(We can do the above in "rails console")To turn it off:old_logger = ActiveRecord::Base.logger ActiveRecord::Base.logger = nilTo turn it back on:ActiveRecord::Base.logger = old_logger
Turn ongrep's line buffering mode.tail -f file | grep --line-buffered my_pattern
$ grep 'warning\|error\|critical' /var/log/messagesTo just match words, add -w swith:
$ grep -w 'warning\|error\|critical' /var/log/messagesegrep command can skip the above syntax and use the following syntax:
$ egrep -w 'warning|error|critical' /var/log/messages
I recommend that you pass the -i (ignore case) and --color option as follows:
$ egrep -wi --color 'warning|error|critical' /var/log/messages
redirect_to(new_user_path(:notice => 'Please register as a new user', :uid => 'ABCD'))The params you want to pass are arguments to thenew_user_pathmethod, not theredirect_tomethod.
Microsoft has recently launched a tool called “App Studio” which will allow you to build a Windows Phone app without any programming skill.
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Windows Phone App Studio lets you easily build apps for immediate publishing, testing and sharing with clients, co-workers, and friends. When you're ready to add advanced programming features or UI changes, the Windows Phone App Studio also generates source code for you to download.
Basically, if we are copying a file, say file1.js from FROM-B branch to TO-B, then:git checkout master # first get back to master git checkout experiment -- app.js # then copy the version of app.js # from branch "experiment"
git diff mybranch master -- myfile.csTo diff all files in 2 branches:
Assuming HTML4, with this markup:<a>Hover over me!</a> <div>Stuff shown on hover</div>You can do something like this:div { display: none; } a:hover + div { display: block; }This uses the adjacent sibling selector, and is the basis of the suckerfish dropdown menu.HTML5 allows anchor elements to wrap almost anything, so in that case thedivelement can be made a child of the anchor. Otherwise the principle is the same - use the:hoverpseudo-class to change thedisplayproperty of another element.
A DOM element is an object, a thing in memory. Like most objects in OOP, it has properties. It also, separately, has a map of the attributes defined on the element (usually coming from the markup that the browser read to create the element). Some of the element's properties get their initial values fromattributes with the same or similar names (valuegets its initial value from the "value" attribute;hrefgets its initial value from the "href" attribute, but it's not exactly the same value;classNamefrom the "class" attribute). Other properties get their initial values in other ways: For instance, theparentNodeproperty gets its value based on what its parent element is; an element always has astyleproperty, whether it has a "style" attribute or not.
car.color
car.send("color=", value)(2009 question/answer)
irb> example_customer.name #=> "Evagation Governessy" irb> field = 'name' #=> "name" irb> example_customer.instance_variable_get(field) NameError: `name` is not allowed as an instance variable name from (irb):8:in `instance_variable_get` from (irb):8 irb> example_customer.instance_variable_get('@'+field) #=> nil irb> example_customer.send(field) #=> "Evagation Governessy" irb> example_customer.send(field+'=', "Evagation Governessy Jr.") #=> "Evagation Governessy Jr." irb> example_customer.send(field) #=> "Evagation Governessy Jr." irb> example_customer.name #=> "Evagation Governessy Jr."
So you can see how#send(field)accesses the record information, and trying to access the attributes doesn't. Also, we can use#send(field+'=')to change record information.
Example of interpolation:A String literal created with single quotes does not support interpolation.The essential difference between using single or double quotes is that double quotes allow for escape sequences while single quotes do not. What you saw above is one such example.“\n”is interpreted as a new line and appears as a new line when rendered to the user, whereas'\n'displays the actual escape sequence to the user.
http://stackoverflow.com/questions/4838399/how-i-can-set-attr-accessible-in-order-to-not-allow-access-to-any-of-the-fieldattr_accessor is a ruby method that makes a getter and a setter. attr_accessible is a Rails method that allows you to pass in values to a mass assignment: new(attrs) or up update_attributes(attrs).Here's a mass assignment:Order.new({ :type => 'Corn', :quantity => 6 })You can imagine that the order might also have a discount code, say :price_off. If you don't tag :price_off as attr_accessible you stop malicious code from being able to do like so:Order.new({ :type => 'Corn', :quantity => 6, :price_off => 30 })Even if your form doesn't have a field for :price_off, if it's in your model it's available by default. This means a crafted POST could still set it. Using attr_accessible white lists those things that can be mass assigned.
By default the attributes are all attr_accessible (which means they can be set my mass-assignment).
- attr_accessible - only this list of attributes can be set by mass-assignment (white-listing).
- attr_protected - these attributes cannot be set by mass-assignment (black-listing).
Beginning with Rails 3.1, the following configuration option is available to disable mass-assignment by default for all models until you explicitly call attr_accessible or attr_protected:
- attr_readonly - these attributes cannot be set except for when the record is created.
config.active_record.whitelist_attributes = true
Rules of Thumb
In summary, here are rules of thumb to guide your use of JavaScript in Rails:
- Logically organize your site-wide scripts in the app/assets/javascripts/ folder.
- Copy external JavaScript libraries (such as jQuery plugins) to the vendor/assets/javascripts folder.
- Let the Rails asset pipeline combine them all in one minimized application.js file.
- List scripts in the app/assets/javascripts/application.js manifest.
In almost all applications, there is no need to add external JavaScript libraries directly in a view template. Use the Rails asset pipeline, even for JavaScript used on just one page (page-specific JavaScript). Copy external scripts to your application and you’ll gain the performance benefits of the Rails asset pipeline and avoid complexity.
Useful rvm commands to manage ruby versions using rvm:check with either:ps -edaf | grep mongo # "ps" flags may differ on your OSorservice mongodb status
Basically taken from http://beginrescueend.com/rvm/:To list the available ruby versions to install type:rvm list knownTo then install from the list of known, type:rvm install VERSION_NUMBERTo then use the ruby version you have installed:rvm use VERSION_NUMBERYou can make a certain ruby version your default system version:rvm use VERSION_NUMBER --defaultTo remove the ruby version, keeping the gemsets:rvm uninstall VERSION_NUMBERTo remove ruby et al:rvm remove VERSION_NUMBERTo learn about your ruby environment and where they are installed/aliased:rvm info
