rails: pass 2-d array to link_to - ruby-on-rails

I have a controller querys with an action send_file.
querys_controller.rb
def send_file
send_data(params[data], :filename => "query.txt")
end
in html.erb I have:
<%=link_to "send data", :controller=>"querys", :action=>"send_file", :data=>#mat, method: :post%>
By clicking on"send data" rails shows me "Bad request" due to the fact that #mat is a 2-D array and it seems I link_to cannot send such structure. How can I send my matrix to my controller ?
#mat:
[["1681", "", "02.05.1955"], ["1680", "", "02.03.1936"], ["1679", "", "26.11.1938"], ["1692", "", "15.05.1958"]]

#Tonja, to me it seems to be very strange what you are doing. First you somewhere generate an array, then pass it over using the browser again back to your application. And then you send it back to the browser in a text format?
You should not pass this array to the user, but keep it on the server. Just store it in the database. Do not pass data to the user, only when absolutely neccesary. Your current implementation also forces you to do quite some checks on the data that is passed.
In the controller method that generates the html.erb, store the #mat instance somewhere, and get the ID of the record. Pass this ID to the link_to, and use this data from the DB as parameter for the send_data call.
(Small tip: do not actually use the ID, that is not secure, but use a random value. Or even better: do not pass anything at all if you can attach the value to the current_user).
You get the Bad Request because Rails does not understand the format you request. And that is because you assemble the url yourself. Use a call like
link_to "send file", send_file_querys_path(format: :txt)
or even a
button_to ....
if it is a POST operation.
You can get the valid routes with 'rake routes'. This makes your app better testable.
I hope my answers help you to rework your code. If what you are doing is the right way, then #m_x gave you the correct pointers.
Best regards,
Hugo

when passing url arguments in the form of a hash, you should separate them from the rest of the arguments for link_to:
<%
= link_to "send data",
{controller: "querys", action: "send_file", data: #mat},
method: :post
%>
However, this will pass the data as query parameters. If you really want to pass the data as POST parameters (for example, if #mat contains a lot of data), you will have to use a form tag with a hidden field and a submit button.
IMO a more efficient approach would be to pass the parameters that were required to populate #mat, repopulate the variable server-side and use it in send_file.
The best practice in this regard is to leverage rails' format capabilities, for example :
def some_action
#mat = populate_mat(params)
respond_to do |format|
format.html
format.txt do
send_data(#mat, :filename => "query.txt")
end
end
end
(note : for this to work, you will probably have to register the txt mime type in config/initializers/mime_types.rb)
then in some_action.html.erb:
<% = link_to "send data", {format: :txt}, class: 'whatever' %>
This will will just add a .txt extension at the end of the current url, which plays nicely with the REST paradigm (one endpoint per resource, with the extension indicating the desired representation).
You can also pass the format option to any url helper, for example :
<%= link_to "root", root_path(format: :txt), class: 'whatever' %>

Try this:
link_to("Send data", send_file_querys_path(data: #mat), method: :post)

Related

Forward parameters in the specific order (using link_to helper)

I want to forward parameters from one view to the another one, and this is what I managed to do. But I want to pass those parameters in the specific order. On first request, after I send the form, I get the params in the order that I want. For example:
http://www.example.com/someurl?project_id=1&start_date=2016-01-10&end_date=2016-01-20
Then, after I have those params in the view, I generate a link with link_to helper, in this kind of a way:
= link_to "link text", some_specific_path(some_id, {"project_id"=>"1", "start_date"=>"2016-01-10", "end_date"=>"2016-01-20"})
But then, the link will be generated as:
http://www.example.com/someurl?end_date=2016-01-20project_id=1&start_date=2016-01-10
So, the problem is - when I send a form, parameters get added to the url in the order of how they appear in the form. But, when you generate a link with link_to helper and path helper, then parameters are always added in the alphabetical order, no matter how they actually appear.
It is Rails bug https://github.com/rails/rails/issues/1146
also, consider send params between request in sessions.
Ok, my solution for you, but it's realy urly:
hash = {"project_id"=>"1", "start_date"=>"2016-01-10", "end_date"=>"2016-01-20"}
query_string = hash.map{|k,v| "#{k}=#{v}"}.join("&")
link_to "link text", some_specific_path(some_id) + "?" + query_string
It's good idea to define a helper here:
module ApplicationHelper
def link_to_with_sorted_params(text, path, _params)
prepared_params = _params.map { |k,v| "#{k}=#{v}" }.join("&")
prepared_link = "#{path}?#{prepared_params}"
link_to text, prepared_link
end
end
Call it
=link_to_with_sorted_params("hi", users_path, {"user" => 1, "res" => 2})
#=> hi

