In a controller, i have:
mailer = MyReminderMailer.new
the mailer looks like this:
class MyReminderMailer < ActionMailer::Base
def change_email
mail(
from: default_from,
to: default_to,
subject: "..."
)
end
def default_from
return '...'
end
def default_to
return '...'
end
end
but got error: private method `new' called for MyReminderMailer:Class
ActionMailer::Base has a rather goofy and unintuitive API. Much like controllers, you never explicitly create instances of your mailers. Instead, you interact with them as classes. new is marked private in ActionMailer::Base, and method calls on the class are subsequently routed through method_missing to a new instance of itself. Like I said, unintuitive.
Have a look at the guides and api docs for more information on the correct usage of ActionMailer.
Ruby does not allow to call private method in normal way.
You can call it with send method
SomeClass.send :method_name
#in your case
MyReminderMailer.send :new
And you don't need ActionMailer object.
To send mail just use the method as like class method.
MyReminderMailer.change_email.deliver
Hope this can help you.
Related
I have a design problem.
I'm writing a REST client in ruby. For reasons beyond my control, it has to extend another gem that uses my networks zookeeper instance to do service lookup. My client takes a user provided tier, and based on that value, queries the zookeeper registry for the appropriate service url.
The problem is that I also need to be able to run my client against a locally running version of the service under test. When the service is running locally, zookeeper is obviously not involved, so I simply need to be able to make GET requests against the localhost resource url.
When a user instantiates my gem, they call something like:
client = MyRestClient.new(tier: :dev)
or in local mode
client = MyRestClient.new(tier: :local)
I would like to avoid conditionally hacking the constructor in MyRestClient (and all of the GET methods in MyRestClient) to alter requests based on :local vs. :requests_via_the_zk_gem.
I'm looking for an elegant and clean way to handle this situation in Ruby.
One thought was to create two client classes, one for :local and the other for :not_local. But then I don't know how to provide a single gem interface that will return the correct client object.
If MyClient has a constructor that looks something like this:
class MyClient
attr_reader :the_klass
def initialize(opts={})
if opts[:tier] == :local
#the_klass = LocalClass.new
else
#the_klass = ZkClass.new
end
#the_klass
end
end
then I end up with something like:
test = MyClient.new(tier: :local)
=> #<MyClient:0x007fe4d881ed58 #the_klass=#<LocalClass:0x007fe4d883afd0>>
test.class
=> MyClient
test.the_klass.class
=> LocalClass
those who then use my gem would have to make calls like:
#client = MyClient.new(tier: :local)
#client.the_klass.get
which doesn't seem right
I could use a module to return the appropriate class, but then I'm faced with the question of how to provide a single public interface for my gem. I can't instantiate a module with .new.
My sense is that this is a common OO problem and I just haven't run into it yet. It's also possible the answer is staring me in the face and I just haven't found it yet.
Most grateful for any help.
A common pattern is to pass the service into the client, something like:
class MyClient
attr_reader :service
def initialize(service)
#service = service
end
def some_method
service.some_method
end
end
And create it with:
client = MyRestClient.new(LocalClass.new)
# or
client = MyRestClient.new(ZkClass.new)
You could move these two into class methods:
class MyClient
self.local
new(LocalClass.new)
end
self.dev
new(ZkClass.new)
end
end
And instead call:
client = MyRestClient.local
# or
client = MyRestClient.dev
You can use method_missing to delegate from your client to the actual class.
def method_missing(m, *args, &block)
#the_class.send(m, *args, &block)
end
So whenever a method gets called on your class that doesn't exist (like get in your example) it wil be called on #the_class instead.
It's good style to also define the corresponding respond_to_missing? btw:
def respond_to_missing?(m, include_private = false)
#the_class.respond_to?(m)
end
The use case you are describing looks like a classic factory method use case.
