added wsgitools.adapters for future wsgi versions

1 files changed, 49 insertions, 0 deletions

diff --git a/wsgitools/adapters.py b/wsgitools/adapters.py
new file mode 100644
index 0000000..9f2ab1c
--- /dev/null
+++ b/wsgitools/adapters.py
@@ -0,0 +1,49 @@
+__all__ = []
+
+from filters import CloseableIterator, CloseableList
+
+__all__.append("WSGI2to1Adapter")
+class WSGI2to1Adapter:
+    """Adapts an application with an interface that might somewhen be known as
+    WSGI 2.0 to the WSGI 1.0 interface."""
+    def __init__(self, app):
+        """app is an application with an interface that might somewhen be known
+        as WSGI 2.0."""
+        self.app = app
+    def __call__(self, environ, start_response):
+        """WSGI 1.0 interface"""
+        status, headers, iterable = self.app(environ)
+        start_response(status, headers)
+        return iterable
+
+__all__.append("WSGI1to2Adapter")
+class WSGI1to2Adapter:
+    """Adapts a WSGI 1.0 application to something that might somewhen be the
+    WSGI 2.0 interface."""
+    def __init__(self, app):
+        """app is a WSGI 1.0 application"""
+        self.app = app
+    def __call__(self, environ):
+        """some interface that might somewhen be known as WSGI 2.0"""
+        results = [None, None, []]
+        def start_response(status, headers, exc_info=None):
+            results[0] = status
+            results[1] = headers
+            def write_callable(data):
+                results[2].append(data)
+            return write_callable
+        iterable = self.app(environ, start_response)
+        if isinstance(iterable, list):
+            # retaining .close attribute this way
+            iterable[:0] = results[2]
+            return results[0], results[1], results[2]
+        close_function = getattr(iterable, "close", None)
+        iterable = iter(iterable)
+        try:
+            first = iterable.next()
+        except StopIteration:
+            return (results[0], results[1],
+                    CloseableList(close_function, results[2]))
+        results[2].append(first)
+        return (results[0], results[1],
+                CloseableIterator(close_function, results[2], iterable))