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wise, someone will inadvertently camp on an endlessly cycling server-
push document and choke off other users' access to the server.
Before choosing to implement server-push documents, make sure that
your server can support the added processing and networking load.
Keep in mind that many simultaneous server-push documents may be
active, multiplying the impact on the server and seriously affecting over-
all server performance.
13.3.4. Creating a Server-Push Document
Create a special application that runs with the HTTP server to enable
server-push dynamic documents. The application must create the spe-
cial MIME
Content-Type
header field that notifies the Mozilla browser that
the following document comes in several partsadded to or replacing a
portion of the current document. The application must create the appro-
priate boundary delimiter and send the
Content-Type
header and data
for each part, perhaps also delaying transmission of each part by some
period of time. Consult your server's documentation to learn how to cre-
ate a server-side application that can be invoked by accessing a specific
URL on the server. With some servers, this may be as simple as placing
the application in a certain directory on the server. With others, you may
have to bend over backward and howl at the moon on certain days.
13.3.4.1. Server-push example application for NCSA and Apache
httpd
The National Center for Supercomputing Applications (NCSA) and
Apache httpd servers run on most Unix and Linux systems. Administrat-
ors usually configure the servers to run server-side applications stored
in a directory named
cgi-bin
.
The following is a simple shell script that illustrates how to send a mul-
tipart document to a Netscape or Firefox client via httpd:
[2]
