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public static ResponseNotHandled ( ) : |
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| return | ||
public async Task <ResponseHandlerResult> HandleResponseAsync(HttpContextBase context, IResponse suggestedResponse, ICache cache, string cacheKey)
{
context.ThrowIfNull("context");
suggestedResponse.ThrowIfNull("suggestedResponse");
StatusAndSubStatusCode statusCode = suggestedResponse.StatusCode;
if (!_statusCodes.Contains(statusCode))
{
return(ResponseHandlerResult.ResponseNotHandled());
}
AcceptHeader[] acceptHeaders = AcceptHeader.ParseMany(context.Request.Headers["Accept"]).ToArray();
if (acceptHeaders.Any() && !acceptHeaders.Any(arg => arg.MediaTypeMatches("text/html")))
{
return(ResponseHandlerResult.ResponseNotHandled());
}
const string format = @"<!DOCTYPE html>
<html>
<head>
<title>{0}</title>
<style>h1 {{ margin: 0; padding: 0; }}</style>
</head>
<body>
<h1>{0}</h1>
<hr/>
HTTP {1}{2}
</body>
</html>";
Response response = new Response(statusCode)
.TextHtml()
.Content(String.Format(format, statusCode.StatusDescription, statusCode.StatusCode, statusCode.SubStatusCode == 0 ? "" : "." + statusCode.SubStatusCode));
response.CachePolicy.NoClientCaching();
await new CacheResponse(response).WriteResponseAsync(context.Response);
context.Response.TrySkipIisCustomErrors = true;
return(ResponseHandlerResult.ResponseWritten());
}
public async Task <ResponseHandlerResult> HandleResponseAsync(HttpContextBase context, IResponse suggestedResponse, ICache cache, string cacheKey)
{
context.ThrowIfNull("context");
suggestedResponse.ThrowIfNull("suggestedResponse");
StatusAndSubStatusCode statusCode = suggestedResponse.StatusCode;
if (!_statusCodes.Contains(statusCode))
{
return(ResponseHandlerResult.ResponseNotHandled());
}
AcceptHeader[] acceptHeaders = AcceptHeader.ParseMany(context.Request.Headers["Accept"]).ToArray();
if (acceptHeaders.Any() && !acceptHeaders.Any(arg => arg.MediaTypeMatches("text/plain")))
{
return(ResponseHandlerResult.ResponseNotHandled());
}
string content = String.Format(
"HTTP {0}{1} {2}",
statusCode.StatusCode,
statusCode.SubStatusCode == 0 ? "" : "." + statusCode.SubStatusCode.ToString(CultureInfo.InvariantCulture),
statusCode.StatusDescription.Length > 0 ? String.Format("({0})", statusCode.StatusDescription) : "");
Response response = new Response(statusCode)
.TextPlain()
.Content(content);
response.CachePolicy.NoClientCaching();
await new CacheResponse(response).WriteResponseAsync(context.Response);
context.Response.TrySkipIisCustomErrors = true;
return(ResponseHandlerResult.ResponseWritten());
}
public async Task <ResponseHandlerResult> HandleResponseAsync(HttpContextBase context, IResponse suggestedResponse, ICache cache, string cacheKey)
{
context.ThrowIfNull("context");
suggestedResponse.ThrowIfNull("suggestedResponse");
if (!suggestedResponse.CachePolicy.HasPolicy || cache == null || cacheKey == null)
{
return(ResponseHandlerResult.ResponseNotHandled());
}
CacheItem cacheItem = await cache.GetAsync(cacheKey);
string responseETag = suggestedResponse.CachePolicy.ETag;
#region If-Match precondition header
IfMatchHeader[] ifMatchHeaders = IfMatchHeader.ParseMany(context.Request.Headers["If-Match"]).ToArray();
// Only consider If-Match headers if response status code is 2xx or 412
if (ifMatchHeaders.Any() && ((suggestedResponse.StatusCode.StatusCode >= 200 && suggestedResponse.StatusCode.StatusCode <= 299) || suggestedResponse.StatusCode.StatusCode == 412))
{
// Return 412 if no If-Match header matches the response ETag
// Return 412 if an "If-Match: *" header is present and the response has no ETag
if (ifMatchHeaders.All(arg => arg.EntityTag.Value != responseETag) ||
(responseETag == null && ifMatchHeaders.Any(arg => arg.EntityTag.Value == "*")))
{
return(await WriteResponseAsync(context.Response, new Response().PreconditionFailed()));
}
}
#endregion
#region If-None-Match precondition header
IfNoneMatchHeader[] ifNoneMatchHeaders = IfNoneMatchHeader.ParseMany(context.Request.Headers["If-None-Match"]).ToArray();
if (ifNoneMatchHeaders.Any())
{
// Return 304 if an If-None-Match header matches the response ETag and the request method was GET or HEAD
// Return 304 if an "If-None-Match: *" header is present, the response has an ETag and the request method was GET or HEAD
// Return 412 if an "If-None-Match: *" header is present, the response has an ETag and the request method was not GET or HEAD
if (ifNoneMatchHeaders.Any(arg => arg.EntityTag.Value == responseETag) ||
(ifNoneMatchHeaders.Any(arg => arg.EntityTag.Value == "*") && responseETag != null))
{
if (String.Equals(context.Request.HttpMethod, "GET", StringComparison.OrdinalIgnoreCase) || String.Equals(context.Request.HttpMethod, "HEAD", StringComparison.OrdinalIgnoreCase))
