使用CSS内联更改HTML以使用数据Url

你不能用HtmlAgilityPack做到这一点,但是试试看 Regex

using System.Text.RegularExpressions;

private string EmbebedImages(string strHtml) {
    var htmlString = .......load html string....;
    string currentURL;

    var images_url = Regex.Matches(htmlString, @"(?:https?:\/\/.*?\.(gif|png|jpg|jpeg))");
    foreach(var url in images_url) {
        currentURL = url.ToString();
        using(var webClient = new WebClient()) {
            var imageAsByteArray = webClient.DownloadData(currentURL);
            string mimeType = MimeMapping.GetMimeMapping(currentURL);
            string dataURL = "data:" + mimeType + ";base64," + Convert.ToBase64String(imageAsByteArray);
            htmlString = htmlString.Replace(currentURL, dataURL);
        }
    }

    return htmlString;
}

虽然这不适用于OP的情况,但如果在Python中希望将URL转换为CSS中的数据URI,我是这样做的:

import requests
import re
import base64

def url_to_base64(url, memo=None):
    if memo is None:
        memo = {}
    if url in memo:
        return memo[url]
    res = requests.get(url)
    mime_type = res.headers['content-type']
    base64_data = base64.b64encode(res.content).decode('utf-8')
    data_url = "data:{};base64,{}".format(mime_type, base64_data)
    memo[url] = data_url
    return data_url


def embed_urls(html, memo=None):
    if memo is None:
        memo = {}
    pattern = re.compile(r"url\('(https?://.*?)'\)")
    urls = set(re.findall(pattern, html))
    for url in urls:
        base64_data = url_to_base64(url, memo)
        html = html.replace(url, base64_data)
    return html