http CacheOptions property
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Applies to
WinHTTP component.  

Declaration
type  
  TWinCacheOption  = (coAlwaysReload, coReloadIfNoExpireInformation,  
                      coReloadUpdatedObjects, coPragmaNoCache,  
                      coNoCacheWrite, coCreateTempFilesIfCantCache,  
                      coUseCacheIfNetFail);  
  TWinCacheOptions = set of TWinCacheOption;  
 
property CacheOptions: TWinCacheOptions;  

Description
The CacheOptions property controls the cache options for the WinHTTP component and determines how the component should use standard Internet Explorer's cache.  
 
The cache control has following options:  
ValueMeaning  
coAlwaysReloadForces a download of the requested file, object, or directory listing from the origin server, not from the cache.;  
coReloadIfNoExpireInformationForces a reload if there was no Expires time and no LastModified time returned from the server when determining whether to reload the item from the network.;  
coReloadUpdatedObjectsReloads HTTP resources if the resource has been modified since the last time it was downloaded;  
coPragmaNoCacheForces the request to be resolved by the origin server, even if a cached copy exists on the proxy;  
coNoCacheWriteDoes not add the downloaded entity to the cache;  
coCreateTempFilesIfCantCacheCauses a temporary file to be created if the file cannot be cached. iiwarning Note: since secure pages won't be cached, this option is always False when downloading document by HTTPS protocol;;  
coUseCacheIfNetFailReturns the resource from the cache if the network request for the resource fails due if connection with the server has been reset, or the attempt to connect to the server failed.  

See also
InternetOptions property;  
Read method; OnHeaderInfo event.