public async Task <CachedObjectResult> GetObjectFromCache(CdnFileObject fileObject)
{
var fileName = $"{BaseCacheFolder}\\{fileObject.Id}.{fileObject.VersionId}";
var result = new CachedObjectResult();
//Get fileObject in current server
var currentServerfileObject = await _fileObjectRepository.GetObjectByKeyAsync(fileObject.Id, 0, _cdnOptions.Server.Id);
if (currentServerfileObject != null)
{
currentServerfileObject.LastAccess = DateTime.Now;
await _fileObjectRepository.UpdateObjectAsync(currentServerfileObject);
result.IsSuccess = true;
result.FileStream = File.OpenRead(fileName);
return(result);
}
//if object was not previously cached and no space for downloading...
if (Startup.CdnServer.FreeSpace < fileObject.Size)
{
result.IsSuccess = false;
result.Exception = new NoFreeSpaceException();
return(result);
}
//Get nearest origin server
var server = await _cdnServerService.GetNearestServerAsync(_cdnOptions.Server.Longitude,
_cdnOptions.Server.Latitude,
CdnServerRole.OriginServer);
var fileUrl = $@"{server.Host.Trim()}/api/download/{fileObject.Id}/{fileObject.VersionId}";
//Download file object and save it locally...
using (var client = new HttpClient())
{
//Hard code auth token...
client.DefaultRequestHeaders.Authorization = new AuthenticationHeaderValue("Bearer", "49ec97b507cc21806861817f2f0564d4");
using (var response = await client.GetAsync(fileUrl))
using (var fileStream = File.Create(fileName))
{
await response.Content.CopyToAsync(fileStream);
}
}
fileObject.ServerId = _cdnOptions.Server.Id;
fileObject.LastAccess = DateTime.Now;
await _fileObjectRepository.AddObjectAsync(fileObject);
result.IsSuccess = true;
result.FileStream = File.OpenRead(fileName);
return(result);
}
public async Task <IActionResult> LoadObject([FromQuery(Name = "lg")] double longitude,
[FromQuery(Name = "lt")] double latitude)
{
var objectKey = Request.Path.ToString().TrimStart('/');
//Check if object exists at all
var fileObject = await _fileObjectRepository.GetObjectByKeyAsync(objectKey);
if (fileObject == null)
{
return(NotFound());
}
var result = await _objectCacheService.GetObjectFromCache(fileObject);
if (!result.IsSuccess)
{
switch (result.Exception)
{
//If no space, just redirect to another nearest Cache server
case NoFreeSpaceException _:
var server = await _cdnServerService.GetNearestServerAsync(longitude,
latitude,
CdnServerRole.CacheServer,
new List <int> {
_cdnOptions.Server.Id
});
return(Redirect($"{server.Host.Trim()}{Request.Path}?lg={longitude}<={latitude}"));
default:
//Rethrow all other errors
throw result.Exception;
}
}
return(File(result.FileStream, "application/octet-stream", objectKey));
}
public Task <CdnServer> SelectNearestServerAsync(double longitude, double latitude)
{
return(_cdnServerService.GetNearestServerAsync(longitude, latitude, CdnServerRole.CacheServer));
}