370 lines
12 KiB
Python
370 lines
12 KiB
Python
"""
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pyexcel_io.readers.csvr
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~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
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csv file reader
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:copyright: (c) 2014-2017 by Onni Software Ltd.
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:license: New BSD License, see LICENSE for more details
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"""
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import re
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import os
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import csv
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import glob
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import codecs
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from pyexcel_io.book import BookReader
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from pyexcel_io.sheet import SheetReader, NamedContent
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import pyexcel_io._compact as compact
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import pyexcel_io.constants as constants
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import pyexcel_io.service as service
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DEFAULT_SEPARATOR = "__"
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DEFAULT_SHEET_SEPARATOR_FORMATTER = "---%s---" % constants.DEFAULT_NAME + "%s"
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SEPARATOR_MATCHER = "---%s:(.*)---" % constants.DEFAULT_NAME
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DEFAULT_CSV_STREAM_FILE_FORMATTER = (
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"---%s:" % constants.DEFAULT_NAME + "%s---%s"
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)
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DEFAULT_NEWLINE = "\r\n"
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BOM_LITTLE_ENDIAN = b"\xff\xfe"
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BOM_BIG_ENDIAN = b"\xfe\ff"
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LITTLE_ENDIAN = 0
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BIG_ENDIAN = 1
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class CSVMemoryMapIterator(compact.Iterator):
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"""
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Wrapper class for mmap object
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mmap object does not handle encoding at all. This class
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provide the necessary transcoding for utf-8, utf-16 and utf-32
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"""
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def __init__(self, mmap_obj, encoding):
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self.__mmap_obj = mmap_obj
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self.__encoding = encoding
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self.__count = 0
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self.__endian = LITTLE_ENDIAN
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if encoding == "utf-8":
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# ..\r\x00\n
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# \x00\x..
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self.__zeros_left_in_2_row = 0
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elif encoding == "utf-16":
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# ..\r\x00\n
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# \x00\x..
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self.__zeros_left_in_2_row = 1
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elif encoding == "utf-32":
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# \r\x00\x00\x00\n
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# \x00\x00\x00\x..
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self.__zeros_left_in_2_row = 3
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elif encoding == "utf-32-be" or encoding == "utf-16-be":
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self.__zeros_left_in_2_row = 0
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self.__endian = BIG_ENDIAN
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elif encoding == "utf-32-le":
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self.__zeros_left_in_2_row = 3
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self.__endian = LITTLE_ENDIAN
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elif encoding == "utf-16-le":
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self.__zeros_left_in_2_row = 1
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self.__endian = LITTLE_ENDIAN
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else:
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raise Exception("Encoding %s is not supported" % encoding)
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def __iter__(self):
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return self
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def __next__(self):
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line = self.__mmap_obj.readline()
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if self.__count == 0:
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utf_16_32 = (
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self.__encoding == "utf-16" or self.__encoding == "utf-32"
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)
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if utf_16_32:
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bom_header = line[:2]
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if bom_header == BOM_BIG_ENDIAN:
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self.__endian = BIG_ENDIAN
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elif self.__endian == LITTLE_ENDIAN:
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line = line[self.__zeros_left_in_2_row :]
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if self.__endian == LITTLE_ENDIAN:
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line = line.rstrip()
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line = line.decode(self.__encoding)
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self.__count += 1
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if line == "":
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raise StopIteration
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if compact.PY2:
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# python 2 requires utf-8 encoded string for reading
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line = line.encode("utf-8")
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return line
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class UTF8Recorder(compact.Iterator):
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"""
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Iterator that reads an encoded stream and reencodes the input to UTF-8.
