Issues implementing ajax for the config for Rails 2.0.2 and Ruby 1.8.7. Jquery/Scriptaculous/Prototy

rubyonrails-talk
1

Hello all,

I am trying to render via javascript a post and an image in my rails app. My app has the config of Ruby 1.8.7 and Rails 2.0.2 .

With great difficulty I have found a suitable version of paperclip( https://github.com/thoughtbot/paperclip/commit/d177c8f838458348a9f4d1fe41918c5bd99a989c ) to meet the above config requirements.

Earlier before integrating image upload feature in my app for each post, post message where being rendered via javascript using AJAX with Jquery 1.4 . This stopped working when I had try to implement uploading images in my app using paperclip... I request you to please look into this for details of the same:- http://stackoverflow.com/questions/6070510/unable-to-figure-out-why-a-photo-attribute-of-the-paperclip-plugin-is-not-being-p .

From this experience I have been able to in a way infer I need to find an appropriate paperclip version suiting my requirements... unless.. they could be other ways to deal with this situation.. If so.. It would be great if you could enlighten me on the same...

Going forward I have the following options with me:-

1. Find a suitable paperclip plugin which would have support for AJAX using Jquery. (I am really not too sure on how I would be doing this..)

2. Try using scriptaculous and/or prototype( I am unsure on whether I need to use either or both of them ). The concern with this is , I have to implement this from the scratch and I have to figure out from scratch how to go about the same and also the fact that Ajax using Jquery already works for me with post and not with post + Image.

I would like to add some details(code, other points) wrt option 1 wrt the problem I am currently facing:-

I have used option 1 with the help of the Railscast by Ryan Bates(#136 jQuery - RailsCasts).

I have made appropriate modifications referring to the same.. The file that I am trying to render via JS is post_message.js.erb looks like this..

    <!--$("#new_post").before('<div id ="new_post"><%= escape_javascript(flash.delete(:notice)) %></div>'); TO-DO the flash messages aren't yet enabled/working completely for now.. -->     <!--$("#latest_post").before('<div id ="latest_post"><%= escape_javascript(flash.delete(:notice)) %></div>');-->     $("#latest_post").prepend("<br/> <%= image_tag @group_post.avatar.url(:thumb) %> <%= @group_post.message %> by <%= Investor.find(@group_post.post_by).first_name %> <div class=contentdispgrp> <%= distance_of_time_in_words(@group_post.created_at,Time.now) %> ago</div> <br/><br/><hr/>");     $("#latest_post").append("<br/> <%for a in @group_all_posts %> <%= image_tag a.avatar.url(:thumb) %> <%= a.message %> by <%= Investor.find(a.post_by).first_name %> <div class=contentdispgrp> <%= distance_of_time_in_words(a.created_at,Time.now) %> ago</div> <br/><br/><hr/><%end%>");     $('#post_msg input').val('');

I am very much a novice with Jquery and hardly have around 3-4 months of experience with RoR, I have one doubt over here if one could help me clarify..If you have read http://stackoverflow.com/questions/6070510/unable-to-figure-out-why-a-photo-attribute-of-the-paperclip-plugin-is-not-being-p , you would observe by just removing the `:id => 'new_post'` from within the `:html` symbol stopped the .js.erb from being rendered..

My doubt is I am pretty much unclear and lack knowledge on exactly what role is the id "new_post" playing.. when I have actually commented the same.. in my post_message.js.erb.. It might be that the id is used to uniquely identlify the HTML partial that is being rendered.. in which I currently have the part of the code taking the parameters of the image and the message along with it... Not too sure.. Or is there any other side to it ...If so kindly widen my horizon on the same..

The part of the file(this is a partial) which otherwise gets rendered via HTML has the following code in it:-

    <%form_for :group_post, @group_post, :url => {:action => :post_message, :id => params[:id]},:html => {:multipart => true}, :id => 'new_post' do |f| %>         Start Discussion:<%=f.text_field :message%>        <%= f.file_field :avatar %>        <%=f.submit "Post" %>       <%end%>

    <div id = "latest_post"> </div>     <%for a in @group_all_posts %>       <%if !a.avatar_file_name.to_s.empty? %>       <br/><%= image_tag a.avatar.url(:thumb) %>       <%end%>     <br/><%= a.message %> <br/> by <%= Investor.find(a.post_by).first_name %> <div class ="contentdispgrp" id="style_chck"> <%= distance_of_time_in_words(a.created_at,Time.now) %> ago </div><br/><br/> <hr/>