Pass data safely from view to controller in rails

I want to pass data from a view (link) to a controller so it can look up the related information. Services for a company, in this case.
I see examples where people have added to params like this:
<div>
<%= link_to 'Services', :controller => 'company', :action => 'services', :company_id => #company.id %>
</div>
...but that results in a transparent (unsafe) URL like this:
http://localhost:5000/company/services?company_id=17
Is there a way to get around this without stuffing data into the Session? What's the best practice on links inside an app that requires authentication?
THere is no such major harm in passing data like this in View.
Still if you insist on having, then check prettyurls:
http://railscasts.com/episodes/314-pretty-urls-with-friendlyid
Prior to we must have valid checks in controller & model files.
1. Valid Checks and redirection in Controller is helpful.
2. Depending on need adding validations in model can be a good support.
<%= link_to "Sign in", new_session_path(:id => Base64.encode64("1")) %>
and in your controller
def new
id=Base64.decode64(params[:id].to_s)
end
this is another form for create a link with data
check your routes with command un console rake routes
for more information read this documention
http://apidock.com/rails/ActionView/Helpers/UrlHelper/link_to

Rails Forms for custom actions

I'm trying to link the input of a form to a specific action in my rails app.
Currently if I go to www.myapp.com/check/:idNumber, I'll be able to trigger the action just fine (which means routes is setup properly?). This action is basically a function call to a ruby/rails script with the parameter "idNumber" being passed to it. If the function is successful, it would return a newly created "Person" object and nil otherwise. This is different than the standard new operation as it determines the the attributes based on some information that it obtained from a database somewhere else.
Rake routes does give me the following:
check /check/:idNumber(.:format) person#check {:id=>/\d+/}
What I'm having trouble implementing is the form itself.
<%= form_tag("/check", :method => "get") do %>
<%= text_field_tag(:idNumber) %>
<% end %>
Controller action:
def check
regCheck = RegCheck.new
#person = regCheck.check_id(params[:idNumber])
if #person.name == nil
redirect_to root_path
end
end
submitting the form above would bring me to myapp.com/check?utf8=✓&idNumber=1234 instead. Can someone tell me what am I doing wrong?
I believe that using the check_path helper that is generated from the routes file is your best bet.
The form should look like this then.
<%= form_tag(check_path) do %>
<%= text_field_tag(:idNumber) %>
<% end %>
Rails forms can be finicky, especially when trying to build really customized forms.
This line
= form_for [#object]
Determines where the form goes, as well as the object that is being implemented. If you want to route the form to a different place, you can user the :url option. This options determines the path of the form, however you must keep in mind that the method is determined by the #object. If it is a new object, the method will be POST, an existing object will use a PUT method.
Let's suppose you want to update an existing object, but you want to send in data for a new object belonging to the existing object. That would look like
= form_for [#object], :as => #child_object, :url => my_optional_custom_path do |f|
# etc...
This generates a form sending a PUT request to the custom url (or the update path for #object if no custom url is supplied. The PUT request is sent with the parameter params[:child_object].
Hopefully this helps!
Best,
-Brian
I don't think it's possible the way you're trying.. The URL for the form is created before the user inputs any data.. So you need to remove the :idNumber from your routing..
If you do you get the following route:
check /check(.:format) person#check
Because the regex is removed now, you need to do this in you're controller:
def check
# Make sure ID is digits only
idNumber = params[:idNumber].gsub(/[^\d]/, '')
regCheck = RegCheck.new
#person = regCheck.check_id(idNumber)
if #person.name == nil
redirect_to root_path
end
end
You're form is allright, but you may want to use check_path like TheBinaryhood suggests..
If you really want it to be check/:idNumber you may also be able to submit the form to another action and redirect it to the right path from there..

