I'd like to send emails from a table every night at midnight, so I've created a model to track all communications to be sent. This Communication model stores who the letter is to, from, and the contents of the letter to be sent as html. The user enters a criteria to match for whom the letter is intended: state, country, favorite color, and so which returns a list of acceptable matches.
This list of acceptable matches is iterated across and a new Communication is generated for each. How do I render the contents of a partial view to a string to store in the database for delivery at midnight.
#communication = Communication.new(params[:communication])
#communication.body = //Render Partial with local variables to string here
January 8, 2010: I've implemented the solution proposed by neutrino, and my code looks like this:
#communication.message_body = render_to_string(
:partial => "letters/small_letter",
:locals => { :quote => #quote})
The drawback to this approach is that it requires a context so it must be rendered within a controller, this rules out generating the email using a rake file. As others have pointed out the approach of using a Communication model may introduce some unnecessary complexity. At this time since the conditions I use to generate the list of recipients is never stored I've opted to continue to use a communication model.
As (almost) always in Rails, there's a method for that: ActionController::Base#render_to_string
In Rails 3, this method was moved to AbstractController::Rendering#render_to_string.
You may want to look at techniques to render a template outside of a controller, such as:
http://geek.swombat.com/rails-rendering-templates-outside-of-a-contro
That being said, it's probably better to make use of the built-in email sending class ActionMailer::Base which can render templates for you. Storing the parameters in your Communication model is probably better than storing your unrolled HTML, as these parameters can be serialized and later pushed back into a "send_X_notification" type call.
These can be built using the generator:
script/generate mailer communications_mailer
you could try this (in the rails console):
class StaticRender < ActionController::Base
def self.render_erb(template_path, params)
view = ActionView::Base.new(ActionController::Base.view_paths, {})
class << view
include ApplicationHelper
end
view.render(:file => "#{template_path}.html.haml", :locals => params, :layout => false)
end
end
StaticRender.render_erb("home", {})
you need to have the view "home" for that....
Have you tried action mailer? It will get your views rendered and provide active record support also.
Related
This is Rails 5 with Mongoid.
I have a MVC structure for load balancers. The model and the controller do all the validation and sanitising I want and need. However, I want to be able to send an array of balancer data structures to an upload controller, which will verify the upload is in a sane format, and then iterate over the array dispatching to the balancers controller to validate, insert, or upsert each entry as needed -- and accumulate statistics so that at the end of the iteration I can produce an HTML or JSON rendering of success count and detailed errors.
I'm pretty sure I need to frob the params structure as part of each iteration/dispatch, but it's unclear how, or whether I want to use the BalancersController's #new, #create, #update, #save, or what method in order to get the validation to work and the insert/upsert to be done properly.
I haven't yet been able to find anything that seems to describe this exact sort of bulk-upload scenario, so any/all help & guidance will be much appreciated.
Thanks!
(There are serveral other models/controllers I want to push through here; the balancer case is just an example.)
I've sort of got the collecting of the statistics summary down, but I' having trouble dispatching to the balancers controller to actually update the database with anything other than nil.
[edited]
Here's an simple example model:
class Puppet::Dbhost
include ::PerceptSys
include Mongoid::Document
include Mongoid::Timestamps
validates(:pdbfqdn,
:presence => true)
field(:pdbfqdn,
:type => String)
field(:active,
:type => Mongoid::Boolean)
field(:phases,
:type => Array)
index(
{
:pdbfqdn => 1,
},
{
:unique => true,
:name => 'dbhosts_pdbfqdn',
}
)
end # class Puppet::Dbhost
The uploads controller has a route post('/uploads/puppet/dbhosts(.:format)', :id => 'puppet_dbhosts', :to => 'uploads#upload').
