From d0c0034cfbdfab1b4312deaec0ab3c7324ce0ff3 Mon Sep 17 00:00:00 2001
From: Dennis Collaris <d.collaris@me.com>
Date: Sun, 5 Nov 2023 11:54:16 +0100
Subject: [PATCH] feat: support non-seekable file-like objects

---
 sklearn_pmml_model/auto_detect/base.py |  3 +++
 tests/auto_detect/test_auto_detect.py  | 37 +++++++++++++++++++++++++-
 2 files changed, 39 insertions(+), 1 deletion(-)

diff --git a/sklearn_pmml_model/auto_detect/base.py b/sklearn_pmml_model/auto_detect/base.py
index 2ab3ca8..e48bbda 100644
--- a/sklearn_pmml_model/auto_detect/base.py
+++ b/sklearn_pmml_model/auto_detect/base.py
@@ -23,6 +23,9 @@ def auto_detect_estimator(pmml, **kwargs):
       Filename or file object containing PMML data.
 
   """
+  if isinstance(pmml, io.IOBase) and not pmml.seekable():
+    pmml = io.StringIO(pmml.read())
+
   base = PMMLBaseEstimator(pmml=pmml)
   target_field_name = base.target_field.attrib['name']
   target_field_type = base.field_mapping[target_field_name][1]
diff --git a/tests/auto_detect/test_auto_detect.py b/tests/auto_detect/test_auto_detect.py
index da5d2d5..8f572db 100644
--- a/tests/auto_detect/test_auto_detect.py
+++ b/tests/auto_detect/test_auto_detect.py
@@ -1,5 +1,5 @@
 from unittest import TestCase
-from io import StringIO
+from io import StringIO, UnsupportedOperation
 import sklearn_pmml_model
 from sklearn_pmml_model.auto_detect import auto_detect_estimator
 from sklearn_pmml_model.tree import PMMLTreeClassifier, PMMLTreeRegressor
@@ -151,6 +151,41 @@ def test_auto_detect_file_object_regressor(self):
 
     assert isinstance(clf, PMMLLinearRegression)
 
+  def test_auto_detect_non_seekable_file_object(self):
+    class NoSeekStringIO(StringIO):
+      def seekable(self) -> bool:
+        return False
+
+      def seek(self, __cookie: int, __whence: int = ...) -> int:
+        raise UnsupportedOperation('seek')
+
+    string = NoSeekStringIO("""
+        <PMML xmlns="http://www.dmg.org/PMML-4_3" version="4.3">
+          <DataDictionary>
+            <DataField name="feature" optype="continuous" dataType="float"/>
+            <DataField name="Class" optype="continuous" dataType="float"/>
+          </DataDictionary>
+          <MiningSchema>
+            <MiningField name="Class" usageType="target"/>
+          </MiningSchema>
+          <RegressionModel>
+              <MiningSchema>
+                  <MiningField name="feature" usageType="active" invalidValueTreatment="returnInvalid"/>
+                  <MiningField name="Class" usageType="predicted" invalidValueTreatment="returnInvalid"/>
+              </MiningSchema>
+              <Output>
+                  <OutputField name="Predicted_Class" optype="continuous" dataType="float" feature="predictedValue"/>
+              </Output>
+              <RegressionTable intercept="-1">
+                  <NumericPredictor name="feature" exponent="1" coefficient="0.1"/>
+              </RegressionTable>
+          </RegressionModel>
+        </PMML>
+        """)
+    clf = auto_detect_estimator(string)
+
+    assert isinstance(clf, PMMLLinearRegression)
+
   def test_auto_detect_tree_classifier(self):
     pmml = path.join(BASE_DIR, '../models/tree-iris.pmml')
     assert isinstance(auto_detect_estimator(pmml=pmml), PMMLTreeClassifier)