CODEWITHSUNDEEP
ruby-on-railsruby-on-rails-3
Mozbi
Mozbi

Reputation: 1479

Ruby on rails upload button with empty file field

I'm new to rails and would like to have a question answered:

I have an upload csv field on my form which works perfectly fine when I actually upload a file. But when I hit the upload button without attaching a file, I get an exception: undefined method `[]' for nil:NilClass. Is there a way to stay on the same page and instead show a "no file uploaded" warning?

I've tried doing if(params[:model][:file].nil?) redirect_to model_path end but it continues to the rest of the code. Thanks in advance for the help.

Views Code: 

<%= form_for (@model), :url=>{ :controller=>"models", :action => 'create'}, :html=>{:multipart => true} do |f| %>           
    <p><%= f.label :file, 'Import csv file' %><br/>
      <%= f.file_field :file, :accept => "text/csv"%></p>
      <%= submit_tag "Upload" %>
  <% end %>

Controller Code:

        def create
   51     @model = Model.new
   52     
   53     @model.date_created = Time.now.utc
   54     
   55   
   56     #handles csv input    
   59     if(params[:model][:file])
   60       
   61       @model.id = SecureRandom.uuid; 
   62       file_data = params[:model][:file].read
   63       @parsed_file  = CSV.parse(file_data)
   64       n=0
   65       @parsed_file.each do |row|
   74   
   75         if @model.save
   76           n=n+1
   77         end 
   79       end

   81     else
   82       @model.id = "different type"
   83     end
   84 
   85       respond_to do |format|
   86         if @model.save
   87           if(params[:model][:file] )
   88             format.html { redirect_to @model, :notice => "Successfully imported the CSV file. #{n} new records added to the database" }
   89           else
   90             format.html { redirect_to @model, notice: 'Model entry was successfully created.' }
   91           end
   92           format.json { render json: @model, status: :created, location: @model }
   93         else
   94           format.html { render action: "new" }
   95           format.json { render json: @model.errors, status: :unprocessable_entity }
   96         end

Upvotes: 0

Views: 3758

Answers (3)

Anjan
Anjan

Reputation: 396

To check if a file is attached for upload or not, you can simply check if a file exits in params with

if params[:file]

If you want to check for the extension of the file, you can with

File.extname(params[:file].path) == '.csv'

better way is to check for the content-type of the file and respond appropriately depending on the content-type you can do this with

params[:file].content_type == 'text/csv'

Upvotes: 0

RahulOnRails
RahulOnRails

Reputation: 6542

You should use Jquery validation.

For example :

<form name="myform" id="myform" action="#" method="post">
<input type="file" name="myfile" id="myfile"  />
<input type="submit" name="submit" value="Submit" />
</form>

then you can validate the file input field when it is changed using the following code...

$(document).ready(function(){
    $("#myform").submit({
        var file_value = $('#myfile').val();
        if ( file_value.length =< 0 ){
            alert('No such file exist');
        }
    });
});

With in the same function, you can validate the format of file as well.

var ext = $('#myfile').val().match(/\.(.+)$/)[1];
    switch (ext) {
        case 'csv', 'CSV':
           alert('CSV File- Correct File');
            break;
        default:
            alert('This is not an allowed file type.');
    }

Upvotes: 0

Sonal S.
Sonal S.

Reputation: 1442

try in controller...

 if params[:model][:file].blank?
      flash[:error] = 'Fields cannot be blank.'
      redirect_to model_path
  end

Second thing.. i wont recommend u to use 'model' as a controller bcoz it is rails keyword. Use another name.

Upvotes: 1

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