I'm trying to get data from my controller into a javascript file in a rails application. The html immediately invokes an ajax request using the select option and the organization id as parameters.
In a before_filter I have
def set_org_id
if params[:id].present?
#org_id = klass.find(params[:id]).id
else
#org_id = 0
end
end
And in the js file I have:
$.ajax({ url: "/admin/analytics/filter",
type: 'GET',
data: {
time_frame: selectedId,
organization_id: <%= #org_id %>
}
})
If I hard code a number as the organization_id everything works fine, but when I try to pass the data from the before filter, I end up with no id in the page.
I should add that the index route is admin/analytics/. The filter action is admin/analytics/filter. The user never navigates to that page, only ajax hits the filter route to get relevant data. Could this be that the ajax request is being send before the instance variable is set? If so, what is the proper solution?
Your JS won't be able to access your #instance variablesunless you call them from your controller itself. The problem here is that if you're loading the ajax to access an instance varialbe - which simply won't work.
Let me explain...
JS
Javascript is known as a client side language - meaning it provides you with the ability to access elements in your HTML / DOM with relative impunity. The problem here is that Rails / Ruby, much like PHP, is server-side, and consequently is only able to provide rendered data to your browser
This means that calling the following simply won't work:
data: {
time_frame: selectedId,
organization_id: <%= #org_id %>
}
As explained, the reason for this is that you cannot access the #org_id from your Javascript. Firstly, you don't know if the #org_id variable will be set (in case you want to use the Rails helpers), and secondly, your JS won't be able to access the variable anyway (because it's Rails)
--
Fix
The purest fix for this is to somehow create the data you need in the DOM. I see from your answer that you have set a hidden field for your form. A much better way to do this is to set an HTML5 "data" attribute, or to use an id
You'd be better doing this:
<%= form_tag route_path, data: { org_id: #org_id } %>
This will give you the ability to call:
$(document).on("submit", "form", function(){
$.ajax({
...
data: {
time_frame: selectedId,
organization_id: $(this).data("org_id")
}
});
});
I was able to solve this by passing the data to a hidden field in the html.erb page.
<%= hidden_field_tag('org_id', #org_id) %>
Then in the javascript refer to the data through the selector.
organization_id: $('#org_id').val()
I don't love this, but at least it works.
Related
I've been reading a lot about Rails and AJAX and 5.1 Unobtrusive javascript. It explains a lot about responding to Rails version of AJAX calls with a .js file for example.
However what im wanting to do isn't serving up an entire .js file, it's simply updating an element after a <% link_to %> POST request. From my understanding setting remote: true submits it as a AJAX request.
Essentially I have a "Post" which a user can like via a linked Like button. This sends a POST request to the "Post" controller which updates a post to liked and adds a like to the post.
Unfortunately to see the effects of the post being liked (Which is simply that the link changes color as well as the font-awesome icon) you need to refresh the page. I basically want it to update without needing refresh.
I "think" based off what i've read I need to make a respond do and respond via .js to the request with a .js file in the view I want to update (for instance if the controller action is called "like", maybe a like.js.erb file in the view im updating?). But I don't want to serve an entire new page..or would this simply just run the .js?
Then I could do something like $('i.fa-icon#id').style.color = "blue" or something? (Im assuming I can send data from the controller to the .js.erb file?). Not sure the best way to do this, don't rails elements a lot of times have some sort of data-attribute or something (Im still a beginner at this).
Your description is quite correct!
Opposed to the other answer, you don't even need a event listener but as you said you want to have a respond_to in the controller.
So starting from the html:
# post/index.html.erb
<div id="like-button">
<%= button_to "Like this post", post_path(#post), remote: true %>
</div>
Note, that when you use a button_to helper it'll be a POST request by default.
If you click it, it'll go to the controller#update, which you want to change to this:
#posts_controller.rb
...
def update
#post.save
respond_to do |format|
format.html { redirect_to post_path(#post) }
format.js # <-- will render `app/views/posts/update.js.erb`
end
end
Note: the format.html is rendered when JS is disabled.
