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# Licensed to the Apache Software Foundation (ASF) under one
# or more contributor license agreements. See the NOTICE file
# distributed with this work for additional information
# regarding copyright ownership. The ASF licenses this file
# to you 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.
# cython: profile=False
# distutils: language = c++
# cython: language_level = 3
from pyarrow.includes.common cimport *
from pyarrow.includes.libarrow cimport *
from pyarrow.lib cimport (check_status, _Weakrefable, Field, MemoryPool,
ensure_type, maybe_unbox_memory_pool,
get_input_stream, pyarrow_wrap_table,
pyarrow_wrap_data_type, pyarrow_unwrap_data_type,
pyarrow_wrap_schema, pyarrow_unwrap_schema)
cdef class ReadOptions(_Weakrefable):
"""
Options for reading JSON files.
Parameters
----------
use_threads : bool, optional (default True)
Whether to use multiple threads to accelerate reading
block_size : int, optional
How much bytes to process at a time from the input stream.
This will determine multi-threading granularity as well as
the size of individual chunks in the Table.
"""
cdef:
CJSONReadOptions options
# Avoid mistakingly creating attributes
__slots__ = ()
def __init__(self, use_threads=None, block_size=None):
self.options = CJSONReadOptions.Defaults()
if use_threads is not None:
self.use_threads = use_threads
if block_size is not None:
self.block_size = block_size
@property
def use_threads(self):
"""
Whether to use multiple threads to accelerate reading.
"""
return self.options.use_threads
@use_threads.setter
def use_threads(self, value):
self.options.use_threads = value
@property
def block_size(self):
"""
How much bytes to process at a time from the input stream.
This will determine multi-threading granularity as well as the size of
individual chunks in the Table.
"""
return self.options.block_size
@block_size.setter
def block_size(self, value):
self.options.block_size = value
cdef class ParseOptions(_Weakrefable):
"""
Options for parsing JSON files.
Parameters
----------
explicit_schema : Schema, optional (default None)
Optional explicit schema (no type inference, ignores other fields).
newlines_in_values : bool, optional (default False)
Whether objects may be printed across multiple lines (for example
pretty printed). If false, input must end with an empty line.
unexpected_field_behavior : str, default "infer"
How JSON fields outside of explicit_schema (if given) are treated.
Possible behaviors:
- "ignore": unexpected JSON fields are ignored
- "error": error out on unexpected JSON fields
- "infer": unexpected JSON fields are type-inferred and included in
the output
"""
cdef:
CJSONParseOptions options
__slots__ = ()
def __init__(self, explicit_schema=None, newlines_in_values=None,
unexpected_field_behavior=None):
self.options = CJSONParseOptions.Defaults()
if explicit_schema is not None:
self.explicit_schema = explicit_schema
if newlines_in_values is not None:
self.newlines_in_values = newlines_in_values
if unexpected_field_behavior is not None:
self.unexpected_field_behavior = unexpected_field_behavior
@property
def explicit_schema(self):
"""
Optional explicit schema (no type inference, ignores other fields)
"""
if self.options.explicit_schema.get() == NULL:
return None
else:
return pyarrow_wrap_schema(self.options.explicit_schema)
@explicit_schema.setter
def explicit_schema(self, value):
self.options.explicit_schema = pyarrow_unwrap_schema(value)
@property
def newlines_in_values(self):
"""
Whether newline characters are allowed in JSON values.
Setting this to True reduces the performance of multi-threaded
JSON reading.
"""
return self.options.newlines_in_values
@newlines_in_values.setter
def newlines_in_values(self, value):
self.options.newlines_in_values = value
@property
def unexpected_field_behavior(self):
"""
How JSON fields outside of explicit_schema (if given) are treated.
Possible behaviors:
- "ignore": unexpected JSON fields are ignored
- "error": error out on unexpected JSON fields
- "infer": unexpected JSON fields are type-inferred and included in
the output
Set to "infer" by default.
"""
v = self.options.unexpected_field_behavior
if v == CUnexpectedFieldBehavior_Ignore:
return "ignore"
elif v == CUnexpectedFieldBehavior_Error:
return "error"
elif v == CUnexpectedFieldBehavior_InferType:
return "infer"
else:
raise ValueError('Unexpected value for unexpected_field_behavior')
@unexpected_field_behavior.setter
def unexpected_field_behavior(self, value):
cdef CUnexpectedFieldBehavior v
if value == "ignore":
v = CUnexpectedFieldBehavior_Ignore
elif value == "error":
v = CUnexpectedFieldBehavior_Error
elif value == "infer":
v = CUnexpectedFieldBehavior_InferType
else:
raise ValueError(
"Unexpected value `{}` for `unexpected_field_behavior`, pass "
"either `ignore`, `error` or `infer`.".format(value)
)
self.options.unexpected_field_behavior = v
cdef _get_reader(input_file, shared_ptr[CInputStream]* out):
use_memory_map = False
get_input_stream(input_file, use_memory_map, out)
cdef _get_read_options(ReadOptions read_options, CJSONReadOptions* out):
if read_options is None:
out[0] = CJSONReadOptions.Defaults()
else:
out[0] = read_options.options
cdef _get_parse_options(ParseOptions parse_options, CJSONParseOptions* out):
if parse_options is None:
out[0] = CJSONParseOptions.Defaults()
else:
out[0] = parse_options.options
def read_json(input_file, read_options=None, parse_options=None,
MemoryPool memory_pool=None):
"""
Read a Table from a stream of JSON data.
Parameters
----------
input_file : str, path or file-like object
The location of JSON data. Currently only the line-delimited JSON
format is supported.
read_options : pyarrow.json.ReadOptions, optional
Options for the JSON reader (see ReadOptions constructor for defaults).
parse_options : pyarrow.json.ParseOptions, optional
Options for the JSON parser
(see ParseOptions constructor for defaults).
memory_pool : MemoryPool, optional
Pool to allocate Table memory from.
Returns
-------
:class:`pyarrow.Table`
Contents of the JSON file as a in-memory table.
"""
cdef:
shared_ptr[CInputStream] stream
CJSONReadOptions c_read_options
CJSONParseOptions c_parse_options
shared_ptr[CJSONReader] reader
shared_ptr[CTable] table
_get_reader(input_file, &stream)
_get_read_options(read_options, &c_read_options)
_get_parse_options(parse_options, &c_parse_options)
reader = GetResultValue(
CJSONReader.Make(maybe_unbox_memory_pool(memory_pool),
stream, c_read_options, c_parse_options))
with nogil:
table = GetResultValue(reader.get().Read())
return pyarrow_wrap_table(table)
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