{
if (cacheItem != null)
{
cacheItem.Response.CachePolicy.Apply(context.Response.Cache);
}
else
{
suggestedResponse.CachePolicy.Apply(context.Response.Cache);
}
return(await WriteResponseAsync(context.Response, new Response().NotModified()));
}
return(await WriteResponseAsync(context.Response, new Response().PreconditionFailed()));
}
}
#endregion
#region If-Modified-Since precondition header
IfModifiedSinceHeader ifModifiedSinceHeader = IfModifiedSinceHeader.Parse(context.Request.Headers["If-Modified-Since"]);
bool validIfModifiedSinceHttpDate = ifModifiedSinceHeader != null && ifModifiedSinceHeader.HttpDate <= _systemClock.UtcDateTime;
// Only consider an If-Modified-Since header if response status code is 200 and the HTTP-date is valid
if (suggestedResponse.StatusCode.ParsedStatusCode == HttpStatusCode.OK && validIfModifiedSinceHttpDate)
{
// Return 304 if the response was cached before the HTTP-date
if (cacheItem != null && cacheItem.CachedUtcTimestamp < ifModifiedSinceHeader.HttpDate)
{
return(await WriteResponseAsync(context.Response, new Response().NotModified()));
}
}
#endregion
#region If-Unmodified-Since precondition header
IfUnmodifiedSinceHeader ifUnmodifiedSinceHeader = IfUnmodifiedSinceHeader.Parse(context.Request.Headers["If-Unmodified-Since"]);
bool validIfUnmodifiedSinceHttpDate = ifUnmodifiedSinceHeader != null && ifUnmodifiedSinceHeader.HttpDate <= _systemClock.UtcDateTime;
// Only consider an If-Unmodified-Since header if response status code is 2xx or 412 and the HTTP-date is valid
if (((suggestedResponse.StatusCode.StatusCode >= 200 && suggestedResponse.StatusCode.StatusCode <= 299) || suggestedResponse.StatusCode.StatusCode == 412) && validIfUnmodifiedSinceHttpDate)
{
// Return 412 if the previous response was removed from the cache or was cached again at a later time
if (cacheItem == null || cacheItem.CachedUtcTimestamp >= ifUnmodifiedSinceHeader.HttpDate)
{
return(await WriteResponseAsync(context.Response, new Response().PreconditionFailed()));
}
}
#endregion
#region No server caching
// Do not cache the response when the response sends a non-cacheable status code, or when an Authorization header is present
if (!_cacheableStatusCodes.Contains(suggestedResponse.StatusCode) || context.Request.Headers["Authorization"] != null)
{
return(await WriteResponseAsync(context.Response, suggestedResponse));
}
CacheControlHeader cacheControlHeader = CacheControlHeader.Parse(context.Request.Headers["Cache-Control"]);
// Do not cache the response if a "Cache-Control: no-cache" or "Cache-Control: no-store" header is present
if (cacheControlHeader != null && (cacheControlHeader.NoCache || cacheControlHeader.NoStore))
{
return(await WriteResponseAsync(context.Response, suggestedResponse));
}
IEnumerable <PragmaHeader> pragmaHeader = PragmaHeader.ParseMany(context.Request.Headers["Pragma"]);
// Do not cache the response if a "Pragma: no-cache" header is present
if (pragmaHeader.Any(arg => String.Equals(arg.Name, "no-cache", StringComparison.OrdinalIgnoreCase)))
{
return(await WriteResponseAsync(context.Response, suggestedResponse));
}
#endregion
// Return 504 if the response has not been cached but the client is requesting to receive only a cached response
if (cacheItem == null && cacheControlHeader != null && cacheControlHeader.OnlyIfCached)
{
return(await WriteResponseAsync(context.Response, new Response().GatewayTimeout()));
}
if (cacheItem != null)
{
// Write the cached response if no Cache-Control header is present
// Write the cached response if a "Cache-Control: max-age" header is validated
// Write the cached response if a "Cache-Control: max-stale" header is validated
// Write the cached response if a "Cache-Control: min-fresh" header is validated
if (cacheControlHeader == null ||
_systemClock.UtcDateTime - cacheItem.CachedUtcTimestamp <= cacheControlHeader.MaxAge ||
cacheControlHeader.OnlyIfCached ||
cacheItem.ExpiresUtcTimestamp == null ||
_systemClock.UtcDateTime - cacheItem.ExpiresUtcTimestamp.Value <= cacheControlHeader.MaxStale ||
cacheItem.ExpiresUtcTimestamp.Value - _systemClock.UtcDateTime < cacheControlHeader.MinFresh)
{
return(await WriteResponseInCacheAsync(context.Response, cacheItem));
}
}
bool cacheOnServer = suggestedResponse.CachePolicy.AllowsServerCaching;
var cacheResponse = new CacheResponse(suggestedResponse);
if (cacheOnServer)
{
DateTime expirationUtcTimestamp = suggestedResponse.CachePolicy.ServerCacheExpirationUtcTimestamp != null
? suggestedResponse.CachePolicy.ServerCacheExpirationUtcTimestamp.Value
: _systemClock.UtcDateTime + suggestedResponse.CachePolicy.ServerCacheMaxAge.Value;
await cache.AddAsync(cacheKey, cacheResponse, expirationUtcTimestamp);
}
return(await WriteResponseAsync(context.Response, cacheResponse));
}