I am looking at the source code of an program trying to figure out how it does certain things. One thing that caught my eye was the use of things like this in the views"
<%= _("Publish settings") %>
and in the controller:
flash[:notice] = _('Article was successfully created')
When I do _("Test") in the console it just returns "Test" string. So what is the use of the _() syntax. Haven't seen it before and can't find anything on google.
Any info will be appreciated.
It surely looks like some localization feature. As far as I can tell preferred method of doing that in Rails3 is t method, but if someone used external GetText gem for this purpose he might end up in such notation.
Related
Let's say I'm in a really huge project and am curious how this line works:
authorize! :read_pipeline_schedule, user_project
authorize! is supposed to be method name. Is it a private function in the class, or DSL provided from a parent block, or including, or declared in a gem? Or maybe none of them?
I was using grep to find internal code and Google for external code such as gems, however I guess it's useful if I can see the call stack of the method. puts caller is printing from the place where I am although it can not be used for analyzing the above case.
I'd like to know the best practice.
You can grep your code and installed gems and, if name is unique enough, you'll quickly locate its definition and associated usages. However, if a name is a common one, like call, then this approach is useless.
Ruby is a dynamic language and, as such, is a nightmare for static analysis. You may guess where this comes from, but you just can't know for sure.
The only way to know is runtime introspection. So, in your example, put a breakpoint right before that line
binding.pry
authorize! :read_pipeline_schedule, user_project
You'll drop out to pry shell. Now you can do
show-source authorize!
And see where exactly this method is defined.
The easiest way is to ask the method itself:
method_object = method(:authorize!)
method_object.owner
# => returns module in which the method resides
method_object.source_location
# => returns file name and line number of source code where the method is defined
Note that source_location may return nil for methods which have no Ruby source code, e.g. dynamically generated methods or methods implemented in the interpreter internals (C functions in YARV, Java methods in JRuby, etc.)
I like caller(0), caller_locations, and the ever-incredible show-source
I have the following error message on my en.yml file:
invalid_transition: "Cannot %{action} a %{state} timesheet"
Problem is that sometimes the state can be approved, other times it can be rejected.
With that, the error can end up being mispelled like "Cannot submit a approved timesheet", instead of "an approved timesheet".
Does Rails provide this flexibility in I18n?
The most simple answer to your question, I think, would be to pass in the entire state with the correct indefinite article together.
There's a question that looks at how to prepend "a" or "an" depending on a given word. A short answer is that there's a gem indefinite_article that does it.
Your translation then becomes:
invalid_transition: "Cannot %{action} %{state_with_article} timesheet"
Then call the I18n.t and pass in "a rejected" or "an approved" as a variable to interpolate.
However, if you want to get your hands a bit dirtier you may be able to use the i18n-inflector gem and it's companion i18n-inflector-rails gem. For many languages the choice is more complicated than in English because of different genders and tenses affecting the choice of indefinite article. (Disclaimer: I've not used either of those gems but they look like they would help you solve the problem).
I'm trying to use some embedded ruby in the subject line of an email coming from ActionMailer but keep getting different errors.
I couldn't find any documentation on the proper syntax. Any resources to fix this line of code?
mail(to: #user.email, subject: "Your Reservation Confirmation for" + #restaurant.name)
I've passed in all of the variables fine. I just need to see how I can combine text and these inputs.
Thanks
There are two common ways to it:
First:(regarding rep)
"...Confirmation for" + #restaurant.name.to_s
Second:
you can use string interpolation
"...Confirmation for #{#restaurant.name}"
I don't know whether this is intentional, but apparently #restaurant.name is returning a number (as you clarified, you're getting a TypeError: no implicit conversion of Fixnum into String). Calling #restaurant.name.to_s will solve that.
As G.B mentioned in another answer, string interpolation like "...Confirmation for #{#restaurant.name}" works too, since it calls #to_s for you automatically.
