将Curl PUT命令转为C# HttpClient代码遇连接失败问题排查

原始Curl命令 #

curl -X PUT --data-binary @Invoice_AGL_20210408.003.xml --user [xxxx]:[xxxxxxxxxxxxxxx] https://sftp.voxelgroup.net:19922/outbox/Invoice_AGL_20210408.003.xml

你的错误代码 #

using (var httpClient = new HttpClient())
{
    using (var request = new HttpRequestMessage(new HttpMethod("PUT"), "https://sftp.voxelgroup.net:19922/outbox/Invoice_AGL_20210408.003.xml"))
    {
        var base64authorization = Convert.ToBase64String(Encoding.ASCII.GetBytes("[xxxx]:[xxxxxxxxxxxxxxx]"));
        request.Headers.TryAddWithoutValidation("Authorization", $"Basic {base64authorization}"); 

        request.Content = new StringContent(new StringContent(File.ReadAllText(@"C:\inetpub\AstroWeb\BavelExport\2022_10_29_03_16\Invoice20220016014.xml")));
        request.Content.Headers.ContentType = MediaTypeHeaderValue.Parse("application/x-www-form-urlencoded"); 

        var response = await httpClient.SendAsync(request);
    }
}

代码中的问题点 #

• 嵌套的StringContent：双重包装StringContent会导致实际发送的是内层对象的字符串表示，而非文件的真实内容。
• 错误的Content-Type：Curl的--data-binary是直接发送二进制XML数据，应设置application/xml或text/xml，而非表单编码格式application/x-www-form-urlencoded。
• 文本读取文件的隐患：File.ReadAllText会按系统默认编码读取XML，可能引发编码转换错误，用二进制读取更贴合--data-binary的原始行为。
• 认证头写法不规范：没必要用TryAddWithoutValidation，直接使用AuthenticationHeaderValue更可靠。

修正后的代码 #

// 推荐复用HttpClient，避免频繁创建销毁连接资源
private static readonly HttpClient _httpClient = new HttpClient();

public async Task UploadInvoiceFileAsync()
{
    var targetUrl = "https://sftp.voxelgroup.net:19922/outbox/Invoice_AGL_20210408.003.xml";
    var authCredentials = "[xxxx]:[xxxxxxxxxxxxxxx]";
    var localFilePath = @"C:\inetpub\AstroWeb\BavelExport\2022_10_29_03_16\Invoice20220016014.xml";

    using (var request = new HttpRequestMessage(HttpMethod.Put, targetUrl))
    {
        // 设置基础认证头
        var base64AuthString = Convert.ToBase64String(Encoding.ASCII.GetBytes(authCredentials));
        request.Headers.Authorization = new AuthenticationHeaderValue("Basic", base64AuthString);

        // 以二进制形式读取文件，对应curl的--data-binary参数
        var fileContentBytes = File.ReadAllBytes(localFilePath);
        request.Content = new ByteArrayContent(fileContentBytes);

        // 设置正确的XML内容类型
        request.Content.Headers.ContentType = MediaTypeHeaderValue.Parse("application/xml");

        var response = await _httpClient.SendAsync(request);
        // 添加响应检查，请求失败时抛出异常，便于排查问题
        response.EnsureSuccessStatusCode();
    }
}

内容的提问来源于stack exchange，提问作者nadun