My post_message method in my controller looks like this:-

     def post_message         @group_post = GroupPost.new(params[:group_post])         #@group_comment = GroupComment.new(params[:group_comment])

        @investor_group = InvestorGroup.find(params[:id])         @group_post.investor_group_id = @investor_group.id         investor_id = session['investor_id']         @group_post.post_by = investor_id         if !@group_post.message.blank?            @group_post.save            flash[:notice] = 'Post was successfully created.'         else           flash[:notice] = 'Post was not successfully created. Post can\'t be blank'         end     # @group_comment.comment_by = investor_id     # @group_comment.group_post_id = :post_id

2

Hello all,

I am trying to render via javascript a post and an image in my rails app. My app has the config of Ruby 1.8.7 and Rails 2.0.2 .

With great difficulty I have found a suitable version of paperclip(has_attached_file respects :whiny_thumbnails. Added validates_attachm… · thoughtbot/paperclip@d177c8f · GitHub… ) to meet the above config requirements.

Earlier before integrating image upload feature in my app for each post, post message where being rendered via javascript using AJAX with Jquery 1.4 . This stopped working when I had try to implement uploading images in my app using paperclip... I request you to please look into this for details of the same:-ruby on rails - Unable to figure out why a photo attribute of the paperclip plugin is not being passed in as a params on submit - Stack Overflow… .

Traditionally, a straight up ajax form can't upload files: when using ajax a piece of javascript serializes the form and sends the request to the server and javascript running inside the browser doesn't have access to the filesystem.

The illusion of an ajax file upload can be provided by having the file upload happen inside a hidden iframe, there are plenty of articles describing how this works (and probably several jquery plugins implementing it). Other options involve using flash for the upload

The file-api specification (File API) does add the ability for javascript to access the filesystem but not all browsers currently support this

Fred

3

Hello Fred,

Thanks for your enlightening inputs...

I am sorry if some part of my question made you say/infer that what I am trying ask is upload an image via AJAX.. What I exactly meant to say..is after I am fetching an image from the filesystem.. How can i display the same onclick of a button without making/getting the entire page to reload.. May be it would require that I somewhere make use of a partial.. The question here is where and how...in case this is the right option or if it isn't... is there another way to deal with this.. I have no issues with only that portion/section of the file reloading in which the most recent image and message is posted, the other images with post should be able to be fetched and displayed without the entire page reloading is what I am basically trying to get working for me...this is actually working for me for each post alone.. but not post+image.. I hope your now better able to understand what I'm exactly looking for..

[Update in ORIGINAL QUESTION] I would like to add Paperclip and Jquery have nothing to do with each other..(based on inputs I could gather from people on other forums). This piece of information would really help....but..

In my case they both to work separately use something in common to the html symbol..As a result I have been able to get them both working separately.. but not yet together.. Please find below the details of what exactly is common among them and what separates the two based on my observation

Firstly in order to get posting of message to work for me with AJAX, i had to apart from adding several change elsewhere also make sure that within my _common.html.erb partial view I add an :id => 'with_some_name' within my html symbol. Something like this:- :html => { :multipart => :true , :id => 'new_post'} within my form_for tag.. Now why exactly this works this way.. I haven't yet figured out and I am researching on the same..

So this basically was working fine until I had integrated uploading of images feature into my code..

Initially I was facing a roadblock in passing my image as a params.. I observed that it was not being passed when I looked into my log file..

The reason behind this, based on what I could figure out, as a solution to get image upload working for me was... when I make use of :html => { :multipart => :true , :id => 'new_post'} in my _common.html.erb partial view, originally as you can see the 'multipart' and 'id' symbol are taken as if as params for the html symbol.. and may be for the entire html.erb partial that is being rendered..

I observed that when I removed the id symbol from its original location as you can see above.. to something like this:- :html => { :multipart => :true }, :id => 'new_post' images were now being taken as a part of params along with each message. html was being rendered and the page reloads..displaying the image and the post.. but this doesn't render the .js.erb file any more.. .

why exactly this contrast in behavior is what I am unable to understand.. and how exactly to get both working is something.. I am trying to figure out..I guess I need to first understand exactly why each thing works as shown..

Frederick Cheung wrote in post #1000053:

4

With Event.preventDefault(). If in Prototype, with Event.stop(). Be sure to wrap this method in a conditional, otherwise you have just killed the button and it will never bubble to submit the form again.

