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
}