a look here:
http://superuser.com/questions/302842/resume-rsync…
In development mode things seemed to take care of themselves. Production mode was a different matter. Let’s just say it was a sensitive and delicate configuration. So in documenting this I’ve tried to condense things to the bare minimum and using the simplest configuration: hosting the “cable” within the host application (i.e. in the same virtual host). For full ActionCable documentation please visit: Rails Guides
Make sure you have a cable.js file (app/assets/javascripts/cable.js)
The “rails new” command should have created this for you.
Create a handler (app/assets/javascripts/channels/chat_channel.coffee)
App.chat = App.cable.subscriptions.create "ChatChannel",
connected: ->
alert 'connected'
disconnected: ->
alert 'disconnected'
received: (data) ->
# do you screen update stuff here
I’ve included popup alerts. These are quite useful when you’re doing this for the first time so you know your basic connection is working.
Make sure you have your channel and connection ActionCable files
Check for app/channels/application_cable/channel.rb and app/channels/application_cable/connection.rb. These should have been created for you. If you’re running ActionCable within your application (rather than on a separate server/vhost) you can add authentication for the connection thus:
module ApplicationCable
class Connection < ActionCable::Connection::Base
identified_by :current_user
def connect
self.current_user = find_verified_user
end
protected
def find_verified_user
if current_user = User.find_by(id: cookies.signed[:user_id])
current_user
else
reject_unauthorized_connection
end
end
end
end
Create your own channel file (app/channels/chat_channel.rb)
Here’s where you subscribe to your own broadcast.
class ChatChannel < ApplicationCable::Channel
def subscribed
stream_from 'chat_channel'
end
def unsubscribed
# Any cleanup needed when channel is unsubscribed
end
end
Set your configuration parameters
There are 2 files to change. First we must update config/environments/production.rb and set the config.action_cable constants:
config.action_cable.url = 'ws://myapp.spannersoftware.com/cable' # ws:// is non-secure, wss:// is secure config.action_cable.allowed_request_origins = [ 'http://myapp.spannersoftware.com' ]
Important: do not add a trailing slash to either of these!
Next update config/cable.yml and set the host and port for the redis server:
development: adapter: async test: adapter: async production: adapter: redis url: redis://localhost:6379/1
You may not need to change this.
Add the ActionCable metatag
In app/views/layouts/application.html.erb add the following line in the <head> section:
<%= action_cable_meta_tag %>
Install and fire up the Redis server
Redis is a cool bit of kit for providing efficient messaging, for more information go here: Redis.io.
apt-get install redis-server service redis-server start
Edit /etc/redis/redis.conf to set the port to 6379 and bind to 127.0.0.1.
Configure Nginx and Puma
Here is my Nginx virtual host example:
upstream my_app {
server unix:/home/myapp/tmp/myapp.sock;
}
server {
listen 10.10.10.10:80;
server_name myapp.spannersoftware.com;
access_log /home/myapp/log/access.log;
error_log /home/myapp/log/error.log;
root /home/myapp/public;
location / {
try_files /maint.html $uri @ruby;
}
location @ruby {
proxy_pass http://my_app;
proxy_set_header X-Real-IP $remote_addr;
proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
proxy_set_header Host $http_host;
proxy_redirect off;
}
location /cable {
proxy_pass http://my_app;
proxy_http_version 1.1;
proxy_set_header Upgrade $http_upgrade;
proxy_set_header Connection "upgrade";
}
}
Here is my Puma config (config/puma.rb):
threads_count = ENV.fetch("RAILS_MAX_THREADS") { 5 }.to_i
threads threads_count, threads_count
bind "unix:/home/myapp/tmp/bluebird2.sock"
environment ENV.fetch("RAILS_ENV") { "production" }
workers ENV.fetch("WEB_CONCURRENCY") { 2 }
daemonize true
pidfile '/home/myapp/tmp/pids/puma.pid'
I'm using a Unix socket here, the default environment is production, the process is daemonized and I've specified a pidfile location. The rest of the settings are default.
Set your app running
Assuming you have the puma gem installed correctly you should be able to run your application complete with working ActionCable.
cd /home/myapp puma -C config/puma.rb -e production
You should see the message “connected” pop up in your browser when you first load the page. Hopefully you’ve found this helpful but please let me know if I’ve missed anything.
Developing in Rails 5 recently I was struggling to think of why my child record IDs were not being set automatically on create. I thought this happened automatically. Then I discovered that setting inverse_of in the model is vital for accessing parent models from the child without relying on a pre-existing physical record (e.g. when you are creating new records). It turns out it’s been like this since Rails 2. How blind was I!
Here’s how it works:
class Publisher < ApplicationRecord
has_many :articles, index_errors: true, dependent: :destroy, inverse_of: :publisher
accepts_nested_attributes_for :articles, allow_destroy: true
class Article < ApplicationRecord
belongs_to :publisher, inverse_of: :articles
has_many :comments, index_errors: true, dependent: :destroy, inverse_of: :article
accepts_nested_attributes_for :comments, allow_destroy: true, reject_if: proc { |item| item[:message].blank? }
class Comment < ApplicationRecord
belongs_to :article, inverse_of: :comments
So using inverse_of allows me to access self.article from the Comment model even when the physical record has yet to be created.
