I'm creating a Facebook app using Rails and hosted on Heroku and I'm having a bit of trouble finding the ideal way to solve a problem. I want the user to be able to move their photos around on the screen, position them, and then download that as either a PDF or a PNG file to be emailed or printed. I have the app getting the user's facebook photos and they can drag them on to a HTML5 Canvas element to position them. Taking this canvas, however, and converting it into something printable is where I'm hitting a dead end.
Basically I have a few ideas I have tried:
Convert the Canvas to a PNG using toDataURL() - Would work perfectly but since the photos are external, the canvas is "dirty" and will throw up a security issue. I've thought about trying to copy the pixels of each image to a pixel array but I've heard this may not work either due to security issues. Since the app is dealing with people's facebook images I really don't want to store them on the app's server.
Use PDFKit/wkhtmltopdf to create a PDF using Rails - I've tried this, but since the app is a Sinatra app (I think), it's confusing me a lot. It's throwing errors with the to_pdf call saying 'Command Failed'. I've tried adding a config.middleware.use line but I'm not 100% sure where to put it and everywhere seems to be failing saying "config" is an undefined variable. Also installing wkhtmltopdf seems to fail on Heroku once I test it outside localhost.
Use Prawn to create a PDF using Rails - I've tried prawn but it seems to have a similar problem to PDFKit and I get confused about what goes where on a Sinatra app. I'm sure I read as well that people were having problems with it too.
Have I missed any obvious solutions to this, or is there something I'm not thinking of? All I want to do is create some kind of easily printable file with positioning intact that can be easily downloaded and printed by the user but I've come across so many problems that I don't know where to go next and I'm going round in circles.
If anyone had any advice for me about how I could get around this problem I'd really appreciate it.
if prawn is giving you grief just use one of the jquery plugins to print your div content. You could even configure a pdf printer and print the document instead of hard copy if you so wish/need images in pdf format.
I use http://archive.plugins.jquery.com/project/jqPrint plugin in one of my projects and it works like a charm.
It sounds like many of your issues relate to the necessary PDF binaries not being accessible on Heroku. In following with the twelve factor approach to dependency isolation Heroku purposely provides a very bare system.
If you need to run a custom binary on Heroku I'd suggest looking at a tool called Vulcan which can compile a binary that's compatible with the Heroku runtime.
Related
With Rails 6, I need to replace Paperclip, but I can't find any substitutions that actually easily replicate it.
Specifically, the file structure paperclip used:
:model/:attachmant_field/000/000/000/:identifier/:style/:original_file_name
Over the last decade we have built several tools that rely on that structure (or something similar) and in addition our users expect that after uploading an image, they can reference the styles with the same file name and a permanent url (not a randomly generated name like ActiveStorage and Shrine does) and change the "style" component in the url to a different one in their html.
I've spent several days both on Shrine and ActiveStorage working to get the file structure and naming to work on and keep failing, as despite being "natural replacements" they don't actually handle things in the same way.
Our end system is on Amazon S3, though integrating with that hasn't been the issue, just the file system.
Thanks for your help, it's been really frustrating having to remove something that works great when there seems to be nothing that actually replaces it, if you want/need things done in the same way. I'd rather not have to start rewriting all of tools that we developed and resetting our customers expectations to work with a new structure.
Thanks so much.
Have you tried Carrierwave? You can specify any storage path and build it dynamically using model name (model.class.to_s.underscore), attachment field (mounted_as), model id (model.id). The original file name is also available as original_filename.
So I've been banging my head on this all day yesterday trying to get PDF rendering to work properly. After trying Prawn and PDFKit, I found that the problem with at least getting it to work at all had to do with wkhtmltopdf on Mac OS 10.7, but now the problem is that it completely ignores any styles I add targeting the pdf, the print media type, and any special templates.
Here is a pastebin of where I'm at now: http://pastebin.com/LW16RYjW
Trying all of these and several others didn't work for me:
http://www.snikt.net/blog/2012/04/26/wicked-pdf/
WickedPDF missing layout
http://akabhilash.wordpress.com/2010/11/27/pdf-generation-with-wicked-pdf-in-rails/
I finally got to this setup:
https://github.com/mileszs/wicked_pdf/issues/87
Not knowing what else to do, I physically copied pdf_helper.rb into my lib/ directory (I don't know why it wasn't there before, or even whether it should've been upon bundling(?))
