Last-Modified header supported for Domino URLs

06 History of changes

Server
Last-Modified header supported for Domino URLs

Domino R5 now sends a Last-Modified header with most Domino responses. This often results in a performance enhancement, since it enables many Web browsers or proxy servers to cache Domino pages.

The HTTP Last-Modified header indicates the date and time that the information in the server response was last modified. For traditional Web servers that store HTML pages and images in the file systems, the Last-Modified time is the last modification time of the file.

Browsers use Last-Modified HTTP header to manage the browser's local cache, depending the user's chosen configuration. Typically, when a user requests a page that is in the browser's cache, the browser sends the page request to the server along with the HTTP header If-Modified-Since, indicating the modification time of the cached page. The server checks the If-Modified-Since header against the time of the page on disk. If the page has not been updated since that time, the server sends back a "Not modified" status code, which informs the browser that it can redisplay the cached page. If the page has been modified, the server sends back the entire new page.

Domino calculates the Last-Modified time for different kinds of requests as follows:

Files in the file system Last-Modified is set to the modification time of the file according to the operating system. This is also supported by Domino R4.5x and R4.6x.

File attachments and other embedded objects in a Domino database Last-Modified is set to the modification time of the document to which the object is attached.

Other Domino database requests Last-Modified is set to the "database modification time", which is the last time that the database was modified (which is essentially the last time any document or design element in the database was modified). The database modification time is displayed in the database properties box.

For these requests, Last-Modified headers are most effective for databases which do not change often such as a help-desk or product-catalog database.

Domino does not send Last-Modified headers in response to the following types of requests:

Pages whose content is dependent on the current time (such a field formula that uses @Now) or whose time dependencies cannot be efficiently determined (for example, a field formula that uses a @DbColumn which references another database)
OpenAgent
OpenNavigator
CreateDocument
EditDocument
SaveDocument
DeleteDocument

Files in the file system	Last-Modified is set to the modification time of the file according to the operating system. This is also supported by Domino R4.5x and R4.6x.
File attachments and other embedded objects in a Domino database	Last-Modified is set to the modification time of the document to which the object is attached.
Other Domino database requests	Last-Modified is set to the "database modification time", which is the last time that the database was modified (which is essentially the last time any document or design element in the database was modified). The database modification time is displayed in the database properties box. For these requests, Last-Modified headers are most effective for databases which do not change often such as a help-desk or product-catalog database.