feature: all de/serializers support content type

doc/frameworks/xgboost/using_xgboost.rst

@@ -192,8 +192,7 @@ inference against your model.
 
 .. code::
 
-    serializer = StringSerializer()
-    serializer.CONTENT_TYPE = "text/libsvm"
+    serializer = StringSerializer(content_type="text/libsvm")
 
     predictor = estimator.deploy(
         initial_instance_count=1,

src/sagemaker/amazon/common.py

@@ -22,15 +22,22 @@
 
 from sagemaker.amazon.record_pb2 import Record
 from sagemaker.deprecations import deprecated_class
-from sagemaker.deserializers import BaseDeserializer
-from sagemaker.serializers import BaseSerializer
+from sagemaker.deserializers import SimpleBaseDeserializer
+from sagemaker.serializers import SimpleBaseSerializer
 from sagemaker.utils import DeferredError
 
 
-class RecordSerializer(BaseSerializer):
+class RecordSerializer(SimpleBaseSerializer):
     """Serialize a NumPy array for an inference request."""
 
-    CONTENT_TYPE = "application/x-recordio-protobuf"
+    def __init__(self, content_type="application/x-recordio-protobuf"):
+        """Initialize a ``RecordSerializer`` instance.
+
+        Args:
+            content_type (str): The MIME type to signal to the inference endpoint when sending
+                request data (default: "application/x-recordio-protobuf").
+        """
+        super(RecordSerializer, self).__init__(content_type=content_type)
 
     def serialize(self, data):
         """Serialize a NumPy array into a buffer containing RecordIO records.
@@ -56,10 +63,18 @@ def serialize(self, data):
         return buffer
 
 
-class RecordDeserializer(BaseDeserializer):
+class RecordDeserializer(SimpleBaseDeserializer):
     """Deserialize RecordIO Protobuf data from an inference endpoint."""
 
-    ACCEPT = ("application/x-recordio-protobuf",)
+    def __init__(self, accept="application/x-recordio-protobuf"):
+        """Initialize a ``RecordDeserializer`` instance.
+
+        Args:
+            accept (union[str, tuple[str]]): The MIME type (or tuple of allowable MIME types) that
+                is expected from the inference endpoint (default:
+                "application/x-recordio-protobuf").
+        """
+        super(RecordDeserializer, self).__init__(accept=accept)
 
     def deserialize(self, data, content_type):
         """Deserialize RecordIO Protobuf data from an inference endpoint.

src/sagemaker/deserializers.py

@@ -21,6 +21,7 @@
 import json
 
 import numpy as np
+from six import with_metaclass
 
 from sagemaker.utils import DeferredError
 
@@ -55,17 +56,44 @@ def ACCEPT(self):
         """The content types that are expected from the inference endpoint."""
 
 
-class StringDeserializer(BaseDeserializer):
-    """Deserialize data from an inference endpoint into a decoded string."""
+class SimpleBaseDeserializer(with_metaclass(abc.ABCMeta, BaseDeserializer)):
+    """Abstract base class for creation of new deserializers.
+
+    This class extends the API of :class:~`sagemaker.deserializers.BaseDeserializer` with more
+    user-friendly options for setting the ACCEPT content type header, in situations where it can be
+    provided at init and freely updated.
+    """
+
+    def __init__(self, accept="*/*"):
+        """Initialize a ``SimpleBaseDeserializer`` instance.
+
+        Args:
+            accept (union[str, tuple[str]]): The MIME type (or tuple of allowable MIME types) that
+                is expected from the inference endpoint (default: "*/*").
+        """
+        super(SimpleBaseDeserializer, self).__init__()
+        self.accept = accept
+
+    @property
+    def ACCEPT(self):
+        """The tuple of possible content types that are expected from the inference endpoint."""
+        if isinstance(self.accept, str):
+            return (self.accept,)
+        return self.accept
 
-    ACCEPT = ("application/json",)
 
-    def __init__(self, encoding="UTF-8"):
-        """Initialize the string encoding.
+class StringDeserializer(SimpleBaseDeserializer):
+    """Deserialize data from an inference endpoint into a decoded string."""
+
+    def __init__(self, encoding="UTF-8", accept="application/json"):
+        """Initialize a ``StringDeserializer`` instance.
 
         Args:
             encoding (str): The string encoding to use (default: UTF-8).
+            accept (union[str, tuple[str]]): The MIME type (or tuple of allowable MIME types) that
+                is expected from the inference endpoint (default: "application/json").
         """
+        super(StringDeserializer, self).__init__(accept=accept)
         self.encoding = encoding
 
     def deserialize(self, stream, content_type):
@@ -84,11 +112,9 @@ def deserialize(self, stream, content_type):
             stream.close()
 
 
-class BytesDeserializer(BaseDeserializer):
+class BytesDeserializer(SimpleBaseDeserializer):
     """Deserialize a stream of bytes into a bytes object."""
 
-    ACCEPT = ("*/*",)
-
     def deserialize(self, stream, content_type):
         """Read a stream of bytes returned from an inference endpoint.
 
@@ -105,17 +131,23 @@ def deserialize(self, stream, content_type):
             stream.close()
 
 
-class CSVDeserializer(BaseDeserializer):
-    """Deserialize a stream of bytes into a list of lists."""
+class CSVDeserializer(SimpleBaseDeserializer):
+    """Deserialize a stream of bytes into a list of lists.
 
