I'd like to create an application that would run on Google's appengine.
However, this application needs to be able to generate PDFs dynamically.
How could I do this?
You can use the
 to generate a PDF from Python. You can just include the ReportLab files in with your application's code, or you can include a
 of the ReportLab code, and insert it into your application's
To overcome the number-of-files limit in google appengine, you could package your reportlib in a zip file and use it. Be sure you check out this issue i bumped into..
Also, you can use pisa, htmllib and pyPdf to generate the pdf using html templates.
All the best.
Google has a new " Conversion API " that may solve all your problems. Here's a description from the site:
The App Engine Conversion API converts documents between common filetypes using Google's infrastructure for efficiency and scale. The API enables conversions between HTML, PDF, text, and image formats, synchronously or asynchronously, with an option to perform optical character recognition (OCR).
I would recommend PyFPDF, which is a pure-Python port of the lightweight yet highly powerful PHP FPDF library. It is hardly a few dozen kilobytes.
If you're only looking for web page to PDF conversion on GOogle Apps, then you can make use of the PDFmyURL.com API. It supports your (and many other platforms) - see PDFmyURL web to PDF API documentation 
Disclosure - I work for the company that owns this service http://pdfmyurl.com/html-to-pdf-api