PDF export not working on specific pages in Arabic & Farsi

[timobrembeck]

Describe the Bug

Steps to Reproduce

https://admin.integreat-app.de/marburg-biedenkopf/fa/wp-json/ig-mpdf/v1/pdf/

Expected Behavior

The PDF should be shown

Actual Behavior

An internal server error occurs (AttributeError: 'ParaLines' object has no attribute 'lineBreak')

Additional Information

Update: Fixed upstream (see https://github.com/xhtml2pdf/xhtml2pdf/pull/643), so wait until a new release is triggered and update xhtml2pdf to fix the issue.

Also, when updating, we can also remove this workaround: https://github.com/digitalfabrik/integreat-cms/blob/d74612683bdc1ab2ad4c9933965911002ae15c6b/integreat_cms/cms/utils/pdf_utils.py#L114-L115

Traceback

  self.handle_flowable(flowables)
File "/opt/integreat-cms/.venv/lib/python3.9/site-packages/reportlab/platypus/doctemplate.py", line 928, in handle_flowable
  if frame.add(f, canv, trySplit=self.allowSplitting):
File "/opt/integreat-cms/.venv/lib/python3.9/site-packages/reportlab/platypus/frames.py", line 212, in _add
  flowable.drawOn(canv, self._x + self._leftExtraIndent, y, _sW=aW-w)
File "/opt/integreat-cms/.venv/lib/python3.9/site-packages/reportlab/platypus/flowables.py", line 112, in drawOn
  self._drawOn(canvas)
File "/opt/integreat-cms/.venv/lib/python3.9/site-packages/reportlab/platypus/flowables.py", line 93, in _drawOn
  self.draw()#this is the bit you overload
File "/opt/integreat-cms/.venv/lib/python3.9/site-packages/xhtml2pdf/xhtml2pdf_reportlab.py", line 684, in draw
  Paragraph.draw(self)
File "/opt/integreat-cms/.venv/lib/python3.9/site-packages/xhtml2pdf/reportlab_paragraph.py", line 1144, in draw
  self.drawPara(self.debug)
File "/opt/integreat-cms/.venv/lib/python3.9/site-packages/xhtml2pdf/reportlab_paragraph.py", line 1641, in drawPara
  dpl(tx, offset, lines[0], noJustifyLast and nLines == 1)
File "/opt/integreat-cms/.venv/lib/python3.9/site-packages/xhtml2pdf/reportlab_paragraph.py", line 405, in _justifyDrawParaLineX
  if last or not nSpaces or abs(extraSpace) <= 1e-8 or line.lineBreak:
AttributeError: 'ParaLines' object has no attribute 'lineBreak'

[timobrembeck]

The error also appears on some Arabic pages:

  File "/opt/integreat-cms/.venv/lib/python3.9/site-packages/django/views/decorators/cache.py", line 44, in _wrapped_view_func
    response = view_func(request, *args, **kwargs)
  File "/opt/integreat-cms/.venv/lib/python3.9/site-packages/integreat_cms/cms/utils/pdf_utils.py", line 115, in generate_pdf
    pisa_status = pisa.CreatePDF(
  File "/opt/integreat-cms/.venv/lib/python3.9/site-packages/xhtml2pdf/document.py", line 155, in pisaDocument
    doc.multiBuild(context.story)
  File "/opt/integreat-cms/.venv/lib/python3.9/site-packages/reportlab/platypus/doctemplate.py", line 1169, in multiBuild
    self.build(tempStory, **buildKwds)
  File "/opt/integreat-cms/.venv/lib/python3.9/site-packages/reportlab/platypus/doctemplate.py", line 1082, in build
    self.handle_flowable(flowables)
  File "/opt/integreat-cms/.venv/lib/python3.9/site-packages/reportlab/platypus/doctemplate.py", line 931, in handle_flowable
    if frame.add(f, canv, trySplit=self.allowSplitting):
  File "/opt/integreat-cms/.venv/lib/python3.9/site-packages/reportlab/platypus/frames.py", line 212, in _add
    flowable.drawOn(canv, self._x + self._leftExtraIndent, y, _sW=aW-w)
  File "/opt/integreat-cms/.venv/lib/python3.9/site-packages/reportlab/platypus/flowables.py", line 112, in drawOn
    self._drawOn(canvas)
  File "/opt/integreat-cms/.venv/lib/python3.9/site-packages/reportlab/platypus/flowables.py", line 93, in _drawOn
    self.draw()#this is the bit you overload
  File "/opt/integreat-cms/.venv/lib/python3.9/site-packages/xhtml2pdf/xhtml2pdf_reportlab.py", line 684, in draw
    Paragraph.draw(self)
  File "/opt/integreat-cms/.venv/lib/python3.9/site-packages/xhtml2pdf/reportlab_paragraph.py", line 1144, in draw
    self.drawPara(self.debug)
  File "/opt/integreat-cms/.venv/lib/python3.9/site-packages/xhtml2pdf/reportlab_paragraph.py", line 1641, in drawPara
    dpl(tx, offset, lines[0], noJustifyLast and nLines == 1)
  File "/opt/integreat-cms/.venv/lib/python3.9/site-packages/xhtml2pdf/reportlab_paragraph.py", line 405, in _justifyDrawParaLineX
    if last or not nSpaces or abs(extraSpace) <= 1e-8 or line.lineBreak:
AttributeError: 'ParaLines' object has no attribute 'lineBreak'

[MizukiTemma]

I've tested some of the not working farsi pages on the current develop branch for PDF export and it works.

The tested pages are the first (عنوان اقامت شهروندان اتحادیه اروپا و کشورهای ثالث) and last (شهروندان اتحادیه اروپا فاقد شغل) under the last parent page with world map icon ( شهروندان اتحادیه اروپا و اتباع کشور های ثالث) under the ID-Card icon (مسائل حقوقی: پناهندگی، اتحادیه اروپا و کشورهای ثالث) in Marburg-Biedenkopf. These pages cannt be successfully exported as PDF, neither individually nor together with other pages.

Though when I copy & past the contents in the current develop branch and export them as PDF, it works.

[charludo]

Looks like it's an xhtml2pdf bug. Opened this issue: xhtml2pdf/xhtml2pdf#642 and corresponding PR upstream. I don't think there's anything further we need to do other than wait until the fix makes it into a release.

IDK if this issue should remain open until then?

[timobrembeck]

@charludo Thank you so much!

Hmm, I guess in this case let's leave it open until the problem is fixed for us by updating the library.

[osmers]

Any updates here? What are we waiting for?

[timobrembeck]

@osmers the problem has been fixed in the upstream library xhtml2pdf, but these fixes have introduced a number of even worse bugs (for example page numbering doesn't work anymore and the text lines are reversed on right to left alphabets), so we decided not to update the library until the new bugs have been fixed as well.

[osmers]

@timobrembeck ah alright, thanks for the explanation - I didn't get that from reading the comments :) hopefully it will be fixed soon!