The common solution for this is the create a method (not new) which returns the relevant class instance:
class MyClient
def self.create_client(opts={})
if opts[:tier] == :local
LocalClass.new
else
ZkClass.new
end
end
end
And now your usage is:
test = MyClient.create(tier: :local)
=> #<LocalClass:0x007fe4d881ed58>
test.class
=> LocalClass
I have what is probably a basic Q, but it appears complex in the setup. I have a module that has some classes. One class contains methods for API calls. Other classes describe a server. Dev for instance has its attributes. The server classes inherit the class that contains all the API calls. I use an instance of the server class to use one of these methods and then apply EventMachine methods to it. Here's a subset of a server class:
class PulseDev < ApiMethods
def base_uri
"http://myserver.com/api"
end
end
And an action in the methods class:
Class ApiMethods
def get_json_api_post_response(url, post_obj={})
http = EM::Synchrony.sync EventMachine::HttpRequest.new(self.base_uri+"#{url}").post(:body => post_obj)
process_response self.class.post(url, :body => post_obj).body
end
def process_response(result)
response = ActiveSupport::JSON.decode(result)
if response["code"].to_i == 200
ToolResult.new(true, response["result"], 200)
else
ToolResult.new(false, response["result"], response["code"])
end
end
end
Class ToolResult < Struct.new(:success, :result, :code)
end
And my invocation of it in the controller:
http = ApiMethods::Dev.new.get_json_api_post_response('/handshake', #j)
OK, my error is undefined method `post' for ApiMethods::PulseDev:Class
and it points to the post in my get_json_api_post_response method.
My question is: I get that it's within the context of the ApiMethods::Dev which is why self.base_uri works but how should I handle the post inside that process_response method so that it's tied to EventMachine? Is there something about method chaining I'm not seeing? In the error output I can verify that http is showing the EventMachine object so the new method seems to be working. Thanks for your time, sam
The answer is to look more carefully at the error msg. The process_response method is the one actually calling the EventMachine method and processing its :body. So it was written with an unneeded call.
I am receiving the following error when running my below ruby script:
s3parse.rb:12:in `block in <class:AccountLog>': undefined method `extract_account_id' for AccountLog:Class (NoMethodError)
I dont think it should be a class method, is there a reason its not taking my method into account?
class AccountLog
attr_accessor :bytes, :account_id, :date
def extract_account_id(line)
line.match(%r{accounts/(\d+)}).captures.join.to_i
end
s3log = File.open('vidcoder.txt').each do |line|
account_log = AccountLog.new
account_log.date = line.match(%r{\[[^:]*}).to_s.delete"[" #need to finish this regex to make it work
account_log.account_id = extract_account_id(line)
account_log.bytes = line.match(%r{^.*\s+HTTP.*\s+-\s+(\d+)\s+}).captures.join.to_i
puts "\n"
puts "The api request on #{account_log.date} was fromm account number #{account_log.account_id} and the bytes were #{account_log.bytes}"
end
end
def extract_account_id will define an instance method.
In the way you call it, you need a class method instead.
Define it like this:
def self.extract_account_id(line)
or, as you already have an AccountLog instance, use it to call extract_account_id:
account_log.account_id = account_log.extract_account_id(line)
Please note that with second way you do not need to alter method definition, just call extract_account_id via account_log instance.
And i guess you would want to put s3log = File... outside class definition.
Or use a constant instead: S3log = ...
Then you'll can access it as AccountLog::S3log
Is there any reason you don't think it should be a class method? You are using it in the context of a class method and that's why it it's saying no such method for class AccountLog.
If you name your method as self.extract_account_id(line) I'm sure it will work.
From what you are trying to do I think this is what you are looking for?
class AccountLog
attr_accessor :bytes, :account_id, :date
def self.extract_account_id(line)
line.match(%r{accounts/(\d+)}).captures.join.to_i
end
end
s3log = File.open('vidcoder.txt').each do |line|
account_log = AccountLog.new
account_log.date = line.match(%r{\[[^:]*}).to_s.delete"[" #need to finish this regex to make it work
account_log.account_id = extract_account_id(line)
account_log.bytes = line.match(%r{^.*\s+HTTP.*\s+-\s+(\d+)\s+}).captures.join.to_i
puts "\n"
puts "The api request on #{account_log.date} was fromm account number #{account_log.account_id} and the bytes were #{account_log.bytes}"
end
While you could take the class method approach, there seems to be a little more going on.