Now in the scenario that JS is enabled, it executes the app/views/posts/update.js.erb file. It can look like this:
const likeButton = document.getElementById('like-button');
likeButton.innerHTML = '<%= j render "posts/liked-link", post: #post %>';
What is the last line doing? Of course, you can change the style directly with the JavaScript, but you can also render a new partial - and this you will create in a new html file:
# app/views/posts/liked_link.html.erb
<div id="like-button ">
<p>"You liked this post!" </p>
</div>
I just changed the link/button to ap now, but of course you can do whatever you want.
Hope that makes sense :)
Not sure if I understand the question, but if you want to update like button:
What you want to do is to add an event listener to the button, and when clicked it makes a POST request to whatever route handles the likes(with the correct parameters) and your controller should respond with the like object (or whatever in the database gets stored). Have your post request on success method to grab the like button and change it to whatever you want it to look like
$(“#like-btn”).click(function(){
Rails.ajax({
url: "/some/url/to/like/controller",
type: "post",
data: [your post data],
success: function(data) { $(`#${ data[“btn-name”] }`).attr(“color”, “blue”; }
})
}
You can stick this script right in the bottom of the html page
You don’t have to do it exactly like this, just giving you an idea of how to set up the pattern of having JavaScript and Ajax handle the post request and updating of the frontend instead of using html buttons
I'm implementing a CSP using rails 5.2.1 content security policy DSL. I've got my policy set to something like:
Rails.application.config.content_security_policy do |policy|
policy.default_src :self, :https
policy.connect_src :self
#...
policy.script_src :self
end
# If you are using UJS then enable automatic nonce generation
Rails.application.config.content_security_policy_nonce_generator = -> request { SecureRandom.base64(16) }
I also have <%= csp_meta_tag %> in my application.html.erb
At this point I need to add a nonce: true flag to any inline scripts for these to satisfy the policy. I've done this and it works as expected. However, I'm having trouble maintaining existing AJAX style functionality. For example, I have something like (note the remote: true):
# index.html.erb
<%= link_to create_object_path, id: "#{object.code}",method: :post, remote: true do %>
<button type="button">Create object</button>
<% end %>
In my controller
def create
#object = current_user.object.create
respond_to do |format|
if #object
format.js
else
redirect_back
format.html
end
end
end
In my *.js.erb file
$("#<%= #object.service.id %>").text("Added!");
The object is successfully created but I believe the policy is blocking the above "Added" success message that I add to the DOM. I have not seen any errors in the console so I'm not sure where to go from here.
My understanding in this scenario is script tags are temporarily inserted with the contents of the *.js.erb file and these script tags do not contain the nonce. Or, it is a mismatch.
I've been stuck on how to troubleshoot from here. Any guidance here is much appreciated even if different architectural pattern for sending data to client is the way forward. Thanks in advance.
I ran into a similar issue. In my case, it didn't refuse to run the js.erb file itself but rather scripts in templates nested within that file through the use of render. So, this answer may have limited utility to your specific case. That said, I did try to reproduce your issue using Rails version 6.1.1 and couldn't.
However, even if you get past the initial hurdle of getting just your .js.erb file to run, you can still run into the issue of nested scripts: if your .js.erb file renders a template that contains a script tag. That script won't run because the request from which it originated assigns it a new nonce, which won't match the nonce in the meta tag.
So, to those coming here from a search engine as I did, here's the general strategy I pursue to get async embedded JS working with CSP for that nested case and assuming the .js.erb file itself runs. Using your case as an example:
Send the nonce along in the AJAX request. I suppose you won't get around writing some custom JS to send the request. Something like:
document.getElementById('<%= object.code %>').addEventListener('click', e => {
e.preventDefault(); // So we don't send two requests
fetch('<%= create_object_path %>', {
method: 'POST',
headers: {
'Content-Type': 'application/json;charset=utf-8'
},
body: JSON.stringify({
nonce: document.getElementsByName('csp-nonce')[0].content
})
});
});
This sends the nonce from the meta tag to the server in the form of a nonce parameter.
You may need to remove remote: true from your link for this to work. And of course, this script will itself need to be 'nonced' or else it won't run!
Assign the nonce to a #nonce instance variable in the controller:
#nonce = params[:nonce]
Wherever you render scripts, do:
<%= javascript_tag nonce: #nonce || true do %>
...