Walter

5

Hi Walter,

Can you please elaborate on how exactly I would be able to use Event.preventDefault() with a conditional..?. Also why would I need to use a conditional..? I ask this as I am a newbie to Jquery and my javascript fundas are not very good.

To make it easier for you to answer this for me.. I have included the part of the code in the partial where you say it would be appropriate to put the button..

<%if @current_user.is_an_existing_member_of_group(@investor_group)%> <%form_for :group_post, @group_post, :url => {:action => :post_message, :id => params[:id]},:html => {:multipart => true} do |f| %>     Start Discussion:<%=f.text_field :message%>    <%= f.file_field :avatar %>    <%=f.submit "Post" %>   <%end%>

<div id = "latest_post"> </div> <%for a in @group_all_posts %>   <%if !a.avatar_file_name.to_s.empty? %>   <br/> <%= image_tag a.avatar.url(:thumb) %>   <%end%> <br/><%= a.message %> <br/> by <%= Investor.find(a.post_by).first_name %> <div class ="contentdispgrp" id="style_chck"> <%= distance_of_time_in_words(a.created_at,Time.now) %> ago </div><br/><br/> <hr/> <%end%>

I would truly appreciate you extra effort in trying to help me..

Kindly bear with my being a novice.

Many Thanks for your inputs..

Walter Davis wrote in post #1000079:

6

Hi Walter,

Can you please elaborate on how exactly I would be able to use Event.preventDefault() with a conditional..?. Also why would I need to use a conditional..? I ask this as I am a newbie to Jquery and my javascript fundas are not very good.

To make it easier for you to answer this for me.. I have included the part of the code in the partial where you say it would be appropriate to put the button..

<%if @current_user.is_an_existing_member_of_group(@investor_group)%> <%form_for :group_post, @group_post, :url => {:action => :post_message, :id => params[:id]},:html => {:multipart => true} do |f| %>    Start Discussion:<%=f.text_field :message%>   <%= f.file_field :avatar %>   <%=f.submit "Post" %> <%end%>

<div id = "latest_post"> </div> <%for a in @group_all_posts %> <%if !a.avatar_file_name.to_s.empty? %> <br/> <%= image_tag a.avatar.url(:thumb) %> <%end%> <br/><%= a.message %> <br/> by <%= Investor.find(a.post_by).first_name %> <div class ="contentdispgrp" id="style_chck"> <%= distance_of_time_in_words(a.created_at,Time.now) %> ago </div><br/><br/> <hr/> <%end%>

I would truly appreciate you extra effort in trying to help me..

Kindly bear with my being a novice.

Many Thanks for your inputs..

I'm looking at this code, and it appears to be a normal post to the server. Where and what do you plan to update to the page using jQuery? Are you saying you want to post to the server, but through JavaScript, and update the current page with a refresh of the list of messages? Because there's a well-worn way to do that. You stop the form.submit method, and use Ajax to send the form instead, then your server replies with the current list of messages, and you update the appropriate list DIV with those.

I don't know the jQuery idiom for this, but in Prototype, it's very simple:

$('your_form_id').observe('submit',function(evt){   evt.stop(); //keep the default submit from happening   this.request({ //send the form through an Ajax request     onSuccess: function(transport){       $('your_list_container').update(transport.responseText);     }   }); });

As to the conditional, it doesn't apply in this pattern. But let's say you had a form submit button, and you wanted it to stop working after the form had been submitted (sort of what :disable_with does in the regular form builder code). You want the button to be pushed once only, so you might do something like:

$('your_button').observe('click',function(evt){   if ( this.clicked ){     evt.stop();   }else{     this['clicked'] = true;   } });

So the first time through, the button click happens and bubbles (and the button is marked so no future clicks will work) and the second + times it is clicked, it does nothing, because Event.stop happens instead. (Event.stop is a belt-and-suspenders form of Event.preventDefault, which is built in to most browsers, and I suspect added by jQuery to those that don't have it. It just makes the current event die and never propagate beyond the current element.

Walter

7

Hi Walter,

Thanks for your reply

Sorry for replying in late.. I had seen your post in the morning itself.. was just doing research from my end..

To give in something that could help my case...

Actually, if you can kindly spare some time... to best explain my case.. I am pretty much doing what has been done in the Railscast by Ryan Bates Jquery( #136 jQuery - RailsCasts )..I am actually overriding the the submit method.... The only difference lies in the fact that I am trying to display a new image which comes along with each new message posted..

