仅使用python请求下载文档的一部分 [英] Only download a part of the document using python requests
问题描述
我正在使用python-requests编写一个web scraper。
I'm writing a web scraper using python-requests.
每个页面超过1MB，但我需要提取的实际数据很早就在文档的流程，所以我浪费时间下载大量不必要的数据。
Each page is over 1MB, but the actual data I need to extract is very early on in the document's flow, so I'm wasting time downloading a lot of unnecessary data.
如果可能，我想在文档中出现所需数据后立即停止下载源代码，以节省时间。
If possible I would like to stop the download as soon as the required data appears in the document's source code, in order to save time.
例如，我只想提取abcDiv中的文本，文档的其余部分是无用的：
For example, I only want to extract the text in the "abc" Div, the rest of the document is useless:
<html>
<head>
<title>My site</title>
</head>
<body>
<div id="abc">blah blah...</div>
<p>Lorem ipsum dolor sit amet, consectetur adipiscing elit. Mauris fermentum molestie ligula, a pharetra eros mollis ut.</p>
<p>Quisque auctor volutpat lobortis. Vestibulum pellentesque lacus sapien, quis vulputate enim mollis a. Vestibulum ultrices fermentum urna ac sodales.</p>
<p>Nunc sit amet augue at dolor fermentum ultrices. Curabitur faucibus porttitor vehicula. Lorem ipsum dolor sit amet, consectetur adipiscing elit.</p>
<p>Etiam sed leo at ipsum blandit dignissim ut a est.</p>
</body>
</html>
目前我只是这样做：
r = requests.get(URL)
推荐答案
你想在这里使用的是范围 HTTP标题。
What you want to use here is called Range HTTP Header.
参见：< a href =http://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html\"rel =noreferrer> http://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html （特别是Range上的位）。
另请参阅自定义标题
示例：
from requests import get
url = "http://download.thinkbroadband.com/5MB.zip"
headers = {"Range": "bytes=0-100"} # first 100 bytes
r = get(url, headers=headers)
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