For those wondering how to get the same to work with their existing asynchronous forms:
Add this form field: <%= hidden_field_tag :nonce %>
On form submit, assign the nonce from the meta tag to the hidden field:
document.getElementById('id_of_submit_button').addEventListener('click', async e => {
document.getElementById('nonce').value = document.getElementsByName('csp-nonce')[0].content;
});
In this case, you don't want to prevent the default behavior on the event because you want the form to submit.
Then continue with step 2 above (assigning the nonce to a controller instance variable).
I hope as a general strategy this is useful to some. And I hope it can serve as inspiration for how to get the .js.erb file itself to run.
UPDATE: Of course, for your specific (but limited) use case, you could simply return the object's service id as part of some JSON object you return to the client instead of rendering a .js.erb template. I say "limited" because this won't work for people who really need to render templates.
If you did want to render your .js.erb file, I suspect something like this could work for your case as well, where instead of checking whether the HTTP_TURBOLINKS_REFERRER header is present, you check for request.xhr?. Just know that starting in newer Rails versions, remote: true doesn't set the requisite header for request.xhr? to work anymore. But since you're on 5.2.1, it may work for you.
Here's what I'm trying to do:
The user pastes a URL.
The input box that the user pastes in has an :onpaste that triggers urlPasted() function.
urlPasted() function submits the form that input box is in, which does an AJAX call to a custom function named lookup_profile.
In the controller, lookup_profile function does some web requests, and then updates some instance variables.
Once those variables are updated (takes ~5 seconds), the view has a function that waits 20 seconds and updates textboxes on the modal with the results of those instance variables.
Here's what I have thus far in the view:
<%= form_tag url_for(:controller => 'users', :action => 'lookup_profile'), id: "profileLookupForm", :method => 'post', :remote => true, :authenticity_token => true do %>
<div class="form-group row">
<div class="col-sm-12">
<%= text_field_tag "paste_data", nil, onpaste: "profileURLPasted();", class: "form-control"%>
</div>
</div>
<% end %>
<script type="text/javascript">
function profileURLPasted() {
// Once the user pastes data, this is going to submit a POST request to the controller.
setTimeout(function () {
document.getElementById("profileLookupForm").submit();
}, 100);
setTimeout(function () {
prefillForm();
}, 20000);
};
function prefillForm() {
// Replace company details.
$('#companyNameTextBox').val("<%= #company_name %>");
};
</script>
Here's what the controller looks like:
def lookup_profile
# bunch of code here
#company_name = "Random"
end
Now here's the problem I have. When the user pastes the data, it submits perfectly to the custom_action lookupProfile. However, after lookupProfile runs its code, rails doesn't know what to do afterwards. By that, I mean it gives me this error:
Users#lookup_profile is missing a template for this request format and
variant. request.formats: ["text/html"] request.variant: []
When in fact, I actually have a file at views/users/lookup_profile.js.erb. For some reason, it's trying to render the HTML version. I don't know why.
Secondly, I've tried putting this in the controller towards the end:
respond_to do |format|
format.js { render 'users/lookup_profile'}
end
but that results in this error:
ActionController::UnknownFormat
Any help would be greatly appreciated. I just want the custom function to run, update the instance variables, and let me update the current form with that data.
Here's another stackoverflow reference of something similar I'm trying to do: Rails submitting a form through ajax and updating the view but this method doesn't work (getting the actioncontroller error)
* EDIT 1 *
Ok, so I fixed the ActionController error by replacing my form_tag with:
<%= form_tag(lookup_profile_users_path(format: :js), method: :post, :authenticity_token => true, id: 'profileLookupForm', remote: true) do %>
But now it's actually rendering the actual javascript into the view, and I don't want that. I simply want to be able to access the instance variables that were updated in the lookup_profile action, not display the view.
* EDIT 2 *
So I think my problem comes down to this: Placing a button in the form and submitting from IT is different than my javascript code that submits the form. If I can figure out what's up with that, then I think I may be in good shape.
You are mixing a few things there. First of all, instead of doing document.getElementById("profileLookupForm").submit() you should do an ajax request, I guess the submit() method ignores the remote: true directive from rails.
So, change the submission to:
form = getElementById("profileLookupForm");
$.post(form.action, {paste_data: this.value}, 'script')
// form.action is the url, `this` is the input field, 'script' tells rails it should render a js script
That way the request is done async and the response does not replace the current page.
