Modifiying CSV export in scrapy

I seem to be missing something very simple. All i want to do is use ; as a delimiter in the CSV exporter instead of ,.

I kn开发者_运维知识库ow the CSV exporter passes kwargs to csv writer, but i cant seem to figure out how to pass this the delimiter.

I am calling my spider like so:

scrapy crawl spidername --set FEED_URI=output.csv --set FEED_FORMAT=csv 

In contrib/feedexport.py,

class FeedExporter(object):

    ...

    def open_spider(self, spider):
        file = TemporaryFile(prefix='feed-')
        exp = self._get_exporter(file)  # <-- this is where the exporter is instantiated
        exp.start_exporting()
        self.slots[spider] = SpiderSlot(file, exp)

    def _get_exporter(self, *a, **kw):
        return self.exporters[self.format](*a, **kw)  # <-- not passed in :(

You will need to make your own, here's an example:

from scrapy.conf import settings
from scrapy.contrib.exporter import CsvItemExporter


class CsvOptionRespectingItemExporter(CsvItemExporter):

    def __init__(self, *args, **kwargs):
        delimiter = settings.get('CSV_DELIMITER', ',')
        kwargs['delimiter'] = delimiter
        super(CsvOptionRespectingItemExporter, self).__init__(*args, **kwargs)

In the settings.py file of your crawler directory, add this:

FEED_EXPORTERS = {
    'csv': 'importable.path.to.CsvOptionRespectingItemExporter',
}

Now, you can execute your spider as follows:

scrapy crawl spidername --set FEED_URI=output.csv --set FEED_FORMAT=csv --set CSV_DELIMITER=';'

HTH.

scraper/exporters.py

from scrapy.exporters import CsvItemExporter
from scraper.settings import CSV_SEP


class CsvCustomSeperator(CsvItemExporter):
    def __init__(self, *args, **kwargs):
        kwargs['encoding'] = 'utf-8'
        kwargs['delimiter'] = CSV_SEP
        super(CsvCustomSeperator, self).__init__(*args, **kwargs)

scraper/settings.py

CSV_SEP = '|'
FEED_EXPORTERS = {
    'csv': 'scraper.exporters.CsvCustomSeperator'
}

In terminal

$ scrapy crawl spider -o file.csv -s CSV_SEP=<delimiter>

I also tried this can work too:

Step 1: Modify C:\Python27\Lib\site-packages\scrapy\exporters.py line 21 to

__all__ = ['BaseItemExporter', 'PprintItemExporter', 'PickleItemExporter',
           'CsvItemExporter', 'TxtItemExporter', 'XmlItemExporter', 
           'JsonLinesItemExporter', 'JsonItemExporter', 'MarshalItemExporter']

This add 'TxtItemExporter' to original __all__ list.

Step 2: Add a new class named TxtItemExporter to C:\Python27\Lib\site-packages\scrapy\exporters.py:

class TxtItemExporter(BaseItemExporter):

    def __init__(self, file, include_headers_line=True, join_multivalued=',', **kwargs):
        self._configure(kwargs, dont_fail=True)
        if not self.encoding:
            self.encoding = 'utf-8'
        self.include_headers_line = include_headers_line
        self.stream = io.TextIOWrapper(
            file,
            line_buffering=False,
            write_through=True,
            encoding=self.encoding
        ) if six.PY3 else file
        self.csv_writer = csv.writer(self.stream, delimiter='\t', **kwargs)
        self._headers_not_written = True
        self._join_multivalued = join_multivalued

    def serialize_field(self, field, name, value):
        serializer = field.get('serializer', self._join_if_needed)
        return serializer(value)

    def _join_if_needed(self, value):
        if isinstance(value, (list, tuple)):
            try:
                return self._join_multivalued.join(value)
            except TypeError:  # list in value may not contain strings
                pass
        return value

    def export_item(self, item):
        if self._headers_not_written:
            self._headers_not_written = False
            self._write_headers_and_set_fields_to_export(item)

        fields = self._get_serialized_fields(item, default_value='',
                                             include_empty=True)
        values = list(self._build_row(x for _, x in fields))
        self.csv_writer.writerow(values)

    def _build_row(self, values):
        for s in values:
            try:
                yield to_native_str(s, self.encoding)
            except TypeError:
                yield s

    def _write_headers_and_set_fields_to_export(self, item):
        if self.include_headers_line:
            if not self.fields_to_export:
                if isinstance(item, dict):
                    # for dicts try using fields of the first item
                    self.fields_to_export = list(item.keys())
                else:
                    # use fields declared in Item
                    self.fields_to_export = list(item.fields.keys())
            row = list(self._build_row(self.fields_to_export))
            self.csv_writer.writerow(row)

The new class is copied from CsvItemExporter and only add delimiter='\t' to csv.writer()

Step3: Add following settings to settings.py

FEED_EXPORTERS = {
                 'txt': 'scrapy.contrib.exporter.TxtItemExporter',
                 }
FEED_FORMAT = 'txt'
FEED_URI = "your_output_file.txt"

Step 4: Run scrapy crawl your_spider and then you can find the output txt in your spider project directory.