Fixes json parser when input is a stream (#27)

Author: xadupre

_unittests/ut_df/data/classic.json

@@ -0,0 +1,35 @@
+[{"name":"cudaGetDeviceCount",
+"ph":"X",
+"cat":"cuda",
+"ts":1634290065724226794,
+"dur":800,
+"tid":"Thread 2080429824: Runtime API",
+"pid":"[89792] Process",
+"args":{}},
+{"name":"_Z25full_reduce_tensor_kernelIfLi256ELi1ELi1ELi256EL21cudnnReduceTensorOp_t0EL21cudnnNanPropagation_t0EEv17cudnnTensorStructPjS3_PT_S5_S4_bii",
+"ph":"X",
+"cat":"cuda",
+"ts":1634290112071305413,
+"dur":1888,
+"tid":"_Z25full_reduce_tensor_kernelIfLi256ELi1ELi1ELi256EL21cudnnReduceTensorOp_t0EL21cudnnNanPropagation_t0EEv17cudnnTensorStructPjS3_PT_S5_S4_bii",
+"pid":"[0:1] Compute",
+"args":{"Grid size":"[ 1, 1, 1 ]",
+"Block size":"[ 256, 1, 1 ]"}},
+{"name":"_Z28op_tensor_kernel_alpha2_zeroILi3EfffLi1ELi256ELi1ELi1EL17cudnnOpTensorOp_t0EEv16alpha2_zero_argsIT0_T1_T2_E",
+"ph":"X",
+"cat":"cuda",
+"ts":1634290112071308133,
+"dur":1440,
+"tid":"Compute",
+"pid":"[0:1] Overview",
+"args":{"Grid size":"[ 1, 1, 1 ]",
+"Block size":"[ 1, 256, 1 ]"}},
+{"name":"_Z28op_tensor_kernel_alpha2_zeroILi3EfffLi1ELi256ELi1ELi1EL17cudnnOpTensorOp_t0EEv16alpha2_zero_argsIT0_T1_T2_E",
+"ph":"X",
+"cat":"cuda",
+"ts":1634290112071308133,
+"dur":1440,
+"tid":"_Z28op_tensor_kernel_alpha2_zeroILi3EfffLi1ELi256ELi1ELi1EL17cudnnOpTensorOp_t0EEv16alpha2_zero_argsIT0_T1_T2_E",
+"pid":"[0:1] Compute",
+"args":{"Grid size":"[ 1, 1, 1 ]",
+"Block size":"[ 1, 256, 1 ]"}}]

_unittests/ut_df/test_dataframe_io_helpers.py

@@ -285,6 +285,51 @@ def test_bug_documentation(self):
             items.append(item)
         self.assertEqual(len(items), 2)
 
+    def test_read_json_classic(self):
+        data = self.abs_path_join(__file__, 'data', 'classic.json')
+        dfs = pandas.read_json(data, orient='records')
+        dfs['ts2'] = dfs['ts'].apply(lambda t: t / 1e9)
+        self.assertEqual(dfs.shape[1], 9)
+        self.assertGreater(dfs.shape[0], 2)
+        it = StreamingDataFrame.read_json(data)
+        it['ts2'] = it['ts'].apply(lambda t: t / 1e9)
+        h1 = it.to_df()
+        h2 = it.to_df()
+        self.assertNotEmpty(h1)
+        self.assertNotEmpty(h2)
+        self.assertEqualDataFrame(h1, h2)
+        self.assertEqual(h1.shape[1], 9)
+
+    def test_read_json_classic_file(self):
+        data = self.abs_path_join(__file__, 'data', 'classic.json')
+        dfs = pandas.read_json(data, orient='records')
+        self.assertEqual(dfs.shape[1], 8)
+        self.assertGreater(dfs.shape[0], 2)
+        with open(data, "r", encoding="utf-8") as f:
+            it = StreamingDataFrame.read_json(f, orient='records')
+            h1 = it.to_df()
+            h2 = it.to_df()
+        self.assertNotEmpty(h1)
+        self.assertNotEmpty(h2)
+        self.assertEqualDataFrame(h1, h2)
+        self.assertEqual(h1.shape[1], 8)
+
+    def test_read_json_classic_file_formula(self):
+        data = self.abs_path_join(__file__, 'data', 'classic.json')
+        dfs = pandas.read_json(data, orient='records')
+        dfs['ts2'] = dfs['ts'].apply(lambda t: t / 1e9)
+        self.assertEqual(dfs.shape[1], 9)
+        self.assertGreater(dfs.shape[0], 2)
+        with open(data, "r", encoding="utf-8") as f:
+            it = StreamingDataFrame.read_json(f)
+            it['ts2'] = it['ts'].apply(lambda t: t / 1e9)
+            h1 = it.to_df()
+            h2 = it.to_df()
+        self.assertNotEmpty(h1)
+        self.assertNotEmpty(h2)
+        self.assertEqualDataFrame(h1, h2)
+        self.assertEqual(h1.shape[1], 9)
+
 
 if __name__ == "__main__":
     unittest.main()

pandas_streaming/df/dataframe_io_helpers.py

@@ -256,6 +256,8 @@ def enumerate_json_items(filename, encoding=None, lines=False, flatten=False, fL
                 encoding=encoding, lines=False, flatten=flatten, fLOG=fLOG):
             yield el
     else:
+        if hasattr(filename, 'seek'):
+            filename.seek(0)
         parser = ijson.parse(filename)
         current = None
         curkey = None