Server Mode

QuatView includes a TCP server mode that provides the capability to communicate with client programs running on remote computers. The QuatView server can receive and display a serialized binary data stream of quaternion history data from any client program that transmits the data in the recognized format. Server mode is similar to playback mode except that playback mode reads and displays the quaternion data from a local file while server mode reads and displays the quaternion data from a remote computer via a TCP network connection.

Pressing the Listen link will display the Server dialog as shown in Figure 16. This dialog allows the user to enable or disable the server. It also allows the user to specify the server IP address and port, the IO timeout, and a directory for the optional log file.

The IO timeout is the amount of time that the server will wait between quaternion messages before giving up and assuming a bad connection. This timeout only applies after the first successful quaternion message is received. The QuatView server will wait indefinitely for a client connection, and it will wait indefinitely for the first message from a connected client. However, after the first message is received, it will wait no longer than the IO timeout value before subsequent messages. The default timeout value is 10 seconds. This timeout value can be decreased to as low as 1 second or increased to any higher value. When the timeout between quaternion messages is exceeded the server will behave as if it received a stop message from the client. It will then reset its message counter to zero, close the optional log file, and then wait again indefinitely to receive another first message from the client.

The On/Off radio buttons on the Server dialog allow the user to request that a log file be written to record all of quaternion data received by the Server. The user can specify the directory for the log file by typing in a directory path or pressing the "Set Path" link button. The log file itself will be automatically named according to the following naming convention:

where YYYY, MM, and DD are the year, month, and day respectively, and HH, MM, and SS are the hour minute and second respectively in universal coordinated time. The log file is formatted as 5 tab-delimited columns with a single header line that specifies the QuatView version along with the date and time stamp for the file creation.

Once server mode has been enabled, the GUI becomes read-only and is ready to start displaying the quaternion data received from the client application. This means that no user input is allowed for the Euler angles or the quaternion components since the quaternion input data will come from the client network stream The conversion tab is also disabled so that no other GUI input can interfere with the server. Figure 17 shows how the GUI looks in server mode.

The server state is indicated by the two lights at the lower left. The left light indicates the connection status and the right light indicates the reception status. If the connection light is green then an active client connection exists. If the reception light is green, then the server is actively receiving quaternion messages. The message format is defined by the QuatMessage class that is included with the client class library described here.