Currently, I have several forms that work with nested attributes. I found out recently about Dropzone JS, so I wanted to implement it in various forms I'm using.
I have two models similar to these:
Games
class Games < ActiveRecord::base
has_many :screenshots, dependent: :destroy
accepts_nested_attributes_for :screenshots, allow_destroy: true
end
Screenshots
class Screenshot < ActiveRecord::Base
belongs_to :game
mount_uploader :ssfile, ScreenshotUploader
end
Normally, I'd handle it with something like this:
new.html.haml
- content_for :breadcrumbs do
%h3.text-center New Game
.col-md-12#content
.row
= render 'form'
.row
.col-md-12
= link_to 'Back', games_path
_form.html.haml
.col-md-12
= form_for @game, :html => {:class => 'form-horizontal form-bordered'} do |f|
.section-title
%h3 General Data
.well
.form-group
=f.label :title, :class => 'col-md-2'
.col-md-6
= f.text_field :title, :class => 'form-control'
.form-group
= f.label :platform, :class => 'col-md-2'
.col-md-6
.input-group
= f.text_field :platform, :class => 'form-control'
.section-title
%h3 Screenshots
.well#screenshots
=f.fields_for :screenshots do |i|
=render 'screenshot_fields', :f => i
%hr
.links
=link_to_add_association 'Add Screenshot', f, :screenshots, :class => 'btn btn-default'
.row
.col-md-12
.actions
= f.submit 'Save', :class => 'btn btn-default'
_screenshot_fields.html.haml
.form-group
-if f.object.ssfile?
.col-md-2
=image_tag(f.object.ssfile_url(:thumb))
.col-md-4
%p
=f.file_field :ssfile, :class => 'styledfileinput'
-if f.object.ssfile?
.col-md-2
%p
=f.check_box :_destroy
=f.label :_destroy, 'Remove'
This works fine. When you click on "Add Screenshot", it loads the link_to_add_association helper, which is part of a gem called Cocoon. This helper will create the necessary JS to add a "block" of code to a form, in this case a file input, though usually you'd have more inputs of other kinds instead of just one.
I want to replace the blocks added by link_to_add_association with a multi-file drop zone.
I've made the following changes to the new.html.haml view:
.col-md-12
= form_for @game, :html => {:class => 'form-horizontal form-bordered', :id => 'gameform'} do |f|
-# *snip*
.well#screenshots
- @game.screenshots.each do |i|
=image_tag i.ssfile_url(:thumb)
%hr
.row
.col-md-12
.actions
= f.submit 'Save', :class => 'btn btn-default'
I added #gameform to the form_for element, and replaced the loop that shows the pictures. So far so good. The problem now is that I don't know how are the files supposed to interact with the form.
I have this on a coffeescript that's loading the Dropzone configuration:
ready = ->
if $('#gameform').length > 0
didthiswork = new Dropzone("#gameform", {
paramName: "game[screenshot_attributes][ssfile]"
})
else
console.log('ruh roh')
$(document).on('page:load ready', ready)
Right now, I can click anywhere in the form and it will bring the upload dialog (which is another problem on itself), but once I pick the pictures, these aren't properly saved. Is there a way to make this work with fields_for? I have a lot of other forms that use a very similar configuration, so I'd much prefer not having to change the entire logic of my application (if possible).
UPDATE
I think I've made some progress. I've managed to make the form send the data, however they're not arriving how I'm expecting it.
I tweaked the configuration, using the information in this link: https://github.com/enyo/dropzone/wiki/Combine-normal-form-with-Dropzone
Resulting in something like this on my coffescript:
Dropzone.options.articuloform =
autoProcessQueue: false
uploadMultiple: true
paramName: "game[screenshot_attributes][ssfile]"
parallelUploads: 100
maxFiles: 100
init: ->
myDropzone = this
# First change the button to actually tell Dropzone to process the queue.
@element.querySelector('input[type=submit]').addEventListener 'click', (e) ->
# Make sure that the form isn't actually being sent.
e.preventDefault()
e.stopPropagation()
myDropzone.processQueue()
