Sending a file to S3

app-client-send-s3.cs

private static byte[] GetMultipartFormData(
    IDictionary<string, string> parameters,
    string caName,
    byte[] fileContents,
    string boundary)
{
    var formDataStream = new MemoryStream();
    byte[] formData;

    using(formDataStream)
    {
        var head = Encoding.UTF8.GetBytes(
            string.Join(
                string.Empty,
                parameters.Select(
                    x =>
                    string.Format(
                        "--{0}\r\nContent-Disposition: form-data; name=\"{1}\"\r\n\r\n{2}\r\n",
                        boundary,
                        x.Key,
                        x.Value
                        )
                    )
                )
            + string.Format(
                "--{0}\r\nContent-Disposition: form-data; name=\"file\"; filename=\"{1}\";\r\nContent-Type: {2}\r\nContent-Length: {3}\r\n\r\n",
                boundary,
                caName,
                parameters["Content-Type"],
                fileContents.Length
                  )
            );

        formDataStream.Write(head, 0, head.Length);
        formDataStream.Write(fileContents, 0, fileContents.Length);
        var foot = Encoding.UTF8.GetBytes("\r\n--" + boundary + "--\r\n");
        formDataStream.Write(foot, 0, foot.Length);

        formDataStream.Position = 0;
        formData = new byte[formDataStream.Length];
        formDataStream.Read(formData, 0, formData.Length);
    }

    return formData;
}

private static async Task<bool> S3Upload(object s3UploadInfo, byte[] contents)
{
    try
    {
        var resp = (JObject) s3UploadInfo;

        var s3PostUrl = resp.SelectToken("s3post_url", true).ToString();
        var caName = resp.SelectToken("caName", true).ToString();
        var formParameters = new Dictionary<string, string>();

        foreach (
            var key in
                new[]
                    {
                        "key",
                        "policy",
                        "signature",
                        "AWSAccessKeyId",
                        "acl",
                        "Content-Type"
                    })
            formParameters[key] = resp.SelectToken(key, true).ToString();

        var boundary = string.Format("----------{0:N}", Guid.NewGuid());

        var formData = GetMultipartFormData(formParameters, caName, contents, boundary);
        File.WriteAllBytes("formdata.bin", formData);

        var request = (HttpWebRequest) WebRequest.Create(s3PostUrl);
        request.ContentLength = formData.Length;
        request.UserAgent = "move_s3test_client";
        request.AuthenticationLevel = AuthenticationLevel.None;
        request.Method = "POST";
        request.CookieContainer = new CookieContainer();
        request.ContentType = "multipart/form-data; boundary=" + boundary;
        using (var requestStream = request.GetRequestStream())
        {
            await requestStream.WriteAsync(formData, 0, formData.Length);
            requestStream.Close();
        }
        var response = (HttpWebResponse) await request.GetResponseAsync();
        return response.StatusCode==HttpStatusCode.NoContent;
    }
    catch (WebException ex)
    {
        // TODO: Handle web exception
        return false;
    }
    catch
    {
        // TODO: handle general exception
        return false;
    }
}