I have a long running job that scrapes information from the internet (approx 2 mins) and I am having trouble with updating my pages/views with the new (additional) instances of the data that I scrape.
I thought it might be doable with a callback (on create/update) but I get an error saying I am redirecting too many times, so I figured I would most likely need some ajax and/or callback combination in order to achieve a continuous updating of the page. Im familiar with using ajax in order to update a section of the page when the user creates a post or comment but Im not sure how to do this coming from a background job.
I briefly toyed with using ActionCable (just opening a channel and somehow stream the data through there) but is there not an easier way to essentially update the page on a change in the database?
My current solution is to simply js reload the page for a while but that seems awefully primitive.
Controller
def create
#search = Search.new(search_params)
if #search.save
PreRunAllJob.perform_later(#search.title, #search.id)
respond_to do |format|
format.html { redirect_to search_path(#search) }
format.js # currently empty
end
else
render :new
end
end
def show
#search = Search.find(params[:id])
#jobs = Job.where(search_id: #search.id).order(quality: :desc)
end
Search Model
class Search < ApplicationRecord
has_many :jobs
end
Job Model
class Job < ApplicationRecord
belongs_to :search
end
searches/show.html.erb
<div class="container">
<%= render "jobs", remote: true %>
</div>
_jobs.html.erb
[...]
<% #jobs.each do |job| %>
<div class="card">
[...]
</div>
<% end %>
[...]
So just to quickly summarise: The long running background job creates an instance of 'Search' which has many instances of 'Job'. On the searches/show.html.erb I display cards, each holding information of a single instance of 'Job'. While the search is ongoing I'd like to update the view correspondingly (trickling in for instance).
What path could/should I take here? pure ajax? Callbacks?
Related
I'm learning RoR by building my first app (yay!). I gotta a question thought as rails guides do not cover this topic:
How to render unique results on #show to a user without storing any data in a model?
Steps I want to take:
Create a basic index view with a form_tag that will allow user to submit a link (string) and click submit button
Write Service Objects that will allow me to parse that link and create a response I want user to see
I want to write a #show method in a separate controller that will allow me to display all the data. (I also want to parse my params[:link] in that method using Service Objects.
I want to finally display this data in a table in #show view (probably I need to create a unique #show/[:id] for each user?
Here's what my app looks like at the moment (more or less):
Static Controller (just to render index.html.erb with a form)
class StaticController < ApplicationController
def index
end
end
Static Index view (yup, parsing imgur link here)
<h1>Hello Rails!</h1>
<%= form_tag("/images", method: "post") do %>
<p>
<%= label_tag(:imgur_link) %><br>
<%= text_field_tag(:imgur) %>
</p>
<p>
<%= submit_tag("Get my cards") %>
</p>
<% end %>
Images Controller (where all the magic SHOULD happen)
class ImagesController < ApplicationController
def show
#collection = params[:imgur_link]
#service1 = service1.new(*args).call
#service2 = service2.new(*args).call
...
end
end
Images Show view
Empty as I'm stuck with the Images controller at the moment.
Any help would be more than appreciated.
Thanks!
There is no reason you should put something into storage just in order to display it. If you get to a point when you have the results in your controller, you could just pass them to view in some #variable
As I see, you have set up the form for step 1. If you also have routes.rb call 'images#show' for POST /images, then you will have params[:imgur_link] available in your show action. This should do:
# config/routes.rb
YourApplication.routes.draw do
# ...
post '/images' => 'images#show'
end
Now you have to somehow process that link. Since I don't know what your results should be, I'm going to assume that you have two classes, Service1 and Service2, both of which accept an URL and return collection of results, and both collections hold the elements of the same class. Then you can leave only unique results for your show view, like this:
# app/controllers/images_controller.rb
class ImagesController < ApplicationController
def show
link = params[:imgur_link]
results1 = Service1.new(link).results
results2 = Service2.new(link).results
#results = (results1 + results2).uniq
end
end
Then you can do something with #results in your show view. E.g.
# app/views/images/show.html.erb
<% #results.each do |result| %>
<%= result.inspect %>
<% end %>
Actually I need a big help, I'm using rails 5.1.4, I get stuck when rendering a partial with ActionCable and background Jobs. In my partial, I have a condition on current_user to check if current_user is the message owner and get his username with green color to make somes differents, so far display an update and delete button for each message he's the owner in the room conversations. But, if I refresh the page or remove current_user in the partial before rendering it works. However, I want that condition happens. Or, looking for a best way if there is one. THANKS IN ADVANCE.
Here is the error displayed in my terminal:
ERROR: ActionView::Template::Error: Devise could not find the warden::Proxy instance on your request environment.
Those are my files content.
