我在从 Base64 字符串转换中找不到错误答案

【问题标题】：I can't find the mistake in Convert From Base64 String我在从 Base64 字符串转换中找不到错误
【发布时间】：2021-03-27 20:38:35
【问题描述】：

我正在尝试从 Base64 字符串转换。我读到 base64 是 ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/= 这是我的字符串：

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 = PGh0bWw + PGhlYWQ + PG1ldGEgaHR0cC1lcXVpdj0iQ29udGVudC1UeXBlIiBjb250ZW50PSJ0ZXh0L2h0bWw7IGNoYXJzZXQ9d2luZG93cy0xMjUyIj48L2hlYWQ + PGJvZHk + PEZPTlQgc3R5bGU9IkFyaWFsIiBzaXplPSIyIj48ZGl2Pi0tLS0tLS0tLS0tLS0tLS0gPHN0cm9uZz5BVEVOw4fDg088L3N0cm9uZz4gLS0tLS0tLS0tLS0tLS08YnIgLz4gIEVzdGEgw6kgdW1hIG1lbnNhZ2VtIGF1dG9tw6F0aWNhLCA8L2Rpd j48ZGl2PjxwPnBvciBmYXZvciBuw6NvIHJlc3BvbmRhLiA8YnIgLz4gICAgLS0tLS0tLS0tLS0tLS0tLS0tLS0tLS0tLS0tLS0tLS0tLS0tLS0tPGJyIC8 + ICAgIDxzdHJvbmc + PGJyIC8 + ICAgICAgPHN0cm9uZz5VUFRJTUUgLSBOb3RpZmljYcOnw6NvIGRlIE1hcmNhw6fDo28gZGUgQXVsYTwvc3Ryb25nPjwvc3Ryb25nPjxiciAvPjwvZGl2Pjx1bD48bGk + PGI + QWx1bm86PC9iPiBUSElBR08gU09BUkVTIE1PVEE8L2xpPjxsaT48Yj5Db250cmF0bzo8L2I + IDU0MjU0MTwvbGk + PGxpPjxiPlVuaWRhZGU6PC9iPiBVTklEQURFIFZFU1BBU0lBTk88L2xpPjwvdWw + PHVsPjxsaT48Yj5BdWxhOjwvYj4gQ09OVkVSU0FUSU9OIElJSTwvbGk + PGxpPjxiPkRhdGEgZGEgQXVsYTo8L2I + IDI3LzAzLzIwMjE8L2xpPjxsaT48Yj5Ib3JhIGRhIEF1bGE6PC9iPiAxMjowMDwvbGk + PC91bD48dWw + PGxpPjxiPkRhdGEgZGEgTWFyY2HDp8Ojbzo8L2I + IDI1LzAzLzIwMjE8L2xpPjxsaT48Yj5Ib3JhIGRhIE1hcmNhw6fDo286PC9iPiAyMToxNTwvbGk + PGxpPjxiPkZvbnRlOjwvYj4gTXlVUFRJTUUgb25saW5lPC9saT48L3VsPjx1bD48bGk + PGI + Rm9uZTo8L2I + IDMxMzY0NTEwMDA8L2xpPjxsaT48Yj5TaXRlOjwvYj4gPGEgaHJlZj0iaHR0cDovL3d3dy51cHRpbWUuY29tLmJyIj5odHRwOi8vd3d3LnVwdGltZS5jb20uYnI8L2E + PC9saT48L3VsPjwvRk9OVD48L2JvZHk + PC9odG1sPg == P>

我找不到其他聊天内容。总是在可接受的闲聊之间。

我是我的代码：

String codedBody = emailClass.Body.Replace("-", "+");
codedBody = codedBody.Replace("_", "/");
byte[] data = Convert.FromBase64String(codedBody);
emailClass.Body = Encoding.UTF8.GetString(data);

