Unexpected 'nil' in rails upload application

[GuruOne]

Hi All,

Please help. I am sure there is something obvious I am overlooking in
the code but I cannot see it. Please note, as detailed below, I am on
Bluehost using Rails 2.2.2.

The code is example code from TutorialsPoint
- URL: http://www.tutorialspoint.com/ruby-on-rails/rails-file-uploading.htm
and modified to run on Linux bluehost.

On bluehost
- http://upload.datajazz.com/
gives standard 'Welcome Page'
- http://upload.datajazz.com/upload/index
presents html page for file upload
upload file selection works
failure occurs on 'Upload' button click

Issue Summary:
- 'nil' whereas it should be variables being passed from
uploadfile.rhtml
- Line 3 in [app/models] data_file.rb
    name = upload['datafile'].original_filename # Line 3
- Line 7 in [app/controllers] upload_controller.rb
    post = DataFile.save(params[:upload]) # Line 7

Regards

### Environment information
Hosting service: Bluehost

### Rails Environment
Ruby version 1.8.6 (x86_64-linux)
RubyGems version 1.3.1
Rails version 2.2.2
Active Record version 2.2.2
Action Pack version 2.2.2
Active Resource version 2.2.2
Action Mailer version 2.2.2
Active Support version 2.2.2
Application root ~/rails/upload
Environment development
Database adapter sqlite3
Database schema version 0

### Relevant source files
### dir: [app/models] file: data_file.rb
class DataFile < ActiveRecord::Base
  def self.save(upload)
    name = upload['datafile'].original_filename # Line 3

    directory = "public/data"
    # create the file path
    path = File.join(directory, name)
    # create or over-write file 'path' with 'datafile' contents
    File.open(path, "wb") { |f| f.write(upload['datafile'].read) }
  end
end

### dir: [app/controllers] file: upload_controller.rb
class UploadController < ApplicationController
  def index
     render :file => 'upload/uploadfile.rhtml'
  end

  def uploadFile
    post = DataFile.save(params[:upload]) # Line 7
    render :text => "File has been uploaded successfully"
  end

end

### dir: [app/views/upload] file: uploadfile.rhtml
<h1>File Upload</h1>
<% form_tag :action => 'uploadFile',
                        :multipart => true do %>
<p><label for="upload_file">Select File</label> :

<%= file_field 'upload', 'datafile' %></p>

<%= submit_tag "Upload" %>
<% end %>

### run application
http://upload.datajazz.com/upload/index

### Error Output
NoMethodError in UploadController#uploadFile

You have a nil object when you didn't expect it!
You might have expected an instance of ActiveRecord::Base.
The error occurred while evaluating nil.[]
RAILS_ROOT: ~/rails/upload

Application Trace | Framework Trace | Full Trace
app/models/data_file.rb:3:in `save'
app/controllers/upload_controller.rb:7:in `uploadFile'

Request
Parameters:

{"multipart"=>"true",
"commit"=>"Upload",
"authenticity_token"=>"82b3eeae67198fb71bb4dea43b1790ac70bda0ae"}
Show session dump

Response

Headers:

{"cookie"=>[],
"Content-Type"=>"",
"Cache-Control"=>"no-cache"}

[GuruOne]

Hi All,

As I suspected, it was a very simple mistake in the original code
which I had picked up from the web.
Issue: the destination path didn't contain a valid directory.
I suspect the original code probably worked on a different platform
(probably Windows).

Here is the complete working solution, which I have rewritten to
eliminate some of the older rails code.

Regards
************ Working solution
### dir: [app/models] file: data_file.rb
class DataFile < ActiveRecord::Base
  def self.save(upload)
    # Changed Default Destination: [__RAILS_DIR__/public/data]
    name = "data/" + upload.original_filename
    File.open(name, "wb") { |f| f.write(upload.read) }
  end
end

### dir: [app/controllers] file: upload_controller.rb
class UploadController < ApplicationController
  def index
     render :file => 'upload/uploadfile.rhtml'
  end

  def uploadFile
    file_param = params[:upload][:datafile]
    post = DataFile.save(file_param)
    render :text => "File has been uploaded successfully"
  end
end

### dir: [app/views/upload] file: uploadfile.rhtml
<h1>File Upload</h1>
<% form_for :upload,:url=>{:action => 'uploadFile'},:html =>
{ :multipart => true } do |f| %>

<p><label for="upload_file">Select File</label> :
<%= f.file_field 'datafile' %></p>
<%= f.submit "Upload" %>
<% end %>

### run application
http://upload.datajazz.com/upload/index