[uapi]Save predict result (#2926)

* sava predict result

ppcls/engine/engine.py

@@ -38,7 +38,7 @@ from ppcls.utils.amp import AutoCast, build_scaler
 from ppcls.utils.ema import ExponentialMovingAverage
 from ppcls.utils.save_load import load_dygraph_pretrain, load_dygraph_pretrain_from_url
 from ppcls.utils.save_load import init_model
-from ppcls.utils import save_load
+from ppcls.utils import save_load, save_predict_result
 
 from ppcls.data.utils.get_image_list import get_image_list
 from ppcls.data.postprocess import build_postprocess
@@ -477,6 +477,9 @@ class Engine(object):
                 results.extend(result)
                 batch_data.clear()
                 image_file_list.clear()
+        save_path = self.config["Infer"].get("save_dir", None)
+        if save_path:
+            save_predict_result(save_path, results)
         return results
 
     def export(self):

ppcls/utils/__init__.py

@@ -26,3 +26,4 @@ from .metrics import multi_hot_encode
 from .metrics import precision_recall_fscore
 from .misc import AverageMeter
 from .save_load import init_model, save_model
+from .save_result import save_predict_result

ppcls/utils/save_result.py

+# Copyright (c) 2023 PaddlePaddle Authors. All Rights Reserved.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+import os
+import json
+
+from . import logger
+
+def save_predict_result(save_path, result):
+    if os.path.splitext(save_path)[-1] == '':
+        if save_path[-1] == "/":
+            save_path = save_path[:-1]
+        save_path = save_path + '.json'
+    elif os.path.splitext(save_path)[-1] == '.json':
+        save_path = save_path
+    else:
+        logger.warning(
+            f"{save_path} is invalid input path, only files in json format are supported."
+        )
+    if os.path.exists(save_path):
+        logger.warning(
+            f"The file {save_path} will be overwritten."
+        )
+    with open(save_path, 'w', encoding='utf-8') as f:
+        json.dump(result, f)