The partial: _conversation.html.erb
<div id="message">
<% if conversation.user == current_user %>
<span style="text-align: center; color: green"><%= conversation.user.username %>
</span>
<% else %>
<span style="text-align: center; color: magenta"><%=
conversation.user.username %></span>
<% end %>
<p style="color: black"><%= conversation.body %></p>
</div>
Message_controller.rb
def create
conversation = #room.conversations.new(conversation_params)
conversation.user = current_user
conversation.save
MessageRelayJob.perform_later(conversation)
End
Room/show.html
<div id="conversations" data-room-id="<%= #room.id %>">
<%= render #room.conversations %>
</div>
MY JOB CLASS
class MessageRelayJob < ApplicationJob
queue_as :default
def perform(conversation)
ActionCable.server.broadcast "room_tchats_#{conversation.room.id}_channel",
conversation: render_conversation(conversation)
end
private
def render_conversation(conversation)
ConversationsController.render partial: 'conversations/conversation', locals: {conversation: conversation}
end
end
It can be happening when you try to get Devise current_user in some part of code being managed by action cable. like a background job to render comment or something else. you can resolve it by using something like following in your controller, since you cant access warden at a model or job level(according to my limited knowledge): (I call a job right after creation of my comment in CommentsController create action, which calls a private method to render a comment partial containing edit and delete button, for which current_user was required)
def create
#product = Product.find(comment_params[:product_id])
#comment = #product.comments.build(comment_params)
#comment.save!
gon.comment_id = #comment.id
gon.comment_user_id = #comment.user_id
ActionCable.server.broadcast "chat", comment: render_comment
render :create, layout: false
end
def render_comment
CommentsController.renderer.instance_variable_set(:#env, {"HTTP_HOST"=>"localhost:3000",
"HTTPS"=>"off",
"REQUEST_METHOD"=>"GET",
"SCRIPT_NAME"=>"",
"warden" => warden})
CommentsController.render(
partial: 'comments/comment_detail',
locals: {
product: #product,
comment: #comment
}
)
end
this will help you resolve warden issue, if you have used devise's current_user in that partial, it will give you the commentor user (as it should since that user initiated the rendering of partial). Now to solve this, if you have a front end framework you might need to fetch the current user from cookies in order to restrict some actions like edit/delete. but if you are working in pure rails the solution I came across is that you have to make a hidden field in the dom having current users id, and you will fetch that id for comparison in a script. you might need to access rails variables in javascript, for that you can use GON gem. I know this answer might contain much more than asked but I've searched alot and no where I found a satisfactory solution to this problem, feel free to discuss.
There doesn't appear to be a gem for this, and I think a CMS is overkill as the client only wants to edit the welcome message on the home page!
Here's what I think I should do:
1) Create Page model:
rails g model Page name:string
2) Create Field model:
rails g model Field name:string content:string page_id:integer
3) Create relationship, Page h1:b2 Field
4) Create rake task to set up the message field that belongs to the welcome page:
namespace :seeder do
namespace :initial_seed do
task pages: :environment do
p = Page.create(name: "Welcome")
p.fields.create(name: "welcomemessage", content: "everything goes here. The long rambling welcome!")
end
end
end
5) Create a 'static' controller for the 'static'-ish pages. The home, the about us etc...
class Static < ApplicationController
def home
#fields = Page.where().fields
end
end
6) In the view, populate the welcome message from the database (I'll create a helper for this):
<% field = #fields.find {|x| x[:name] == 'welcomemessage' } %>
<%= field.content %>
So that's the reading done. Now onto the creation, updation and deletion:
6) Create a control panel controller:
class Panel < ApplicationController
def pages
#pages = Page.all
end
end
7) Display fields in the view at panel/pages.html.erb: (I'll use partials here)
<% #pages.each do |page| %>
Title: <%= page.name %>
<% page.fields.each do |field|%>
Field: <%= field.name %>
<% form_for(field) do |f| %>
<% f.text_area :content%>
<% f.submit %>
<%= end %>
<% end %>
<% end %>
Now this is just a rough run down of what I want to do. There are a few problems I want to query, though.
Is this sort of how you would do this?
How should I configure my routes? What is a clever way of populating the #fields variable (see step 5) with the fields for the page we're viewing?
If I do have a panel/pages.html.erb view, should it simply display all of the editable fields in text areas? How should it update these areas? Multiple submit buttons inside multiple forms? What if someone wants to edit many fields at once and submit them all at once?
Where should these forms go? Should I create multiple RESTful actions all inside the Panel controller like this?:
class Panel < ApplicationController
# new and create not present as the pages have to be created manually
# Enabling the user to create their own pages with their own layouts is a bit insane
def pages
#pages = Page.all
end
def pages_update
end
def pages_destroy
end
end
Multiple restful routes in one controller doesn't strike me as organised, but it would make it easier to lock down the panel controller with a before_action hook to redirect if not admin...
Also, I'm nearing the end of a big job, and all I need to do is add the ability to edit one field on one page and them I'm done and I really don't want to have to figure out alchemy_cms or whatever. In future, yes, but, please, please, please someone give me some small pointers here.
I would strongly advise against building your own CMS. It's fraught with difficulties, and it seems like you're running up against some of those now. You should go and check out something like AlchemyCMS.