Ruby On Rails: using arrays with link_to

I was curious on how to use arrays in the link_to method in ruby on rails for example:
Controller:
def index
#test = [1,2,3]
end
View:
<%= link_to "test", {:action => 'index'}, :test => #test %>
When looking at the source then, I end up with something to the effect of:
test
My guess is that the array's to_string or something similar is getting called to set the value of test in the html.
My goal is to be able to have a form in which people can submit data on the page, and then once they've submitted the data and return to the page, if they click on the link the data will persist through clicking on the link.
*Ideally I would like to do this without having to pass the parameters in the url.
Thank you.
If you want to keep data you should probably use cookies. They are very easy to use, just assign a value with the following in the action:
cookies[:some_key] = "some value"
and retrieve it with this:
cookies[:some_key] # returns "some value"
However, just to clarify what link_to is doing in your example:
<%= link_to "test", {:action => 'index'}, :test => #test %>
When looking at the source then, I end up with something to the effect of:
test
The reason is that you are passing #test to the third argument in link_to, which is a hash of html attributes, hence why it's turned into one. To have it become an parameter on the link, you need to pass it with the second, eg, {:action => 'index', :text => #test}. As noted above, however, this is not necessarily the best way to tackle this and, in addition, it's usually best to also pass the controller name to link_to or, better yet, use a named route.
If I understand well, you want to keep the datas submitted by the user after they validate the form ?
Well Rails is able to do that without any of your code line needed.
Based on the supposition that you have a route resource "objects"
In your controller :
def edit
#object = Object.find_by_id params[:id]
end
def update
#object = Object.find_by_id params[:id]
if #object.update_attributes params[:object]
# The datas have been successfully saved. You redirect wherever you want to.
else
render :action => 'edit'
end
end
and in your view :
<% form_for #object do |f| %>
<%= text_field :name %>
<% end %>
When the form fails to validate, the "name" text field automatically gets the previous entered data.
If after that you still need to reload your datas, you don't need to add them as a parameter in a link tag.
You get the object in your controller and passes it's datas to the view where you display it.
I would just write a view helper that formats it into a string with good separators, like commas.
That isn't a good way to be passing along information though. Try session variables, cookies, or url-encoded variables instead.
The best match to what you are doing would be url-encoded variables, which will show up in a form similar to this:
test
My guess is that it is using Array#join.
You could try something like
:test => #test.join( ',' )
and then parse the string in your controller. But it is somewhat error prone if the user enters the same character you chose as delimiter.
But, assuming the linked page is also served by Rails, I think the best solution would be to use the flash area to store the results on the server
flash[ :submitted_params ] = params;
and in the controller for the linked page
old_params = flash[ :submitted_params ] || {}

how can I hide params I transmit to a method (like form_for seems to do)?

