So, I'm working on an app where users can upload and manage photos with a bunch of industry specific metadata attached to them.
The Photo model has all this metadata in it, and I'm using Paperclip to attach the actual image file to the model and store the images on Amazon S3.
The user interaction currently works like this:
A user clicks "Add Photo" and is taken to the "New Photo" page where he is presented a form.
The first thing on the form is a file chooser. The user selects a file.
Beneath this are several different fields of metadata for the user to fill out, so the user fills these out.
The user hits submit, the file uploads and a new Photo object is created, the user is redirected to a different page.
So, the obvious improvement that I'd like to make is for the photo to actually upload at the beginning of this process so that there isn't such a noticeable delay between hitting submit and being redirected to the next page. It would also be nice to be able to show the user a thumbnail preview of their photo once it's done uploading, so that they can see the photo they're putting in metadata about as they fill in the form.
I figure I could make that happen if I split the image file into its own model, but I'd then be referring to the images like so:
#photo.attachment.file.url instead of the simpler #photo.file.url that I use now. I'd rather not "nest it" more deeply than I have to.
Also, splitting it into two models raises the issue of managing orphans, which I currently don't have to deal with.
So my questions are:
Is there a good way - preferably not using Flash - to create this asynchronous upload behavior without splitting into two models, OR --
If I must split the metadata and the file into two models, is there a way to get Paperclip to treat an attachment as its own model so that I can access it using <modelname>.<paperclip_method> instead of <model_name>.<attachment_attribute>.<paperclip_method>?
I know that's a big question, so thank you very much in advance for your help!
I'd recommend that you replace the new action with an edit action (you can auto-create a photo model when the user selects the action. This way, you can use an AJAX file upload (supported in some modern browsers) with a Flash fallback for doing the upload, and also edit the metadata. For doing the upload, try looking at plupload or uploadify.
What's wrong with simply defining Photo#url like so?
class Photo
def url(*args)
attachment.url(*args)
end
end
No need to get fancy here.
After a week of experimentation I just thought I'd post what I finally did:
I did in fact split the photo into two models, because I ended up having to create empty records with any approach I tried. I found it was easier in the end to have two seperate models because:
It made it easier to work within Rails convention (use the standard REST actions for the second model to handle asynchronous updates, rather than having to add several custom actions to the parent model).
No matter which option I tried I ended up having orphan records as a possibility. I found it was easier to have a parent object which does not ever save unless valid (the Photo model in my case), and to have attachments which may be orphans. The attachments are never called directly anywhere in the app, so there's no risk of accidentally having an empty record being pulled up, and no need to set a default scope or something in order to only show "valid" photos. Cleaning up orphans is pretty easy, just do Attachment.where( :parent_id => nil ) and delete all those.
I can maintain the previous code by simply delegating attachment to photo. See this answer on another question.
I hope this saves others some trouble down the road. If you need Ajax functionality with attachments it is best to make them their own model. Also, for adding ajax file upload to forms, check out https://github.com/formasfunction/remotipart. This saved my app.
Just wondering, are you not setting the dependent clause on your association? For example,
Class Photo < ActiveRecord::Base
:has_one :attachment, :dependent => :destroy
end
This will prevent orphan records, as anytime a destroy method is called on Photo, it'll first do Photo.attachment.destroy. It works with :has_many as well.
Basically, you're splitting up the creation of the Photo object into two parts: uploading the photo, and adding the meta-data. In a non-AJAX site, this would be two separate steps on two separate pages.
What I would do is allow the AJAX upload to instantiate a Photo object, and save it (with the uploaded photo). I would then have the AJAX code return a token to the site that corresponds to a session variable to let the form know the record for the photo has already been created. When the user submits the rest of the form, if the token is present, it will know to populate the data on the already created photo object. If the token is not present, it will know it needs to create the Photo object from scratch.
Related
I have rather esoteric usecase for nested forms, multi-file uploads, and progress bars in Rails. I haven't found any online discussions about precisely about this so far. If I have overlooked something, I am sorry. Please correct me.
Here is what I want:
A given form has multiple dynamic fields. One of which is 'attach a file'.
For this 'Attach a file', I would like an interface which is essentially similar to gmail.
That interface enables you to :
click 'attach file'.
select a local file, which starts uploading immediately in the background, giving you a progress bar in the mean time.
this allows you to write your message, or add more files.
You can cancel a live upload and even delete attachments after the fact by un-checking a box.
Here are the models and associations I am working with.
I have a model Recording which has many AudioFiles.
