The request URL for retrieving the list of channels for a server has the following form:
/channels/by-server/
<server ID>
/
The
<server ID>
has to be replaced by
the UUID associated with the respective
server.
The request must use the
GET
method.
The response is a JSON object with the
channels
and
statusAvailable
attributes as its members.
The
statusAvailable
attribute is a boolean
indicating whether the list of channels
includes status information
(
true
) or only configuration information
(
false
).
Status information is only available if the specified server
is
online.
The
channels
attribute has an array as its value
that contains an element
for each channel.
Each of these elements is an object with the
following attributes:
| Field name | Internal data type | JSON data type | Description |
|---|---|---|---|
| channelDataId | UUID | string | internal ID for the channel |
| channelName | string | string | channel’s name |
| controlSystemName | string | string | human-readable name of the control-system support used for the channel |
| controlSystemType | string | string | internal identifier for the control-system support used for the channel |
| decimationLevelToRetentionPeriod | map of int to int | object with string attribute values | decimation levels that exist for the channel and their respective retention periods (both specified in seconds) |
| enabled | boolean | boolean |
true
if the channel is enabled,
false
if it is disabled.
|
| errorMessage | string | string |
error message for the channel. May be
null
.
|
| options | map of string to string | object with string attribute values | control-system-specific configuration options that have been specified for the channel (the attribute name is the option name and the attribute value is the option value) |
| state | string | string |
channel’s current state. One of
destroyed
,
disabled
,
disconnected
,
error
,
initializing
,
or
ok
.
null
if status information is not
available.
|
| totalSamplesDropped | long | string |
number of samples that have been dropped for the
channel
(since the last reinitialization).
null
if status information is not
available.
|
| totalSamplesSkippedBack | long | string |
number of samples that were discarded because they
skipped
back in time (since the last reinitialization).
null
if status information is not
available.
|
| totalSamplesWritten | long | string |
number of samples that have been written for the
channel
(since the last reinitialization).
null
if status information is not
available.
|
If the list of channels is currently not available, HTTP error code 503 (service unavailable) is returned and the response body is invalid. If the specified server does not exist, HTTP error code 404 (not found) is returned and the response body is invalid.
Request:
GET /admin/api/1.0/channels/by-server/7cf8f393-cd00-46ae-9343-53e9cb5793fd/
Response:
{
"channels": [
{
"channelDataId": "ef126a63-375b-4f28-a1d1-17e8f42271a9",
"channelName": "someChannel",
"controlSystemName": "Channel Access",
"controlSystemType": "channel_access",
"decimationLevelToRetentionPeriod": {
"0": "864000",
"30": "31536000",
"900": "0"
},
"enabled": true,
"errorMessage": null,
"options": {},
"state": "OK",
"totalSamplesDropped": "0",
"totalSamplesSkippedBack": "1",
"totalSamplesWritten": "42"
},
{
"channelDataId": "0993955f-d16e-486d-ac3b-6a1841c0fd3f",
"channelName": "someOtherChannel",
"controlSystemName": "Channel Access",
"controlSystemType": "channel_access",
"decimationLevelToRetentionPeriod": {"0": "0"},
"enabled": true,
"errorMessage": "Invalid control-system option \"noSuchOption\".",
"options": {
"noSuchOption": "some value"
},
"state": "ERROR",
"totalSamplesDropped": "0",
"totalSamplesSkippedBack": "0",
"totalSamplesWritten": "0"
}
],
statusAvailable: true
}