Both #save and #destroy come wrapped in a transaction that ensures that whatever you do in validations or callbacks will happen under its protected cover. So you can use validations to check for values that the transaction depends on or you can raise exceptions in the callbacks to rollback, includin...
Create a file named launch-server.yaml, that will be our playbook.
The first part of the playbook is a list of hosts that your playbook will run on, we only have one, localhost.
- hosts: localhost
Then we need to define a list of tasks to perform in this playbook. We will only have one that lau...
Run the Ansible playbook:
$ ansible-playbook launch-server.yaml
You should see output like
PLAY [localhost]
***************************************************************
TASK [setup]
*******************************************************************
ok: [localhost]
TASK [launch an U...
The number that follows the associativity information describes in what order the operators are applied. It must always be between 0 and 9 inclusive. This is commonly referred to as how tightly the operator binds. For example, consider the following fixity declarations (in base)
infixl 6 +
infixl ...
The following will prompt a user for input, and then store that input as a string (text) in a variable. The variable is then used to give a message to the user.
#!/usr/bin/env bash
echo "Who are you?"
read name
echo "Hello, $name."
The command read here reads one line of ...
When matching the path of a route, you can do it explicitly, matching only one path, like so:
get "/hello" do
return "Hello!"
end
You can also use a regular expression to match complex routes. Any route which matches the regular expression will run that code block. If m...
To print a test field (TestField) from a test feature class (TestFC) in a test file geodatabase (Test.gdb) located in a temporary folder (C:\Temp):
with arcpy.da.SearchCursor(r"C:\Temp\Test.gdb\TestFC",["TestField"]) as cursor:
for row in cursor:
print row[0]
from django.db import models
from django.contrib.auth.models import User
from django.db.models.signals import post_save
from django.dispatch import receiver
class UserProfile(models.Model):
user = models.OneToOneField(User, related_name='user')
website = models.URLField(default='', ...
If an arithmetic operation that yields a floating point type produces a value that is not in the range of representable values of the result type, the behavior is undefined according to the C++ standard, but may be defined by other standards the machine might conform to, such as IEEE 754.
float x =...
C++11
The type_traits header contains a set of template classes and helpers to transform and check properties of types at compile-time.
These traits are typically used in templates to check for user errors, support generic programming, and allow for optimizations.
Most type traits are used to c...
Sometimes in a development or testing environment, the SSL certificate chain might not have been fully established (yet).
To continue developing and testing, you can turn off SSL verification programmatically by installing an "all-trusting" trust manager:
try {
// Create a trust mana...
Emacs uses the terms point, mark, and region to provide more precision about the selected text and position of the cursor. By understanding these terms, it'll help you understand and use other operations and functions.
The point is the place in a buffer where editing (i.e. insertion) is currently t...
Exceptions are powerful, but a single overzealous except clause can take it all away in a single line.
try:
res = get_result()
res = res[0]
log('got result: %r' % res)
except:
if not res:
res = ''
print('got exception')
This example demonstrates 3 symptoms of t...
Download
Use Firebird site to download the correct "server package" for your system.
First, select the version of Firebird that you would like to install.
Next, select the appropriated installer for your system. Example, for almost any version of Windows 32 bits, you would select under ...
Add this line at the beginning of your view.
<?php
use yii\widgets\Pjax;
?>
Add the following two lines around the content that needs partial updating.
<?php Pjax::begin(['id'=>'id-pjax']); ?>
Content that needs to be updated
<?php Pjax::end(); ?>
reload pjax
$.pjax...
