Best Practices for HTTP Servers
How can web servers be optimised to perform faster? Can resources be cached, compressed, etc. There are a number of HTTP headers that one needs to understand in order to deal with performance optimisations. Last-Modified – Origin server indicates when the resource was believed to have been last modified. Given by both date and time. Etag – Entity tag or unique ID for each version of a resource which is usually comprised of the file-location, file-size and last modified date Expires – Origin server indicates to the browser when the resource becomes stale or how long to keep in cache. Applicable to HTTP/1.0; apparently deprecated in HTTP/1.1 Cache-control – Origin server indicates to the browser and intermediaries whether or not to cache the resource and if to cache, for how long (cache-control:max-age). Applicable to HTTP/1.1 Notice the similarity in some definitions. In practice, Last-Modified and Etag are similar validators and can be grouped together. Expires and ...