Unicode fonts in pdf at GAE with web2py/pyfpdf - google-app-engine

Question

I'm writing an app, which results with pdf file with some text with unicode characters. On GAE devserver it works good, but after deploy it can't import font file (crash after add_font() (pyfpdf)).
The code is:
# -*- coding: utf-8 -*-
def fun1():
from gluon.contrib.pyfpdf import FPDF, HTMLMixin
class MyFPDF(FPDF, HTMLMixin):
pass
pdf =MyFPDF()
pdf.add_font('DejaVu', '', 'DejaVuSansCondensed.ttf', uni=True)
pdf.add_page()
pdf.set_font('DejaVu','',16)
pdf.write(10,'test-ąśł')
response.headers['Content-Type']='application/pdf'
return pdf.output(dest='S')
The font files (with a file DejaVuSansCondensed.pkl generated after first run on web2py server...) is in /gluon/contrib/fpdf/font. I didn't add anything to routers.py (I'm using Pattern-based system) also app.yaml is not changed. And I get this:
In FILE: /base/data/home/apps/s~myapp/web2py-04.369240954601780983/applications/app3/controllers/default.py
Traceback (most recent call last):
File "/base/data/home/apps/s~myapp/web2py-04.369240954601780983/gluon/restricted.py", line 212, in restricted
exec ccode in environment
File "/base/data/home/apps/s~myapp/web2py-04.369240954601780983/applications/app3/controllers/default.py", line 674, in <module>
File "/base/data/home/apps/s~myapp/web2py-04.369240954601780983/gluon/globals.py", line 194, in <lambda>
self._caller = lambda f: f()
File "/base/data/home/apps/s~myapp/web2py-04.369240954601780983/applications/app3/controllers/default.py", line 493, in fun1
pdf.add_font('DejaVu', '', 'DejaVuSansCondensed.ttf', uni=True)
File "/base/data/home/apps/s~myapp/web2py-04.369240954601780983/gluon/contrib/fpdf/fpdf.py", line 432, in add_font
font_dict = pickle.load(fh)
File "/base/data/home/runtimes/python27p/python27_dist/lib/python2.7/pickle.py", line 1378, in load
return Unpickler(file).load()
File "/base/data/home/runtimes/python27/python27_dist/lib/python2.7/pickle.py", line 858, in load
dispatch[key](self)
File "/base/data/home/runtimes/python27/python27_dist/lib/python2.7/pickle.py", line 966, in load_string
raise ValueError, "insecure string pickle"
ValueError: insecure string pickle
As I said on local (both web2py/rocket and gae) it works well. After deploy only something like this works:
pdf =MyFPDF()
pdf.add_page()
pdf.set_font('Arial','',16)
pdf.write(10,'testąśł')
But without "unusual" characters...
The best solution would be to add my font files (like DejaVu), but basically I need unicode characters in any font... maybe some "half-solution" to use "generic GAE unicode" fonts... if it exist something like this...

Answer 1

Thanks for suggestion Tim!
I found some solution... it isn't the best one, but it works...
The problem is with using pickle on GAE. The best solution (probably) would be to overload/rewrite the add_font() function where for GAE, in such a way, that it would write to a datastore instead of a filesystem. Additionaly ValueError: insecure string pickle error can still occur, I tried b64 encoding according to this. But still I get errors. So my solution is to overload add_font() function with commented out/deleted parts:
if os.path.exists(unifilename):
fh = open(unifilename)
try:
font_dict = pickle.load(fh)
finally:
fh.close()
else:
and
try:
fh = open(unifilename, "w")
pickle.dump(font_dict, fh)
fh.close()
except IOError, e:
if not e.errno == errno.EACCES:
raise # Not a permission error.
Because of this the function every time calculates little bit more instead of just reading data from the pickle... but it works on GAE.