This section describes the HTTPD agent. This is a collection agent for real-time workflow configurations.
It also includes APL functions for connecting a client to an external HTTP server.
Prerequisites
The reader of this information should be familiar with:
Hypertext Transfer Protocol version 1.1 (RFC 2616: http://www.ietf.org/rfc/rfc2616.txt)
- The Transport Layer Security (TLS) Protocol version 1.2 (RFC 5246: https://www.ietf.org/rfc/rfc5246.txt)
The HTTPD agent (in combination with Analysis or Aggregation agents) can act as a web server, receiving requests and sending responses on a TCP/IP connection. The requests are turned into UDRs, using the standard Hypertext Transfer Protocol, and inserted into a workflow.
When a workflow acting as a web server is started, the HTTPD agent opens a port for listening and awaits a request. The workflow remains active until manually stopped. In addition, the agent offers the possibility to use an encrypted communication setup through SSL.
Note!
To fully support HTTP pipelining, you must add the property ec.httpd.ordered.response
with the value true
to the configuration file for the EC/ECSA. If this property is set to true
, responses will be guaranteed to be sent in the same order as the pipelined requests were received. For further information on how to add a property to a pico configuration file, see Updating Pico Configurations.
To ensure that a request is not blocking responses from being sent for too long, the Server Timeout (sec) should be configured. If a response is not sent for a request within the specified time, the response for the next request will be sent.
This property should not be set unless support for pipelining is required!
Setting this property to true
will also have some effect on the performance since the requests will be cached until the responses have been sent.
The section contains the following subsections: