public override Task ExecuteAsync(VclHandler handler, RequestContext requestContext, VclContext vclContext)
{
var nextState = handler.VclSynth(vclContext);
SwitchState(handler, nextState);
return(Task.CompletedTask);
}
public override Task ExecuteAsync(VclHandler handler, VclContext vclContext)
{
// Handle case where we exceed number of backend retries
if (++handler._backendAttempt >= handler.MaxBackendRetries)
{
SwitchState(handler, VclBackendAction.Abandon);
return(Task.CompletedTask);
}
// Setup BE request parameters
vclContext.BackendRequest =
new VclBackendRequest
{
Method = vclContext.Request.Method,
Uri = vclContext.Request.Url
};
foreach (var entry in vclContext.Request.Headers)
{
vclContext.BackendRequest.Headers.Add(entry.Key, entry.Value);
}
// TODO: Handle translation of certain request METHOD values
// TODO: Handle filtering out certain HTTP headers
// TODO: Handle adding/modifying certain HTTP headers
// Enter fetch state
SwitchState(handler, VclBackendAction.Fetch);
return(Task.CompletedTask);
}
public override Task ExecuteAsync(VclHandler handler, RequestContext requestContext, VclContext vclContext)
{
// Copy information from object into response
vclContext.Response =
new VclResponse
{
StatusCode = vclContext.Object.StatusCode,
StatusDescription = vclContext.Object.StatusDescription,
};
foreach (var header in vclContext.Object.Headers)
{
vclContext.Response.Headers.Add(header.Key, header.Value);
}
if (vclContext.Object.Body != null)
{
vclContext.Response.CopyBodyFrom(vclContext.Object.Body);
}
// Get result of calling extended code
var nextState = handler.VclDeliver(vclContext);
// Translate official supported action into internal code
if (nextState == VclFrontendAction.Deliver)
{
nextState = VclFrontendAction.DeliverContent;
}
SwitchState(handler, nextState);
return(Task.CompletedTask);
}
public override Task ExecuteAsync(VclHandler handler, VclContext vclContext)
{
// Disconnect backend request/response objects (unless we are in pipe mode)
vclContext.BackendRequest = null;
vclContext.BackendResponse = null;
return(Task.CompletedTask);
}
public override Task ExecuteAsync(VclHandler handler, RequestContext requestContext, VclContext vclContext)
{
// Allow VCL to tweak receive parameters
var nextState = handler.VclReceive(vclContext);
SwitchState(handler, nextState);
return(Task.CompletedTask);
}
protected virtual void SwitchState(VclHandler handler, VclFrontendAction frontendAction)
{
if (!ValidTransitionStates.Contains(frontendAction))
{
throw new InvalidOperationException($"Invalid attempt to transition front-end from {State} to {frontendAction}.");
}
handler.Logger?.LogDebug($"Client state transition from {State} to {frontendAction}");
handler._currentFrontendState = VclFrontendHandlerStateFactory.Get(frontendAction);
}
public override Task ExecuteAsync(VclHandler handler, RequestContext requestContext, VclContext vclContext)
{
// Get result of calling extended code
var nextState = handler.VclError(vclContext);
// Translate official supported action into internal code
if (nextState == VclFrontendAction.Deliver)
{
nextState = VclFrontendAction.DeliverContent;
}
SwitchState(handler, nextState);
return(Task.CompletedTask);
}
public override Task ExecuteAsync(VclHandler handler, RequestContext requestContext, VclContext vclContext)
{
// Attempt to do a lookup given the hash code
var result = handler.Cache.Get <VclObject>($"VclObject:{vclContext.Request.Hash}");
if (result == null)
{
SwitchState(handler, VclFrontendAction.Miss);
}
else
{
vclContext.Object = result;
SwitchState(handler, VclFrontendAction.Hit);
}
return(Task.CompletedTask);
}
public override Task ExecuteAsync(VclHandler handler, RequestContext requestContext, VclContext vclContext)
{
// Setup real response
requestContext.Response.StatusCode = vclContext.Response.StatusCode;
requestContext.Response.ReasonPhrase = vclContext.Response.StatusDescription;
foreach (var header in vclContext.Response.Headers)
{
requestContext.Response.Headers.Add(header.Key, new StringValues(header.Value));
}
// Copy content body if we have one
vclContext.Response.Body?.CopyTo(requestContext.Response.Body);
// TODO: Setup cache TTL value (this uses kernel caching in HTTP.SYS driver)
//requestContext.Response.CacheTtl = TimeSpan.FromSeconds(vclContext.Response.)
SwitchState(handler, VclFrontendAction.Done);
return(Task.CompletedTask);
}
public override Task ExecuteAsync(VclHandler handler, VclContext vclContext)
{
var result = handler.VclBackendResponse(vclContext);
if (result != VclBackendAction.Deliver)
{
SwitchState(handler, result);
}
// Create an object from the response
vclContext.Object =
new VclObject
{
StatusCode = vclContext.BackendResponse.StatusCode,
StatusDescription = vclContext.BackendResponse.StatusDescription,
DoEsiProcessing = vclContext.BackendResponse.DoEsiProcessing,
Uncacheable = vclContext.BackendResponse.Uncacheable,
Ttl = vclContext.BackendResponse.Ttl,
};
foreach (var header in vclContext.BackendResponse.Headers)
{
vclContext.Object.Headers.Add(header.Key, header.Value);
}
if (vclContext.BackendResponse.Body != null)
{
vclContext.Object.CopyBodyFrom(vclContext.BackendResponse.Body);
}
// Handle caching the object if we are allowed to
if (!vclContext.Object.Uncacheable)
{
handler.Cache.Set(
$"VclObject:{vclContext.Request.Hash}",
vclContext.Object,
TimeSpan.FromSeconds(vclContext.Object.Ttl));
}
SwitchState(handler, result);
return(Task.CompletedTask);
}
public override async Task ExecuteAsync(VclHandler handler, RequestContext requestContext, VclContext vclContext)
{
// Instruct backend request to execute
var result = await handler
.ProcessBackendFetchAsync(vclContext)
.ConfigureAwait(false);
// Detect error state and force request restart
if (result == VclBackendAction.Abandon)
{
SwitchState(handler, VclFrontendAction.Restart);
return;
}
// If the result is cachable then do it now
if (!vclContext.BackendResponse.Uncacheable)
{
}
SwitchState(handler, VclFrontendAction.Deliver);
}
public override Task ExecuteAsync(VclHandler handler, RequestContext requestContext, VclContext vclContext)
{
// Update restart count and abort with hard error if we exceed max-retries
vclContext.Request.Restarts++;
if (vclContext.Request.Restarts >= handler.MaxFrontendRetries)
{
vclContext.Response =
new VclResponse
{
StatusCode = 500,
StatusDescription = "IMProxy request failed"
};
SwitchState(handler, VclFrontendAction.Synth);
return(Task.CompletedTask);
}
vclContext.Local.Ip = requestContext.Request.LocalIpAddress;
vclContext.Remote.Ip = requestContext.Request.RemoteIpAddress;
vclContext.Client.Ip = requestContext.Request.RemoteIpAddress;
vclContext.Client.Port = requestContext.Request.RemotePort;
vclContext.Server.HostName = Environment.MachineName;
vclContext.Server.Identity = "foobar";
vclContext.Server.Ip = requestContext.Request.LocalIpAddress;
vclContext.Server.Port = requestContext.Request.LocalPort;
vclContext.Request.Method = requestContext.Request.Method;
vclContext.Request.Url = requestContext.Request.RawUrl;
vclContext.Request.CanGzip =
requestContext.Request.Headers["Accept-Encoding"].Equals("gzip") ||
requestContext.Request.Headers["Accept-Encoding"].Equals("x-gzip");
vclContext.Request.ProtocolVersion = requestContext.Request.ProtocolVersion.ToString(2);
foreach (var header in requestContext.Request.Headers)
{
vclContext.Request.Headers.Add(header.Key, header.Value.ToString());
}
SwitchState(handler, VclFrontendAction.Receive);
return(Task.CompletedTask);
}
public override Task ExecuteAsync(VclHandler handler, VclContext vclContext)
{
return(Task.CompletedTask);
}
public abstract Task ExecuteAsync(VclHandler handler, RequestContext requestContext, VclContext vclContext);
public override async Task ExecuteAsync(VclHandler handler, VclContext vclContext)
{
var result = handler.VclBackendFetch(vclContext);
if (result != VclBackendAction.Fetch)
{
SwitchState(handler, result);
return;
}
// Issue request to backend
var httpClient = new HttpClient();
var backendRequest =
new HttpRequestMessage
{
Method = new HttpMethod(vclContext.BackendRequest.Method),
RequestUri = new Uri(vclContext.BackendRequest.Uri)
};
foreach (var entry in vclContext.BackendRequest.Headers)
{
backendRequest.Headers.Add(entry.Key, entry.Value);
}
// Get raw response from backend
var backendResponse = await httpClient
.SendAsync(backendRequest)
.ConfigureAwait(false);
// Setup VCL backend response
vclContext.BackendResponse =
new VclBackendResponse
{
StatusCode = (int)backendResponse.StatusCode,
StatusDescription = backendResponse.ReasonPhrase
};
foreach (var item in backendResponse.Headers)
{
vclContext.BackendResponse.Headers.Add(item.Key, string.Join(",", item.Value));
}
// Detect backend error
if (!backendResponse.IsSuccessStatusCode)
{
SwitchState(handler, VclBackendAction.Error);
return;
}
// If we have a content body in the response then copy it now
// TODO: May need to steal VirtualStream code that uses MemoryStream until content
// exceeds certain size where it switches to a temporary file
if (backendResponse.Content != null)
{
using (var contentBodyStream = await backendResponse.Content.ReadAsStreamAsync())
{
vclContext.BackendResponse.CopyBodyFrom(contentBodyStream);
}
}
// Setup response TTL value
if (backendResponse.Headers.CacheControl.SharedMaxAge != null)
{
vclContext.BackendResponse.Ttl = (int)backendResponse.Headers.CacheControl.SharedMaxAge.Value.TotalSeconds;
}
else if (backendResponse.Headers.CacheControl.MaxAge != null)
{
vclContext.BackendResponse.Ttl = (int)backendResponse.Headers.CacheControl.MaxAge.Value.TotalSeconds;
}
else if (backendResponse.Headers.TryGetValues("Expires", out var expiryValues))
{
var expiryDate = DateTime.Parse(expiryValues.First());
vclContext.BackendResponse.Ttl = (int)(expiryDate - DateTime.UtcNow).TotalSeconds;
}
else
{
vclContext.BackendResponse.Ttl = handler.DefaultTtl;
}
// Switch state
SwitchState(handler, VclBackendAction.Response);
}
public abstract Task ExecuteAsync(VclHandler handler, VclContext vclContext);