Retrieval Documentation

HTTP API documentation

This API follows the common convention that the addition of a key to a json object is not considered a breaking change.

Currently available:

• Query binned data
• Search channel

Query binned data

Method: GET

URL: http://sf-daqbuf-21:8380/api/4/binned

Query parameters:

• channel_backend (e.g. "sf-databuffer")
• channel_name (e.g. "SLAAR-LSCP4-LAS6891:CH7:1")
• beg_date (e.g. "2021-05-26T07:10:00.000Z")
• end_date (e.g. "2021-05-26T07:16:00.000Z")
• bin_count (e.g. "6")

Request header: "Accept" must be "application/json"

CURL example:

curl -H 'Accept: application/json' 'http://sf-daqbuf-21:8380/api/4/binned?channel_backend=sf-databuffer
  &channel_name=SLAAR-LSCP4-LAS6891:CH7:1&beg_date=2021-05-25T00:00:00.000Z&end_date=2021-05-26T00:00:00.000Z&bin_count=3'

Partial result

If the requested range takes longer time to retrieve, then a partial result with at least one bin is returned.

The partial result will contain the necessary information to send another request with a range that starts with the first missing bin.

This information is provided by the continue_at and missing_bins fields.

This enables the user agent to start the presentation to the user while updating the UI as new bins are retrieved.

Example:

{
  "continue_at": "2021-05-25T16:00:00.000Z",
  "missing_bins": 2,
  "avgs": [
    340.87640380859375,
    340.7442321777344,
    340.58685302734375,
    341.04608154296875
  ],
  "counts": [
    143076,
    143077,
    143076,
    143076
  ],
  "maxs": [
    452,
    452,
    459,
    458
  ],
  "mins": [
    231,
    240,
    239,
    239
  ],
  "ts_bin_edges": [
    "2021-05-25T00:00:00.000Z",
    "2021-05-25T04:00:00.000Z",
    "2021-05-25T08:00:00.000Z",
    "2021-05-25T12:00:00.000Z",
    "2021-05-25T16:00:00.000Z"
  ]
}

Complete result

A complete result will not have a continue_at key.

Finalised range

If the server can determine that no more data will be added to the requested time range then it will add the flag finalised_range: true to the response.

Search channel

Method: GET

URL: http://sf-daqbuf-21:8380/api/4/search/channel

Query parameters:

• nameRegex (e.g. "LSCP.*6")
• sourceRegex (e.g. "178:9999")
• descriptionRegex (e.g. "celsius")

Request header: "Accept" must be "application/json"

CURL example:

curl -H 'Accept: application/json' 'http://sf-daqbuf-21:8380/api/4/search/channel?sourceRegex=CV.E.+37&nameRegex=120.+y2$'

Example result

{
  "channels": [
    {
      "name": "S10MA01-DBPM120:Y2",
      "source": "tcp://S20-CVME-DBPM2371:9000",
      "type": "Float32",
      "shape": [],
      "unit": "",
      "description": ""
    },
    {
      "name": "S20SY02-DBPM120:Y2",
      "source": "tcp://S20-CVME-DBPM2371:9000",
      "type": "Float32",
      "shape": [],
      "unit": "",
      "description": ""
    }
  ]
}

Feedback and comments very much appreciated!

dominik.werder@psi.ch

or please assign me a JIRA ticket.