Make ContentNotFoundError optional

1 files changed, 88 insertions, 0 deletions

diff --git a/wkhtmltopdf/process.py b/wkhtmltopdf/process.py
new file mode 100644
index 0000000..d36aacb
--- /dev/null
+++ b/wkhtmltopdf/process.py
@@ -0,0 +1,88 @@
+import os
+from subprocess import Popen, PIPE, STDOUT, CalledProcessError
+
+
+def check_output(*popenargs, **kwargs):
+    r"""Run command with arguments and return its output as a byte string.
+
+    If the exit code was non-zero it raises a CalledProcessError.  The
+    CalledProcessError object will have the return code in the returncode
+    attribute and output in the output attribute.
+
+    The arguments are the same as for the Popen constructor.  Example:
+
+    >>> check_output(["ls", "-l", "/dev/null"])  #doctest: +ELLIPSIS
+    'crw-rw-rw-  1 root  wheel    3...
+
+    The stdout argument is not allowed as it is used internally.
+    To capture standard error in the result, use stderr=STDOUT.
+
+    >>> check_output(["/bin/sh", "-c",
+    ...               "ls -l non_existent_file ; exit 0"],
+    ...              stderr=STDOUT)
+    'ls: non_existent_file: No such file or directory\n'
+
+    Calling check_output without the ignore_404 keyword argument
+    will raise a CalledProcessError if wkhtmltopdf exits with a non-zero code
+
+    >>> check_output(['wkhtmltopdf',             #doctest: +ELLIPSIS
+    ...               '--quiet',
+    ...               '--encoding', 'utf8',
+    ...               os.getenv('WKHTML_IN'), os.getenv('WKHTML_OUT')])
+    Traceback (most recent call last):
+    ...
+    CalledProcessError...
+
+    Calling check_output WITH the ignore_404 keyword will not raise
+    the CalledProcessError, but only if the error == ContentNotFoundError
+
+    >>> check_output(['wkhtmltopdf',
+    ...               '--quiet',
+    ...               '--encoding', 'utf8',
+    ...               os.getenv('WKHTML_IN'), os.getenv('WKHTML_OUT')],
+    ...               ignore_404=True)
+    ''
+
+    Calling check_output WITH the ignore_404 keyword should still
+    raise a CalledProcessError if the error != ContentNotFoundError
+
+    >>> check_output(['wkhtmltopdf',            #doctest: +ELLIPSIS
+    ...               '--blaa',
+    ...               '--encoding', 'utf8',
+    ...               os.getenv('WKHTML_IN'), os.getenv('WKHTML_OUT')],
+    ...               ignore_404=True)
+    Traceback (most recent call last):
+    ...
+    CalledProcessError...
+    """
+    if 'stdout' in kwargs:
+        raise ValueError('stdout argument not allowed, it will be overridden.')
+
+    ignore_404 = kwargs.pop('ignore_404', False)
+
+    if not kwargs.get('stderr'):
+        kwargs['stderr'] = PIPE
+
+    process = Popen(stdout=PIPE, *popenargs, **kwargs)
+    output, error_message = process.communicate()
+    retcode = process.poll()
+
+    if retcode:
+        if ignore_404:
+            if 'ContentNotFoundError' in error_message:
+                return output
+        cmd = kwargs.get("args")
+        if cmd is None:
+            cmd = popenargs[0]
+        error = CalledProcessError(retcode, cmd)
+        # Add the output attribute to CalledProcessError, which
+        # doesn't exist until Python 2.7.
+        error.output = output
+        raise error
+
+    return output
+
+
+if __name__ == "__main__":
+    import doctest
+    doctest.testmod()