创建bytesIO对象 [英] Creating bytesIO object

问题描述

我正在研究 Scrapy 蜘蛛，试图从中的多个PDF文件提取文本使用 slate 的目录.我对将实际的PDF保存到磁盘没有兴趣，因此建议我在

I am working on a Scrapy spider, trying to extract the text from multiple PDF files in a directory, using slate. I have no interest in saving the actual PDF to disk, and so I've been advised to look into the io.bytesIO subclass at https://docs.python.org/2/library/io.html#buffered-streams.

但是我不确定如何将PDF正文传递给bytesIO类，然后传递虚拟PDF平板以获取文本.到目前为止，我有:

However I'm not sure how to pass the PDF body to the bytesIO class and then pass the virtual PDF slate to get the text. So far I have:

class Ove_Spider(BaseSpider):

    name = "ove"


    allowed_domains = ['myurl.com']
    start_urls = ['myurl/hgh/']


    def parse(self, response):
        for a in response.xpath('//a[@href]/@href'):
            link = a.extract()
            if link.endswith('.pdf'):
                link = urlparse.urljoin(base_url, link)
                yield Request(link, callback=self.save_pdf)

    def save_pdf(self, response):

      in_memory_pdf = BytesIO()
      in_memory_pdf.read(response.body) # Trying to read in PDF which is in response body

我得到了:

in_memory_pdf.read(response.body)
TypeError: integer argument expected, got 'str'

我该如何工作?

推荐答案

执行in_memory_pdf.read(response.body)时，应该传递要读取的字节数.您要初始化缓冲区，而不是读入缓冲区.

When you do in_memory_pdf.read(response.body) you are supposed to pass the number of bytes to read. You want to initialize the buffer, not read into it.

在python 2中，只需将BytesIO初始化为:

In python 2, just initialize BytesIO as:

 in_memory_pdf = BytesIO(response.body)

在Python 3中，不能将BytesIO与字符串一起使用，因为它需要字节.错误消息显示response.body的类型为str:我们必须对其进行编码.

In Python 3, you cannot use BytesIO with a string because it expects bytes. The error message shows that response.body is of type str: we have to encode it.

 in_memory_pdf = BytesIO(bytes(response.body,'ascii'))

但是由于pdf可以是二进制数据，所以我想response.body将是bytes，而不是str.在这种情况下，简单的in_memory_pdf = BytesIO(response.body)可以工作.

But as a pdf can be binary data, I suppose that response.body would be bytes, not str. In that case, the simple in_memory_pdf = BytesIO(response.body) works.

这篇关于创建bytesIO对象的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！