if you are using turbolink there are links to sites where you might not want that turbolink is used.
you can prevent that by adding "data-turbolinks" => "false"
<%= link_to "link", "/link","data-turbolinks" => "false" %>
postgresql truncate tables
if you need to truncate tables and want to reset the autoincrement counter use this command
TRUNCATE TABLE someTable RESTART IDENTITY;
if you want to delete connected tables (e.g. via foreign key)
TRUNCATE TABLE someTable CASCASE;
of course this commands can be used sequenced.
raspberry touch 7 inch rotate 90
if you want to rotate the display of your raspberry 7 inch touchscreen (with latest raspian) you need to do the following
- install xinput
sudo apt-get install xinput - get the name of your display
xinput --list - flip your display
xinput --set-prop 'FT5406 memory based driver' 'Coordinate Transformation Matrix' 0 -1 1 1 0 0 0 0 1 - add flipping to /boot/config.txt
display_rotate=1 (for 90 degrees) - reboot
done!
calendar in your terminal
if you want to have a quick look at calendar without leaving the terminal:
just type cal and you see the current month
to see a whole year type cal 20xx
to see a specific month type cal 12 20xx
mysql not problem
if you query a mysql database and ask for all rows that do not have a specific value in a specific field, you might expect to also get those rows where the field is null.
but this is not the case.
so if you want to get all rows you have to query all rows that do not have the specific value in this field or where this is field is null.
or in code
wrong:
select * from database where field not like '%value%'
right:
select * from database where field not like '%value%' or field is null
iframe cross browser communication
If you want the iframe of a site not of the same domain to transfer data to your parent site this is normally prohibited because of the potential security risk of cross domain access. So if you want to communicate you can send messages via javascript.
in iframe
$('.button').click(function(){window.top.postMessage('hello', '*');})
on parent site
window.onmessage = function(e){if (e.data == "hello") {alert('hello')}
this works the other way also.
html_safe in pdf prawn
If you want to show a text with all html formatting html_safe doesn’t work but this line of code
ActionView::Base.full_sanitizer.sanitize(@string)
helpful unix commands
ps aux | grep firefox find process id of a process
find . -name '*firefox*' find all filenames including firefox
dig -x 10.10.10.10 find information on ip address
history | grep x find all command with x in your history
history -d 1234 delete command from history
pagination gem
there is a lot of different pagination gem. while will_paginate is quite good I recommend Kamari because it also can page arrays and not only ActiveRecord::Relation
ruby replace blanks within string
if you have a string containing blank characters you get rid of them using this function
field.gsub("\s",'')