Each AudioFile contains audio data, as well as metadata like size, type, date created etc.
A Recording has several other child collections as well.
Here is how the 'Create Recording' form should behave:
It should enable the user to add multiple number of child fields, including multiple audio files..
So far, I am using the excellent Nested Form (https://github.com/ryanb/nested_form) gem to create the non-AudioFile children of a Recording. IT works brilliantly.
What I want is to be able to have similar nested fields to upload multiple audio files, asynchronously, with progress indicators, and with an ability to cancel or delete uploaded files.
There are many resources which demonstrate how to use uploaders in conjunction with carrierwave to store files with progress information. For instance, https://github.com/yortz/carrierwave_jquery_file_upload, and https://github.com/blueimp/jQuery-File-Upload/wiki/Rails-setup-for-V5 .
Essentially, what these examples do is to generate a request from one of these uploaders which is directed to a controller create action for a model which has a carrierwave uploader attached to it. I have got this much to work OK.
What I can't figure out is how to do this in a nested form context. The tricky bits are:
Suppose I write up the AJAX to do a post from a 'Create Recording' form, and have that post create a new AudioFile record. How do I associate that audio file with the as-yet-un-created recording?
If the user aborts the transaction, how will the AudioFile record thus created be cleaned up?
I can think of hacky-ways to do both of the above, but I am wondering if there are more elegant approaches. I am rather new to rails so I am guessing that I am not using it to the fullest.
Thanks,
Apurva
I thought I would contribute back to the community by sharing how I solved this problem.
To summarize, the major problem was to reconcile the behavior of CarrierWave, nested forms, and fine grained control of file uploads.
The crux of the issue was that Nested Forms create the root record and all its associations in a single POST operation to the #create action of the root Controller.
In the example above, the Recording model was the root, while AudioFile, Note, and Categorization were the associations to be created along with a Recording.
So with Nested Forms, I would have to create all these records in a single POST, which would preclude the possibility of canceling uploads in isolation, or uploading in parallel with adding other fields (like Notes).
That would not make for a good user experience. My solution was really simple:
I chose not to use nested forms.
Recording#create would always be called with empty parameters. The Recording attributes would get sensible default values in the create operation.
The user would only see the Recording#edit page.
On the Recording#edit page, I had independent controls for CRUD operations on the associated models which would route to different controllers through AJAX calls. This worked because each associated model had a valid recording_id to use.
The various controllers would return HTML fragments which would be written into the main recording page.
This enabled inline editing of all the fields on the Recording page, even though these fields mapped to different (associated) models. Thus the user would be able to upload multiple files, add notes while they were uploading, play back already uploaded files, and cancel uploads at will.
As a result the whole user experience was a lot smoother. This would never have been achievable with Nested forms by definition.
I have a project where I have several content types (Article, Interview, etc) with nested images. To handle the images, what I did was implement a popup 'image upload' box (using a combination of Paperclip and Uploadify) so the user can upload an image immediately to the article.
The process works like this: the user clicks the 'upload an image' icon, then a box pops up where they can add paperclip file upload fields to upload as many images as they want. Uploadify instantly uploads the photos and assigns them the article ID number they're attached to. Then the photo's HTML gets sent to the WYSIWYG editor. If they want to delete photos as well, they can. If it sounds like WordPress, that's what it's based on.
Anyway, I have this working great. Photos remain associated and attached with their respective articles, as opposed to throwing everything in one huge folder (like many WYSIWYG image uploaders do) where anyone can add/delete anything.
But there is one little flaw to this...as I said, the image is assigned the content's ID number when an upload is performed. Well, you can see how this is an issue when creating a brand new article, as a new article doesn't have an ID number before saving it. So the image upload fails. Thus, this whole process only works on the 'edit/update' action.
In the interim, I told the team to make sure to SAVE the article first, then when they go back to edit it they can then upload their images to the body. But naturally, they forget as it's an easy thing to do, and as this is very user-unfriendly, I gotta solve this.
I see two ways I can go about this.
Assign an ID (hidden field or otherwise) to an article on the 'new' form. This would appease the uploader as it fills the 'nil' value it errors out on, then when the article gets saved the first time, it would assign it that very same number. But I see a potential issue...what if another user creates an article at the same time and the database assigns it an identical ID number?
I noticed that the moment you create a new WordPress document, the new document 'autosaves' immediately as a draft. So my line of thinking is this...when the user goes to create a new document, the 'new' action would actually trigger a 'save' operation, bypass any validation errors (since the fields are blank), then immediately redirect to the 'edit' action. That way, the ID is saved and everything would work as normal, and the entire process may look seamless to the user.
