Server Interfaces

Client interface / telnet

CAPS provides a line based client interface for requesting data and showing available streams. The telnet command may be used to connect to the server:

telnet localhost 18002

The following commands are supported by the server:

  • HELLO - prints server name and version

  • HELP prints descriptive help

  • BYE - disconnects from server

  • AUTH <user> <password> - performs authentication

  • INFO STREAMS [stream id filter] - lists available streams and time spans, see section ref{sec:ci_info_streams}

  • BEGIN REQUEST - starts a request block, followed by request parameters, see section ref{sec:ci_request}

    • REALTIME ON|OFF - enables/disables real-time mode, if disabled the connection is closed if all archive data was sent

    • STREAM ADD|REMOVE <NET.STA.LOC.CHA> - adds/removes a stream from the request, may be repeated in one request block

    • TIME [<starttime>]:[endtime] - defines start and end time of the request, open boundaries are allowed

    • HELI ADD|REMOVE <NET.STA.LOC.CHA> - similar to STREAM but re-sample the data to 1Hz

    • META{@[version]} [ON|OFF] - request delivery of packet header information only

    • OUTOFORDER [ON|OFF] - delivers data in order of sampling or transmission time

    • SEGMENTS [ON|OFF] - request delivery of times of contiguous segments (API >= 4)

    • GAPS [ON|OFF] - request delivery of times of gaps (API >= 4)

    • TOLERANCE [value in us] - Define data segment continuation tolerance in microseconds (API >= 4)

    • RESOLUTION [value in d] - Resolution in days of the returned data segments or gaps (API >= 4)

  • END - finalizes a request and starts acquisition

  • PRINT REQUESTS - prints active request of current session

  • ABORT - aborts current data transmission

Requests to server are separated by a new line. For the response data the server prepends the message length to the data. In this way non ASCII characters or binary content can be returned.

List available streams

The following example shows a telnet conversation of a request for available streams. The first line contains the request command. All other lines represent the server response. The response is 124 characters long. The length parameter is interpreted by telnet and converted to its ASCII representation, in this case: |.

1INFO STREAMS VZ.HILO.*
2|STREAMS
3VZ.HILO.WLS.CAM 2013-07-26T00:00:01 2013-08-02T09:28:17
4VZ.HILO.WLS.SSH 2008-06-06T00:00:00 2013-08-02T09:04:00
5END

Data requests

Data request are initiated by a request block which defines the stream and the time span to fetch.

 1BEGIN REQUEST
 2REALTIME OFF
 3STREAM ADD VZ.HILO.WLS.SSH
 4TIME 2013,08,02,09,00,02:
 5END
 6DSTATUS OK
 7SESSION_TABLE VERSION:1
 8PACKET_HEADER IDSIZE:2,DATASIZE:4
 9FREQUESTS
10ID:1,SID:VZ.HILO.WLS.SSH,SFREQ:1/60,UOM:mm,FMT:RAW/FLOAT
11END
12[unprintable data]
13'REQUESTS
14ID:-1,SID:VZ.HILO.WLS.SSH
15END
16�EOD

The listing above shows such a request block in lines 1-5. Line 2 disables the real-time mode which will close the session after all data was read. Line 3 adds the stream to the request set. More streams may be added in successive lines. Line 4 specifies a start time and an open end time.

The first response chunk starts at line 6 and ends at line 11. I has a length of 68 byte (= ACCII D) and contains version information and a session table. The table maps a 2 byte integer id to data stream meta information. In this way following data chunks can be distinguished by only 2 bytes and the header information has to be transmitted only once.

Line 12 contains the data chunks. It is omitted here because it contains unprintable characters. A data chunk starts with the 2 id bytes followed by the 4 byte chunk size.

After all data was transmitted the server reports the end of the stream (line 13-15) and the end of the session (line 16).

Web interface

CAPS ships with a read-only web interface for viewing information and downloading data. The Web interface is disabled by default and may be enabled by configuring a valid port number under AS.http.port. It provides different tabs:

  • Channels (figure 43): View and filter available streams. For the RAW and miniSEED packets it is also possible to view the waveform data by clicking on a an entry of the stream table.

  • Server stats (figure 44): View server traffic statistics. This tab is only accessible if the logged in user is member of the admin group as defined by AS.auth.basic.users.passwd.

  • Settings (figure 45): Set the login credentials and parameters of the other perspectives.

../_images/web_streams.png

Stream perspective of CAPS Web interface allowing to filter availability streams and to view waveform data for RAW and minSEED records.

../_images/web_overview.png

Overview perspective of CAPS Web interface showing traffic and file statistics.

../_images/web_settings.png

Settings perspective of CAPS Web interface.