/// <summary>
/// Gets UTF-8 text from the given URI.
/// </summary>
/// <param name="res">URI and public key for signature verification</param>
/// <param name="param">Parameters to be sent as <c>application/x-www-form-urlencoded</c> name-value pairs</param>
/// <param name="token">OAuth access token</param>
/// <param name="responseType">Expected response MIME type</param>
/// <param name="previous">Previous content, when refresh is required</param>
/// <param name="ct">The token to monitor for cancellation requests</param>
/// <returns>Content</returns>
public static Response Get(ResourceRef res, NameValueCollection param = null, AccessToken token = null, string responseType = "application/json", Response previous = null, CancellationToken ct = default)
{
// Create request.
var request = WebRequest.Create(res.Uri);
request.CachePolicy = CachePolicy;
request.Proxy = null;
if (token != null)
{
token.AddToRequest(request);
}
if (request is HttpWebRequest httpRequest)
{
httpRequest.UserAgent = UserAgent;
httpRequest.Accept = responseType;
if (previous != null && param != null)
{
httpRequest.IfModifiedSince = previous.Timestamp;
if (previous.ETag != null)
{
httpRequest.Headers.Add("If-None-Match", previous.ETag);
}
}
}
if (param != null)
{
// Send data.
UTF8Encoding utf8 = new UTF8Encoding();
var binBody = Encoding.ASCII.GetBytes(string.Join("&", param.Cast <string>().Select(e => string.Format("{0}={1}", HttpUtility.UrlEncode(e, utf8), HttpUtility.UrlEncode(param[e], utf8)))));
request.Method = "POST";
request.ContentType = "application/x-www-form-urlencoded";
request.ContentLength = binBody.Length;
try
{
using (var requestStream = request.GetRequestStream())
requestStream.Write(binBody, 0, binBody.Length, ct);
}
catch (WebException ex) { throw new AggregateException(Resources.Strings.ErrorUploading, ex.Response is HttpWebResponse ? new WebExceptionEx(ex, ct) : ex); }
}
ct.ThrowIfCancellationRequested();
// Wait for data to start comming in.
WebResponse response;
try { response = request.GetResponse(); }
catch (WebException ex)
{
// When the content was not modified, return the previous one.
if (ex.Response is HttpWebResponse httpResponse)
{
if (httpResponse.StatusCode == HttpStatusCode.NotModified)
{
previous.IsFresh = false;
return(previous);
}
throw new WebExceptionEx(ex, ct);
}
throw new AggregateException(Resources.Strings.ErrorDownloading, ex);
}
ct.ThrowIfCancellationRequested();
using (response)
{
// Read the data.
var data = new byte[0];
using (var stream = response.GetResponseStream())
{
var buffer = new byte[1048576];
for (; ;)
{
// Read data chunk.
var count = stream.Read(buffer, 0, buffer.Length, ct);
if (count == 0)
{
break;
}
// Append it to the data.
var newData = new byte[data.LongLength + count];
Array.Copy(data, newData, data.LongLength);
Array.Copy(buffer, 0, newData, data.LongLength, count);
data = newData;
}
}
if (res.PublicKeys != null)
{
// Generate signature URI.
var uriBuilderSig = new UriBuilder(res.Uri);
uriBuilderSig.Path += ".minisig";
// Create signature request.
request = WebRequest.Create(uriBuilderSig.Uri);
request.CachePolicy = CachePolicy;
request.Proxy = null;
if (token != null)
{
token.AddToRequest(request);
}
if (request is HttpWebRequest httpRequestSig)
{
httpRequestSig.UserAgent = UserAgent;
httpRequestSig.Accept = "text/plain";
}
// Read the Minisign signature.
byte[] signature = null;
try
{
using (var responseSig = request.GetResponse())
using (var streamSig = responseSig.GetResponseStream())
{
ct.ThrowIfCancellationRequested();
using (var readerSig = new StreamReader(streamSig))
{
foreach (var l in readerSig.ReadToEnd(ct).Split(new string[] { "\r\n", "\n" }, StringSplitOptions.RemoveEmptyEntries))
{
if (l.Trim().StartsWith($"untrusted comment:"))
{
continue;
}
signature = Convert.FromBase64String(l);
break;
}
if (signature == null)
{
throw new SecurityException(string.Format(Resources.Strings.ErrorInvalidSignature, res.Uri));
}
}
}
}
catch (WebException ex) { throw new AggregateException(Resources.Strings.ErrorDownloadingSignature, ex.Response is HttpWebResponse ? new WebExceptionEx(ex, ct) : ex); }
ct.ThrowIfCancellationRequested();
// Verify Minisign signature.
using (var s = new MemoryStream(signature, false))
using (var r = new BinaryReader(s))
{
if (r.ReadChar() != 'E')
{
throw new ArgumentException(Resources.Strings.ErrorUnsupportedMinisignSignature);
}
byte[] payload;
switch (r.ReadChar())
{
case 'd': // PureEdDSA
payload = data;
break;
case 'D': // HashedEdDSA
payload = new eduEd25519.BLAKE2b(512).ComputeHash(data);
break;
default:
throw new ArgumentException(Resources.Strings.ErrorUnsupportedMinisignSignature);
}
ulong keyId = r.ReadUInt64();
if (!res.PublicKeys.ContainsKey(keyId))
{
throw new SecurityException(Resources.Strings.ErrorUntrustedMinisignPublicKey);
}
var sig = new byte[64];
if (r.Read(sig, 0, 64) != 64)
{
throw new ArgumentException(Resources.Strings.ErrorInvalidMinisignSignature);
}
using (eduEd25519.ED25519 key = new eduEd25519.ED25519(res.PublicKeys[keyId]))
if (!key.VerifyDetached(payload, sig))
{
throw new SecurityException(string.Format(Resources.Strings.ErrorInvalidSignature, res.Uri));
}
}
}
return
(response is HttpWebResponse webResponse ?
