So I am trying to find a better way of refreshing the page. I have an app that builds an Excel spreadsheet using data you capture on the system. So what I was having it do is just reloading the page every 10 seconds till it's completed, so that the notice could be displayed properly.
Something like this (it's in the HAML syntax)
.pending_downloads
- if downloads_policy.pending?
.notification_notice
= image_tag 'spinner.gif'
Your data download is being prepared. This should only take a few minutes. It is safe to leave this page and return later.
= link_to "Cancel download.", download_path(downloads_policy.pending), :method => :delete, :class => "delete_link"
= javascript_tag("ToolkitApplication.periodical_reload();")
The Ajax (it's in coffeescript) for the periodical_reload(); method looks like this:
class #ToolkitApplication
this.periodical_reload = () ->
setInterval (->
window.location.reload()
), 10000
This approach I feel could be done better. I would like to have the ajax rather query the model every 3 seconds to see when the objects state has changed and then once it has changed then it will reload the window. So you dont get the page reloading like 10 times before the download is ready, every time I try reasearch if this is possible I get this rubyonrails guide which isnt really insightful with this sort of edge case. Is this possible and if so is there any good tutorials/blog posts/advice on how to do this? Google is yielding nothing.
So what i ended up doing was easy. Thanks to all that helped. in my controller i set a private method to check state
def any_uploads_status_changes?
return true if !Upload.exists?(params[:id])
return true if Upload.find(params[:id]).status
end
And then set another call in the controller called status:
def status
if any_uploads_status_changes?
render :text => 'window.location.reload();'
else
render :nothing => true
end
end
then set up an ajax request method(its in coffeescript syntax) ->
this.periodically_send_ajax_request = (url, method, interval) ->
setInterval (->
$.ajax
url: url
type: method
success: (result) ->
), interval
And then in the view just under condition called this request using js:
:javascript
ToolkitApplication.periodically_send_ajax_request("#{status_download_path(:id => downloads_policy.pending.id, :class => #model_class).html_safe }",'get', 2000);
just make sure that the path exists to the controller action
resources :downloads, :only => [:show, :destroy] do
member do
get :status
end
end
and there you go it will then query the controller according to what ever interval you specify and only if there are changes will it then reload the page. its a bit more code then simply reloading periodically but the user will appreciate it! :)
Related
I'm working on mashup that scrapes a couple of sites for data. I want to scrape and cache the data on demand rather than index the entire sites.
The first time the data is fetched, the operation can be extremely slow--at least a couple of minutes.
What's the best practice for displaying pages line-by-line like this? Is there a way to display the page dynamically, showing data as it's fetched?
Related:
How to display HTML to the browser incrementally over a long period of time?
How to create an Incremental loading webpage
How to make sure an HTML table renders incrementally
Display the result on the webpage as soon as the data is available at server
I've used jquery to allow each expensive partial to be rendered on clicking a button:
view:
#book_forecast
= link_to 'See Sales Estimates' , book_forecast_work_update_path(:work => #work), :remote => true
book_forecast.js.erb:
$( "#book_forecast" ).html( "<%= escape_javascript( render( :partial => 'works/work_update/evaluation_forecast', :locals => { :work => #work} ) ) %>" );
work_update controller:
def book_forecast
#work = Work.find(params[:work])
respond_to do | format |
format.js
end
end
works/work_update/evaluation_forecast.html.haml:
# slow-loading code
The downside is that the user has to click on a button to render each partial, but on the other hand, using jquery instead of rendering as normal means the expensive code doesn't run when the page loads.
You can also use a 'loading' icon so that the user's got something to look at whilst the heavy code runs, something like:
same view:
#loading
%h2
.notice
Loading, please wait...
js:
$(document).ready(function () {
$('#loading')
.hide()
.ajaxStart(function() {
$(this).show();
})
.ajaxStop(function() {
$(this).hide();
})
;
It looks like Rails Live Streaming is one approach. Disadvantage is that it appears to be highly web server dependent and touchy. Here's a tutorial:
http://tenderlovemaking.com/2012/07/30/is-it-live.html
class MyController < ActionController::Base
include ActionController::Live
def index
100.times {
response.stream.write "hello world\n"
}
response.stream.close
end
end
I have an idea and a problem I can't seem to find answer or solution to.
Some info if required later or helpful:
Rails version 3.2.9
best_in_place (git://github.com/straydogstudio/best_in_place.git)
Ruby 1.9.3p327
Ok, so i have settings page where i can update individual setting by editing them with use of best_in_place gem. Works fine. Happy with that.
