#region License Information (GPL v3)
/*
ShareX - A program that allows you to take screenshots and share any file type
Copyright (C) 2007-2014 ShareX Developers
This program is free software; you can redistribute it and/or
modify it under the terms of the GNU General Public License
as published by the Free Software Foundation; either version 2
of the License, or (at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
Optionally you can also view the license at .
*/
#endregion License Information (GPL v3)
// Credits: https://github.com/alanedwardes
using HelpersLib;
using Newtonsoft.Json;
using System;
using System.Collections.Generic;
using System.IO;
using System.Security.Cryptography;
using System.Text;
namespace UploadersLib.FileUploaders
{
public sealed class AmazonS3 : FileUploader
{
private AmazonS3Settings S3Settings { get; set; }
public AmazonS3(AmazonS3Settings accessKeys)
{
S3Settings = accessKeys;
}
private string GetObjectStorageClass()
{
return S3Settings.UseReducedRedundancyStorage ? "REDUCED_REDUNDANCY" : "STANDARD";
}
// Helper class to construct the S3 policy document (below)
private class S3PolicyCondition : Dictionary
{
public S3PolicyCondition(string key, string value)
{
Add(key, value);
}
}
private string GetPolicyDocument(string fileName, string objectKey)
{
var policyDocument = new
{
expiration = DateTime.UtcNow.AddDays(2).ToString("yyyy-MM-ddTHH:mm:ssZ"), // The policy is valid for 2 days
conditions = new List {
new S3PolicyCondition("acl", "public-read"),
new S3PolicyCondition("bucket", S3Settings.Bucket),
new S3PolicyCondition("Content-Type", Helpers.GetMimeType(fileName)),
new S3PolicyCondition("key", objectKey),
new S3PolicyCondition("x-amz-storage-class", GetObjectStorageClass())
}
};
return JsonConvert.SerializeObject(policyDocument);
}
private string GetEndpoint()
{
return string.Format("{0}{1}", S3Settings.Endpoint, S3Settings.Bucket);
}
// http://codeonaboat.wordpress.com/2011/04/22/uploading-a-file-to-amazon-s3-using-an-asp-net-mvc-application-directly-from-the-users-browser/
private string CreateSignature(string secretKey, byte[] policyBytes)
{
ASCIIEncoding encoding = new ASCIIEncoding();
string base64Policy = Convert.ToBase64String(policyBytes);
byte[] secretKeyBytes = encoding.GetBytes(secretKey);
byte[] signatureBytes;
using (HMACSHA1 hmacsha1 = new HMACSHA1(secretKeyBytes))
{
byte[] base64PolicyBytes = encoding.GetBytes(base64Policy);
signatureBytes = hmacsha1.ComputeHash(base64PolicyBytes);
}
return Convert.ToBase64String(signatureBytes);
}
private string GetObjectKey(string fileName)
{
NameParser parser = new NameParser(NameParserType.FolderPath);
string objectPrefix = S3Settings.ObjectPrefix.Trim('/');
return Helpers.CombineURL(parser.Parse(objectPrefix), fileName);
}
private string GetObjectURL(string objectName)
{
objectName = objectName.Trim('/');
objectName = Helpers.URLPathEncode(objectName);
string url = string.Empty;
if (S3Settings.UseCustomCNAME)
{
if (!string.IsNullOrEmpty(S3Settings.CustomDomain))
{
url = Helpers.CombineURL(S3Settings.CustomDomain, objectName);
}
else
{
url = Helpers.CombineURL(S3Settings.Bucket, objectName);
}
}
else
{
url = Helpers.CombineURL(GetEndpoint(), objectName);
}
if (!URLHelpers.HasPrefix(url))
{
url = "http://" + url;
}
return url;
}
public string GetURL(string fileName)
{
return GetObjectURL(GetObjectKey(fileName));
}
private Dictionary GetParameters(string fileName, string objectKey)
{
string policyDocument = GetPolicyDocument(fileName, objectKey);
byte[] policyBytes = Encoding.ASCII.GetBytes(policyDocument);
string signature = CreateSignature(S3Settings.SecretAccessKey, policyBytes);
Dictionary parameters = new Dictionary();
parameters.Add("key", objectKey);
parameters.Add("acl", "public-read");
parameters.Add("content-type", Helpers.GetMimeType(fileName));
parameters.Add("AWSAccessKeyId", S3Settings.AccessKeyID);
parameters.Add("policy", Convert.ToBase64String(policyBytes));
parameters.Add("signature", signature);
parameters.Add("x-amz-storage-class", GetObjectStorageClass());
return parameters;
}
public override UploadResult Upload(Stream stream, string fileName)
{
if (string.IsNullOrEmpty(S3Settings.AccessKeyID)) throw new Exception("'Access Key' must not be empty.");
if (string.IsNullOrEmpty(S3Settings.SecretAccessKey)) throw new Exception("'Secret Access Key' must not be empty.");
if (string.IsNullOrEmpty(S3Settings.Endpoint)) throw new Exception("'Endpoint' must not be emoty.");
if (string.IsNullOrEmpty(S3Settings.Bucket)) throw new Exception("'Bucket' must not be empty.");
string objectKey = GetObjectKey(fileName);
UploadResult uploadResult = UploadData(stream, GetEndpoint(), fileName, arguments: GetParameters(fileName, objectKey), responseType: ResponseType.Headers);
if (uploadResult.IsSuccess)
{
uploadResult.URL = GetObjectURL(objectKey);
}
return uploadResult;
}
}
public class AmazonS3Settings
{
public string AccessKeyID { get; set; }
public string SecretAccessKey { get; set; }
public string Endpoint { get; set; }
public string Bucket { get; set; }
public string ObjectPrefix { get; set; }
public bool UseCustomCNAME { get; set; }
public string CustomDomain { get; set; }
public bool UseReducedRedundancyStorage { get; set; }
}
}