robust css/preamble path finding despite symlinks

ivanov · ivanov · commit 2af1087d9b2b · 2012-10-27T13:51:01.000-07:00
I have a `~/bin/nbconvert` symlink to ~/code/nbconvert/nbconvert.py so
that I can call it from anywhere in the filesystem. Stylesheets were
found previously using `__file__`, which can change depending on where
one puts symlinks.

Additionally, I found one other place where such a situation was
anticipated, but the solution was using a bit too much code. The
simplest way to get around this situation is to used `os.path.realpath`,
which is what I've done here.

Here's a traceback of the error, in case someone stumbles into this.
$ nbconvert -f html test_display.ipynb
Traceback (most recent call last):
  File "/home/pi/bin/nbconvert", line 1490, in &lt;module&gt;
    main(infile=args.infile[0], format=args.format)
  File "/home/pi/bin/nbconvert", line 1459, in main
    htmlfname = converter.render()
  File "/home/pi/bin/nbconvert", line 311, in render
    self.output = self.convert()
  File "/home/pi/bin/nbconvert", line 293, in convert
    lines.extend(self.optional_header())
  File "/home/pi/bin/nbconvert", line 808, in optional_header
    return ['&lt;html&gt;', '&lt;head&gt;'] + self.header_body() + \
  File "/home/pi/bin/nbconvert", line 790, in header_body
    header.extend(self._stylesheet(sheet))
  File "/home/pi/bin/nbconvert", line 756, in _stylesheet
    with io.open(fname, encoding='utf-8') as f:
IOError: [Errno 2] No such file or directory: '/home/pi/bin/css/static_html.css'
diff --git a/nbconvert.py b/nbconvert.py
@@ -774,7 +774,7 @@ def header_body(self):
         static = os.path.join(path.get_ipython_package_dir(),
         'frontend', 'html', 'notebook', 'static',
         )
-        here = os.path.split(os.path.abspath(__file__))[0]
+        here = os.path.split(os.path.realpath(__file__))[0]
         css = os.path.join(static, 'css')
         for sheet in [
             # do we need jquery and prettify?
@@ -1014,8 +1014,7 @@ def convert(self):
                  ]
         # Load our own preamble, which is stored next to the main file.  We
         # need to be careful in case the script entry point is a symlink
-        myfile = __file__ if not os.path.islink(__file__) else \
-          os.readlink(__file__)
+        myfile = os.path.realpath(__file__)
         with open(os.path.join(os.path.dirname(myfile), 'preamble.tex')) as f:
             final.append(f.read())
             