After some researching I found these quotes very interesting:-

" 5.2 Dealing with Ajax Unlike other forms making an asynchronous file upload form is not as simple as replacing form_for with remote_form_for. With an Ajax form the serialization is done by JavaScript running inside the browser and since JavaScript cannot read files from your hard drive the file cannot be uploaded. The most common workaround is to use an invisible iframe that serves as the target for the form submission. "

This is taken from the site:-

This actually compliments what Fred had mentioned previously.. ..would like to requote that:-

[

"

Posted by Frederick Cheung (Guest) on 2011-05-21 12:39 (Received via mailing list)

1.4 . This stopped working when I had try to implement uploading images in my app using paperclip... I request you to please look into this for details of the

same:-ruby on rails - Unable to figure out why a photo attribute of the paperclip plugin is not being passed in as a params on submit - Stack Overflow…

.

Traditionally, a straight up ajax form can't upload files: when using ajax a piece of javascript serializes the form and sends the request to the server and javascript running inside the browser doesn't have access to the filesystem.

The illusion of an ajax file upload can be provided by having the file upload happen inside a hidden iframe, there are plenty of articles describing how this works (and probably several jquery plugins implementing it). Other options involve using flash for the upload

The file-api specification (File API) does add the ability for javascript to access the filesystem but not all browsers currently support this

Fred

"

]

I tried to better understand what was happening for me .. based on the part of AJAX, that I could implement.. I found that as in my first post.. the latest_post represents "all" the entries of all messages posted so far along with images as shown in the partial.. the only thing that is happening is that the "latest" message is being "prepended" or one can say prefixed in a way to the already existing list.. so that list is not being fetched again from the DB and its just moved a step/level down giving place for the latest post to come.. All this is cool..:slight_smile: but now... to get the same working with each image.. is my real challenge going forward....

Also since your also unfamiliar with the jquery syntax..

I found this as a good substitute to start somewhere:-

http://www.williambharding.com/blog/rails/rails-ajax-image-uploading-made-simple-with-jquery/

He has have made use of the attachment-fu plugin..

Now my challenge is to somehow use them together to get it working for me.. I am working on it...Javascript is not something that I am quite good at though..:).. will do what best I can from my end.. would be grateful if you could help me with the your inputs , if you get time checking out the above urls..

Thanks again Walter..:slight_smile:

Walter Davis wrote in post #1000100:

8

So is your question then how to go about uploading the file through "faux Ajax" methods, like a hidden iframe? Have a quick search on Github -- I would be startled if you didn't find a few ways to do this using a gem or plugin. The code itself is very simple, all you have to do is add the target attribute to your form, and make the value of that attribute the name and/or id of an iframe you have styled to be invisible. Everything else is the same. Then to get the response back from that iframe, you need to do a little more JavaScripting.

Walter

9

Hi Walter,

Sorry for replying in late..I was held up with things for the release due yesterday.. I had in a way luckily been given more time to implement this image upload via AJAX after yesterday's release.

I am not sure if calling it a "faux" AJAX call would be the appropriate thing to say..,

I guess I need to really understand this tutorial(Rails Ajax Image Uploading Made Simple with jQuery – Relentless Simplicity) fully before I could really discover and then decide if I am using a faux AJAX call or not..

But yes, after referring to this(jQuery Form Plugin)… it seems like I am implementing something on the lines of using iframe..figuring my way out.. wondering how could I make use of text-area.

As of now I'm just trying a POC

Walter Davis wrote in post #1000273:

10

Hi Walter,

Sorry for replying in late..I was held up with things for the release due yesterday.. I had in a way luckily been given more time to implement this image upload via AJAX after yesterday's release.

I am not sure if calling it a "faux" AJAX call would be the appropriate thing to say..,

I guess I need to really understand this tutorial(http://www.williambharding.com/blog/rails/rails-ajax-image-uploading-made-simple-with-jquery/) fully before I could really discover and then decide if I am using a faux AJAX call or not..

I built one of these last year, and as of that time, the only browsers that could truly accept a real Ajax upload were WebKit nightlies and FF4 beta. Obviously time moves on. But the upload kit I used (noswfupload) had code paths for both kinds of browsers, and made it very simple to factor out the differences. Under the covers, for most browsers (AFAIK) an iframe is dynamically injected into the page and the file upload is ported through that keyhole. The "page" doesn't refresh, but the iframe's document certainly does, so the browser is happy either way.

Walter