The document containing upload information looks like this:
{
"puppet_dbhosts" : [
{
"pdbfqdn" : "some-fqdn",
"active" : true
}
]
}
The uploads#upload method vets the basic syntax of the document, and then is where I get stuck. I've tried
before_action(:upload, :set_upload_list)
def set_upload_list
params.require(:puppet_dbhosts)
end
def upload
reclist = params.delete(:puppet_dbhosts)
reclist.each do |dbhrec|
params[:puppet_dbhost] = dbhrec
dbhost = Puppet::Dbhost.new
dbhost.update
end
end
In very broad strokes. The logic for validating a puppet_dbhost entry is embedded in the model and the controller; the uploads controller is meant to simply dispatch and delegate, and tabulate the results. There a several models accepting uploads in this manner, hence the separate controller.
Well, I feel sheeeepish. Obviously the correct path is to abstract the generic upload methods and logic into a separate module and mix it in. Routes can be adjusted. So no need for controllers to know about the internals of others for this scenario. Thanks for the hint!
I am facing an issue with accessing a particular variable of a method say A , in another method say B in the controller.. The size of the object(variable) is too big since it contains the results of a service call made.. My usecase is like on selecting an option from a drop down box, it redirects to a method B in controller and the same object(variable) should be parsed. How can I access the variable in the other method?
I tried storing in a cookie and since the size is too big I am getting Cookie Overflow exception. I am not using a DB. So I guess using memcache won't work. Also tried storing it as hidden field in view and passed its value as a data through ajax call. But I am getting it as a string. Tried to specify datatype as json and several other ways.. but of no use..Using ##var also din work..Not sure why..
Code:
On change of the drop down:
$(document).ready(function(){
$('#filter_service').change(function() {
$.ajax({type: "GET",
url: "/device_troubleshootings/query_operation",
data: { filter_service: $('# filter_service').val()},
});
});
});
Service call:
def log_results
//Service call
#get_log_results = LogQueryService.client.get_logs(Com::Amazon::Logqueryservice::DeviceSerialNumberQuery.new(:search_text => # search , :index => 'dms', :index_type => '_all', :from_time_stamp => #from_time_stamp, :to_time_stamp => #to_time_stamp))
#dsn_result = #get_log_results.logs_result_obj_list
end
Here, I am trying to access #dsn_result object in "/device_troubleshootings/query_operation” method.
Please suggest me ways to access the variable.
MVC
I think you're getting confused with how Rails should work
Remember, Rails (which is just a framework for Ruby) is built on the "MVC" programming pattern. This means each time you send a request to your Rails application, it has to be handled by a single controller#action which you will then allow you to pull the relevant data from your models
The problem you have is you're trying to load multiple controller methods, and pass the same data to both. This might work in Ruby, but not Rails (Rails is stateless):
--
Model
The correct way to handle this type of setup is by creating another request for your application, which will load another controller#action, allowing you to access the data you need
As demonstrated by the MVC diagram above, each time you send a request to Rails, it's basically a new request. This means that unless you've persisted your data in the likes of a cookie, you'll need to load the data from the model.
The problem you have is you're trying to store an entire data-set in the front-end of your system. This issue is very bad, as not only is it inefficient, but it goes against the MVC pattern completely.
You'll be much better storing the bare-minimum data set you need in the front-end (ids or similar), which you will then be able send to your controller via ajax; building a new data-set from
--
Class Variables
You mentioned you tried to declare some ##class variables to no avail. The problem with this is that the class vars will only be available for an instance of a class.
As mentioned, since Rails is stateless, the class variables won't persist between requests (how can they?). I think you know this already, considering you've been trying to use cookies to store your data
The way to resolve this is to rebuild the data each time from the model (as detailed above)
Solution
The solution for you is to "go stateless"
Here's how:
Treat Method A and Method B as completely separate "ACTIONS"
When using these actions, you need to consider the smallest piece of data to pass between the two
To load Method B, you need to send a new request from your browser (as if you've never loaded Method A before)
Your method_a can be handled in the "standard" way:
#config/routes.rb
resources :your_controller do
collection do
get :method_a
get :method_b
end
end
This will mean that you can load method_a relatively simply:
#app/controllers/your_controller.rb
Class YourController < ApplicationController
def method_a
#get_log_results = LogQueryService.client.get_logs(Com::Amazon::Logqueryservice::DeviceSerialNumberQuery.new(:search_text => # search , :index => 'dms', :index_type => '_all', :from_time_stamp => #from_time_stamp, :to_time_stamp => #to_time_stamp))
#dsn_result = #get_log_results.logs_result_obj_list
end
end
As you know, the #dsn_result will not persist through to the next request.
