G'day guys, currently have almost finished writing a rails application that allows a CSV download of the database. This is generated when the index is first viewed.
Is there an easy way to insert a link to a helper that returns a CSV document? That is to say is it easy to insert links to helpers? This would make a lot of problems I've been having much easier
If you sticked to the general conventions, then you registered a mime-type for csv and return the csv file content via your #index action. So your link helper would be like this:
link_to 'export as csv', posts_path(:format => :csv)
If, in exchange, your file is generated WHEN index is first view but NOT BY Rails, you may want to avoid standart render and call send_data or send_file instead (check the api for them).
# in your controller:
def index
# your suff here
#csv_path = find_or_generate_csv_file
send_data #csv_path, :type=>"text/csv", :disposition=>'attachment'
end
protected
def find_or_generate_csv_file
#your file generation logic
end
Related
We're using Activeadmin to manage a number of data tables within our app. One function we want to use is CSV download, but, the CSV download links generated by ActiveAdmin do not respect filters.
In one table we have 8+ million records. We want to be able to filter by text, and then export the CSV of the filtered list. Filtering works fine in browser, but if you click CSV - you get a CSV of the entire table.
What is the trick for getting ActiveAdmin to use filters during exports?
I had to solve this once to, this could be a way. I made an action_item like:
action_item :special, only: :index do
link_to 'Custom CSV with filters and scopes', custom_csv_admin_your_own_pluralized_resource_name_here_path(params.permit!.slice(:q, :scope))
end
collection_action :custom_csv, :method => :get do
collection = find_collection
# here you can iterate over collection (maybe in batches) and generate CSV
end
You may want to read this file in the GEM source:
lib/active_admin/resource_controller/data_access.rb
at: https://github.com/activeadmin/activeadmin/blob/master/lib/active_admin/resource_controller/data_access.rb
I am very new to rails and following a tutorial for RESTful API so let me excuse if it is of not very good quality as I am equally a starter for these kind of terminologies as well.
I created a controller kitten with a command rails g controller kitten index
and in the index method I posted this code -
class KittenController < ApplicationController
def index
require 'open-uri'
kittens = open('http://placekitten.com/')
response_status = kittens.status
response_body = kittens.read[559, 441]
puts response_status
puts response_body
end
end
and un commented match ':controller(/:action(/:id))(.:format)' in routes.rb
When i navigate through this - http://localhost:3000/kitten
this is what i am getting in my browser -
Kitten#index
Find me in app/views/kitten/index.html.erb
and this in my command line -->
Now my question why it so although i am expecting it in my browser but the cat is shown in command prompt instead of browser ..i am new to rest resource so please excuse if it is a bad one :(
I don't know what tutorial you're following, but doing this seems like a very odd thing to do for Rails in general and learning RESTful APIs in particular.
Anyway, the puts in your controller outputs text to Ruby's standard out, which is going to be the terminal where the server started. That's why this is appearing in the console rather than in your browser: puts is putting it there.
If you want this to appear in a web page, you'll need to make a view for that controller action. Perhaps following further along your tutorial will get you there: if not, you might want to find a better one.
You should read the Model-View-Controller rails guide.
Controllers provide the “glue” between models and views. In Rails, controllers are responsible for processing the incoming requests from the web browser, interrogating the models for data, and passing that data on to the views for presentation.
Define your variable in the controller and display it in the view:
class KittenController < ApplicationController
def index
#variable = 'Hello World'
end
end
In your view (app/views/kitten/index.html.erb):
<%= #variable %>
Rails controllers setup responses with a render call.
When the call is not performed it instantiates the appropriate view and renders that view. In your case that is index.html.erb
Try this:
render :text => kittens.read[559, 441], :status => kittens.status
I'm working on my first application and I need some help with allowing my users to download a text file with certain variables that are being displayed on the page.
Take a shopping list for example.
Let's say you allow your users to create a shopping list of products, and then display the shopping list with the items on a shopping list page,
e.g. localhost:3000/list/my-list
Take a look at the example code below (which is probably incorrect):
File.open('shopping_list.txt', 'w') do |file|
file.puts 'Item 1: #{product_1.name}'
file.puts 'Item 2: #{product_2.name}'
file.puts 'Item 3: #{product_3.name}'
end
Which then creates a text file that has the following content:
Item 1: Eggs
Item 2: Butter
Item 3: Bread
Users should then be able to download this file (i don't want this file to be stored on the server) via a download link.
I have no idea how to achieve this, but I'm hoping you guys can guide me. :D
TL;DR
create text files populated with model data (perhaps create a method to achieve this?)
text files should not be stored on the server, but created as users click the download button (not sure if this is the rails way but perhaps someone could show me a better way)
I am assuming there is a resource for List with the attribute name as the name of the list and a list has_many Item which has an attribute description
First off, create a download path change your routes config/routes.rb
resources :lists do
member {get "download"}
end
Now if you run a rake routes in the console you should see a route like
/lists/:id/download
Whats more you should now have the helpers download_list_url & download_list_path to use in your view like
<ul>
<% #lists.each do |list| %>
<li> <%= list.name %> - <%= link_to 'Download List', download_list_path(list) %> </li>
<% end %>
</ul>
In your lists_controller add the action, and as you dont actually want to keep the file on the server disk just stream the data as a string
def download
list = List.find(params[:id])
send_data list.as_file,
:filename => "#{list.name}.txt",
:type => "text/plain"
end
Finally you see I have used a as_file method which you should add to the model (I prefer not to do this stuff in controllers, fat models, skinny controllers). So in the List model
def as_file
output = [self.name]
self.items.each {|item| output << item.description }
output.join("\n")
end
You say you don't want to store the file on the server, but "download" it on request; this sounds like you just want to generate and deliver a text document in response to the download link. There are several approaches, but you want to be sure of setting the mime-type so the browser sees it as a text file instead of an html document.