I've been searching for hours now and haven't found anything that helps.
What I want to do:
I need to call the check_login-Method (as below), which needs parameters.
redirect_to check_login_users_url(
:user => {:name => input[1], :password => input [2] },
:stylesheet => 'scaffold',
:method => :get)
The point is that these params are sent in the method-call as in the "Redirected to"-line below.
Processing ApplicationController#execute(for 127.0.0.1 at 2009-12-19 00:28:40) [POST]
Parameters: {"command"=>{"line"=>"log dodo wg"}, "authenticity_token"=> <...token>}
Redirected to http://localhost:3000/benutzer/check_login?method=get&stylesheet=scaffold&user%5Bname%5D=dodo&user%5Bpassword%5D=wg
Completed in 9ms (DB: 0) | 302 Found [http://localhost/execute]
I want to prevent rails from putting the params into the url and pass them hidden instead.
When I send a form created with form_for, there's nothing in the url, so I assume it must be possible.
Please tell me how to do that.
Steps tried
I have tried different "html-verbs": get, put, post - no difference. Though the call of check_login is really short the url-with-params shows up in my Console
create an instance variable and pass it as param (strange, didn't work either)
watch form_for working – without results, got no clue
//edith:
Thanks for all your help so far. Perhaps I didn't specify my problem in enough detail.
I've got a text_field in which I enter short commands (experimentally). Its form calls execute in AppController, which in case of login-data performs redirect_to check_login. I don't need to access a webpage, I simply want to run the method. I liked the idea of putting it into :flash, but I'm wondering if there's a "neater" way to do pass the data hidden.
TL; DR Version: Use a form.
You're never going to be able to fully hide parameters, tools can be used to monitor requests and view the post data/parameters. You could however obfuscate it with an encrypted session. Also it appears that you're sending login info via a GET request, this is generally a bad practice.
That said...
What is going wrong for you is that you're not generating any post data with link_to :method => :post. link_to will use what ever parmas you give it to generate the url. Wheres forms will send all the params generated by the form as POST data to the url generated in the form_for call.
Upon receiving a POST request, Rails will merge parameters routing picks up from from the URL with the post data it receives into one params hash.
As in POST to
http://localhost:3000/benutzer/check_login?stylesheet=scaffold&user%5Bname%5D=dodo&user%5Bpassword%5D=wg
produces the same params hash in the receiving controller action as a POST to http://localhost:3000/benutzer/check_login with the following data:
stylesheet=scaffold&user[name]=dodo&user[pasword]=wg
There will be no distinction in the server log between the two requests.
If you look at what form_for is doing, it submits POST data built from the form inputs to the url generated by the arguments.
form_for #user, create_user_url(:stylesheet => "scaffold") do |f|
f.text_field :name
f.password_field, :password
end
This form will submit the form data to the url generated from the options. In this example the url is: http://localhost:3000/users/create?stylesheet=scaffold and the form data is:
user[name]=name_field_value_at_submit&user[password]=password_field_value_at_submit
link_to will not populate post data for you. You must either do it through a form or with javascript. The link_to documentation contains an example of doing this with javascript. Look for how the destroy with :onclick is handled.
If you really don't like buttons, you could use link_to_function to submit a form.
Replace
:method => :get)
with
:method => :post)
What's the difference between :get and :post? Read Methods GET and POST in HTML forms - what's the difference?
With form_for you create form which is then POSTed to server, that's why you don't see parameters in url - they're in http request body. But it is not possible to redirect user's browser from some action in controller to make another POST - if it would be possible, then I could redirect user to (for example) email change form of gmail or other forms. You can only redirect user to other site, which user's browser then GETs.
If you really don't want to show parameters in url, and both actions are in same application, then you can store those parameters in session or flash store, and retrieve in next request after redirect.
You can use Ajax request to send form data to action :
In some cases its not good to change :get into :post.
For instance in case of Controller's :index action its not good approach to use :post
So Use ajax call to submit form and update only dynamic content of the page.
In js.coffe script file
$ ->
$("#button-id").on "click", (ev) ->
$.ajax
type: "GET"
dataType: "html"
url: "/horoscope_dailies"
data:
date: date
success: (data) ->
$("#index_content").html data
error: (object, error) ->
console.log error
In your controller action
render partial: 'partial_name' if request.xhr?
In your view file:
%div{:id => 'partial_content'}
= render 'partial_name'

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