We Keep Coding

How to get data from response of event ajax:error in Rails 5.1

Iam building a form in Rails. I want to submit it by ajax, so I setted remote: true
<%= form_for #post, html: { multipart: true }, remote: true do |f| %>
...
<%= end %>
In my controller:
def create
#post = Post.new(post_param)
respond_to do |format|
if #post.save
format.html { redirect_to #post, notice: 'Post was successfully created.' }
format.json { render :show, status: :created, location: #post }
else
format.html { render json: #post.errors, status: 400 }
format.json { render json: #post.errors, status: 400 }
end
end
end
In form on view
$('#new_post').on('ajax:success', function(data) {
console.log(data);
}).on('ajax:error', function(evt, xhr, status, error) {
console.log(xhr);
});
But in event 'ajax:error', I can't parse to get data about validation errors of post. All params 'xhr', 'status', 'error' both equal undefined.
How to parse response in 'ajax:error' to get data about validation errors ?

Rails 5.1 introduced rails-ujs, which changes the parameters of these event handlers. The following should work:
// ...
.on('ajax:error', function(event) {
var detail = event.detail;
var data = detail[0], status = detail[1], xhr = detail[2];
// ...
});
Source: http://edgeguides.rubyonrails.org/working_with_javascript_in_rails.html#rails-ujs-event-handlers

Triggering callback after rendering login form from rails

I am building a single-page-app with rails and client-side javascript. To dynamically manage the interface, I need to trigger a callback after the login form view (loginForm.html.erb) is returned (for user authentication via Bcrypt). I've tried jquery $.ajax requests, and can get the form OR the json responses but not both.
Here's the request to get the login form:
loginMenuEl.on("click", function(event){
event.preventDefault();
$.ajax({
url: "http://localhost:3000/login",
type: "GET",
dataType: "json"
}).done(function(jsonData) {
self.initLoginButton();
self.processContent(jsonData);
}).fail(function(){
console.log("*** ajax fail L1 ***");
});
});
Here are the relavent routes:
get "/login" => "sessions#login"
get "/loginForm" => "sessions#loginForm"
get "/login_attempt" => "sessions#login_attempt"
post "/login_attempt" => "sessions#login_attempt"
Here is the Sessions controller that processes the form and json:
def login
#contentInfo = Content.find_by_id(1)
respond_to do |format|
format.html { render :loginForm }
format.json { render json: #contentInfo }
end
end
I've tried other versions of the respond_to block but the form never returns:
format.html { redirect_to (:action => 'loginForm') }
format.html { redirect_to (action: 'loginForm') }
format.html { redirect_to action: 'loginForm' }
format.json { render json: #contentInfo }
Am I correct to believe that rails can return both json and a view file (loginForm.html.erb)

What am I doing wrong with this AJAX request using a form_for in Rails 4?

I'm trying to do a form submission through AJAX in Rails and I am not too sure what is wrong here. I got everything to work using "remote: true" but I want to gain a better understanding of how the AJAX works with jQuery. This is my javascript code:
$(document).ready(function(){
$("#new_user_friendship").on("submit", function(event){
event.preventDefault();
var friendId = $("#user_friendship_friend_id").val();
var _this = $(this);
$.ajax({
url: "/user_friendships",
data: _this.serialize(),
method: "POST",
dataType: "json",
success: function(data){
console.log(data);
friendButton.hide();
$(".friend-request-form").html("<p>Friend request sent</p>");
}
});
});
});
I am suspecting this line url: "/user_friendships/new?friend_id="+friendId containing the url is the culprit of my errors. I wrote this because a hidden field is being passed as a person's friend id but it throws a "404 error", I've also tried url: "/user_friendships" which doesn't return any errors but it also doesn't properly execute the Javascript as I expected.
This is the corresponding form_for that the AJAX request is sent to:
<div class="friend-request-form">
<%= form_for current_user.user_friendships.build(friend_id: #user), id: "new_user_friendship", method: :post do |f| %>
<%= f.hidden_field :friend_id, value: #user.id %>
<%= submit_tag "Send friend request", class: "button radius tiny", id: "friend-request-button" %>
<% end %>
</div>
What this form does is it sends a friend request to another user using a hidden field.
And in my user_friendships_controller.rb I have this code:
def create
if params[:user_friendship] && params[:user_friendship].has_key?(:friend_id)
#friend = User.find(params[:user_friendship][:friend_id])
#user_friendship = UserFriendship.request(current_user, #friend)
respond_to do |format|
if #user_friendship.new_record?
format.html do
flash[:error] = "There was a problem creating that friend request."
redirect_to user_path(#friend)
end
format.json {render json: #user_friendship.to_json, status: :precondition_failed}
else
format.html do
flash[:success] = "Friend request sent"
redirect_to user_path(#friend)
end
format.json {render json: #user_friendship.to_json, status: :precondition_failed}
end
end
else
flash[:error] = "Friend required"
redirect_to root_path
end
end
If anyone can provide any suggestions or feedback that'd be great!
UPDATE:
Now that I added in data: _this.serialize() and changed the url to: url: "/user_friendships" I'm now getting a 412 (Precondition Failed) error. Despite this error the data is actually being saved into the database. Does anyone know why I'm getting this 412 (Precondition Failed) error?

