Scrapy如何在上传到S3时在一个项目中为多个文件URL提供自定义路径？

import boto3

class S3Pipeline(object):
    def __init__(self, aws_access_key_id, aws_secret_access_key, aws_region_name, s3_bucket_name):
        self.aws_access_key_id = aws_access_key_id
        self.aws_secret_access_key = aws_secret_access_key
        self.aws_region_name = aws_region_name
        self.s3_bucket_name = s3_bucket_name

    @classmethod
    def from_crawler(cls, crawler):
        return cls(
            aws_access_key_id=crawler.settings.get('AWS_ACCESS_KEY_ID'),
            aws_secret_access_key=crawler.settings.get('AWS_SECRET_ACCESS_KEY'),
            aws_region_name=crawler.settings.get('AWS_REGION_NAME'),
            s3_bucket_name=crawler.settings.get('S3_BUCKET_NAME')
        )

    def open_spider(self, spider):
        self.s3_client = boto3.client(
            's3',
            aws_access_key_id=self.aws_access_key_id,
            aws_secret_access_key=self.aws_secret_access_key,
            region_name=self.aws_region_name
        )

    def process_item(self, item, spider):
        file_url = item['file_url']
        file_path = self.generate_file_path(item)  # 根据自定义逻辑生成文件的存储路径

        # 将文件上传到S3
        self.s3_client.put_object(
            Bucket=self.s3_bucket_name,
            Key=file_path,
            Body=file_url
        )

        return item

    def generate_file_path(self, item):
        # 根据自定义逻辑生成文件的存储路径
        # 可以根据item中的其他字段来生成路径，例如根据日期、分类等信息
        # 返回的路径应该是一个字符串，表示文件在S3中的存储路径
        pass

AWS_ACCESS_KEY_ID = 'your_access_key_id'
AWS_SECRET_ACCESS_KEY = 'your_secret_access_key'
AWS_REGION_NAME = 'your_region_name'
S3_BUCKET_NAME = 'your_bucket_name'

ITEM_PIPELINES = {
    'your_project.pipelines.S3Pipeline': 300,
}