peis/src/Shentun.Utilities/FileHelper.cs

using System;
using System.Collections.Generic;
using System.IO;
using System.Net.Http;
using System.Text;

namespace Shentun.Utilities
{
    public class FileHelper
    {
        public static string ToBase64(string filename)
        {
            Stream stream;  
            string fileBase64;
            if (filename.StartsWith("http"))
            {
                using (var httpClientHandler = new HttpClientHandler())
                {
                    using (var httpClient = new HttpClient(httpClientHandler))
                    {
                        var response = httpClient.GetAsync(filename).Result;
                        if (response.IsSuccessStatusCode)
                        {
                            var contentStream = response.Content.ReadAsStreamAsync().Result;
                            using var memoryStream = new MemoryStream();
                            contentStream.CopyTo(memoryStream);
                            var fileBytes = memoryStream.ToArray();
                            return Convert.ToBase64String(fileBytes);
                        }
                        else
                        {
                            throw new Exception("转换base64时，返回错误:" + response.StatusCode);
                        }
                    }
                }
                      
            }
            else
            {
                using (stream = new FileStream(filename, FileMode.Open, FileAccess.Read))
                {
                    byte[] byteData = new byte[stream.Length];
                    stream.Read(byteData, 0, byteData.Length);
                    fileBase64 = Convert.ToBase64String(byteData);
                    stream.Close();
                }
                return fileBase64;
            }
         
        }
    }
}