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"""
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def __init__(self, file_handle, encoding):
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self.__file_handle = file_handle
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self.reader = codecs.getreader(encoding)(file_handle)
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def close(self):
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self.__file_handle.close()
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def __iter__(self):
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return self
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def __next__(self):
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# python 2 requires utf-8 encoded string for reading
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line = next(self.reader).encode("utf-8")
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return line
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class CSVSheetReader(SheetReader):
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""" generic csv file reader"""
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def __init__(
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self,
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sheet,
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encoding="utf-8",
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auto_detect_float=True,
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ignore_infinity=True,
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auto_detect_int=True,
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auto_detect_datetime=True,
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pep_0515_off=True,
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ignore_nan_text=False,
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default_float_nan=None,
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**keywords
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):
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SheetReader.__init__(self, sheet, **keywords)
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self._encoding = encoding
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self.__auto_detect_int = auto_detect_int
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self.__auto_detect_float = auto_detect_float
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self.__ignore_infinity = ignore_infinity
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self.__auto_detect_datetime = auto_detect_datetime
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self.__file_handle = None
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self.__pep_0515_off = pep_0515_off
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self.__ignore_nan_text = ignore_nan_text
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self.__default_float_nan = default_float_nan
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def get_file_handle(self):
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""" return me unicde reader for csv """
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raise NotImplementedError("Please implement get_file_handle()")
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def row_iterator(self):
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self.__file_handle = self.get_file_handle()
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return csv.reader(self.__file_handle, **self._keywords)
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def column_iterator(self, row):
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for element in row:
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if compact.PY2:
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element = element.decode("utf-8")
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if element is not None and element != "":
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element = self.__convert_cell(element)
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yield element
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def __convert_cell(self, csv_cell_text):
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ret = None
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if self.__auto_detect_int:
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ret = service.detect_int_value(csv_cell_text, self.__pep_0515_off)
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if ret is None and self.__auto_detect_float:
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ret = service.detect_float_value(
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csv_cell_text,
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self.__pep_0515_off,
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ignore_nan_text=self.__ignore_nan_text,
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default_float_nan=self.__default_float_nan,
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)
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shall_we_ignore_the_conversion = (
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ret in [float("inf"), float("-inf")]
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) and self.__ignore_infinity
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if shall_we_ignore_the_conversion:
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ret = None
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if ret is None and self.__auto_detect_datetime:
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ret = service.detect_date_value(csv_cell_text)
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if ret is None:
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ret = csv_cell_text
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return ret
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def close(self):
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if self.__file_handle:
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self.__file_handle.close()
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# else: means the generator has been run
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# yes, no run, no file open.
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class CSVFileReader(CSVSheetReader):
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""" read csv from phyical file """
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def get_file_handle(self):
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unicode_reader = None
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if compact.PY2:
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file_handle = open(self._native_sheet.payload, "rb")
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unicode_reader = UTF8Recorder(file_handle, self._encoding)
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else:
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unicode_reader = open(
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self._native_sheet.payload, "r", encoding=self._encoding
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)
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return unicode_reader
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class CSVinMemoryReader(CSVSheetReader):
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""" read csv file from memory """
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def get_file_handle(self):
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unicode_reader = None
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if compact.PY2:
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if hasattr(self._native_sheet.payload, "read"):
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unicode_reader = UTF8Recorder(
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self._native_sheet.payload, self._encoding
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)
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else:
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unicode_reader = self._native_sheet.payload
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else:
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if isinstance(self._native_sheet.payload, compact.BytesIO):
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# please note that
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# if the end developer feed us bytesio in python3
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# we will do the conversion to StriongIO but that
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# comes at a cost.
