Reimplement custom warnings with overwriteWarnings flag

PyPDF2/pdf.py

@@ -61,7 +61,7 @@
 import codecs
 from .generic import *
 from .utils import readNonWhitespace, readUntilWhitespace, ConvertFunctionsToVirtualList
-from .utils import b_, u_, ord_, chr_, str_, string_type
+from .utils import b_, u_, ord_, chr_, str_, string_type, formatWarning
 
 if version_info < ( 2, 4 ):
    from sets import ImmutableSet as frozenset
@@ -772,7 +772,18 @@ def setPageMode(self, mode):
 #               also causes some correctable problems to be fatal. Defaults
 #               to True. 
 class PdfFileReader(object):
-    def __init__(self, stream, strict=True, warndest = None):
+    def __init__(self, stream, strict=True, warndest = None, overwriteWarnings = True):
+        if overwriteWarnings:
+            # have to dynamically override the default showwarning since there are no
+            # public methods that specify the 'file' parameter
+            def _showwarning(message, category, filename, lineno, file=warndest, line=None):
+                if file is None:
+                    file = sys.stderr
+                try:
+                    file.write(formatWarning(message, category, filename, lineno, line))
+                except IOError:
+                    pass
+            warnings.showwarning = _showwarning
         self.strict = strict
         self.flattenedPages = None
         self.resolvedObjects = {}

PyPDF2/utils.py

@@ -33,6 +33,11 @@
 __author__ = "Mathieu Fenniak"
 __author_email__ = "biziqe@mathieu.fenniak.net"
 
+#custom implementation of warnings.formatwarning
+def formatWarning(message, category, filename, lineno, line=None):
+    file = filename.replace("/", "\\").rsplit("\\", 1)[1] # find the file name
+    return "%s: %s [%s:%s]\n" % (category.__name__, message, file, lineno)
+
 def readUntilWhitespace(stream, maxchars=None):
     """
     Reads non-whitespace characters and returns them.