There are two ways to resolve this (set a CONSTANT -- if you're pulling from an API, this will give you a single call -- or use a before_action to set the variable for as many actions as you need). I'll detail both for you:
#app/controllers/your_controller.rb
Class YourController < ApplicationController
before_action :set_log_data
def method_a
end
def method_b
end
private
def set_log_data
#get_log_results = LogQueryService.client.get_logs(Com::Amazon::Logqueryservice::DeviceSerialNumberQuery.new(:search_text => # search , :index => 'dms', :index_type => '_all', :from_time_stamp => #from_time_stamp, :to_time_stamp => #to_time_stamp))
#dsn_result = #get_log_results.logs_result_obj_list
end
end
This will work if you pull data from your own data-set (using the models), however, the better way to do this in your case will likely be to set a constant (considering, of course, that you don't want the data to change):
#config/initializers/dsn_result.rb
get_log_results = LogQueryService.client.get_logs(Com::Amazon::Logqueryservice::DeviceSerialNumberQuery.new(:search_text => # search , :index => 'dms', :index_type => '_all', :from_time_stamp => #from_time_stamp, :to_time_stamp => #to_time_stamp))
DSN_RESULT = get_log_results.logs_result_obj_list
In my case I solved with global variable $my_global_var
So my files look like this
routes.rb
Rails.application.routes.draw do
resources :pages
root 'pages#index'
post 'pages/test'
end
pages_controller.rb
class PagesController < ApplicationController
def firstaction
$my_global_var = "My global var"
puts $my_global_var
end
def secondaction
puts $my_global_var
end
end
index.html.erb
<%= button_to 'Test', pages_test_path, method: :post %>
As title says, why does Rails prefer to use the #params variable inside of a Controller action when you are responding to the action instead of passing the individual parameters through the function arguments when we call the function?
Other frameworks use this (i.e, ASP MVC) and I was just wondering if there was a reason for that design decision, because it doesn't seem very intuitive.
Ie. Why does Rails do
def index
name = params[:name]
end
Instead of
def index(name)
end
The point is, most of the actions in a controller handles the view REST-fully. The params comes from the user's browser when they interact with the page or send a new variable request to the page.
These requests are variable, and Rails makes it uniform by maintaining the parameters in params hash. If the following GET requests arrive:
http://localhost:3000/products?color=red&quality=best
the params hash will automatically be populated as {'color' => 'red', 'quality' => 'best'}. Rails doesn't expect your action to manually handle the parameters.
Similarly, consider you are getting a POST request from a page where a user filled a form. In that scenario, the params obtain the parameters which are composed with form helpers inside views.
Though in hyptothetical case you are dealing with general methods instead of actions, such as below, you will have to do it by passing arguments.
def show
if params['color'] == 'red'
#product = obtain_product('red')
else
#,..
end
end
def obtain_product(color)
Product.where('color = ?', color).first
end
Hope it is clear. :)
#kidorrails has a great answer, and I wanted to add to it:
If you wanted to pass the params to each method directly, it would go against the #1 Rails convention - keep it DRY. By having a separate params hash, you not only have access to all the params you want, but you can access them through as many methods as you need
For example, take strong_params:
#controller
def new
#model = Model.new
end
def create
#model = Model.new(strong_params)
#model.save
end
private
def strong_params
params.require(:model).permit(:your, :params)
end
As #apneadiving mentioned, the params hash is created in another part of the stack, meaning it's available over all the methods required. It's most efficient & versatile way to do it IMO
I used the nested model gem to create a Picture that can take tags. Now I have added an attribute to my model Picture so it has an attribute taglist. When I create a new tag, I want this to happen
class TagsController < ApplicationController
def create
#tag = Tag.new(params[:id])
if #tag.save
taglist = picture.taglist
taglist+=#tag.tagcontent
#tag.picture.update_attributes(:taglist => taglist)
end
end
end
and in my routes
resources :pictures do
resources :tags
end
When i make a new tag, nothing happens in the taglist attribute, like nothing happened, why?
