External Web

The Web server also supports the browser local caching of Web pages stored on SD Card at the Web server. In general the files on SD Card are bigger, and so the performance gain, much better. The space, available for Internal Web pages is limited with the size of internal flash memory. So all large images, java script archives and other large web resources, have to be located on externally attached SD Card.

Static Web Resources

The static web resource files are copied to SD Card when the application is built and are not modified later. You might use the SD Card Reader attached to PC to copy the files. In this case, the file modification date is set correctly by the PC. If you use an embedded application to copy the files, the file modification date is most likely set to the FlashFS default time. This however does not create any problems in browser local caching. Once the web is locally cached by the browser, the cache is always valid and is used in subsequent browser requests.

Using Web Update

Web resource files, which are updated later with one of the update options provided by RL-TCPnet, are dynamic Web resource files. You must provide the file modification date and time to the Flash File System. If this information is not available, the FlashFS uses a default file modification time. This might create troubles in local caching by the browser.

If you upload an updated web page to the server, but the FlashFS adds a default file modification date, the Web server is not able to recognize the updated files. It always reports the same Last-Modified date. The the browser then uses locally cached, but outdated web resources instead of the updated ones.

To load the updated web page in the browser, you have to manually clear the cache in the browser first and then reload the web page again.

• If the FlashFS does not have a Real Time Clock information, the Web Server will not work for updated Web pages.