当我运行byte[] data = Convert.FromBase64String(codedBody); 行时，我收到了例外：

{"输入不是有效的 Base-64 字符串，因为它包含非 base 64 字符、两个以上的填充字符或填充字符中的非法字符。"}

我使用 de Repair Base64，站点将我的字符串拆分为两个有效的 base64Strings。

PGh0bWw + PGhlYWQ + PG1ldGEgaHR0cC1lcXVpdj0iQ29udGVudC1UeXBlIiBjb250ZW50PSJ0ZXh0L2h0bWw7IGNoYXJzZXQ9d2luZG93cy0xMjUyIj48L2hlYWQ + PGJvZHk + PEZPTlQgc3R5bGU9IkFyaWFsIiBzaXplPSIyIj48ZGl2Pi0tLS0tLS0tLS0tLS0tLS0gPHN0cm9uZz5BVEVOw4fDg088L3N0cm9uZz4gLS0tLS0tLS0tLS0tLS08YnIgLz4gIEVzdGEgw6kgdW1hIG1lbnNhZ2VtIGF1dG9tw6F0aWNhLCA8L2Rpdj48ZGl2PjxwPnBvciBmYXZvciBuw6NvIHJlc3BvbmRhLiA8YnIgLz4gICAgLS0tLS0tLS0tLS0tLS0tLS0tLS0tLS0tLS0tLS0tLS0tLS0tLS0tPGJyIC8 + ICAgIDxzdHJvbmc + PGJyIC8 + ICAgICAgPHN0cm9uZz5VUFRJTUUgLSBOb3RpZmljYcOnw6NvIGRlIE1hcmNhw6fDo28gZGUgQXVsYTwvc3Ryb25nPjwvc3Ryb25nPjxiciAvPjwvZGl2Pjx1bD48bGk + PGI + QWx1bm86PC9iPiBUSElBR08gU09BUkVTIE1PVEE8L2xpPjxsaT48Yj5Db250cmF0bzo8L2I + IDU0MjU0MTwvbGk + PGxpPjxiPlVuaWRhZGU6PC9iPiBVTklEQURFIFZFU1BBU0lBTk88L2xpPjwvdWw + PHVsPjxsaT48Yj5BdWxhOjwvYj4gQ09OVkVSU0FUSU9OIElJSTwvbGk + PGxpPjxiPkRhdGEgZGEgQXVsYTo8L2I + IDI3LzAzLzIwMjE8L2xpPjxsaT48Yj5Ib3JhIGRhIEF1bGE6PC9iPiAxMjowMDwvbGk + PC91bD48dWw + PGxpPjxiPkRhdGEgZGEgTWFyY2HDp8Ojbzo8L2I + IDI1LzAzLzIwMjE8L2xpPjxsaT48Yj5Ib3JhIGRhIE1hc mNhw6fDo286PC9iPiAyMToxNTwvbGk + PGxpPjxiPkZvbnRlOjwvYj4gTXlVUFRJTUUgb25saW5lPC9saT48L3VsPjx1bD48bGk + PGI + Rm9uZTo8L2I + IDMxMzY0NTEwMDA8L2xpPjxsaT48Yj5TaXRlOjwvYj4gPGEgaHJlZj0iaHR0cDovL3d3dy51cHRpbWUuY29tLmJyIj5odHRwOi8vd3d3LnVwdGltZS5jb20uYnI8L2E + PC9saT48L3VsPjwvRk9OVD48L2JvZHk + PC9odG1sPg == P>

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 = P>

这是规定吗？当我有= 时，我会滑掉我的绳子？

【问题讨论】：

我必须问，在我自己解码后，仅出于调试目的，最后应该是什么？
我在此代码中阅读了我的电子邮件以创建个人电子邮件管理器。

标签： c# base64 decode

【解决方案1】：

我承认我的方法需要改进，但我解决这个问题的方法是根据“=”拆分中间字符串，然后将“=”附加到每个新字符串上，创建一个包含两个 base64 值的简单字符串数组然后你就可以进行正常的 base64 解码了！

Demo

【讨论】：

如果您在= 上拆分，所有这些符号都会从结果字符串中删除。然后您必须检查每个字符串的长度并附加 = 字符，直到长度可以除以 4。例如，int missing = 4 - ([Part].Length % 4); if (missing > 0 && missing != 4) parts[i] += new string('=', missing);

【解决方案2】：

我使用正则表达式 ([a-zA-Z0-9\+\/]*={0,3}) 来获取有效的 Base64String。后来我添加了 de Base64Strings。

String codedBody = emailClass.Body.Replace("-", "+");
codedBody = codedBody.Replace("_", "/");
byte[] DataBody = new byte[0];

try
{
    byte[] data = Convert.FromBase64String(codedBody);
    DataBody = AddBiteArray(DataBody, data);
}
catch(Exception e)
{
    var GetBase64Maches = _regexTOGetBase64.Matches(codedBody);
    
    foreach(Match Base64StringMatch in GetBase64Maches)
    {
        var Base64String = Base64StringMatch.Groups[1].Value;
        byte[] data = Convert.FromBase64String(Base64String);
        DataBody = AddBiteArray(DataBody, data);
    }

}

emailClass.Body = Encoding.UTF8.GetString(DataBody);

编码主体是：

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

和：

static byte[] AddBiteArray(Byte[] destino, Byte[] origem)
{
    var retorno = new Byte[destino.Length + origem.Length];
    destino.CopyTo(retorno, 0);
    origem.CopyTo(retorno, destino.Length);
    return retorno;
}

【讨论】：