Overview

This is an interface to push data to the Xively cloud-based service.

The initial implementation of <ctl_xively.h> is somewhat inspired by, and takes some direction from, the existing C and mbed APIs offered by Xively. However, we believe that the existing API implementations are not sufficiently balanced for small systems. The existing mbed API has a number of shortcomings:

• It uses static buffers and a configuration header file to size them. It builds the static buffers into the implementation, where necessary, and repurposes the C API, based on dynamic allocation, using them.
• Datastreams and datapoint arrays are statically allocated as a matrix and very large. Every datastream contains the same number of datapoints, irrespective of the datapoint production rate.
• There is no capability to queue data to be sent to Xively and the API is not thread safe.

The CrossWorks Xively API is more flexible, uses memory in a more efficient manner, and supports posting datapoints to queues from interrupt service routines or from threads.

API Summary

API
CTL_XIVELY_API_t	Xively API context
ctl_xively_api_initialize_http_csv	Initialize API context
Feeds
CTL_XIVELY_FEED_ID_t	Feed identifier
CTL_XIVELY_FEED_t	Feed controller
ctl_xively_feed_has_pending_data	Outstanding data?
ctl_xively_feed_register_datastream	Register datastream
ctl_xively_feed_update	Push feed data to Xively
Datastreams
CTL_XIVELY_DATASTREAM_t	Datastream buffer
ctl_xively_datastream_create	Create datastream
ctl_xively_datastream_delete	Delete datastream from server
ctl_xively_datastream_initialize	Initialize datastream
ctl_xively_datastream_post	Post datapoint to a datastream
ctl_xively_datastream_update	Single-point datastream update
Datapoints
CTL_XIVELY_DATAPOINT_VALUE_t	Datapoint value
CTL_XIVELY_DATAPOINT_t	Datapoint
CTL_XIVELY_VALUE_TYPE_t	Datapoint value type
ctl_xively_datapoint_delete	Delete datapoint from server
ctl_xively_datapoint_delete_range	Delete datapoints from server
ctl_xively_datapoint_write_float	Initialize floating datapoint
ctl_xively_datapoint_write_int	Initialize integer datapoint
ctl_xively_datapoint_write_stamped_float	Initialize timestamped floating datapoint
ctl_xively_datapoint_write_stamped_int	Initialize timestamped integer datapoint
Utility
ctl_xively_register_error_decoder	Register Xively error decoder