Is it possible that I create my model using "rails generate model..." which creates all them CRUD stuff including views for create, update and delete, AND then I override rails CRUD methods to do something else instead for example printing them all out or whatever?
I need to instead encode my model into JSON and send that to a middleware that will save it into a database.
A small example will really help... thanks a lot...
Please help!
Answer to my question that I have eventually found is to use ActiveModel instead.
Thanks for you input lads!
The only thing that really connects scaffold to ActiveRecord is class Model << ActiveRecord::Base. So just take that away.
Then run the scaffold and take away the line at the top of the class that inherits from ActiverRecord. After that you need to connect to your db with whatever you want.
Related
In rails/activerecord, is it possible to have three ruby classes, two of which inherit from one main class, and then have two separate tables for pots and pans. Like so...
class Tupperware < ActiveRecord::Base
end
class Pot < Tupperware
end
class Pan < Tupperware
end
and the advantage would be that I could use the Tupperware.find() method, and a few other things, without having to customize for each different type.
I know for sure it works with mongoid – I've done it myself a couple of times. I'm not sure if this would work in relative database engine...
But you're actually asking a question you could answer yourself, by just trying to do what you said.
[In response to OP's comment]:
I'm just saying you should do a test rails application using a relative db, such as mySQL or SQLite and define your models exactly the way you think.
I have an abstract model I use in my application. It's working perfectly and the find() method works just as you'd expect, but I'm working on Mongoid, so I don't use ActiveResource and can't say for sure if this will work for you. The only thing you can do is try.
Here, take a look at this excerpt from my code:
https://gist.github.com/ellmo/5262681
I am currently going through Hartl's Rails Tutorial, and through the first 10 chapters or so have gotten used to the convention of putting most of the actions/methods in the controller. Currently, as the book is going through and defining a feed method for the Microposts, the method is placed with the User.rb model instead. As I am relatively new to the world of rails (and programming in general), I was wondering what the rationale or convention followed for putting this method (copied below) in the Model?
The method placed in the User.rb model:
def feed
# This is preliminary. See "Following users" for the full implementation.
Micropost.where("user_id = ?", id)
end
There is actually quite some contention on what code to put where, but in general, there are some easy guidelines to follow.
Does the method have to know some detail about the underlying data structure? Put it in the model.
An easy way to determine this is when it uses ActiveRecord methods like find, where, or specific columns in the database. By keeping this logic in the model, that means if you need to change the underlying datastore, you only have to change the model.
Does the method have some say in how a page is going to be rendered? Put it in the controller.
Generally, controllers should be pretty thin, pushing data to views and saving form data back to models.
While (if I remember correctly) Hartl does not take about non-rails classes, don't be afraid to put 'business logic' outside of the rails structure. You can create a app/lib or app/services or app/x directory and put plain old ruby objects in there, which can then be called from your controllers and models to handle those things they are good at.
Aim to 'push' things 'up' into the model as much as possible, then they will be repeated less and available to more. Don't just use models for Active Record database tables.
You can often unit test models easier.
Another 'next' place to put stuff that is shared is in /lib
In Ruby on Rails 3, I can't scaffold a model called Data. I can make the Data controller but I can't make the Data model. It has to be UserData or something along those lines.
Ruby on Rails says, it is being used already (my guess is) by the gem itself.
Am I the only one getting this?
How come I cannot create the model name to be Data only?
I think your problem is that there is already a Data class in the Ruby standard library (both 1.9+ and 1.8.7). The Data class is only defined in one of the C source files but it is still publicly visible. I'm not sure what the Data class is for (and the documentation is rather sparse) but the name is already in use so Rails won't let you use it. You can make the controller easily enough because the controller will be DataController and that name isn't taken.
I need perform some extra logic on an object before it is saved to the database. I would assume that using a before_filter would be the correct way to accomplish this, but I'm not sure how to pass the object to be saved into my before_filter method.
This is my first ever post here so go easy on me!
Theres a before_save method, in Rails 3 at least, that can be called in the model.
in Posts model
before_save :add_url_and_ID
def add_url_and_ID
#extra logic
self[:url] = whatever.com
self[:member_id] = member.id
end
I'm probably way off but its my first go!
That all sounds like model code to me. To get the most out of Rails (or any MVC framework) follow the 'Fat Models, Skinny Controllers' rule of thumb. It can be taken too far, but I think in this case it's pretty clear. If there are errors with the helper functions you mention, shouldn't the save action fail with appropriate error messages?
There's lots of good posts on SO on this subject. Here's one
If this doesn't give you enough to work with I'd suggest posting some code.
This is a complicated question with many possible answers, so I'll break down my situation into simple bullet points to help narrow down the solution:
My Rails App Has the Following 'Objects'
Author
Feed
Update
FeedTypes
The Objects are Related Like So:
Authors can have 1 or more Feeds
Feeds can have one or more Updates
A Feed has one feedType
Example Setup:
Author: Levi Hackwith
Feed: view-source:http://www.twitter.com/statuses/user_timeline/opnsrce.xml
FeedType: Twitter
Update: The tweets inside the Feed
My problem and My Questions:
Problem:
I need to parse the above-mentioned feed and store each tweet in the updates table. To parse the feed, I was thinking of writing a custom Feed class which would get inherited by TwitterFeed, FacebookFeed, TumblrFeed, etc.
However, I'm not sure if this is the 'Best Practice' for solving this kind of problem.
Questions:
When is it appropriate to develop a custom class to perform an action in RoR (as opposed to going through the Model or Controller)?
If this situation does not call for a custom class, which element should I apply the parsing logic to? The model or the controller?
If this is an appropriate situation for a custom class, where in my rails application should I store it (in other words, what's the right 'convention')?
You are probably going to have a background task invoked from time-to-time to check all the feeds, fetch new updates and store those in database. This task is completely separate from controllers and it should be possible to invoke it without any controller logic.
Your abstraction looks fine. You can further have something like XmlFeed < Feed if several feeds share a common XML structure.
1) Controllers should talk to database/models and pass relevant data to the view to render. Everything else should be either in a model, helper or library.
2) Are you asking where the parsing logic belongs to? In MVC, I think this would belong under the Model and/or a helper class, but definitely not the controller.. it's not its responsibility.
3) Classes holding data go into app/models. Classes that have nothing to do with holding data, go into the lib directory.
Don't shy away from using a custom class if it's appropriate. If you need another a class, then add one, the fact you are using rails is not relevant to that decision.