Message-driven mode: httpQuery

The system can also be used to help web-enable legacy applications. This includes the requirement to send message-driven web-queries to remote web servers, and to receive web responses back in the form of messages. These types of interactions are message-driven. Otherwise, a protocol thread is limited to communicating with a single web page.

Other protocol drivers connect to a single remote resource, that is, remote TCP host on a predefined socket port. This provides a constant flow of information. Connecting to a single URL provides only one page of data, thus becoming a stale source of data. Therefore, the driver can connect to various URLs dynamically, as instructed by messages routed from other system threads.

This is performed by passing HTTP-specific information within the message’s metadata. Although it could be passed within the message data itself using metadata, driver data is kept isolated from the message data.