Tools for generating PDFs from django.

For a Django project i’m working on i needed to generate PDF reports. For example a “job ticket” that displays the client data, the material list and a list of “processing” actions to be performed, or an invoice (classic use case).

What i wanted was a way to generate these PDF files from a template using Django’s templating language. I had previously done something similar using PISA but i was not satisfied. There documentation was rather bad, generating HTML/CSS is not my strong point and automatic tools produce unreadable code. It does work though.

After some heavy and masterful googling i came up with several options.

  1. Reportlab. Very well known, very powerful, but the good parts are not free. I did not want to write the layout using Python code. I’d rather use some high level abstraction on top of Reportlab. Their RML framework (which does exactly that) seems great but as far as i can see it is not free. There are open source alternatives though, which i’ll talk about later.
  2. Pod Uses OpenOffice in server mode to generate documents in PDF. I’ll be running my software in a memory limited VPS and running OpenOffice (even in server mode) seems very scary. I did not investigate the exact memory requirements though because it seemed like a waste of time.
  3. rst2pdf. RST is very awesome, Sphinx uses it but from my reading of rst it seems that generating accurate and custom layouts seems somewhat difficult (for a report that needs specific elements in specific locations).
  4. trml2pdf. This is a tiny and free implementation of RML. This seemed to be a better solution, but what i wanted was a way to generate RML documents using a GUI tool (i’m a lazy bastard). The solution is tiny_sxw2rml which produces an RML document from an OpenOffice .odt file.
  5. JasperReports. This is a very impressive Java package and GUI designer that can generate beautiful reports from various data sources. This was a serious contender (** especially** with their very nice GUI designer) but i chose to avoid it because i could not use the Django ORM to do templating (i can use raw SQL but that is severely suboptimal in templating , especially on complex templates). I could use the Django ORM to produce an XML file with all the information but the prospect of using an XML file (using XPath ) seemed dreadful (but it would work nicely). It is a Java package with Python bindings available for it and a web interface that can be used to access it using a standard interface (HTTP)

The fourth solution (trml2pdf) is the one i chose. These tools are developed by the openerp framework for their reporting needs.

However, it is far from a perfect solution. There is no official repository for this package with various versions floating around the web with different features. More specifically, i was only able to use barcode generation using the version from openerp server source code, which i had to patch to make it work (because it relied on other modules of OpenERP).

Additionally, i had to patch it to make it work with unicode fonts as per the instructions from the OpenErp Docs. Not something you would want to depend on.

Nevertheless i was able to make it all work. I could use the tool tiny_sxw2rml to produce an rml template that would first be processed by the Django templating system and then fed into trml2pdf to produce a PDF. It works.

All in all i would have to say that JasperReports is the best solution from a technical standpoint since it has a great GUI designer that produces beautiful documents with perfect layout, has a lot of features, a large community, can be used as an independent server that produces PDF documents and much much more. The main problem is that you lose that advantage of integrating your workflow into the philosophy of Django (ORM/templates etc) and have to walk the extra mile.

I’ve already integrated trml2pdf but i’m keeping my eye open for a way to switch to JasperReports.

I’d like to hear what solutions others may have used/considered for this.

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