Some of the settings are interconnected, meaning, i have to sum or subtract them.
As a helpful tip for the user, in my view, right beside the in place form for that settings there is also a calculated value.
Now, of course, I would like to see this value be update along with the attribute itself.
I can't find a way to do that.
If i do it with the :data => it works, but i get the old and not the new value, so my view is always "1 step behind".
i have also tried with update.js.erb and _test.html.erb partial, but javascript file doesn't work. It is like it doesn't exist. I have double, triple checked where to put it and it is OK (app/views/controller/_partial.html.erb)
So. Pretty straightforward question would be; how can i access an updated value and use it back in view to update calculations. I personally think I should go with the partial and js file - but I have no clue why JS file isn't picked up. Any idea on that?
If there are any other options, i would more than appreciate the hint.
Thanks!
--EDIT (code added)
view:
<td>
<%= best_in_place #s,:pay_after_bonus, :display_with => :number_to_percentage, :type => :input, :nil => "Klikni tu za spremembo!", :cancel_button=> "Prekliči" %>
Cena: <span id="test"><%= number_to_currency(#s.family_member_price - ((#s.pay_after_bonus * #s.family_member_price)/100)) %></span>
</td>
settings_controller.rb:
def update
#s = Setting.find(params[:id])
respond_to do |format|
#s.update_attributes params[:setting]
#s.create_activity :update, :params => { :setting => params[:setting].keys.first }, owner: current_user
format.json { respond_with_bip(#s) }
format.js
end
end
update.js.erb:
$( "#test" ).html( "<%= escape_javascript( render( :partial => "update") ) %>" );
_update.html.erb:
<strong>Test</strong>
-- EDIT 2:
OK, apparently it is possible to do something like I want this way:
$('.best_in_place[data-attribute="model_attribute"]').bind(
"ajax:success", function(event, data) {
// function that will update whatever
});
in combination with
// respond to json request with
render :json => {"model" => #model}
&
"ajax:success", function(event, data) {
var result = $.parseJSON(data);
// from here the result var will be accessible with all the data returned by the controller.
// result.model is your object - use result.model.attribute to get specific values...
}
But here it ends for me.
I don't know how to use render :json => {"model" => #model} in my case, as it has to be done in combination with format.json { respond_with_bip(#s) }.
Where do I put render in controller?
Currently I get 500 internal server errors trying to do this as a response.
I have found this solution here.
Thanks!!
In the ajax callback you can make another request to get the partial you want:
$('.best_in_place.myclass').bind("ajax:success", function () {
$.getScript("http://www.someurl.com");
});
Then in the action you render a JS file (eg: show.js.erb), where you replace the target element with the results of the render:
$("#div-<%= #div.id %>").replaceWith("<%= escape_javascript(render(partial: 'some/partial', :layout => false)) %>");
You can use jQuery to parse the dom for the element that best in place just changed, and get the updated value from there. For example, of you have this code (haml)
= best_in_place #user, :name, :classes => 'name-edit'
Then your callback would look like this (coffeescript)
$('.name-edit').on 'ajax:success', (event, data, status, xhr) ->
newValue = $('.name-edit').html # could also use .attr() here
$('.some-other-widget').html(newValue) # again could also set .attr here
You can even skip looking up the new value with jQuery. In the context of the callback handler, 'this' represents the element the call was made from, so you could just do
$('.name-edit').on 'ajax:success', (event, data, status, xhr) ->
$('.some-other-widget').html this.innerHTML
and get the new value to the other widget that way. My guess is the event returned by the ajax handler also has currentTarget, which again would be the widget that trigged the ajax request. My only worry on all this would be that your success handler somehow beats the best in place handler, and you get the widget before it's updated. In my testing that hasn't ever happened.
I just answered a question like that:
Answer here
but instead of just inserting the value you need to use the sum that you need.
I need to have a button to save the current web site (just like clicking on "Save as"), I created a method in the controller which works great for any external site (like http://www.google.com) but doesn't work for the sites inside my application, I get a timeout error!. This has no explanation to me :(
Any clue what is the issue?
#CONTROLLER FILE
def save_current_page
# => Using MECHANIZE
agent = Mechanize.new
page = agent.get request.referer
send_data(page.content, :filename => "filename.txt")
end
I tried also Open URI, same problem!
#CONTROLLER FILE
def save_current_page
# => USANDO OPEN URI
send_data(open(request.referer).read, :filename => "filename.txt")
end
I'm using rails 3.2 and ruby 1.9, any help is appreciated, I already spent like 10 hours trying to make it work!!