return
# Listen to the sendingmultiple event. In this case, it's the sendingmultiple event instead
# of the sending event because uploadMultiple is set to true.
@on 'sendingmultiple', ->
# Gets triggered when the form is actually being sent.
# Hide the success button or the complete form.
return
@on 'successmultiple', (files, response) ->
# Gets triggered when the files have successfully been sent.
# Redirect user or notify of success.
return
@on 'errormultiple', (files, response) ->
# Gets triggered when there was an error sending the files.
# Maybe show form again, and notify user of error
return
return
This prevents the automatic data upload when I select images (which is great), however, once I press the Submit button, the data is arriving with the wrong structure. They're arriving like this in the from data:
Parameters: {
"utf8"=>"✓",
"authenticity_token"=>"l2siCG2D4xW0eto48WM152MTusc6K5cQYem8K2a9c/Y=",
"game"=>{
"title"=>"Super Amazing AAA Title",
"platform"=>"Xbox One",
"screenshot_attributes"=>{
"ssfile"=>{
"0"=>#<ActionDispatch::Http::UploadedFile:0x000000055c7e98 @tempfile=#<Tempfile:/tmp/RackMultipart20150408-9276-14rfzqm>,
@original_filename="screenshot01.png",
@content_type="image/png",
@headers="Content-Disposition: form-data; name=\"game[screenshot_attributes][ssfile][0]\"; filename=\"screenshot01.png\"\r\nContent-Type: image/png\r\n">,
"1"=>#<ActionDispatch::Http::UploadedFile:0x000000055c7df8 @tempfile=#<Tempfile:/tmp/RackMultipart20150408-9276-1opclgk>,
@original_filename="screenshot02.png",
@content_type="image/png",
@headers="Content-Disposition: form-data; name=\"game[screenshot_attributes][ssfile][1]\"; filename=\"screenshot02.png\"\r\nContent-Type: image/png\r\n">,
"2"=>#<ActionDispatch::Http::UploadedFile:0x000000055c7d30 @tempfile=#<Tempfile:/tmp/RackMultipart20150408-9276-16r4kdq>,
@original_filename="screenshot03.png",
@content_type="image/png",
@headers="Content-Disposition: form-data; name=\"game[screenshot_attributes][ssfile][2]\"; filename=\"screenshot03.png\"\r\nContent-Type: image/png\r\n">,
"3"=>#<ActionDispatch::Http::UploadedFile:0x000000055c7c90 @tempfile=#<Tempfile:/tmp/RackMultipart20150408-9276-qp1au3>,
@original_filename="screenshot04.png",
@content_type="image/png",
@headers="Content-Disposition: form-data; name=\"game[screenshot_attributes][ssfile][3]\"; filename=\"screenshot04.png\"\r\nContent-Type: image/png\r\n">,
"4"=>#<ActionDispatch::Http::UploadedFile:0x000000055c7ba0 @tempfile=#<Tempfile:/tmp/RackMultipart20150408-9276-8g3pap>,
@original_filename="screenshot05.png",
@content_type="image/png",
@headers="Content-Disposition: form-data; name=\"game[screenshot_attributes][ssfile][4]\"; filename=\"screenshot05.png\"\r\nContent-Type: image/png\r\n">
}
}
},
"null"=>"",
"commit"=>"Save",
"id"=>"2"
}
The important part is in the name of each segment, they're arriving as game[screenshot_attributes][ssfile][XXXX] which is wrong, the right format should be game[screenshot_attributes][XXXX][ssfile]. I can configure this in the part I pasted above, but the important part is the paramName section, which I have as paramName: "game[screenshot_attributes][ssfile]".
If anyone could have any clues, I'd greatly appreciate.
Finally found a way to make dropzone.js working with rails nested attributes. You have to edit dropzone.js to set the format of rails nested attribute array for multiple attachments.
Dropzone.prototype._getParamName = function(n) {
if (typeof this.options.paramName === "function") {
return this.options.paramName(n);
} else {
return "" + this.options.paramName1 + (this.options.uploadMultiple ? "[" + n + "]" : "") + this.options.paramName2 + "";
}
};
Then inside dropzone initialization javascript initialize both params:
Dropzone.options.newTicket =
clickable:'#previews'
previewsContainer: "#previews"
dictDefaultMessage: "Drop files here or click to select files"
autoProcessQueue: false
uploadMultiple: true
paramName1: "ticket[attachments_attributes]"
paramName2: "[file]"
parallelUploads: 5
maxFiles: 5
addRemoveLinks: true
来源：https://stackoverflow.com/questions/29487666/carrierwave-with-dropzone-js-is-it-possible-to-use-these-with-nested-attributes