CODEWITHSUNDEEP
pythongoogle-app-enginefont-facetemporary-filesxhtml2pdf
user2779653
user2779653

Reputation: 927

How to generate a PDF with custom font with xhtml2pdf on App Engine?

xhtml2pdf works fine to generate a simple PDF on App Engine.

But now I need to add a custom font in the generated PDF, and I don't seem to find an easy solution to do this.

I added this CSS to the HTML to convert to PDF:

    @font-face {
       font-family: OpenSans;
       src: url("http://mydomain/fonts/Open-Sans-regular.ttf");
    }
    body {
        font-family: OpenSans;
    }

Which yields this error:

  File "[..]/xhtml2pdf/util.py", line 613, in getNamedFile
self.tmp_file = tempfile.NamedTemporaryFile()
  File "/Applications/GoogleAppEngineLauncher.app/Contents/Resources/GoogleAppEngine-default.bundle/Contents/Resources/google_appengine/google/appengine/dist/tempfile.py", line 61, in PlaceHolder
  raise NotImplementedError("Only tempfile.TemporaryFile is available for use")
  NotImplementedError: Only tempfile.TemporaryFile is available for use

tempfile is not supported by GAE, so I have tried to replace tempfile.NamedTemporaryFile() by creating a temporary file in GCS like this:

self.tmp_file = gcs.open('/gcs_bucket_temp/temp_file', 
                         'w',
                         retry_params=gcs.RetryParams(backoff_factor=1.1))

but that creates breaking changes that are difficult to fix: xhtml2pdf makes a lot of read accesses to the tempfile in ttfonts.py (e.g. ttfonts.py:321 unpack('>L',self._ttf_data[self._pos - 4:self._pos])[0]), which seems difficult to migrate over to work with a GCS file.

Has anyone been able to generate PDFs using xhtml2pdf on App Engine, with custom fonts?

Upvotes: 0

Views: 1946

Answers (1)

user2779653
user2779653

Reputation: 927

Here are the changes to xhtml2pdf library I had to make to allow custom @font-face support on App Engine. Basically using GCS to store the tempfile instead of the file system.

In ttfonts.py:239, replace:

self.filename, f = TTFOpenFile(f)
self._ttf_data = f.read()

by:

self.filename = f
gcs_file = gcs.open(f) #, 'w', retry_params=gcs.RetryParams(backoff_factor=1.1))
self._ttf_data = gcs_file.read()
gcs_file.close()

In util.py:608, replace:

self.tmp_file = tempfile.NamedTemporaryFile()
if self.file:
    shutil.copyfileobj(self.file, self.tmp_file)
else:
    self.tmp_file.write(self.getData())
    self.tmp_file.flush()
return self.tmp_file

by:

filename = '/%s/temp_file'%gcs_bucket
self.tmp_file = gcs.open(filename, 'w', retry_params=gcs.RetryParams(backoff_factor=1.1))
if self.file:
    self.tmp_file.write(self.file._fetch_response.content)
else:
    self.tmp_file.write(self.getData())
self.tmp_file.close()
return filename

This seems to do the trick. Custom fonts appear well in the generated PDFs now.

Upvotes: 3

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