[Mpuls-commits] r4203 - in base/trunk: . mpulsweb/lib

[scm-commit@wald.intevation.org]

Author: bh
Date: 2010-11-16 20:23:34 +0100 (Tue, 16 Nov 2010)
New Revision: 4203

Modified:
   base/trunk/ChangeLog
   base/trunk/mpulsweb/lib/export.py
Log:
* mpulsweb/lib/export.py: Add a comment explaining the
pyExcelerator kludge for writing to a StringIO instance.
(fake_file): Add a doc-string.


Modified: base/trunk/ChangeLog
===================================================================
--- base/trunk/ChangeLog	2010-11-16 17:35:37 UTC (rev 4202)
+++ base/trunk/ChangeLog	2010-11-16 19:23:34 UTC (rev 4203)
@@ -1,5 +1,11 @@
 2010-11-16  Bernhard Herzog  <bh at intevation.de>
 
+	* mpulsweb/lib/export.py: Add a comment explaining the
+	pyExcelerator kludge for writing to a StringIO instance.
+	(fake_file): Add a doc-string.
+
+2010-11-16  Bernhard Herzog  <bh at intevation.de>
+
 	* mpulsweb/lib/export.py (MyStringIO.real_close): Actually call
 	the real close method, i.e. the one from the base class.
 

Modified: base/trunk/mpulsweb/lib/export.py
===================================================================
--- base/trunk/mpulsweb/lib/export.py	2010-11-16 17:35:37 UTC (rev 4202)
+++ base/trunk/mpulsweb/lib/export.py	2010-11-16 19:23:34 UTC (rev 4203)
@@ -15,6 +15,12 @@
 log = logging.getLogger(__name__)
 
 
+# Helpers to work around a problem in pyExcelerator.  pyExcelerator can
+# only write to a file that it opens itself using the filename passed to
+# the Workbook.save method.  We want the output in a StringIO object,
+# though.  To achieve that we override the built-in "file" with the
+# fake_file function defined below in pyExcelerator.CompoundDoc.
+
 class MyStringIO(StringIO):
 
     def close(self):
@@ -30,6 +36,12 @@
         self.buf = buf
 
 def fake_file(x, *args):
+    """Wrapper around the built-in 'file' which treats FakeStr specially.
+    If the filename argument is an instance of FakeStr, simply return
+    its buf attribute.  Otherwise delegate to file.  This allows us to
+    pass e.g. a MyStringIO instance to pyExcelerator as a 'filename'
+    when we wrap it in a FakeStr.
+    """
     return isinstance(x, FakeStr) and x.buf or file(x, *args)
 
 pyExcelerator.CompoundDoc.file = fake_file