Now, what I think you are mixing is that #company_name won't change with that ajax request. When you render the form and everything else, #company_name is replaced with the actual value IN THAT MOMENT and will not change after your post request since the reference is lost. So this line:
$('#companyNameTextBox').val("<%= #company_name %>");
will be
$('#companyNameTextBox').val("");
al the time.
What you want is to respond with a script that updates the field with the value that you set to #company_name (also, waiting arbitrarilly X seconds is a really bad practice).
So, instead of responding with:
format.js { render 'users/lookup_profile'}
create a view lookup_profile.js with the code that you want to execute
$('#companyNameTextBox').val("<%= #company_name %>");
here, #company_name will actually be the value obtained with those requests you told before, the script is generated at the moment and excecuted as a response of the request.
There are two ways I know of to pass variables defined in a controller (/action) to JS...
The official way is
.js.erb:
var banana = "<% #banana %>"
Another way (that I'm currently using is)
.html.erb
<span id="banana-variable" style="display:none"><% #banana %></span>
.js
var banana = $("#banana-variable").html()
This js file is loaded on multiple actions/views across the controller. It makes sense to me to not use a .erb extension: users cache it the first time they hit any action/view in the controller. They then won't have to download different versions of the file when they browse to different pages. Am I right?
Yes, are right. The javascript will be cached on the client's browser.
Still you want to send data on the 'js' or script files you can use this gem called Gon.
http://railscasts.com/episodes/324-passing-data-to-javascript
I recommend you use gem 'gon', which is thoroughly introduced in RailsCast. It makes your controller cleaner. Your method will make it more troublesome if you're trying to pass an array or hash to js.
I think your issue is that you are using <% %> which will execute the code, instead of <%= %> which will execute the code and render the result back into the template.
With Gon you can access the page only after the html page is loaded. From what I understand it uses web page as a proxy to transfer data from rails server to javascript.
But if you want to use the variable at any point of time you want, you can do an ajax(post) request from javascript to the rails controller and retrieve the value as json.
Example:
AJAX Request:
$.ajax({
type: "POST",
url: <PageURL>,
async: false,
dataType: 'application/json',
success: function(data){
data = JSON.parse(data);
},
});
your "data" will contain the returned value.
On the controller side it should be:
Controller:
def <PageURL>
render :json => {:result => <value_you_want_to_return>}
end
Do not forget to define the controller's path in routes.rb file.
I have an html text-area which uses ajax-autocomplete where it populates the dropdown as i start typing. When I select an entry from the dropdown it will set some field to the id of that object.
Once I get the id of the object is there a way I could do something like this?
<% #myObjects.find(1) do |myObj| %>
<h1><%= myObj.attr1 %><h1>
<h2><%= myObj.attr1 %><h2>
<% end %>
Right now, when I get the id of the object I am using jquery's attr() function to set the values which exposes my javascript logic which I don't really like. Is there a way I can activate the field? Or, hide the fields and where the id is populated show the field and let ruby do its magic with myObjects.find?
UPDATE:
Right now the way I am populating the fields in the view like this:
$(function() {
// Executes a callback detecting changes with a frequency of 1 second
$("#id_element_placeholder").observe_field(1, function(){
//alert('Change observed! new value: ' + this.value );
$.ajax({
type: "GET",
dataType: "json",
url: "/myobj/get/" + this.value,
success: function(data){
$('#last_name').attr('value', data.myobj.last_name);
$('#first_name').attr('value', data.myobj.first_name);
}
});
});
});
Is there a way around exposing the above javascript code?
There is nothing wrong with your javascript and you seem to be confused between client side and server side technologies. Ruby cannot directly update your page once it has been sent to your user. It is on your web server and your page has been sent to the clients browser. It can however send javascript in response to a further request made by your application from the clients browser to do exactly that, just as you are doing.
You could send a new html snippet to your browser and replace the entire node but really there is no point. What you are doing is the same as everybody else who uses javascript.
Answer is simple, you can't :)
What you are doing is ok, using AJAX for such things is the way to have such a things done.
If you are concerned about exposures don't look at javascript, look at what the server side code allow a user to do with get/post methods ;)