Running svg2rlg second time returns None.

[hovodab]

I have to draw an image on every page of a PDF file. For that I have a function that does something like this:

def draw_logo(file_path):
      rlg = svg2rlg(file_path)
      # Draw on PDF. This part doesn't matter...

And for every page I call the function draw_logo. It draws the image on the first page, but when the function is called second time(for second page) svg2rlg returns None. Yet I have found a way to bypass this case, I still think things shouldn't work so.

[claudep]

I cannot reproduce. Are you sure file_path is a real file path, or is it another file-like Python object?
Do you get a "Failed to load input file!" error log line the second time?

[hovodab]

@claudep It is a real file path(str). What is your version of svglib? I use 0.8.1.
Yes. In the body of the function svg2rlg an exception is risen

  File "src/lxml/lxml.etree.pyx", line 3442, in lxml.etree.parse (src/lxml/lxml.etree.c:81716)
  File "src/lxml/parser.pxi", line 1832, in lxml.etree._parseDocument (src/lxml/lxml.etree.c:118903)
  File "src/lxml/parser.pxi", line 1852, in lxml.etree._parseFilelikeDocument (src/lxml/lxml.etree.c:119186)
  File "src/lxml/parser.pxi", line 1747, in lxml.etree._parseDocFromFilelike (src/lxml/lxml.etree.c:117974)
  File "src/lxml/parser.pxi", line 1162, in lxml.etree._BaseParser._parseDocFromFilelike (src/lxml/lxml.etree.c:112701)
  File "src/lxml/parser.pxi", line 595, in lxml.etree._ParserContext._handleParseResultDoc (src/lxml/lxml.etree.c:105896)
  File "src/lxml/parser.pxi", line 706, in lxml.etree._handleParseResult (src/lxml/lxml.etree.c:107604)
  File "src/lxml/parser.pxi", line 635, in lxml.etree._raiseParseError (src/lxml/lxml.etree.c:106458)
  File "/var/www/control/media/logos/logo.svg", line 1
lxml.etree.XMLSyntaxError: Document is empty, line 1, column 1

[claudep]

Changes on master from the 0.8.1 release are minor, I don't think that makes a difference.
Are you able to place a breakpoint inside the svg2rlg function to see what's happening?
Is your file a .svg or .svgz file? Which Python? On Linux, Mac, Windows?

[hovodab]

File is .svg
Ubuntu==16.04, python==3.5.2
Exception is risen on the line doc = etree.parse(path, parser=parser)

[claudep]

I have quite a similar configuration (Debian instead of Ubuntu). That's a weird behavior.
Is the following Python code running fine for you?:

from lxml import etree
etree.parse("/var/www/control/media/logos/logo.svg")
etree.parse("/var/www/control/media/logos/logo.svg")

I don't see how the document would be empty the second time.

[hovodab]

Yes, this runs without errors.

[claudep]

I'm sorry, I don't see any obvious error on svglib side which would explain this error. I'm afraid you'll have to debug a bit more on your side.

[hovodab]

@claudep Yes, I think I should. Thank you for your help. I will try to dig deeper.