[Django] Generating PDF with PDFForm

Transcript

1. Generating PDF with PDFForm Sébastien Fievet Djangocong Marseille April 16, 2011
2. Case study: outputting “simple” PDFs
3. Simple things should remain simple
4. Focus on skills
5. Designer == templating
6. Developper == rendering
7. The solution ?
11. pip install fdfgen
12. from fdfgen import forge_fdf def fill_form(fields, src, pdftk_bin): ... fdf_stream = forge_fdf(fdf_data_strings=fields) ...
13. Issue
14. Issue Breaks on accentuated character
15. “ ” Fork it, fix it, contribute it. -- a DVCS convinced guy
17. aptitude install pdftk
18. pdftk <PDF input> dump_data_fields
19. pdftk <PDF input> fill_form <FDF file> output <PDF output> flatten
20. import subprocess ... def fill_form(fields, src, pdftk_bin): ... cmd = ' '.join([pdftk_bin, src, 'fill_form', '-', 'output', '-', 'flatten']) try: process = subprocess.Popen(cmd, stdin=subprocess.PIPE, stdout=subprocess.PIPE, shell=True) return process.communicate(input=fdf_stream) except OSError, e: return None, e
21. But...
22. But... utf8 support broken on Ubuntu 10.10(binary package, v1.41)
23. But... utf8 support broken on Ubuntu 10.10(binary package, v1.41) Use the source luke (v1.44)
24. But... utf8 support broken on Ubuntu 10.10(binary package, v1.41) Use the source luke (v1.44) wget && make && make install
26. Django template engine == The challenge
27. Template loading
28. Template loading PDFs are binary file
29. Template loading PDFs are binary file We don't care about the file content
30. Template loading PDFs are binary file We don't care about the file content But we ALWAYS need the template path
31. import codecs from django.template.loader import find_template def get_template(template_name): def strict_errors(exception): raise exception def fake_strict_errors(exception): return (u'', -1) codecs.register_error('strict', fake_strict_errors) template, origin = find_template(template_name) codecs.register_error('strict', strict_errors) return template
32. from django.template import loader, Template ... def get_template_from_string(source, origin=None, name=None): if name and name.endswith('.pdf'): return PdfTemplate('pdf', origin, name) return Template(source, origin, name) loader.get_template_from_string = get_template_from_string
33. Template origin * Paranoiac mode
34. Template origin TEMPLATE_DEBUG = True * Paranoiac mode
35. Template origin TEMPLATE_DEBUG = True Or monkey-patch make_origin * * Paranoiac mode
36. Template rendering
37. Template rendering Custom rendering method Leveraging pdftk and FDFGen Use a dedicated Template class
38. from django.template import Template ... class PdfTemplate(Template): def __init__(self, template_string, origin=None, name='<Unknown Template>'): self.origin = origin def render(self, context): context = context.items() output, err = fill_form(context, self.origin.name) if err: raise PdfTemplateError(err) return output
39. https://gist.github.com/918403
41. Usage
42. from django.http import HttpResponse from pdf import get_template def pdf_view(request, template_name='pdf/awesome.pdf'): context = { 'foo': 'bar', 'bar': 'baz', 'awesome': True, 'user': request.user, } response = HttpResponse(mimetype='application/pdf') response['Content-Disposition'] = 'attachment; filename=awesome.pdf' template = get_template(template_name) response.write(template.render(context)) return response
43. Demo
44. Questions?