As the title says, I have a simple ActiveResource in my application that is supposed to get data from an api. The collection works perfectly both locally and on the production server. However, .find doesn't work in production, i get a weird error:
MyResource.find(1, params: { website_id: 2 })
ArgumentError: wrong number of arguments (given 2, expected 0..1)
The same query works if I run it from local console connected to the api. API returns a valid response. I have no idea how else to debug it.
class MyResource < ActiveResource::Base
self.site = Rails.configuration.content_url
self.prefix = "/api/websites/:website_id/"
self.element_name = "game"
end
I have to say, i have other resources in the application using the same api, find method works for them, only this one has issues.
for some reason it makes a call to
https://github.com/rails/rails/blob/master/activerecord/lib/active_record/core.rb#L330
with 2 arguments, but i can't figure out who makes such call. And it only happens in production mode, not in dev.
I found the problem, but it's the weirdest thing ever.
In my show method in the api controller i was returning an object but i was merging the hash with some extra data. If i opened in the browser, the response was fine, development worked, but for some reason, in production it doesn't want to accept the merge.
So problem solved, but still have no idea why it's happening like that.
I ran into a similar issue in an app that used ActiveRecord for a vendor model and ActiveResource for a delivery model that has a vendor attribute. In development, if the vendor model has not yet been loaded, you can fetch a delivery and deserialize it, including the vendor attribute. If, however, the vendor model has been loaded already, attempting to fetch a delivery leads to the error described in this issue.
How to reproduce in a console:
Vendor.connection
Delivery.find(1)
Seems that AResource is trying to create a new instance of Vendor.
Related
I'm working on a rails based web backend, and I've ran into a bit of an issue. I'm building a crypto trading based application, which relies on knowing the exact current price of many cryptos/stocks. To do this I seem to need a websocket to update certain data, however I can't figure out how to store this data. I need to be able to write to it on every websocket update, as well as read from it when sending out data to the front end. Both of these actions seem too fast to rely on my database, so I'm wondering if there is a better option. My idea was to use a class with a class method that is set on server startup. Then read from/write to that method when needed. The class looks something like this
class CryptoSocket
def self.start
##cryptos = {
BTC: 0,
ETH: 0,
DOGE: 0
}
end
def self.value(symbol)
##cryptos[symbol]
end
end
Inside the start method is a websocket which gets opened, and on message writes to ##cryptos with the updated value of the coin. I call CryptoSocket.start when the server boots up
To get the value for a symbol I can just call CryptoSocket.value(symbol) anywhere in my app. This seemed like it was working, however I've noticed sometimes it fails telling me NameError: uninitialized class variable ##cryptos in CryptoSocket
It seems like the issue is running reload! in the rails console, or entering a binding.pry then exiting. My guess is some garbage collection is happening, but overall it's something I'd like to avoid.
Does anyone have a suggestion for a better way to go about setting this class up? Does rails have a better way to persist an object in memory? It's fine to lose it when the server shuts down, but I would like to keep access to it when the server stays up
I am trying to implement 2FA(two factor authentication) in my existing rails 4.2.10 application, I have configured many bits.
Issue I am facing is to get/retrieve a code which is valid for 5 minutes and send this code over to user on his defined phone number or email.
I did tried ROTP::TOTP.new(user.otp_secret).at(Time.now), guessing from gem's source code, which seems to work fine and give a valid otp_code in console, but in sessions_controler, as weird as it sounds, user.otp_secret is null, always...
I have posted an issue on the gem.
I don't think this can be bug, rather this is a functionality I want to build.
My stack:
Ruby: 2.4.2
Rails: 4.2.10
Devise: 4
attr_encrypted: 1.4(if it matters)
Additionally, I want to extend drift period(code acceptance time) to 5 minutes. I think that will be easy, but doing it for single code, not universally, or for all codes, this has me thinking for a while now.
My main issue is the first one, getting the code to send through SMS, this is a subproblem, which I think is doable, but if anyone has/had experience with this and can help, that will be great.
UPDATE: I updated attr_encrypted and restarted the system, it started working, also I realized there is a method current_otp in which devise_two_factor adds in the user model, so I started using that. BUT after a few minutes, it is also throwing the same issue of user.otp_secret being nil. Its getting weird...