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content = self._native_sheet.payload.read()
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unicode_reader = compact.StringIO(
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content.decode(self._encoding)
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)
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else:
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unicode_reader = self._native_sheet.payload
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return unicode_reader
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class CSVBookReader(BookReader):
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""" read csv file """
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def __init__(self):
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BookReader.__init__(self)
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self._file_type = constants.FILE_FORMAT_CSV
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self._file_content = None
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self.__load_from_memory_flag = False
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self.__line_terminator = constants.DEFAULT_CSV_NEWLINE
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self.__sheet_name = None
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self.__sheet_index = None
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self.__multiple_sheets = False
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self.__readers = []
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def open(self, file_name, **keywords):
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BookReader.open(self, file_name, **keywords)
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self._native_book = self._load_from_file()
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def open_stream(self, file_stream, multiple_sheets=False, **keywords):
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BookReader.open_stream(self, file_stream, **keywords)
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self.__multiple_sheets = multiple_sheets
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self._native_book = self._load_from_stream()
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def open_content(self, file_content, **keywords):
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try:
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import mmap
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encoding = keywords.get("encoding", "utf-8")
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if isinstance(file_content, mmap.mmap):
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# load from mmap
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self.__multiple_sheets = keywords.get("multiple_sheets", False)
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self._file_stream = CSVMemoryMapIterator(
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file_content, encoding
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)
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self._keywords = keywords
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self._native_book = self._load_from_stream()
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else:
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if compact.PY3_ABOVE:
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if isinstance(file_content, bytes):
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file_content = file_content.decode(encoding)
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# else python 2.7 does not care about bytes nor str
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BookReader.open_content(self, file_content, **keywords)
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except ImportError:
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# python 2.6 or Google app engine
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BookReader.open_content(self, file_content, **keywords)
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def read_sheet(self, native_sheet):
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if self.__load_from_memory_flag:
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reader = CSVinMemoryReader(native_sheet, **self._keywords)
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else:
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reader = CSVFileReader(native_sheet, **self._keywords)
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self.__readers.append(reader)
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return reader.to_array()
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def close(self):
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for reader in self.__readers:
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reader.close()
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def _load_from_stream(self):
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"""Load content from memory
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:params stream file_content: the actual file content in memory
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:returns: a book
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"""
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self.__load_from_memory_flag = True
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self.__line_terminator = self._keywords.get(
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constants.KEYWORD_LINE_TERMINATOR, self.__line_terminator
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)
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separator = DEFAULT_SHEET_SEPARATOR_FORMATTER % self.__line_terminator
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if self.__multiple_sheets:
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# will be slow for large files
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self._file_stream.seek(0)
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content = self._file_stream.read()
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sheets = content.split(separator)
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named_contents = []
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for sheet in sheets:
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if sheet == "": # skip empty named sheet
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continue
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lines = sheet.split(self.__line_terminator)
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result = re.match(constants.SEPARATOR_MATCHER, lines[0])
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new_content = "\n".join(lines[1:])
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new_sheet = NamedContent(
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result.group(1), compact.StringIO(new_content)
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)
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named_contents.append(new_sheet)
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return named_contents
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else:
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if hasattr(self._file_stream, "seek"):
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self._file_stream.seek(0)
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return [NamedContent(self._file_type, self._file_stream)]
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def _load_from_file(self):
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"""Load content from a file
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:params str filename: an accessible file path
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:returns: a book
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"""
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self.__line_terminator = self._keywords.get(
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constants.KEYWORD_LINE_TERMINATOR, self.__line_terminator
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)
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names = os.path.splitext(self._file_name)
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filepattern = "%s%s*%s*%s" % (
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names[0],
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constants.DEFAULT_MULTI_CSV_SEPARATOR,
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constants.DEFAULT_MULTI_CSV_SEPARATOR,
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names[1],
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)
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filelist = glob.glob(filepattern)
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if len(filelist) == 0:
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file_parts = os.path.split(self._file_name)
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return [NamedContent(file_parts[-1], self._file_name)]
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else:
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matcher = "%s%s(.*)%s(.*)%s" % (
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names[0],
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constants.DEFAULT_MULTI_CSV_SEPARATOR,
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constants.DEFAULT_MULTI_CSV_SEPARATOR,
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names[1],
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)
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tmp_file_list = []
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for filen in filelist:
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result = re.match(matcher, filen)
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tmp_file_list.append((result.group(1), result.group(2), filen))
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ret = []
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for lsheetname, index, filen in sorted(
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tmp_file_list, key=lambda row: row[1]
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):
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ret.append(NamedContent(lsheetname, filen))
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return ret
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