Refs #42 - Introduced StringIteratorIO, for use in VirtualDownloadView when you need to stream generated content (yield).

django_downloadview/io.py

@@ -0,0 +1,65 @@
+# -*- coding: utf-8 -*-
+"""Low-level IO operations, for use with file wrappers."""
+from __future__ import absolute_import
+import io
+
+
+class StringIteratorIO(io.TextIOBase):
+    """A dynamically generated StringIO-like object.
+
+    Original code by Matt Joiner <anacrolix@gmail.com> from:
+
+    * http://stackoverflow.com/questions/12593576/adapt-an-iterator-to-behave-like-a-file-like-object-in-python
+    * https://gist.github.com/anacrolix/3788413
+
+    """
+    def __init__(self, iterator):
+        self._iter = iterator
+        self._left = ''
+
+    def readable(self):
+        return True
+
+    def _read1(self, n=None):
+        while not self._left:
+            try:
+                self._left = next(self._iter)
+            except StopIteration:
+                break
+        ret = self._left[:n]
+        self._left = self._left[len(ret):]
+        return ret
+
+    def read(self, n=None):
+        l = []
+        if n is None or n < 0:
+            while True:
+                m = self._read1()
+                if not m:
+                    break
+                l.append(m)
+        else:
+            while n > 0:
+                m = self._read1(n)
+                if not m:
+                    break
+                n -= len(m)
+                l.append(m)
+        return ''.join(l)
+
+    def readline(self):
+        l = []
+        while True:
+            i = self._left.find('\n')
+            if i == -1:
+                l.append(self._left)
+                try:
+                    self._left = next(self._iter)
+                except StopIteration:
+                    self._left = ''
+                    break
+            else:
+                l.append(self._left[:i + 1])
+                self._left = self._left[i + 1:]
+                break
+        return ''.join(l)