UPDATE 2/Hacky solution: Weirdly enough, I had to add these 3 methods in user model and everything started working:
def encrypted_otp_secret
self[:encrypted_otp_secret]
end
def encrypted_otp_secret_iv
self[:encrypted_otp_secret_iv]
end
def encrypted_otp_secret_salt
self[:encrypted_otp_secret_salt]
end
As you can suspect, i got here by examining a behavior thatdoing user.encrypted_otp_secret was giving me nil while it was not, even after reloading user model. And doing user[:encrypted_otp_secret] was giving me the actual value.
It seems like a bug in attr_encrypted. I am not sure yet.
For anyone else that runs into this issue, I have found a next step needed to get the current_otp method to work. In the method pre_otp method call
> u = User.find_by(email: 'test#example.com')
> u.otp_required_for_login = true
> u.otp_secret = User.generate_otp_secret
> u.save!
and then you can call u.current_otp...
https://blog.tommyku.com/blog/integrating-two-step-two-factor-authentication-into-rails-4-project-with-devise/
I am new to rails and notice a very odd pattern. I thought some error messages in Django were obscenely cryptic, but building my second app in rails I notice my errors come up NoMethodError more than 90% of the time.
How do rails people tell the difference between all these errors with the same name?
What does NoMethodError mean at it's core? It seems like what you're calling in the template is misspelled, or you're accessing attributes that don't exist?
Where can this error happen? Is the only possible cause in the template/view (the html.erb file)? Or can a bad call in the controller and whatnot cause same error?
Also, what is the best debugger gem to alleviate these issues? Reading the full trace isn't too helpful for beginners at least for a while, I;d like a first hand account of what debugger someone uses instead of reading hype
Thank you kindly
NoMethodError means you are calling a method on an object, but that object doesn't provide such method.
This is a quite bad error in the sense that is reveals a poorly designed and tested application. It generally means your code is not behaving as you are expected.
The way to reduce such errors is:
Make sure that when you are writing the code you are taking care of the various edge cases that may happen, not just the correct path. In other words, you need to take care of validating what's going on and making sure that if something is not successful (e.g. the user is not supplying all the input requested) your application will handle the case gracefully.
Make sure you write automatic test cases that covers the behavior of each method in your codebase
Keep track of the errors. When an error occurs, write a test to reproduce the behavior, fix the code and check the test passes. That will reduce the risk of regression.
This is not a Rails specific error actually. I'll try to explain what's happening at its core.
Ruby is a language that functions through message passing. Objects communicate by sending messages to each other.
The message needs to be defined as a method on the object to respond to it. This can be directly defined on the object itself, the object's class, the object's class's parents/ancestors or through included modules.
class MyObject
def some_method
puts "Yay!"
end
end
> MyObject.new.some_method
Yay!
Objects can define method_missing to handle unexpected messages.
class MyObject
def method_missing(name, *args, &block)
puts name
end
end
> MyObject.new.some_undefined_method
some_undefined_method
Without the method_missing handler, the object will raise a NoMethodError
class MyObject
end
> MyObject.new.some_undefined_method
NoMethodError: undefined method 'some_undefined_method' for #<MyObject...>
So what does this look like in Rails?
$ rails generate model User name:string
Produces this
# models/user.rb
class User < ActiveRecord::Base
end
Which has the following methods implemented among others (by ActiveRecord)
def name
end
def name=(value)
end
When you do the following:
# create a new User object
> user = User.new
#<User ... >
# call the 'name=' method on the User object
> user.name = "name"
"name"
# call the 'name' method on the User object. Note that these are 2 different methods
> user.name
"name"
> user.some_undefined_method
NoMethodError: undefined method 'some_undefined_method' for #<User...>
You'll see the same results whether you're calling it in your console, your model, your controller or in the view as they're all running the same Ruby code.
ERB view templates are slightly different in that what you enter is only evaluated as Ruby code when it's between <% %> or <%= %>. Otherwise, it gets written out to the page as text.
How do rails people tell the difference between all these errors with
the same name?
We usually look at the stack trace that comes back with the response (in development mode) as well as looking in the logs. In a dev environment, I am running my server in a console where I can scroll through the request.
What does NoMethodError mean at it's core? It seems like what you're
calling in the template is misspelled, or you're accessing attributes
that don't exist?