Let’s say we want to set-up rsync over SSH to securely backup a folder from one server to another. Our aim is to run a daily backup in cron with a command like this:
rsync -avz -e ssh /home/somefolder/important_files remoteuser@target_host:/home/mybackup/important_files_copy
The following steps work well for me but change as you wish (you may wish to create a folder under an existing user for example):
cd /home mkdir mybackupuser
useradd -d /home/mybackupuser mybackupuser chown mybackupuser.root mybackupuser chmod 750 mybackupuser passwd mybackupuser
vi /etc/ssh/sshd_config
Add or amend the “AllowUsers” directive:
AllowUsers mybackupuser
cd /home/mybackupuser mkdir .ssh chown mybackupuser.root .ssh chmod 700 .ssh
cd /home/mybackupuser vi valid-rsync
Copy and paste the following lines and then save the file:
#!/bin/sh
case "$SSH_ORIGINAL_COMMAND" in
*\&*)
echo "Rejected"
;;
*\(*)
echo "Rejected"
;;
*\{*)
echo "Rejected"
;;
*\;*)
echo "Rejected"
;;
*\<*)
echo "Rejected"
;;
*\`*)
echo "Rejected"
;;
*\|*)
echo "Rejected"
;;
rsync\ --server*)
$SSH_ORIGINAL_COMMAND
;;
*)
echo "Rejected"
;;
esac
I cannot claim credit for writing the above script but unfortunately I can’t remember where I got it from originally. Suffice to say it seems to be quite widely distributed on the web. To whoever wrote it: thank you!
chown mybackupuser.root valid-rsync chmod 700 valid-rsync
Now, in case you were getting bored, we move to the source machine to create an ssh key. The public part of this key will then be copied to the target machine.
ssh-keygen -t rsa -b 2048
Or, if it’s not your own server then you might want to specify a path for the key generation (rather than the default which is ~/.ssh/id_rsa):
ssh-keygen -t rsa -b 2048 -f /home/someuser/rsync-key
scp ~/.ssh/id_rsa.pub mybackupuser@target_host:.ssh/authorized_keys
If you specified a path (the -f option) then use the following command:
scp /home/someuser/rsync-key.pub mybackupuser@target_host:/home/mybackupuser
Now append the contents of rsync-key.pub to /home/mybackupuser/.ssh/authorized_keys on the target machine.
from="xx.xx.xx.xx",command="/home/jjbb/valid-rsync" ssh-rsa ASHAKJSDHhaisudhfaksjfhHAISUDHiauegfkjaHSDKJHDjkh.....
“xx.xx.xx.xx” is the IP address of the source machine.
rsync -avz -e ssh /home/somefolder/important_files remoteuser@target_host:/home/mybackup/important_files_copy
If you are using your own file (see -f option earlier) you must add “-i /home/someuser/rsync-key” to the ssh options thus:
rsync -avz -e "ssh -i /home/someuser/rsync-key" /home/somefolder/important_files remoteuser@target_host:/home/mybackup/important_files_copy
Private browsing may be handy if you want to cover your tracks; naturally you are not looking at anything you shouldn’t but merely planning a nice surprise for a loved one and don’t want them to find out. However, if you are a parent seeking to protect their children or an employer who doesn’t want their employees wasting time then disabling private browsing is a helpful step in reducing temptation: if they know they can’t browse privately then they may be less inclined to look at stuff they shouldn’t.
IE requires a Windows Registry edit. Simply paste the required settings from the lines below into a text file (e.g. “ie.reg”) and then “run” it to merge these settings into the Windows Registry.
Windows Registry Editor Version 5.00 [HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Microsoft\Internet Explorer\Control Panel] "DisableDeleteBrowsingHistory"=dword:00000001 [HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Microsoft\Internet Explorer\Privacy] "EnableInPrivateBrowsing"=dword:00000000 [HKEY_CURRENT_USER\Software\Policies\Microsoft\Internet Explorer\Control Panel] "DisableDeleteBrowsingHistory"=dword:00000001 [HKEY_CURRENT_USER\Software\Policies\Microsoft\Internet Explorer\Privacy] "EnableInPrivateBrowsing"=dword:00000000
I believe this works on versions 8, 9 and 10. Please let me know if not. I have included settings for both the whole machine and current user, you don’t actually need both.
I have also included the “DisableDeleteBrowsingHistory” setting as this is useful.
Firefox is the easiest. You simply have to install the “Disable Private Browsing Plus” add-on and then you can do what many marketers do like buying youtube views for example. Once added it cannot be easily removed once added. You can find it here:
https://addons.mozilla.org/en-US/firefox/addon/disable-private-browsing-pl/?src=api
Chrome used to accept registry settings similar to IE but that is no longer the case. You now need to download and install Group Policy Templates from here:
http://dl.google.com/dl/edgedl/chrome/policy/policy_templates.zip
Then follow this procedure:
For more information please see this article:
https://support.google.com/chrome/a/answer/187202?hl=en
If you have installed the Android SDK but find the emulator hopelessly slow (even on a fast PC) then this might just make your day. It did mine; in my adult nerdhood I am easily pleased.
Install the Intel x86 Emulator Accelerator (HAXM):
Check your configuration in the AVD Manager:
If you try running the emulator now you will get the following error:
emulator: Failed to open the HAX device! emulator: Open HAX device failed HAX is not working and emulator runs in emulation mode
To fix this you simply need to run the installation program for HAXM:
You should now find that your Android Emulator runs a lot faster!
See you soon…on www.workbootsnerd.com
Does your Adobe Acrobat/Reader always print on your Xerox Phaser 8550 (or other Xerox) with half-size output locked into landscape even when you force orientation to portrait? An illustration will explain the problem better:
It appears that this is a legacy driver problem. Here is the fix I used:
Thank you to those who took the trouble to post their solution in the Adobe Community.