*what* is the method to upload files thru an FBML canvas app to my site?

[lunaclaire]

I seem to have seen posts around that said that you have to create an
iframe within your canvas to upload files back to your server (i.e.
not photos being uploaded to a FB album).

Any ptrs on how (or ptrs to postings describing how) to do this?

Or is there some Facebooker support for this that I havent spotted
yet?

Thx,

Steve

[Mike Mangino]

You don't have to create an iframe, you just need the action of the form to be directly to your server. Facebook will strip the files out if you go through them.

Mike

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[lunaclaire]

Hmmm... interesting because I was just about to post that I jumped in
and am trying to do it with an fb:iframe containing a simple form with
a file_field_tag and when I receive the upload action in my
controller, the file param is stripped out

I understand that you're saying that I dont even need to do the
iframe, but with the iframe, I guess I'm having the file stripped out
because it's only using the iframe to get the template containing the
file_field_tag's form for display, but it posts back via FB...? I
guess this is true because I'm getting fb_sig_params back on the
receiving action. Is that right?

Now, I'm trying to do all of this in the context of a
facebook_form_for where I'm creating/editing an model that has an
associated image. So, in the context of the form_for, I now tried:

<%= f.file_field :banner, :label => "Select File" %>

but I find that when my controller's action is hit, I only get the
filename, none of the data.

So, is it still getting stripped (regardless of the use of an iframe)
and there's no way to have this in the context of this form?

[Joseph Sofaer]

I think what Mike is trying to point out is that if you direct the
request to your canvas url (ie apps.facebook.com/myapp) the data will
not get passed on. You have to set your form to point straight to your
app (like: <form action="<%= ActionController::Base.asset_host +
"/photos" %> method="post" enctype="multipart/form-data">").
Best,
Joseph

[lunaclaire]

to do that, though, wouldnt that need to be part of a sub-form that
I'd put in there? Since this is part of the facebook_form_for to edit
the model obj that has this file as an attachment...?

In other words, I guess that's why I cant just do the

<%= f.file_field :banner, :label => "Select File" %>

within\ that form.

I'll need a subform with its own submit button posting back directly
to my server?

On Feb 4, 2:50 pm, Joseph Sofaer <joseph.sof...@gmail.com> wrote:
> I think what Mike is trying to point out is that if you direct the
> request to your canvas url (ie apps.facebook.com/myapp) the data will
> not get passed on. You have to set your form to point straight to your
> app (like: <form action="<%= ActionController::Base.asset_host +
> "/photos" %> method="post" enctype="multipart/form-data">").
> Best,
> Joseph
>

[Joseph Sofaer]

I haven't use facebook_form_for but you might be able to overwrite the
action. The other thing I had to do here was redirect explicitly back
to http://apps.facebook.com/canvas_name on that request.
J.

[lunaclaire]

I've tried explicitly setting the action to submit directly back to my
servers, but the value I'm getting back from the file_field in the
params is still just a string with the filename in it and not a
StringIO object.

Any other ideas?

Joseph - It sounds like you've gotten something liek this to work...
If so, any code you can post showing what you did?

On Feb 4, 3:17 pm, Joseph Sofaer <joseph.sof...@gmail.com> wrote:
> I haven't use facebook_form_for but you might be able to overwrite the
> action. The other thing I had to do here was redirect explicitly back

> tohttp://apps.facebook.com/canvas_nameon that request.
> J.

[Joseph Sofaer]

That was the code I use.
j.

[lunaclaire]

OK for anyone who needs it, I got it working and will document it
here...

The idea is that I have a Forum model object that needs to have a
banner image file uploaded.

Given that I have an upload form within the form for editing the
Forum, I had to do it as an iframe.

So, within the template for model object's editing form I have:

<%= f.text '<fb:iframe width="420" height="100" frameborder="0"
src="' + url_for(:controller => :forums, :action
=> :upload_banner, :id => @forum.id, :only_path => false, :canvas =>
false) + '"></fb:iframe>' %>

note that I set the src for the iframe with url_for() and
set :only_path => false and :canvas => false. This gives me a full url
that pts back to an action in my controller on my server, thus
bypassing FB for what happens in the iframe.

The 'upload_banner' is both an action in my controller and a template
for the upload form.

upload_banner.erb is that template and looks like this:

<% form_tag(url_for(:controller => :forums, :action
=> :upload_banner_post, :id => @forum.id, :only_path => false, :canvas
=> false), :multipart => true) do %>
<div style="font-family:lucida grande,tahoma,verdana,arial,sans-
serif; font-size:11px;">
<label style="font-family:lucida grande,tahoma,verdana,arial,sans-
serif; font-size:11px;" for="upload_file">Select File</label>: <%=
file_field_tag :file %> <%= submit_tag "Upload" %>
</div>
<% end %>

Note again the url_for() which ensures that the POST'ing action from
the form goes directly back to my server instead of thru FB so that
the file contents get submitted to me. (If you're wondering about that
styling, I grabbed that from the FB css so that what's in the iframe
would look like the rest of the canvas page)

Then in my controller, I have:

def upload_banner
@forum= Forum.find(params[:id])
render :layout => false
end

def upload_banner_post
@forum= Forum.find(params[:id])
@forum.save_banner(params[:file])
flash[:notice] = 'Your banner image was successfully uploaded.'
redirect_to(:action => :upload_banner, :id => @forum.id)
end

That's it. Works pretty good.