Due to dynamic coupling nature of Ruby. When Ruby determines that an object doesn't have a method by the name of the one that was called. It looks for a method by the name of "method_missing" within that object. If it's not defined then the super one is called which has the default behaviour of raising an exception. Rails leverages this mechanism heavily in it's internal dispatching
Where can this error happen? Is the only possible cause in the
template/view (the html.erb file)? Or can a bad call in the controller
and whatnot cause same error?
This error can happen wherever you have Ruby code, It has nothing to do with rails
Also, what is the best debugger gem to alleviate these issues? Reading
the full trace isn't too helpful for beginners at least for a while,
I;d like a first hand account of what debugger someone uses instead of
reading hype
An Invaluable tool for debugging is the gem 'pry'. It has many useful plug-able tools that greatly simplify debugging
I have a rather odd situation here.
My OrdersController has an edit method and at some point I have the following statement:
order_item.item = item
As you can guess, order_item.item expects a reference to an Item object, which is exactly what item is. Here comes the mistery. The first time I send a request to orders/{some_order_id}/edit, I receive the expected response. But if I send a new request (even if I just press F5) the application crashes and I receive the following error message:
ActiveRecord::AssociationTypeMismatch in OrdersController#edit
Item(#177601092) expected, got Item(#67520280)
What have I discovered so far? I have put an puts "#{Item.object_id}" just before the order_item.item = item and found out that Item.object_id changes from a request to another, which means that the Item ActiveRecord is changing its position on memory. (For instance, in the above example, during the first request Item.object_id is 67520280, while in the second it changes to 177601092.)
My question is: What can be causing the Item ActiveRecord to change its position on memory?
Useful info: I'm using rails 3.0.20
Update:
I found out that this change of ID is pretty common. But I still can't figure out why the expectation doesn't change as the Item.object_id does.
Despite the fact that I am not using Factory Girl, this answer and this discussion helped me a lot.
tl;dr
The problem was solved when I set cached_classes to true in my environment.
I'm running into a weird bug on Heroku, which I believe may be a race condition, and I'm looking for any sort of advice for solving it.
My application has a model that calls an external API (Twilio, if you're curious) after it's created. In this call, it passes a url to be called back once the third party completes their work. Like this:
class TextMessage < ActiveRecord::Base
after_create :send_sms
def send_sms
call.external.third.party.api(
:callback => sent_text_message_path(self)
)
end
end
Then I have a controller to handle the callback:
class TextMessagesController < ActiveController::Base
def sent
#textmessage = TextMessage.find(params[:id])
#textmessage.sent = true
#textmessage.save
end
end
The problem is that the third party is reporting that they're getting a 404 error on the callback because the model hasn't been created yet. Our own logs confirm this:
2014-03-13T18:12:10.291730+00:00 app[web.1]: ActiveRecord::RecordNotFound (Couldn't find TextMessage with id=32)
We checked and the ID is correct. What's even crazier is that we threw in a puts to log when the model is created and this is what we get:
2014-03-13T18:15:22.192733+00:00 app[web.1]: TextMessage created with ID 35.
2014-03-13T18:15:22.192791+00:00 app[web.1]: ActiveRecord::RecordNotFound (Couldn't find TextMessage with id=35)
Notice the timestamps. These things seem to be happening 58 milliseconds apart, so I'm thinking it's a race condition. We're using Heroku (at least for staging) so I think it might be their virtual Postgres databases that are the problem.
Has anyone had this sort of problem before? If so, how did you fix it? Are there any recommendations?
after_create is processed within the database transaction saving the text message. Therefore the callback that hits another controller cannot read the text message. It is not a good idea to have an external call within a database transaction, because the transaction blocks parts of the database for the whole time the slow external request takes.
The simples solution is to replace after_save with after_commit (see: http://apidock.com/rails/ActiveRecord/Transactions/ClassMethods/after_commit)
Since callbacks tend to become hard to understand (and may lead to problems when testing), I would prefer to make the call explicit by calling another method. Perhaps something like this:
# use instead of .save
def save_and_sent_sms
save and sent_sms
end
Perhaps you want to sent the sms in the background, so it does not slow down the web request for the user. Search for the gems delayed_job or resque for more information.
Do you have master/slave database where you always write to master but read from slave? This sounds like the db replication lag.
We solved such problems by forcing a read being made from the master database in the specific controller action.
Another way would be to call send_sms after the replication has been finished.