diff --git a/pywb/rewrite/test/test_url_rewriter.py b/pywb/rewrite/test/test_url_rewriter.py
index 3d324069..a78a5529 100644
--- a/pywb/rewrite/test/test_url_rewriter.py
+++ b/pywb/rewrite/test/test_url_rewriter.py
@@ -103,12 +103,17 @@
 'http://example.com/file.html?param=https://example.com/filename.html&other=value&a=b&param2=http://test.example.com'
 
 # HttpsUrlRewriter tests
->>> HttpsUrlRewriter('http://example.com/', None).rewrite('https://example.com/abc')
+>>> httpsrewriter = HttpsUrlRewriter('http://example.com/', None)
+>>> httpsrewriter.rewrite('https://example.com/abc')
 'http://example.com/abc'
 
->>> HttpsUrlRewriter('http://example.com/', None).rewrite('http://example.com/abc')
+>>> httpsrewriter.rewrite('http://example.com/abc')
 'http://example.com/abc'
 
+# rebase is identity
+>>> httpsrewriter.rebase_rewriter('https://example.com/') == httpsrewriter
+True
+
 """
 
 
diff --git a/pywb/utils/bufferedreaders.py b/pywb/utils/bufferedreaders.py
index 7e461dee..7ca89780 100644
--- a/pywb/utils/bufferedreaders.py
+++ b/pywb/utils/bufferedreaders.py
@@ -46,9 +46,6 @@ class BufferedReader(object):
         self.buff_size = 0
 
     def set_decomp(self, decomp_type):
-        if self.num_read > 0:
-            raise Exception('Attempting to change decompression mid-stream')
-
         self._init_decomp(decomp_type)
 
     def _init_decomp(self, decomp_type):
diff --git a/pywb/utils/loaders.py b/pywb/utils/loaders.py
index 34eca14b..affae74f 100644
--- a/pywb/utils/loaders.py
+++ b/pywb/utils/loaders.py
@@ -49,12 +49,12 @@ def extract_post_query(method, mime, length, stream):
          not mime.lower().startswith('application/x-www-form-urlencoded'))):
         return None
 
-    if not length or length == '0':
-        return None
-
     try:
         length = int(length)
-    except ValueError:
+    except (ValueError, TypeError):
+        return None
+
+    if length <= 0:
         return None
 
     #todo: encoding issues?
diff --git a/pywb/utils/test/test_loaders.py b/pywb/utils/test/test_loaders.py
index 312af81b..e43cdc41 100644
--- a/pywb/utils/test/test_loaders.py
+++ b/pywb/utils/test/test_loaders.py
@@ -56,6 +56,32 @@ True
 >>> extract_client_cookie(dict(HTTP_COOKIE='x'), 'x')
 
 >>> extract_client_cookie({}, 'y')
+
+
+# extract_post_query tests
+
+# correct POST data
+>>> post_data = 'foo=bar&dir=%2Fbaz'
+>>> extract_post_query('POST', 'application/x-www-form-urlencoded', len(post_data), BytesIO(post_data))
+'foo=bar&dir=/baz'
+
+# unsupported method
+>>> extract_post_query('PUT', 'application/x-www-form-urlencoded', len(post_data), BytesIO(post_data))
+
+# unsupported type
+>>> extract_post_query('POST', 'text/plain', len(post_data), BytesIO(post_data))
+
+# invalid length
+>>> extract_post_query('POST', 'application/x-www-form-urlencoded', 'abc', BytesIO(post_data))
+>>> extract_post_query('POST', 'application/x-www-form-urlencoded', 0, BytesIO(post_data))
+
+# length too short
+>>> extract_post_query('POST', 'application/x-www-form-urlencoded', len(post_data) - 4, BytesIO(post_data))
+'foo=bar&dir=%2'
+
+# length too long
+>>> extract_post_query('POST', 'application/x-www-form-urlencoded', len(post_data) + 4, BytesIO(post_data))
+'foo=bar&dir=/baz'
 """
 
 
@@ -64,7 +90,7 @@ import re
 import os
 from io import BytesIO
 from pywb.utils.loaders import BlockLoader, HMACCookieMaker, to_file_url
-from pywb.utils.loaders import LimitReader, extract_client_cookie
+from pywb.utils.loaders import LimitReader, extract_client_cookie, extract_post_query
 
 from pywb import get_test_dir