A Pure ruby library to merge PDF files, number pages and maybe more...
A Pure ruby library to merge PDF files, number pages and maybe more...
CombinePDF is a nifty model, written in pure Ruby, to parse PDF files and combine (merge) them with other PDF files, watermark them or stamp them (all using the PDF file format and pure Ruby code).
I decided to stop maintaining this gem and hope someone could take over the PR reviews and maintenance of this gem (or simply open a successful fork).
I wrote this gem because I needed to solve an issue with bates-numbering existing PDF documents.
However, since 2014 I have been maintaining the gem for free and for no reason at all, except that I enjoyed sharing it with the community.
I love this gem, but I cannot keep maintaining it as I have my own projects to focus own and I need both the time and (more importantly) the mindspace.
Install with ruby gems:
gem install combine_pdfQuick rundown:
When reading PDF Forms, some form data might be lost. I tried fixing this to the best of my ability, but I'm not sure it all works just yet.
When combining PDF Forms, form data might be unified. I couldn't fix this because this is how PDF forms work (filling a field fills in the data in any field with the same name), but frankly, I kinda liked the issue... it's almost a feature.
When unifying the same TOC data more then once, one of the references will be unified with the other (meaning that if the pages look the same, both references will link to the same page instead of linking to two different pages). You can fix this by adding content to the pages before merging the PDF files (i.e. add empty text boxes to all the pages).
Some links and data (URL links and PDF "Named Destinations") are stored at the root of a PDF and they aren't linked back to from the page. Keeping this information requires merging the PDF objects rather then their pages.
Some links will be lost when ripping pages out of PDF files and merging them with another PDF.
Some encrypted PDF files (usually the ones you can't view without a password) will fail quietly instead of noisily. If you prefer to choose the noisy route, you can specify the raise_on_encrypted option using CombinePDF.load(pdf_file, raise_on_encrypted: true) which will raise a CombinePDF::EncryptionError.
Sometimes the CombinePDF will raise an exception even if the PDF could be parsed (i.e., when PDF optional content exists)... I find it better to err on the side of caution, although for optional content PDFs an exception is avoidable using CombinePDF.load(pdf_file, allow_optional_content: true).
The CombinePDF gem runs recursive code to both parse and format the PDF files. Hence, PDF files that have heavily nested objects, as well as those that where combined in a way that results in cyclic nesting, might explode the stack - resulting in an exception or program failure.
CombinePDF is written natively in Ruby and should (presumably) work on all Ruby platforms that follow Ruby 2.0 compatibility.
However, PDF files are quite complex creatures and no guaranty is provided.
For example, PDF Forms are known to have issues and form data might be lost when attempting to combine PDFs with filled form data (also, forms are global objects, not page specific, so one should combine the whole of the PDF for any data to have any chance of being preserved).
The same applies to PDF links and the table of contents, which all have global attributes and could be corrupted or lost when combining PDF data.
If this library causes loss of data or burns down your house, I'm not to blame - as pointed to by the MIT license. That being said, I'm using the library happily after testing against different solutions.
To combine PDF files (or data):
pdf = CombinePDF.new
pdf "application/pdf"If you prefer to save the PDF data to a file, you can always use the save method as we did in our earlier examples.
Some PDF files contain optional content sections which cannot always be merged reliably. By default, an exception is
raised if one of these files are detected. You can optionally pass an allow_optional_content parameter to the
PDFParser.new, CombinePDF.load and CombinePDF.parse methods:
new_pdf = CombinePDF.new
new_pdf << CombinePDF.load(pdf_file, allow_optional_content: true)
attachments.each { |att| new_pdf << CombinePDF.load(att, allow_optional_content: true) }You can see a Demo for a "Bates stumping web-app" and read through it's code . Good luck :)
Some PDF files are encrypted and some are compressed (the use of filters)...
There is very little support for encrypted files and very very basic and limited support for compressed files.
I need help with that.
If you want to help with the code, please be aware:
I'm a self learned hobbiest at heart. The documentation is lacking and the comments in the code are poor guidlines.
The code itself should be very straight forward, but feel free to ask whatever you want.
Stefan Leitner (@sLe1tner) wrote the outline merging code supporting PDFs which contain a ToC.
Caige Nichols wrote an amazing RC4 gem which I used in my code.
I wanted to install the gem, but I had issues with the internet and ended up copying the code itself into the combine_pdf_decrypt class file.
Credit to his wonderful is given here. Please respect his license and copyright... and mine.
MIT
You can look at the GitHub Issues Page and see the "help wanted" tags.
If you're thinking of donations or sending me money - no need. This project can sustain itself without your money.
What this project needs is the time given by caring developers who keep it up to date and fix any documentation errors or issues they notice ... having said that, gifts (such as free coffee or iTunes gift cards) are always fun. But I think there are those in real need that will benefit more from your generosity.
No open issues yet, or sync has not completed.