Rails can only handle one request at a time. It's a never-ending standoff between the two requests - the first request is waiting for the second request, but the second request is waiting for the first request, and therefore you get a Timeout error. Even if you're running multiple instances of the app with Passenger or something, it's a bad idea.
The only way I can think to get around it would be to use conditional statements like so:
referer = URI.parse(request.referer)
if Rails.application.config.default_url_options[:host] == referer.host
content = "via yoursite.com"
else
agent = Mechanize.new
page = agent.get request.referer
content = page.content
end
send_data content, filename: "filename.txt"
A little dirty but it should get around the Timeout problem. As far a getting the actual content of a page from your own site - that's up to you. You could either render the template, grab something from cache, or just ignore it.
A much better solution would be to enqueue this code into something like Resque or Delayed Job. Then the queue could make the request and wait in line to request the page like normal. It would also mean that the user wouldn't have to wait while your application make a remote request, which is dangerous because who knows how long the page will take to respond.
After several hours and lots of other posts I got to a final solution:
Bricker is right in that it is not possible for rails to render more than once in a call, as taken from http://guides.rubyonrails.org/layouts_and_rendering.html "Can only render or redirect once per action"
The site also states "The rule is that if you do not explicitly render something at the end of a controller action, Rails will automatically look for the action_name.html.erb template in the controller’s view path and render it."
Then, the solution that worked great for me was to tell the controller to render to a string if a download flag (download=true) was set in :params (I also use request.url to have it working from any view in my application)
View:
= link_to 'Download', request.url+"&downloadexcel=true", :class => 'btn btn-primary btn-block'
Controller:
def acontrolleraction
#some controller code here
if params[:downloadexcel]
save_page_xls
else
# render normally
end
end
def save_page_xls
#TRESCLOUD - we create a proper name for the file
path = URI(request.referer).path.gsub(/[^0-9a-z]/i, '')
query = URI(request.referer).query.gsub(/[^0-9a-z]/i, '')
filename = #project_data['NOMBRE']+"_"+path+"_"+query+".xls"
#TRESCLOUD - we render the page into a variable and process it
page = render_to_string
#TRESCLOUD - we send the file for download!
send_data(page, :filename => filename, :type => "application/xls")
end
Thanks for your tips!
I'm building a simple tasks application for our company as part of an ordering system.
I have a list of tasks with a number of rules. Nothing complex... What I'm stuck on is the addition of a checkbox to complete the task. I want it done live, from the index view without having to hit submit..
Am really not sure even where to look. I figure I need to use ajax to do this - can anyone recommend a tutorial or tell me what I should be looking for.
Have also thought about a plugin, like the edit in place ones out there.
Thanks in advance
--- EDIT 1 --
Following advice from #pcg79 below, I've added the following to my application but am not understanding how I go out actually changing the status.
In my index view I have this:
<%= check_box_tag 'complete_task_1', '', false, { 'data-href' => tasks_path(#task) } %><
I've added the following to my application.js (added a # to get it to call properly)
$('#complete_task_1').click(function() {
$.ajax({
url: $(this).data('href'),
type: 'PUT',
dataType: 'html',
success: function(data, textStatus, jqXHR) {
// Do something here like set a flash msg
}
});
});
For lack of understanding, I added this to my tasks controller:
def completed
#task = Task.find(params[:id])
#task.status = true
end
Which seemed reasonable but wasn't sure how to actually call that in the ajax?
In my development log I can see it sort of working but it says this:
ActionController::RoutingError (No route matches "/tasks"):
-- EDIT 2 --
As per advice from #jdc below, I've tried adding the following to routes.rb:
get 'tasks/:id/completed' => 'tasks#completed', :as => :completed_task
But still get the RoutingError.
-- Slight Update --
Following the excellent advise from #pcg79 below, I've updated my files with the following.
Routes.rb
get 'task/:id' => 'tasks#completed', :as => :completed_task
Index.html.erb
<td><%= check_box_tag 'complete_task_1', '', false, { 'data-href' => completed_task_path(:id => task.id) } %></td>
Tasks controller
def completed
#task = Task.find(params[:id])
#task.status = true
#task.save
end
I get no errors in my browser, but my development log shows this:
ActionController::RoutingError (No route matches "/tasks"):
For a simple checkbox, this is hard work!!!
