private void UpdateFromDependencies(HttpResponse response)
{
CacheDependency dep = null;
if ((this._etag == null) && this._generateEtagFromFiles)
{
dep = response.CreateCacheDependencyForResponse();
if (dep == null)
{
return;
}
string uniqueID = dep.GetUniqueID();
if (uniqueID == null)
{
throw new HttpException(System.Web.SR.GetString("No_UniqueId_Cache_Dependency"));
}
DateTime time = this.UpdateLastModifiedTimeFromDependency(dep);
StringBuilder builder = new StringBuilder(0x100);
builder.Append(HttpRuntime.AppDomainIdInternal);
builder.Append(uniqueID);
builder.Append("+LM");
builder.Append(time.Ticks.ToString(CultureInfo.InvariantCulture));
this._etag = MachineKeySection.HashAndBase64EncodeString(builder.ToString());
this._etag = "\"" + this._etag + "\"";
}
if (this._generateLastModifiedFromFiles)
{
if (dep == null)
{
dep = response.CreateCacheDependencyForResponse();
if (dep == null)
{
return;
}
}
DateTime utcDate = this.UpdateLastModifiedTimeFromDependency(dep);
this.UtcSetLastModified(utcDate);
}
}
/*
* Calculate LastModified and ETag
*
* The LastModified date is the latest last-modified date of
* every file that is added as a dependency.
*
* The ETag is generated by concatentating the appdomain id,
* filenames and last modified dates of all files into a single string,
* then hashing it and Base 64 encoding the hash.
*/
void UpdateFromDependencies(HttpResponse response) {
CacheDependency dep = null;
// if _etag != null && _generateEtagFromFiles == true, then this HttpCachePolicy
// was created from HttpCachePolicySettings and we don't need to update _etag.
if (_etag == null && _generateEtagFromFiles) {
dep = response.CreateCacheDependencyForResponse();
if (dep == null) {
return;
}
string id = dep.GetUniqueID();
if (id == null) {
throw new HttpException(SR.GetString(SR.No_UniqueId_Cache_Dependency));
}
DateTime utcFileLastModifiedMax = UpdateLastModifiedTimeFromDependency(dep);
StringBuilder sb = new StringBuilder(256);
sb.Append(HttpRuntime.AppDomainIdInternal);
sb.Append(id);
sb.Append("+LM");
sb.Append(utcFileLastModifiedMax.Ticks.ToString(CultureInfo.InvariantCulture));
_etag = Convert.ToBase64String(CryptoUtil.ComputeSHA256Hash(Encoding.UTF8.GetBytes(sb.ToString())));
//WOS 1540412: if we generate the etag based on file dependencies, encapsulate it within quotes.
_etag = "\"" + _etag + "\"";
}
if (_generateLastModifiedFromFiles) {
if (dep == null) {
dep = response.CreateCacheDependencyForResponse();
if (dep == null) {
return;
}
}
DateTime utcFileLastModifiedMax = UpdateLastModifiedTimeFromDependency(dep);
UtcSetLastModified(utcFileLastModifiedMax);
}
}