There is something I do not understand, with the dataType json, you said that you had a precondition failed status right ?
But you wrote
format.json {render json: #user_friendship.to_json, status: :precondition_failed}
So I don't think there is any problem, indeed, it seems to work fine, as you explicitly passed the status in your render command, try removing it and I think you will have a 200 (success) status instead.
Of course, you can keep the previous post ajax request, or use this short version
$.post(
/user_friendships',
{ user_friendship: { friend_id: friendId } },
function(){
console.log(data);
friendButton.hide();
$(".friend-request-form").html("<p>Friend request sent</p>");
},
'json')

Add a data attribute to the post params instead of passing it in the url:
$.ajax({
url: "/user_friendships",
data: { user_friendship: { friend_id: friendId } }, // <<< Updated
method: "POST",
dataType: "json",
success: function(data){
console.log(data);
friendButton.hide();
$(".friend-request-form").html("<p>Friend request sent</p>");
}
});
Update
The url should be /user_friendships, assuming that you're using RESTful actions. Have a look to this article about REST in Rails.
Also, when you do an AJAX request like this, your are not sending the rails authenticity tokens that are crated by the form helper. This may be the cause of your 412 (Precondition Failed) error.
See: Understanding the Rails Authenticity Token

Use ajax to post back to same page

I would like to post the result of an ajax request back to the same page that it was requested from. Here are the interacting parts:
AJAX in Jquery
var ids = 1
$(document).ready(function(){
$('#showbtn').on('click', function() {
$.ajax({
url: "http://localhost:3000/teamplayers.json",
data: {'resolution':ids},
type:"post",
dataType: "json",
cache: true,
success:function(){
$('#test3').val(1);
alert("test 3");
},
error: function(error) {
alert("Failed " + console.log(error) + " " + error)
}
});
});
});
This is supposed to set a variable here:
Teamplayer Controller
# GET /teamplayers
# GET /teamplayers.json
def index
#teamplayers = Teamplayer.all
#fteams = Fteam.all
#teamplayer2 = 1
tid = params[:resolution] <-It should set here per the data section above
#ids = tid
end
unfortunately it calls this section of the same controller
# POST /teamplayers
# POST /teamplayers.json
def create
#teamplayer = Teamplayer.new(teamplayer_params)
respond_to do |format|
if #teamplayer.save
format.html { redirect_to #teamplayer, notice: 'Teamplayer was successfully created.' }
format.json { render action: 'show', status: :created, location: #teamplayer }
else
format.html { render action: 'new' }
format.json { render json: #teamplayer.errors, status: :unprocessable_entity }
end
end
end
So what do I do to make it post to the same page.

You are POSTing the ajax, which means the create action will be hit, not the index action. You should be able to see this in your server log output when you hit the page.
If you want to hit the index action, you need to do an GET ajax request with the resolution data set so you can get the data you want.
Additionally, you probably maybe don't want to cache this ajax request if it is actually dynamic data, but it is up to you.
Edit from comments:
You need to add your parameter as a query string for a GET, not as generic "data".
Try something like this:
$.ajax({
url: "http://localhost:3000/teamplayers.json?resolution="+ids,
type:"GET",
dataType: "json",
success:function(){
$('#test3').val(1);
alert("test 3");
},
error: function(error) {
alert("Failed " + console.log(error) + " " + error)
}
});
});
Another edit from comments:
# GET /teamplayers
# GET /teamplayers.json
def index
#teamplayers = Teamplayer.all
#fteams = Fteam.all
#teamplayer2 = 1
tid = params.fetch(:resolution) { 0 } # make sure we got something
#ids = tid.to_i # coerce string param to integer
end

How to pass the params from JS to rails3 controller

Here is my JS.coffee codes:
fetchselect =(val) ->
$.ajax(url: '/firstpages/page', dataType: 'json', par_id: val )
$('.homeNav').find('.unactive').click ->
id = $(this).attr('id')
fetchselect(id)
and Here is my controller codes:
def page
#select = Firstpage.where(:pid=>params[:par_id])
respond_to do |format|
format.html # page.html.erb
format.js { render :layout => false }
format.json { render :json => #select }
end
end
It can't pass the params to #select ,when I click $('.homeNav') ,the log tell me:
Started GET "/firstpages/page" for 127.0.0.1 at 2012-09-07 05:27:07 +0800
Processing by FirstpagesController#page as JSON
Firstpage Load (0.2ms) SELECT "firstpages".* FROM "firstpages" WHERE "firstpages"."pid" IS NULL
Completed 200 OK in 2ms (Views: 0.1ms | ActiveRecord: 0.2ms)

Looks like the problem is in the actual ajax request. Try:
$.ajax({
type: "POST",
url: '/firstpages/page',
dataType: 'json',
data: {par_id : val})
})
For more examples, check out the jQuery $.ajax documentation.