The Art of SQL Server FILESTREAM - Red Gate Software

Chapter 12: Planning, Configuration and Best PracticesAdd a content-type column on FILESTREAM tablesIf you intend to serve the FILESTREAM data from a web application, it may be beneficialto store the appropriate MIME type on each row. When the web application serves theFILESTREAM data to the client, it can set the appropriate content type in the HTTPResponse header. Based on the content type, the client browser/application can open thefile using the appropriate application.In most cases, if you have a column that stores the file extension or file type, you canbuild the content type (such as "application/msword" for Word documents, "image/jpeg"for jpeg images, and so on). But if you deal with a large number of different file types, itmay be a good idea to store the MIME type of the BLOB value stored in each row.Add a timestamp or date column to track lastmodified date for cache controlIf you are serving FILESTREAM data from web applications, caching is an importantfactor to consider. When a client browser and web server communicate over HTTPprotocol, they exchange some caching information. The client tells the server about thecopy of the file locally available (local cache) and the server instructs the client to use thelocal copy or to download a new copy of the file.If the web server tells the client that the file on the server is the same as the copy thatthe client has in the local cache, the file is not downloaded again. Instead, the clientbrowser serves it from the local cache. This significantly enhances the performance ofweb applications.Caching information is exchanged between the client browser/application and web serverusing the HTTP cache headers. The client browser sends the time stamp or etag ofthe file it has in the local cache. After examining the cache header information of the454