product_info = [
"Item 1: #{product_1.name}",
"Item 2: #{product_2.name}",
"Item 3: #{product_3.name}",
].join("\n")
render :text => product_info # implies :content_type => Mime::Type["text/plain"]
BTW, your example with open/puts above won't output what you think since single-quoted strings don't interpolate.
so, you wish to :
create text files populated with model data (perhaps create a method
to achieve this?)
text files should not be stored on the server, but
created as users click the download button (not sure if this is the
rails way but perhaps someone could show me a better way)
You have the right idea, here's what to do :
Create a method in your model to generate the text file contents. Let's say this method is called list_data
It seems like you have an existing controller action called my_list. Hence we can call our new method in the controller like so :
.
def my_list
# pre-existing code
respond_to do |format|
format.html # show html page as before
format.text do
send_data #list.list_data, :content_type => 'text/plain', :filename => 'my-shopping-list.txt'
end
end
end
To link to the download, just use link_to :action => my_list, :format => 'text'
See http://api.rubyonrails.org/classes/ActionController/DataStreaming.html#method-i-send_data for full docs on send_data
Caveat & explanations : Using the method above, there isn't really an explicit creation of files, Rails is streaming it for you. Hence this method is not suitable for very large files, or when the generation of the file content will take a while. Use a delayed method to generate the file and store it - the file contents somewhere if that's the case - but we can use send_data once it has been generated
You could try a combination of TempFile and send_file. In your controller action ..
file = Tempfile.new('foo')
file.write("hello world")
file.close
send_file file.path
At Rails 2.3 you can use Template Streaming. Working with Redmine I can remember something like that, you have to adapt for your case. Reference: Streaming and file downloads
require "prawn"
class ClientsController < ApplicationController
# Generate a PDF document with information on the client and return it.
# The user will get the PDF as a file download.
def download_pdf
client = Client.find(params[:id])
send_data(generate_pdf, :filename => "#{client.name}.pdf", :type => "application/pdf")
end
private
def generate_pdf(client)
Prawn::Document.new do
text client.name, :align => :center
text "Address: #{client.address}"
text "Email: #{client.email}"
end.render
end
end
Using the Thong Kuah you must just change the "content_type" param:
def my_list
# pre-existing code
respond_to do |format|
format.html # show html page as before
format.text do
send_data #list.list_data, :content_type => 'text/plain', :filename => 'my-shopping-list.txt'
end
end
end
I have a ruby on rails website. The page is dynamically loaded and generated using ruby and rails. However, I'd like to also generate a static .html page to ease my server rather than calling the rails page every time.
In PHP I know how to capture the output buffer using ob_start() and ob_get_contents() to get the outputted text.
How do I capture the output from my rails page into a variable?
EDIT: The reason I want to do this is so that I can save my page as .html for use on other machines. So I generate the HTML using ruby and distribute to others in a format they can view.
You should use Rails caching to achieve this result. It achieves the ends you are looking for.
Alternatively, you can render_to_string and output the result using render:
#ticket_controller.rb
def TicketController < ApplicationController
def show_ticket
#ticket = Ticket.find(params[:id])
res = render_to_string :action => :show_ticket
#... cache result-- you may want to adjust this path based on your needs
#This is similar to what Rails caching does
#Finally, you should note that most Rails servers serve files from
# the /public directory without ever invoking Rails proper
File.open("#{RAILS_ROOT}/public/#{params[:action]}.html", 'w') {|f| f.write(res) }
# or .. File.open("#{RAILS_ROOT}/public/#{params[:controller]}/#{params[:action]}/#{params[:id]}.html", 'w') {|f| f.write(res) }
# or .. File.open("#{RAILS_ROOT}/snapshots/#{params[:controller]}/#{params[:action]}/#{params[:id]}.html", 'w') {|f| f.write(res) }
render :text => res
end
end
You probably want to look into caching rather then saving the output of your rails app directly. Check out:
http://guides.rubyonrails.org/caching_with_rails.html
http://api.rubyonrails.org/classes/ActionController/Caching/Pages.html
I ended up going with the following:
#page_data = render_to_string() # read the entire page's output to string
if (File.exist?('../cache.html'))
file = File.open('../cache.html','rb')
contents = file.read
else
contents = ''
end
if (#page_data!=contents) # if the page has changed
# save the output to an html version of the page
File.open('../cache.html','w') {|f| f.write(#page_data) }
end
I'm creating a website in Ruby on Rails, where users can login using RESTful Authentication. Someone can get a specific user using html, xml and json, just like scaffolding. But I want to add one more format: vCard (e.g. /users/1.vcard). This has a specific format, but how do I define my own formats? Using views, or must I use another way? Thanks
In your /config/initializers/mime_types.rb file, add a new registration for your format. It should look something like this:
Mime::Type.register "text/x-vcard", :vcard #The :vcard is the important part
After that (you'll have to restart your app to pick up the change), you can respond to the symbol like any other format:
# then in your controller action
def show
respond_to do |format|
format.html # render html
format.vcard { #render vcard }
end
end
Adding from comments (thanks nanda):
In your views folder, then, you would put the vCard template into a show.vcard.erb file (for example).