Can anyone tell me why it doesn't seem to be picking up any of the rendering options in the controller, and how I can get the styles to register without affecting the screen (html) version? Any help would be greatly appreciated. Thanks in advance for your time.
Turn off the middleware, or add the route you are trying to customize in the middleware call as documented in the README.
wicked_pdf (or wkhtmltopdf) behaves strange in production mode. It took a bit time to track down the problem, but seemingly the reason that my PDF is broken are too much images or too large file sizes.
When i try to use a 300dpi pic (4 MB), it´s broken. When i decrease to 72 dpi, it works… sometimes. When i use just a thumbnail, it works always.
I made a test: One coversheet with a small test image works. Two coversheets also, … up to 30 sheets it works. When i attach cover sheet 31, my pdf is broken, always.
In development everything is fine, 300dpi images, 5 MB, 50 MB, no problem.
Does anybody know about this problem? And how to fix it? :-)
PS: when i do wkhtmltopdf via command line it shows no images at all, so it´s hard to test if wkhtmltopdf or wicked_pdf is the issue. I really don´t like generating PDFs!
wkthmltopdf does a best-effort to gather up and render all the resources in a pdf just like the webkit browser that powers it. If it isn't able to retrieve and render them all in time, it can sometimes output an unfinished pdf.
There are a few things we can check or do to optimize this process.
Make sure all your assets (images, javascript, css) are correctly rendered with a full path like 'http://images/foo.jpg', not a relative one like '/foo.jpg'.
This causes wkhtmltopdf to reach out over the web to get these assets, and sometimes that isn't quick enough, so if you can, try to use filesystem resource links like 'file:///projects/foo/images/foo.jpg'. The wicked_pdf_image and other related helpers attempt to do this for you, but depending on what version of Rails you are on, the result may be a little different.
Wkhtmltopdf uses a lot of memory and cpu (especially with big images), make sure your production server isn't starved for it.
The git master version of wicked_pdf has an optimization to use tempfiles instead of I/O streaming. Point your Gemfile at that git://github.com/mileszs/wicked_pdf.git and see if that improves things for you. A new version of the gem will likely be published in the next few days (I do a lot of the maintenance and release management for wicked_pdf).
Please report back. I'm interested to know if any or all of the above improve the situation.
I'm aware of pdf-stamper, but I'm trying to avoid switching everything to jruby right now.
I just need to "stamp" an image that I generate within the rails app (a PDF417 barcode) into a form field in the PDF document (there's an FDF; it's a document template kinda thing).
I'm filling out the text-based fields by just shelling out to pdftk, so if there's a way to do it using pdftk, I'd be fine with that, but I've looked high and low for one without any luck.
How about using a barcode font? some alternatives too. I haven't used that one but there may be others available too
I know I'm late to the party, but the PDF417 Rubygem should do what you need. https://rubygems.org/gems/pdf417 will generate it and if you have chunky_png installed you can easily write out PNGs to a file.
Can anyone recommend a way of creating a view where users can upload images to my app through a WYSIWYG editor?
I've tried solving this using CK Editor and Paperclip but am having lots of trouble... Maybe I'm going about this the wrong way.
If someone's done this before I'd really like to know how! I don't have a editor or file storage mechanism preference so fire away...
This is all dependent on the WYSIWYG's file upload API. From there, just build an ImagesController to handle requests from that API, use whatever system (Paperclip is good) to handle those files internally, and you should be good to go. You won't find a plug-and-play solution; you'll have to hand-roll it.
Turns out that, with more targeted Google searching, you can find a preexisting solution. Here's one for TinyMCE and Rails. You may, however, end up finding that it doesn't meet your needs, in which case I would not be surprised to find that creating your own solution would be simpler than you expect :)
You could try Bootsy. It's a WYSIWYG editor with image upload capability. Includes a (rather simple) image manager as well.
https://github.com/volmer/bootsy
There is an other solution for rails out there:
https://github.com/spohlenz/tinymce-rails
You can load it as gem and configure it via a yml file. And it comes with an extra language gem.