It's hard to help due to lack of information, but I see two possible issues:
Tag.new(params[:id]) doesn't make sense. Assuming Tag inherits from ActiveRecord::Base, you need to pass it a hash of attributes (e.g. Tag.new(:name => 'mytag')) You are likely not getting into the if #tag.save block at all due to validation errors. Also, you don't need to provide an id to an object you want to create. The database chooses the id.
Inside the block, picture is undefined on the first line.
Why not try debugging with something like:
if #tag.save
taglist = picture.taglist
taglist+=#tag.tagcontent
#tag.picture.update_attributes(:taglist => taglist)
else
p "ERRORS:"
p #tag.errors.full_messages
end
See what errors that prints out into your console.
I definitely think that picture is probably undefined in the create method of the controller. Can you show us the view, the form you're using to create a new tag? Is there a form field through which you're choosing which photo gets the tag?
Please show us the association and your view for creating the new tag.
Actually, what I'd really recommend instead of cooking up your own is to use:
Agile Web Development's acts_as_taggable_on_steroids
It's an excellent plugin to make tagging easy; it has quite a few nifty features built in, including the searches, tag clouds, etc. We use it on our projects.
My rails app produces XML when I load /reports/generate_report.
On a separate page, I want to read this XML into a variable and save it to the database.
How can I do this? Can I somehow stream the response from the /reports/generate_report.xml URI into a variable? Or is there a better way to do it since the XML is produced by the same web app?
Here is my generate_report action:
class ReportsController < ApplicationController
def generate_report
respond_to do |format|
#products = Product.all
format.xml { render :layout => false }
end
end
end
Here is the action I am trying to write:
class AnotherController < ApplicationController
def archive_current
#output = # get XML output produced by /reports/generate_report
# save #output to the database
respond_to do |format|
format.html # inform the user of success or failure
end
end
end
Solved: My solution (thanks to Mladen Jablanović):
#output = render_to_string(:file => 'reports/generate_report.xml.builder')
I used the following code in a model class to accomplish the same task since render_to_string is (idiotically) a protected method of ActionController::Base:
av = ActionView::Base.new(Rails::Configuration.new.view_path)
#output = av.render(:file => "reports/generate_report.xml.builder")
Perhaps you could extract your XML rendering logic to a separate method within the same controller (probably a private one), which would render the XML to a string using render_to_string, and call it both from generate_report and archive_current actions.
What I typically do in this type of situation is to create a separate module/class/model to generate the report (it could even potentially be right in the Product model). This separate component could be in app/models or it could be in lib. In any case, once you have it extracted you can use it anywhere you need it. The controller can call it directly. You can generate it from the console. You can have a cron job generate it. This is not only more flexible, but it also can help smooth out your request response times if the report becomes slow to generate.
Since you are using a template it's understandable that the controller route is convenient, but even if you have to include some kind of ruby templating system in your auxiliary lib, it's still probably going to be less hassle and more flexible then trying to go through the controller.
#output = Product.all.to_xml
I'm sorry, is you question about Xml or about sessions? I mean is the fact that your action generates Xml material to the question? Or do you just want to save the output of the action for latter use?
You said on a "separate" page - you mean on another request? (like after user approved it?)
Why do you want to save the output? Because it should be saved exactly as rendered? (for example user can get frustrated if he clicked to save one report and you saved another)
Or is this thing expensive to generate?
Or may be, I got it wrong and it's about refactoring?