I'm putting the solution into an answer, since we found it while clarifying in the comments.
I'm building a method that ingests incoming email, and processes the email. Along the way there are a lot of things that could prevent the email from being processes successfully. The wrong reply-to address, the wrong from address, an empty message body etc..
The code is full of Switch Statements (case/when/end) and If statements. I'd like to learn a smarter, cleaner way of doing this. Additionally, a way to can track an error and at the end have one location where it emails back the user with an error. Is something like this possible with rails?
#error = []
Case XXX
when xxxx
if XXXXX
else
#error = 'You don't have permission to reply to the xxxxx'
end
else
#error = 'Unfamilar XXXX'
end
Then something at the end like...
If #errors.count > 0
Send the user an email letting them know what went wrong
else
do nothing
end
Thanks for the help here. If you know of any other tutorials that would teach me how to write logic like the above smarter, that'd be great. Right now I have case/if statements going 3 levels deeps, it's hard to keep it straight.
Thanks
First, I would just assign a symbol to each error message as a simple hash:
ErrorsDescription = {
:first => "First error",
:second => "Second error",
...
}
And use symbols instead of strings.
Then, your if and switch statements. Basicaly I can't really help you, because I don't see what kind of condition statements you have. What are you checking? Why do you have 3 level deep conditions? Probably you can write it simpler using if and switch - so this is my first answer to this issue. Another solution may be writing simple methods to improve readability, so you can write like this:
if #email.has_wrong_reply_to_address?
#errors << :wrong_reply_to_address
else
...
end
Also, as #mpapis suggested, you can use Rails build in validation system, but not as ActiveRecord but as ActiveModel. Here you have some examples how to do it and how it works (also take a look here). Of course you may need to write custom validations, but they are just simple methods. Once you do all above job, you can just use:
#email.valid?
And if it is not, you have all errors in hash:
#email.errors
Just as in ordinary ActiveRecord object.
Then you may extend your Emial class with send_error_email method which sends an email if there was an error.
EDIT:
This is about new information you attached in comment.
You don't have to use nested ifs and switch here. You can have it looking like this:
def is_this_email_valid?
if !email_from_user_in_system?
#errors << :user_not_in_system
return false
end
if comment_not_exists?
#errors << :comment_not_exists
return false
end
if user_cannot_comment_here?
#errors << :permision_error
return false
end
...
true
end
Then you can use it:
if !#email.is_this_email_valid?
#email.send_error_mail
end
I suggest using Exceptions. Start with this tutorial, then use Google, trial and error to go from there.
Edit: In more complex cases, exceptions may not be the right tool. You might want to use validator functions instead, for example (see other answers), or you could just return early instead of nesting ifs, e.g.:
unless sender_valid?
#error = "Sender invalid"
return
end
unless subject_valid?
#error = "Invalid command"
return
end
# normal no-errors flow continues here...
You could throw an error when something is not right. Then catch it at the end of your method.
http://phrogz.net/programmingruby/tut_exceptions.html
To make your code more readable and not have a lot of switch and if/then statements, you could create separate methods that validate certain aspects and call them from your main error-checking method.
Is it possible to map your message to a model ? then all the if/switch logic would be validations and automatically handled by rails. Good starting point is active record validations guide
Also worth reading is action mailer guide
Im trying to use Liquid Template Language in my Rails Application, i've watched Ryan Bates' video over at rails cast, i pretty much follow the instructions but it just doesnt seem to work!
When I try something like
#template = Liquid::Template.parse("Hi {{name}}")
#template.render('name' => 'toby')
I get
hi toby
but when i try something like
category = Category.first
#template = Liquid::Template.parse("Hi {{category.name}}")
#template.render('category' => category)
I don't get the desired result, I get only
hi ""
Can someone please help me out with this?
When the value is not a hash, you need to tell liquid which methods it can read from the passed object.
This documentation page show you how to instruct ActiveRecord.
The quickest way is to use the liquid_methods macro.