How would you handle this situation? Like I suggested above, or is there an even better way?
I decided to go the second route and perform a save on the new action and bypassing the validations, then redirecting to the edit form, throwing as "autosaved" flash message in for good measure. It works well.
I have a head aching problem that I can't seem to find an easy solution to.
I have a couple of models, each with an image attachment, that belongs to a user. I have made a very nice ajax file upload and image cropping form, but there is a problem. Everything works fine when I am editing objects that is already in the database but when I upload a file as I create a new object it doesn't. The thing is, to be able to upload and save the image, the object already has to be in the database. I have found two possible solutions to this problem but none of them will work properly.
The first one is to create the object in the database in the new action and redirect to edit action. The pros is that it is a very simple fix. The cons is that the objects will show up in the list with previously created ones even if the user canceled or never submitted the form, which is very confusing.
The second possible solution is to lift out the attachment fields of the model to a separate model. On creation I would then only need to create an attachment object. If the user canceled it would leave the attachment orphaned, but that is probably okay as the orphans could be cleared periodically. The problem with this is that I can't find a way to prevent users from hijacking the orphaned images, or any other image for that sake. Unless I cant solve this problem I'm stuck.
I'm all out of ideas and would really need some help on this one.
Thanks, godisemo
EDIT:
I was probably unclear. In my form it is possible to upload an image. The image is uploaded instantly to the server with javascript, before the form is submitted. The reason is that I want to allow the users to crop the image. This is no problem wen working with existing objects but it is when creating new ones, as I tried to explain earlier.
I've never had to have the model already in the db for paperclip to work.
One thing you can try though is the following. I don't know what your model is called but let's say User has an image. Make your new form so that all of your user fields are passed in the params[:user] var, but then make your image upload file separate from params[:user], say params[:my_image].
Then in your controller validate and save the user, then after user.save, attach the image.
I solved the problem now, with a completly different approach. Instead of thinking databases, objects and models I solved it using file system and temporary files. When the image is uploaded it is processed by paperclip, I then move the generated images to a folder where I have control over them.
I based my solution on a really great article which you can find here, http://ryantownsend.co.uk/articles/storing-paperclip-file-uploads-when-validation-fails.html
I want to give my user the ability to re-use photos they already uploaded in different pages and different orientations so I need to create multiple records for each photos in the database. I want though that if user delete one instance the photo stays until all instances are deleted then delete the file.
What is the best way to do so in Paperclip?
If you only want a photo to be used in several pages but in no different ways, i.e. no different style configurations in paperclip, then you should only have one record for each photo and associate it to other records by a has_many :through association. That way you can let the middle model call the photo record upon destruction to see if there are any other associations left for the photo.
However, it is very difficult to be specific without seeing at least you current model structure and associations and some example of what your users will be allowed to do.
In any case, I would not recommend to actually have two separate paperclip records point to the exact same file on the file system.
Edit:
If it is the actual upload you want to avoid then you could always use the original file when creating the new record:
#first_photo = Photo.find(1)
#new_photo = Photo.new
#new_photo.attachment = #first_photo.attachment
#new_photo.save
The photo would still be stored once for every instance but the upload is avoided.
Here's my question. I have a user model with one attached avatar. This model has many personal photos (with accepts_nested_attributes_for).
I want to be able to initialize a personal photo automatically after saving a user object with whatever the user avatar turns out to be. So say Bob uploads his avatar, bob will automatically have one personal photo (with the correct different paperclip styles) generated from the avatar image.
I'm not really sure how to go about doing this. Would I put it in my controller or user an after_save hook in the model? I'm using Paperclip with db storage so it would be good if somehow during save this was initialized so I don't have to pull it back out...Maybe I could use a hidden form field?
Honestly... I'm not sure I'd recommend this course of action. Many people upload avatars that aren't photos. If you do this, certainly you should give the user the option to delete the photo without also deleting their avatar at the same time. This means that you need to duplicate the attachment. To do that, you have to hook into the after_avatar_post_process callback. In this callback, create a new personal photo object. On the photo model's photo attachment, call something like personal_photo.photo.assign(avatar.path). I think that should work, but I haven't tried it. My main worry is that the assign call might not create a new location for the attachment. I think it does, but I don't know absolutely for sure. At the very least, it's close to what you need to do and should get you moving in the right direction.
Paperclip API