new Response()
{
Value = Encoding.UTF8.GetString(data),
Timestamp = DateTime.TryParse(webResponse.GetResponseHeader("Last-Modified"), out var timestamp) ? timestamp : default,
public static Response Get(Uri uri, NameValueCollection param = null, AccessToken token = null, string response_type = "application/json", byte[] pub_key = null, CancellationToken ct = default(CancellationToken), Response previous = null)
{
// Create request.
var request = WebRequest.Create(uri);
request.CachePolicy = CachePolicy;
request.Proxy = null;
if (token != null)
{
token.AddToRequest(request);
}
if (request is HttpWebRequest request_http)
{
request_http.UserAgent = UserAgent;
request_http.Accept = response_type;
if (previous != null && param != null)
{
request_http.IfModifiedSince = previous.Timestamp;
if (previous.ETag != null)
{
request_http.Headers.Add("If-None-Match", previous.ETag);
}
}
}
if (param != null)
{
// Send data.
UTF8Encoding utf8 = new UTF8Encoding();
var body_binary = Encoding.ASCII.GetBytes(String.Join("&", param.Cast <string>().Select(e => String.Format("{0}={1}", HttpUtility.UrlEncode(e, utf8), HttpUtility.UrlEncode(param[e], utf8)))));
request.Method = "POST";
request.ContentType = "application/x-www-form-urlencoded";
request.ContentLength = body_binary.Length;
try
{
using (var stream_req = request.GetRequestStream())
{
var task = stream_req.WriteAsync(body_binary, 0, body_binary.Length, ct);
try { task.Wait(ct); }
catch (AggregateException ex) { throw ex.InnerException; }
}
}
catch (WebException ex) { throw new AggregateException(Resources.Strings.ErrorUploading, ex); }
}
ct.ThrowIfCancellationRequested();
// Wait for data to start comming in.
WebResponse response;
try { response = request.GetResponse(); }
catch (WebException ex)
{
// When the content was not modified, return the previous one.
if (ex.Response is HttpWebResponse response_http)
{
if (response_http.StatusCode == HttpStatusCode.NotModified)
{
previous.IsFresh = false;
return(previous);
}
// Create our own version of the exception, which will contain the body of response as text.
throw new WebExceptionEx(ex, ct);
}
else
{
throw new AggregateException(Resources.Strings.ErrorDownloading, ex);
}
}
ct.ThrowIfCancellationRequested();
using (response)
{
// Read the data.
var data = new byte[0];
using (var stream = response.GetResponseStream())
{
var buffer = new byte[1048576];
for (; ;)
{
// Read data chunk.
var task = stream.ReadAsync(buffer, 0, buffer.Length, ct);
try { task.Wait(ct); }
catch (AggregateException ex) { throw ex.InnerException; }
if (task.Result == 0)
{
break;
}
// Append it to the data.
var data_new = new byte[data.LongLength + task.Result];
Array.Copy(data, data_new, data.LongLength);
Array.Copy(buffer, 0, data_new, data.LongLength, task.Result);
data = data_new;
}
}
if (pub_key != null)
{
// Generate signature URI.
var builder_sig = new UriBuilder(uri);
builder_sig.Path += ".sig";
// Create signature request.
request = WebRequest.Create(builder_sig.Uri);
request.CachePolicy = CachePolicy;
request.Proxy = null;
if (token != null)
{
token.AddToRequest(request);
}
if (request is HttpWebRequest request_http_sig)
{
request_http_sig.UserAgent = UserAgent;
request_http_sig.Accept = "application/pgp-signature";
}
// Read the signature.
byte[] signature = null;
using (var response_sig = request.GetResponse())
using (var stream_sig = response_sig.GetResponseStream())
{
ct.ThrowIfCancellationRequested();
using (var reader_sig = new StreamReader(stream_sig))
{
var task = reader_sig.ReadToEndAsync();
try { task.Wait(ct); }
catch (AggregateException ex) { throw ex.InnerException; }
signature = Convert.FromBase64String(task.Result);
}
}
ct.ThrowIfCancellationRequested();
// Verify signature.
using (eduEd25519.ED25519 key = new eduEd25519.ED25519(pub_key))
if (!key.VerifyDetached(data, signature))
{
throw new System.Security.SecurityException(String.Format(Resources.Strings.ErrorInvalidSignature, uri));
}
}
return
(response is HttpWebResponse response_web ?
new Response()
{
Value = Encoding.UTF8.GetString(data),
Timestamp = DateTime.TryParse(response_web.GetResponseHeader("Last-Modified"), out var _timestamp) ? _timestamp : default(DateTime),
ETag = response_web.GetResponseHeader("ETag"),
IsFresh = true
} :