-- Another update --
Having played all day, I decided to see what would happen with a button_to instead, forgetting the ajax side of things. I put this in my code:
<%= button_to "Complete", completed_task_path(task.id) %>
And changed routes to:
match 'tasks/:id/completed' => 'tasks#completed', :as => :completed_task
Which worked a treat. Changing back to check_box_tag breaks it all again :(
Pretty much worked out it's the contents of my function. Having removed some code, I can update the css for a #:
$('#complete_task_1').click(function() {
$.ajax({
success: function(data, textStatus, jqXHR) {
$('#thing').css("color","red");
}
});
});
Any idea what I'd need to call my action?? J
If I understand what you're looking for (when the checkbox is checked or unchecked an Ajax request is sent to the server and the associated object is saved with the result of the checkbox), then yes you'll want to do it in Ajax.
With Rails 3 you're probably using jQuery (or, IMO, you should be). You'll need to implement a click event on the checkbox element. That click event, when it's fired, will do an Ajax call to your server. You'll want to do a PUT request since it's an update. You'll send the id of the object and the value of the checkbox.
There are a decent amount of sites that have examples of Rails and Ajax. This one (http://net.tutsplus.com/tutorials/javascript-ajax/using-unobtrusive-javascript-and-ajax-with-rails-3/) is good as it has you use the HTML 5 "data" fields which I like. There's also a bunch of similar questions here on SO. Here's one that's not Rails but will give you an idea of how to write the jQuery (AJAX Checkboxes).
Edit to answer question in comment
The checkbox can be wherever you want it since you're doing Ajax. If you want it on your index view, that's where you put it. Your checkbox will look something like this (please understand I'm not double checking my syntax or anything):
= check_box_tag 'complete_task_1', '', false, { 'data-href' => task_path(#task_1) }
Then your jQuery will look something like:
$('complete_task_1').click(function() {
$.ajax({
url: $(this).data('href'),
type: 'PUT',
dataType: 'html',
success: function(data, textStatus, jqXHR) {
// Do something here like set a flash msg
}
});
});
Second edit: I realized I forgot to actually send the value of the checkbox in the Ajax. You can do that and just call #task.update_attributes or you can make the url a specific method that only completes tasks.
Edit for updated question:
To explain my second edit, in order to update the task to be completed, you can do one of two things. You can either call a method that is expressly for setting the status attribute. Or you can call your normal, RESTful update method passing in :task => {:status => true} and call #task.update_attributes(params[:task]). You've chosen to do the former which, IMO, is fine.
So you have two problems. The first is that you aren't referencing the new route which points to your completed method. The second is that you aren't saving your object in the completed method.
To fix the first problem, you need to change the path your data-href attribute in the check_box_tag method points to. You don't want task_path. IIRC, you'll want completed_task_path(#task). The easiest way to find out the name of the path is to run rake routes in your Rails project's root directory.
To fix the second problem, just make sure to call #task.save at the end.
def completed
#task = Task.find(params[:id])
#task.status = true
#task.save
end
In your updated example, try replacing:
<%= check_box_tag 'complete_task_1', '', false, { 'data-href' => tasks_path(#task) } %>
with:
<%= check_box_tag 'complete_task_1', '', false, { 'data-href' => task_path(#task) } %>
Provided #task.id = 1, tasks_path(#task) returns /tasks.1, while task_path(#task) returns /tasks/1
I have div tag named update_info in the view my_view.html.erb and update action takes several minute to complete in the controller my_controller.rb.
I'd like to update update_info div tag every seconds as update action's progress.
How can I do this?
Is it possible update view from the action's loop?
Or using Ajax?, if so, how can I access to server-side data and where is the data stored?(I don't know much about Ajax, please explain using Rails' Ajax helper methods if needed)
Tell me detail plz. thanks.
You can use partials for updating certain div.
You can call controller through ajax.
and then render your output using partial.
render :partial => "partial_name", :layout => false, :locals => {:local_var => xyz}
Note : partial name start with '_'
A comment first: you should avoid having several minutes requests (you should use background processing).
Now, depending of what you are actually doing in that request, the standard method is to interrogate the server (throught an ajax repetitive request, other than the current request) about the progress of current task.
You can do this by using the periodically_call_remote function.
To have an idea:
In your view:
<%= periodically_call_remote(
:condition => "check_var == false",
:frequency => 3,
:url => { :action => "evaluate_progress" }) %>
In your controller:
def evaluate_progress
# replace it with code that actually computes the progress
done = 0.6
render :update do |page|
if(done == 1)
page << "check_var = false" #To stop querying the server
else
page << "check_var = true"
page.replace_html('your_div_id', "The task is #{done*100}% complete.")
end
end
end
Again, this is just a proof of concept, i haven't tested it. The actual code depends also on what you are actually doing in the long-lasting request.