I have an app displaying events in lists. The events can be displayed either for the wholde community or by organizer.
class CommunitiesController < ApplicationController
def show
#community = Community.find(params[:id])
end
end
class OrganizersController < ApplicationController
def show
#organizer = Organizer.find(params[:id])
end
end
show.html.erb:
<%= #community.events.limit(15).each do |event| %>
...
<% end %>
I want to implement a "Load more events"-button at the end of the list, that loads the sequential events via an ajax-call in batches of 15.
So, for the sake of good MVC-design, I have the following questions:
Where should this additional action (the request for more events) go, in Communities/Organizers or in Events? Or even somewhere else as it breaks REST?
And in what model (or controller?) should the logic, calculating where in the sequence we are and what to send, go?
Feels like controller logic. I would have the controller extract the appropriate chunk of 15 records based on some index specified by a :page parameter, then the view just displays whatever it is passed, e.g.
page_size = 15 # configure this somewhere
...
#events = #community.events.offset(page_size * (params[:page] || 0).to_i).limit(page_size)
Then in your view...
<%= #events.each do |event| %>
...
<% end %>
There are other ways to pass the #events into your view, and probably better approaches to paging, but this should be the basic idea.
I'm building a martial arts related database, currently I have the following associations set up:
Student has_and_belongs_to_many :styles
Style has_many :ranks
Student has_many :ranks, through: :gradings (and vice versa)
I'm generating a form as follows, depending on the student's styles:
So the headings are generated by the Style model (Tai Chi, Karate...), then their rankings listed below (taken from the Rank model), and the "Dojo" and "Date" fields should belong to the Grading model once created.
The question: I know how to build a form that creates one association (or one association + its children), but how do I build a form that creates multiple associations at once?
Also, what would be a clean way to implement the following:
Only lines which are ticked become associations
Dojo and date must be filled in for ticked lines to save successfully
If a line is unticked it will destroy any previously created associations
This is what I've currently implemented to retrieve the correct records:
class GradingsController < ApplicationController
before_filter :authenticate_sensei!
def index
#student = Student.includes(:styles).find(params[:student_id])
#ranks = Rank.for_student_styles(#student)
split_ranks_by_style
end
private
def split_ranks_by_style
#karate = #ranks.select_style("Karate")
#tai_chi = #ranks.select_style("Tai Chi")
#weaponry = #ranks.select_style("Weaponry")
end
end
# Rank model
def self.for_student_styles(student)
includes(:style).where("styles.id in (?)", student.styles.map(&:id))
end
def self.select_style(style)
all.map { |r| r if r.style.name == style }.compact
end
Complicated forms like this are best handled in a service object initiated in the primary resource's create or update action. This allows you to easily find where the logic is happening afterwards. In this case it looks like you can kick off your service object in your GradingsController. I also prefer formatting a lot of the data in the markup, to make the handling easier in the service object. This can be done a'la rails, by passing a name like "grade[style]" and "grade[rank]". This will format your params coming in as a convenient hash: {grade: {style: "karate", rank: "3"}}. That hash can be passed to your service object to be parsed through.
Without really grasping the full extent of your specific requirements, let's put together an example form:
<%= form_for :grading, url: gradings_path do |f| %>
<h1><%= #rank.name %></h1>
<%- #grades.each do |grade| %>
<div>
<%= hidden_field_tag "grade[#{grade.id}][id]", grade.id %>
<%= check_box_tag "grade[#{grade.id}][active]" %>
...
<%= text_field_tag "grade[#{grade.id}][date]" %>
</div>
<%- end %>
<%= submit_tag %>
<%- end %>
With a form like this, you get your params coming into the controller looking something like this:
"grade"=>{
"1"=>{"id"=>"1", "active"=>"1", "date"=>"2013-06-21"},
"3"=>{"id"=>"3", "date"=>"2013-07-01"}
}
Nicely formatted for us to hand off to our service object. Keeping our controller nice and clean:
class GradingsController < ApplicationController
def index
# ...
end
def create
builder = GradeBuilder.new(current_user, params['grade'])
if builder.run
redirect_to gradings_path
else
flash[:error] = 'Something went wrong!' # maybe even builder.error_message
render :action => :index
end
end
end
So now we just need to put any custom logic into our builder, I'd probably recommend just making a simple ruby class in your /lib directory. It could look something like this:
class GradeBuilder
attr_reader :data, :user
def self.initialize(user, params={})
#user = user
#data = params.values.select{|param| param['active'].present? }
end
def run
grades = data.each{|entry| build_grade(entry)}
return false if grades.empty?
end
private
def build_grade(entry)
grade = Grade.find(entry['id'])
rank = grade.rankings.create(student_id: user, date: entry['date'])
end
end
There will obviously need a lot more work to pass all the specific data you need from the form, and extra logic in the GradeBuilder to handle edge cases, but this will give you a framework to handle this problem in a maintainable and extensible way.