Typed JSON API

srsly/_json_api.py

@@ -1,4 +1,4 @@
-from typing import Union, Iterable, Sequence, Any, Optional, Iterator
+from typing import Any, Iterable, Dict, List, Optional, Iterator, Union, Type, cast
 import sys
 import json as _builtin_json
 import gzip
@@ -39,6 +39,32 @@ def json_loads(data: Union[str, bytes]) -> JSONOutput:
     return ujson.loads(data)
 
 
+def json_loads_dict(data: Union[str, bytes]) -> Dict[str, Any]:
+    """Deserialize unicode or bytes to a Python dict.
+
+    data (str / bytes): The data to deserialize.
+    RAISES: ValueError if the loaded data is not a dict
+    RETURNS: The deserialized Python dict.
+    """
+    obj = json_loads(data)
+    if not isinstance(obj, dict):
+        raise ValueError("JSON data could not be parsed to a dict.")
+    return obj
+
+
+def json_loads_list(data: Union[str, bytes]) -> List[Dict[str, Any]]:
+    """Deserialize unicode or bytes to a Python list of dicts.
+
+    data (str / bytes): The data to deserialize.
+    RAISES: ValueError if the loaded data is not a list
+    RETURNS: The deserialized Python list.
+    """
+    loaded = json_loads(data)
+    if not isinstance(loaded, list):
+        raise ValueError("JSON data could not be parsed to a list of dicts.")
+    return loaded
+
+
 def read_json(path: FilePath) -> JSONOutput:
     """Load JSON from file or standard input.
 
@@ -53,6 +79,42 @@ def read_json(path: FilePath) -> JSONOutput:
         return ujson.load(f)
 
 
+def read_json_dict(path: FilePath) -> Dict[str, Any]:
+    """Load JSON from file or standard input.
+
+    path (FilePath): The file path. "-" for reading from stdin.
+    RETURNS (JSONOutput): The loaded JSON content.
+    """
+    data = read_json(path)
+    if not isinstance(data, dict):
+        raise ValueError("Invalid JSON, data could not be parsed to a dict.")
+    return data
+
+
+def read_json_list(path: FilePath, validate_inner: bool = False, skip_invalid: bool = False) -> List[Dict[str, Any]]:
+    """Load JSON from file or standard input.
+
+    path (FilePath): The file path. "-" for reading from stdin.
+    RETURNS (JSONOutput): The loaded JSON content.
+    """
+
+    data = read_json(path)
+    if not isinstance(data, list):
+        raise ValueError("Invalid JSON, data could not be parsed to a list of dicts.")
+
+    if validate_inner:
+        output = []
+        for i, obj in enumerate(data):
+            if not isinstance(obj, dict):
+                if skip_invalid:
+                    continue
+                raise ValueError(f"Invalid JSON Object at index: {i + 1}. Value is not a valid dict.")
+            output.append(obj)
+    else:
+        output = data
+    return data
+
+
 def read_gzip_json(path: FilePath) -> JSONOutput:
     """Load JSON from a gzipped file.
 
@@ -149,6 +211,22 @@ def read_jsonl(path: FilePath, skip: bool = False) -> Iterable[JSONOutput]:
                 yield line
 
 
+def read_jsonl_dicts(path: FilePath, skip: bool = False) -> Iterable[Dict[str, Any]]:
+    """Read a .jsonl file or standard input and yield contents line by line.
+    Blank lines will always be skipped. Validates the contents of each line is a dict.
+
+    path (FilePath): The file path. "-" for reading from stdin.
+    skip (bool): Skip broken lines and don't raise ValueError.
+    YIELDS (JSONOutput): The loaded JSON contents of each line.
+    """
+    for i, line in enumerate(read_jsonl(path, skip=skip)):
+        if not isinstance(line, dict):
+            if skip:
+                continue
+            raise ValueError(f"Invalid JSON Object on line: {i + 1}. Line is not a valid dict.")
+        yield line
+
+
 def write_jsonl(
     path: FilePath,
     lines: Iterable[JSONInput],

srsly/tests/test_json_api.py

@@ -4,8 +4,13 @@
 import gzip
 import numpy
 
+from typing import Any, Dict, List, Union
+
 from .._json_api import (
     read_json,
+    read_json_dict,
+    read_json_list,
+    read_jsonl_dicts,
     write_json,
     read_jsonl,
     write_jsonl,
@@ -262,3 +267,40 @@ def test_read_jsonl_gzip():
     assert len(data[1]) == 1
     assert data[0]["hello"] == "world"
     assert data[1]["test"] == 123
+
+
+READ_JSON_DICT_TEST_CASES = {
+
+}
+
+
+READ_JSONL_DICT_TEST_CASES = {
+    "invalid_str": ('"test"', ValueError()),
+    "invalid_num": ('-32', ValueError()),
+    "invalid_json_list": ('[{"hello": "world"}\n{"test": 123}]', ValueError()),
+    "valid_dicts": ('{"hello": "world"}\n{"test": 123}', [{"hello": "world"}, {"test": 123}]),
+}
+
+@pytest.mark.parametrize(
+    "file_contents, expected",
+    READ_JSONL_DICT_TEST_CASES.values(),
+    ids=READ_JSONL_DICT_TEST_CASES.keys()
+)
+def test_read_jsonl_dicts(file_contents: str, expected: Union[List[Dict[str, Any]], ValueError]):
+
+    with make_tempdir({"tmp.json": file_contents}) as temp_dir:
+        file_path = temp_dir / "tmp.json"
+        assert file_path.exists()
+        data = read_jsonl_dicts(file_path)
+        # Make sure this returns a generator, not just a list
+        assert not hasattr(data, "__len__")
+        try:
+            # actually consume the generator to trigger errors
+            data = list(data)
+        except ValueError:
+            assert isinstance(expected, ValueError)
+        else:
+            assert isinstance(expected, list)
+            assert len(data) == len(expected)
+            for data_item, expected_item in zip(data, expected):
+                assert data_item == expected_item