diff --git a/python/obitools3/files/uncompress.pxd b/python/obitools3/files/uncompress.pxd
index 3d959b2..80c5b5d 100644
--- a/python/obitools3/files/uncompress.pxd
+++ b/python/obitools3/files/uncompress.pxd
@@ -1,10 +1,11 @@
 #cython: language_level=3
 
 cdef class MagicKeyFile:
+    cdef object stream
     cdef str    stream_mode
     cdef object binary
     cdef bytes  key 
-    cdef int    keylength
+    cdef int    keylength 
     cdef int    pos
     
     cpdef bytes read(self,int size=?)
diff --git a/python/obitools3/files/uncompress.pyx b/python/obitools3/files/uncompress.pyx
index 4a871ac..ecd5d77 100644
--- a/python/obitools3/files/uncompress.pyx
+++ b/python/obitools3/files/uncompress.pyx
@@ -15,17 +15,20 @@ import io
 cdef class MagicKeyFile:
     def __init__(self,stream,length=2):
         
-        self.stream_mode = None
+        binary=stream
+        self.stream = stream
+        self.stream_mode = None 
         if hasattr(stream, "mode"):
             self.stream_mode = stream.mode
-            if 'b' in stream.mode:
-                binary=stream
-            elif hasattr(stream, "buffer") and 'b' in stream.buffer.mode:
+            if (not 'b' in stream.mode and 
+                hasattr(stream, "buffer") and 
+                'b' in stream.buffer.mode):
                 binary=stream.buffer
-            else:
-                self.stream_mode = None
-                
-        if self.stream_mode is None:
+
+        if (self.stream_mode is None and 
+            not (hasattr(stream, 'headers') and 
+                 hasattr(stream.headers, "keys") and
+                 'Content-type' in stream.headers)):
             raise TypeError("stream does not present the good interface")
         
         self.binary=binary
@@ -94,9 +97,12 @@ cdef class CompressedFile:
         
         if self.accessor is None:
             self.accessor = magic
-            
-            
-        if 'b' not in magic.stream_mode:
+        
+        if ((hasattr(stream, 'headers') and 
+             hasattr(stream.headers, "keys") and
+             'Content-type' in stream.headers and
+             stream.headers['Content-type'].startswith('text/')) or
+            'b' not in magic.stream_mode):
             self.accessor = io.TextIOWrapper(self.accessor)
         
     
@@ -105,7 +111,4 @@ cdef class CompressedFile:
     
     def __iter__(self):
         for x in self.accessor:
-            yield x
-    
-
-
+            yield x 
\ No newline at end of file