added ReusableWSGIInputFilter

1 files changed, 42 insertions, 0 deletions

diff --git a/wsgitools/filters.py b/wsgitools/filters.py
index 1c7d03b..07675ba 100644
--- a/wsgitools/filters.py
+++ b/wsgitools/filters.py
@@ -388,3 +388,45 @@ class GzipWSGIFilter(BaseWSGIFilter):
         self.gzip.close()
         data = self.sio.getvalue()
         return [data]
+
+class ReusableWSGIInputFilter(BaseWSGIFilter):
+    """Make environ["wsgi.input"] readable multiple times. Although this is not
+    required by the standard it is sometimes desirable to read wsgi.input
+    multiple times. This filter will therefore replace that variable with a
+    StringIO instance which provides a seek method.
+    """
+    @classmethod
+    def creator(cls, maxrequestsize):
+        """
+        Returns a function creating ReusableWSGIInputFilters with desired
+        maxrequestsize being set. If there is more data than maxrequestsize is
+        available in wsgi.input the rest will be ignored. (It is up to the
+        adapter to eat this data.)
+        @type maxrequestsize int
+        @param maxrequestsize is the maximum number of bytes to store in the
+                StringIO
+        """
+        return lambda:cls(maxrequestsize)
+    def __init__(self, maxrequestsize=65536):
+        """ReusableWSGIInputFilters constructor.
+        @type maxrequestsize int
+        @param maxrequestsize is the maximum number of bytes to store in the
+                StringIO, see creator
+        """
+        BaseWSGIFilter.__init__(self)
+        self.maxrequestsize = maxrequestsize
+
+    def filter_environ(self, environ):
+        """BaseWSGIFilter interface
+        @type environ: {str: str}
+        """
+
+        if isinstance(environ["wsgi.input"], StringIO):
+            return environ # nothing to be done
+
+        # XXX: is this really a good idea? use with care
+        environ["wsgitools.oldinput"] = environ["wsgi.input"]
+        data = StringIO(environ["wsgi.input"].read(self.maxrequestsize))
+        environ["wsgi.input"] = data
+
+        return environ