You should put the extraction logic in a method in itself rather than let it hangout in your class. Then outside of the class, have an instance of AccountLog where you can call on the methods for log and account id extraction. At that point you can do something with those values.
Class method or not is a detail we can explore after the class is a bit more clean I think.
RuNubie here. I've got a class Login that logs into gmail using the net/IMAP library. What is happening is that I create a new instance of that class, such as:
a = Login.new("username", "gmail.com", "passw")
Then, I'm working on other classes that will do some "stuff" with the mailbox. The problem is that the #imap variable I've defined in Login seems to have disappeared (due to scoping I assume).
This is how #imap is declared in Login class:
#imap = Net::IMAP.new('imap.gmail.com',993,true,nil,false)
So this:
#today = Date.today
#received_today = imap.search(["SINCE", #today.strftime("%d-%b-%Y")]).count.to_s
...returns an error. These are the two errors I've gotten while playing around with this. The first one is when I use imap, the second one is when I try #imap:
NameError: undefined local variable or method `imap' for #<Object:0x10718d2a8>
NoMethodError: undefined method `search' for nil:NilClass
What are the best practices for dealing with a situation like this? Is the only solution to define my methods that do "stuff" in the same class where I'm creating the new instance of Net::IMAP? Is declaring #imap as a global variable $imap a bad practice? So confused, I bet the answer is very simple and obvious too, but I'm just not seeing it. Thanks!
This:
#received_today = imap.search(["SINCE", #today.strftime("%d-%b-%Y")]).count.to_s
won't work because, well, there is no imap in scope at that point and so you get a NameError. When you try it like this:
#received_today = #imap.search(["SINCE", #today.strftime("%d-%b-%Y")]).count.to_s
You get a NoMethodError because instance variables, such as #imap, are automatically created at first use and initialized as nil. Your real #imap is in another object so you can't refer to it as #imap anywhere else.
I think you want a structure more like this:
class User
def imap
if(!#imap)
#imap = Net::IMAP.new('imap.gmail.com', 993, true, nil, false)
# and presumably an #imap.authenticate too...
end
#imap
end
end
class OtherOne
def some_method(user)
#today = Date.today
#received_today = user.imap.search(["SINCE", #today.strftime("%d-%b-%Y")]).count.to_s
end
end
Keep your Net::IMAP localized inside your User and let other objects use it by providing a simple accessor method.
Oh and that global $imap idea, I'll just pretend I didn't see that as globals are almost always a really bad idea.
a shorter way to define the imap variable in the User class, which is pretty much the same as what mu posted:
class User
def imap
#imap ||= Net::IMAP.new...
end
end
I would like to implement this
class SecurityTransgression < StandardError; end
def create
raise SecurityTransgression unless ...
end
class ApplicationController < ActionController::Base
def rescue_action(e)
case e
when SecurityTransgression
head :forbidden
end
end
end
from the this blogpost.
The problem is it does not work. I dont see a forbidden page but standard Rails error page "SecurityViolation in MyController#action". I digged that some rescue_action methods works only in the production mode. I tried that and it is the same. No change.
My question: is there any good documentation of the rescue_action method (and others)? Does this work under Rails 3.0? Because it seems this is some old
Take a look at rescue_from at the API documentation.
The rescue_action method is normally called internally with the #_env hash being passed as a parameter. The method is expecting the Exception instance to exist within the "action_dispatch.rescue.exception" key.
If you must use the rescue_action method directly, you can do the following:-
#_env[ "action_dispatch.rescue.exception" ] = exception
rescue_action( #_env )
or even more simple:-
rescue_action( { "action_dispatch.rescue.exception" => exception } )