-    ACCEPT = ("text/csv",)
+    Consider using :class:~`sagemaker.deserializers.NumpyDeserializer` or
+    :class:~`sagemaker.deserializers.PandasDeserializer` instead, if you'd like to convert text/csv
+    responses directly into other data types.
+    """
 
-    def __init__(self, encoding="utf-8"):
-        """Initialize the string encoding.
+    def __init__(self, encoding="utf-8", accept="text/csv"):
+        """Initialize a ``CSVDeserializer`` instance.
 
         Args:
             encoding (str): The string encoding to use (default: "utf-8").
+            accept (union[str, tuple[str]]): The MIME type (or tuple of allowable MIME types) that
+                is expected from the inference endpoint (default: "text/csv").
         """
+        super(CSVDeserializer, self).__init__(accept=accept)
         self.encoding = encoding
 
     def deserialize(self, stream, content_type):
@@ -136,15 +168,13 @@ def deserialize(self, stream, content_type):
             stream.close()
 
 
-class StreamDeserializer(BaseDeserializer):
-    """Returns the data and content-type received from an inference endpoint.
+class StreamDeserializer(SimpleBaseDeserializer):
+    """Directly return the data and content-type received from an inference endpoint.
 
     It is the user's responsibility to close the data stream once they're done
     reading it.
     """
 
-    ACCEPT = ("*/*",)
-
     def deserialize(self, stream, content_type):
         """Returns a stream of the response body and the MIME type of the data.
 
@@ -158,20 +188,20 @@ def deserialize(self, stream, content_type):
         return stream, content_type
 
 
-class NumpyDeserializer(BaseDeserializer):
-    """Deserialize a stream of data in the .npy format."""
+class NumpyDeserializer(SimpleBaseDeserializer):
+    """Deserialize a stream of data in .npy or UTF-8 CSV/JSON format to a numpy array."""
 
     def __init__(self, dtype=None, accept="application/x-npy", allow_pickle=True):
-        """Initialize the dtype and allow_pickle arguments.
+        """Initialize a ``NumpyDeserializer`` instance.
 
         Args:
             dtype (str): The dtype of the data (default: None).
-            accept (str): The MIME type that is expected from the inference
-                endpoint (default: "application/x-npy").
+            accept (union[str, tuple[str]]): The MIME type (or tuple of allowable MIME types) that
+                is expected from the inference endpoint (default: "application/x-npy").
             allow_pickle (bool): Allow loading pickled object arrays (default: True).
         """
+        super(NumpyDeserializer, self).__init__(accept=accept)
         self.dtype = dtype
-        self.accept = accept
         self.allow_pickle = allow_pickle
 
     def deserialize(self, stream, content_type):
@@ -198,21 +228,18 @@ def deserialize(self, stream, content_type):
 
         raise ValueError("%s cannot read content type %s." % (__class__.__name__, content_type))
 
-    @property
-    def ACCEPT(self):
-        """The content types that are expected from the inference endpoint.
-
-        To maintain backwards compatability with legacy images, the
-        NumpyDeserializer supports sending only one content type in the Accept
-        header.
-        """
-        return (self.accept,)
-
 
-class JSONDeserializer(BaseDeserializer):
+class JSONDeserializer(SimpleBaseDeserializer):
     """Deserialize JSON data from an inference endpoint into a Python object."""
 
-    ACCEPT = ("application/json",)
+    def __init__(self, accept="application/json"):
+        """Initialize a ``JSONDeserializer`` instance.
+
+        Args:
+            accept (union[str, tuple[str]]): The MIME type (or tuple of allowable MIME types) that
+                is expected from the inference endpoint (default: "application/json").
+        """
+        super(JSONDeserializer, self).__init__(accept=accept)
 
     def deserialize(self, stream, content_type):
         """Deserialize JSON data from an inference endpoint into a Python object.
@@ -230,10 +257,17 @@ def deserialize(self, stream, content_type):
             stream.close()
 
 
-class PandasDeserializer(BaseDeserializer):
+class PandasDeserializer(SimpleBaseDeserializer):
     """Deserialize CSV or JSON data from an inference endpoint into a pandas dataframe."""
 
-    ACCEPT = ("text/csv", "application/json")
+    def __init__(self, accept=("text/csv", "application/json")):
+        """Initialize a ``PandasDeserializer`` instance.
+
+        Args:
+            accept (union[str, tuple[str]]): The MIME type (or tuple of allowable MIME types) that
+                is expected from the inference endpoint (default: ("text/csv","application/json")).
+        """
+        super(PandasDeserializer, self).__init__(accept=accept)
 
     def deserialize(self, stream, content_type):
         """Deserialize CSV or JSON data from an inference endpoint into a pandas
@@ -258,10 +292,17 @@ def deserialize(self, stream, content_type):
         raise ValueError("%s cannot read content type %s." % (__class__.__name__, content_type))
 
 
-class JSONLinesDeserializer(BaseDeserializer):
+class JSONLinesDeserializer(SimpleBaseDeserializer):
     """Deserialize JSON lines data from an inference endpoint."""
 
-    ACCEPT = ("application/jsonlines",)
+    def __init__(self, accept="application/jsonlines"):
+        """Initialize a ``JSONLinesDeserializer`` instance.
+
+        Args:
+            accept (union[str, tuple[str]]): The MIME type (or tuple of allowable MIME types) that
+                is expected from the inference endpoint (default: ("text/csv","application/json")).
+        """
+        super(JSONLinesDeserializer, self).__init__(accept=accept)
 
     def deserialize(self, stream, content_type):
         """Deserialize JSON lines data from an inference endpoint.