The only thing that I still cant get right is that I'd like to refresh
the page that contains the iframe to display something about the
banner after the upload, but I cant figure out how to ref any div's
from the these controller actions served into the iframe.

Hope that helps someone. Thx for the help, Mike and Joseph.

On Feb 4, 6:03 pm, Joseph Sofaer <joseph.sof...@gmail.com> wrote:
> That was the code I use.
> j.
>

> On Thu, Feb 4, 2010 at 5:59 PM, lunaclaire <szager...@gmail.com> wrote:
> > I've tried explicitly setting the action to submit directly back to my
> > servers, but the value I'm getting back from the file_field in the
> > params is still just a string with the filename in it and not a
> > StringIO object.
>
> > Any other ideas?
>
> > Joseph - It sounds like you've gotten something liek this to work...
> > If so, any code you can post showing what you did?
>
> > On Feb 4, 3:17 pm, Joseph Sofaer <joseph.sof...@gmail.com> wrote:
> >> I haven't use facebook_form_for but you might be able to overwrite the
> >> action. The other thing I had to do here was redirect explicitly back

> >> tohttp://apps.facebook.com/canvas_nameonthat request.

[nnahum]

I have the same problem.
The following code works perfect as an iFrame application but doesn't
upload the file as an FBML.
Could somebody point me out what I need to change in order to direct
the action of the form to the server and not through Facebook as Mike
pointed out?

<h1>New Location</h1>

<% form_for(@location, :html => {:multipart => true}) do |f| %>
<%= f.error_messages %>

<p>
<%= f.label :name %><br />
<%= f.text_field :name %>
</p>
<p>
<%= f.label :address %> <br />
<%= f.text_field :address %>
</p>

<p><label for="upload_file">Upload image file (160x100 png)</label> :
<%= file_field 'upload', 'datafile' %></p>

<p>
<%= f.submit 'Create' %>
</p>
<% end %>

<%= link_to 'Back', locations_path %>

Thanks!
nnahum

> > > servers, but the value I'm getting back from thefile_fieldin the

[Stéphane Akkaoui]

Hi,

Your problem is explained in the Facebook Documentation

http://wiki.developers.facebook.com/index.php/UsageNotes/Forms
"File uploads (that is, forms with enctype="multipart/form-data" and
<input type="file"> fields) will not work when the form is submitted
to a canvas URL. Instead, you need to submit file uploads directly to
your application and redirect back to a canvas page after the form is
processed."

So in order to get your form working in a FBML canvas page, you have
to point your form to your server url.

Something like this should do the tricks:

<% form_for(@location, locations_url(:canvas => false), :html =>

{:multipart => true}) do |f| %>

HTH,

--
Stéphane Akkaoui
http://imeuble.info
http://sociabliz.com

Le 24 févr. 10 à 07:22, nnahum a écrit :

[nnahum]

Thank you Stephane! after some whrestling it worked.
For those with the same problem, the magic line was in the view "<%
form_for(@location, :url => {:action => :create, :canvas =>
false, :only_path => false}, :html => {:multipart => true}) do |f| %>
and then in the controller upon success returned to the canvas by
doing " format.html { redirect_to(:controller => :locations, :action
=> :show, :id => @location.id, :canvas => true, :only_path =>
false) }"

The only problem I still have is that when I redirect to the server I
get error "ActionController::InvalidAuthenticityToken" because in my
ApplicationController I have a "protect_from_forgery"
The way I got around this was to include in my controller the
statement: "skip_before_filter :verify_authenticity_token" but
doesn't seems to me very elegant and may introduce some security
issues.

Any idea how to solve this authenticity token problem differently?

Thanks for the help!
nnahum

On Feb 24, 6:19 am, Stéphane Akkaoui <sakka...@gmail.com> wrote:
> Hi,
>
> Your problem is explained in the Facebook Documentation
>
> http://wiki.developers.facebook.com/index.php/UsageNotes/Forms
> "File uploads (that is, forms with enctype="multipart/form-data" and  
> <input type="file"> fields) will not work when the form is submitted  
> to a canvas URL. Instead, you need to submit file uploads directly to  
> your application and redirect back to a canvas page after the form is  
> processed."
>
> So in order to get your form working in a FBML canvas page, you have  
> to point your form to your server url.
>
> Something like this should do the tricks:
>
> <% form_for(@location, locations_url(:canvas => false), :html =>  
> {:multipart => true}) do |f| %>
>
> HTH,
>
> --

> Stéphane Akkaouihttp://imeuble.infohttp://sociabliz.com

> ...
>
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