| 16 |
|
----------- |
| 17 |
|
All protocols in this document assume a valid connection of |
| 18 |
|
the appropriate type has been made, and that data streams |
| 19 |
< |
already available. All strings should and will be |
| 19 |
> |
are already available. All strings should, and will be, |
| 20 |
|
terminated with a \n (newline character) to indicate the end |
| 21 |
|
of the message. All messages are sent as ASCII Strings. |
| 22 |
|
|
| 23 |
|
Fixed protocol messages will appear in [] brackets, if there |
| 24 |
< |
is a variety of options they will be seperated with the | |
| 24 |
> |
is a variety of options they will be separated with the | |
| 25 |
|
character. For example: |
| 26 |
|
|
| 27 |
|
[OK|ERROR] |
| 28 |
< |
|
| 28 |
> |
|
| 29 |
|
Indicates that the message "OK" OR the message "ERROR" will |
| 30 |
|
be sent depending on the result of the last action. |
| 31 |
|
|
| 35 |
|
|
| 36 |
|
{lastmodified} |
| 37 |
|
|
| 38 |
< |
Indicates that data indicating for use as last modified will |
| 39 |
< |
be returned. |
| 38 |
> |
Indicates that data for use as 'last modified' will be |
| 39 |
> |
returned. |
| 40 |
|
|
| 41 |
< |
If ever [ERROR] is sent back at any time, this indicates |
| 42 |
< |
that all communication is over. EXCEPT where specified! |
| 41 |
> |
If [ERROR] is sent back at any time, this indicates that all |
| 42 |
> |
communication is over. EXCEPT where otherwise specified! |
| 43 |
|
|
| 44 |
|
Host Connection Protocol |
| 45 |
|
------------------------ |
| 46 |
|
The initial connection of a host to the i-scream server is |
| 47 |
|
through the FilterManager. A Host gets its configuration |
| 48 |
< |
and then gets assigned a filter to connect to and start |
| 48 |
> |
and then gets assigned a Filter to connect to and start |
| 49 |
|
sending data. |
| 50 |
|
|
| 51 |
< |
The port number of the filter manager is fully configurable, |
| 51 |
> |
The port number of the FilterManager is fully configurable, |
| 52 |
|
however the default at this time is 4567. |
| 53 |
|
|
| 54 |
|
Host (direction) Server Comment |
| 56 |
|
[STARTCONFIG]----------> Requests to start |
| 57 |
|
receiving config |
| 58 |
|
information |
| 59 |
< |
|
| 59 |
> |
|
| 60 |
|
<---------- [OK|ERROR] If the server ok's |
| 61 |
|
the request or not |
| 62 |
|
|
| 63 |
|
[LASTMODIFIED]----------> Asks when the config |
| 64 |
|
was last modified |
| 65 |
|
(used when checking |
| 66 |
< |
if the config has |
| 66 |
> |
if the config has |
| 67 |
|
changed) |
| 68 |
< |
|
| 68 |
> |
|
| 69 |
|
<---------- [{lastmodified}Returns a long int |
| 70 |
< |
|ERROR] time since epoc |
| 70 |
> |
|ERROR] time since epoch |
| 71 |
|
eg, 123456789 |
| 72 |
< |
|
| 72 |
> |
To indicate what |
| 73 |
> |
format this is in, |
| 74 |
> |
I quote from the |
| 75 |
> |
Java 1.3 JDK API |
| 76 |
> |
"measured in milli |
| 77 |
> |
-seconds since the |
| 78 |
> |
epoch" |
| 79 |
> |
|
| 80 |
|
[FILELIST] ----------> Asks the server for |
| 81 |
|
the list of files |
| 82 |
|
that were used to |
| 84 |
|
(used when checking |
| 85 |
|
if the config has |
| 86 |
|
changed) |
| 87 |
< |
|
| 87 |
> |
|
| 88 |
|
<---------- [{filelist} Returns a semi-colon |
| 89 |
< |
|ERROR] seperated list of |
| 89 |
> |
|ERROR] separated list of |
| 90 |
|
filenames |
| 91 |
|
eg, |
| 92 |
|
a.conf;b.conf;c.conf |
| 93 |
|
|
| 94 |
+ |
[FQDN] ----------> Asks the server to |
| 95 |
+ |
send the FQDN (fully |
| 96 |
+ |
qualified domain |
| 97 |
+ |
name) of the |
| 98 |
+ |
connecting host. |
| 99 |
+ |
|
| 100 |
+ |
<---------- [{fqdn} Returns the FQDN of |
| 101 |
+ |
|ERROR] the connected host, |
| 102 |
+ |
or error if it can't |
| 103 |
+ |
be looked up. |
| 104 |
+ |
|
| 105 |
|
********** LOOP START ********** |
| 106 |
|
This loop reads configuration |
| 107 |
|
properties from the config |
| 111 |
|
retrieved from the |
| 112 |
|
config file |
| 113 |
|
eg, UDPUpdateTime |
| 114 |
< |
|
| 114 |
> |
|
| 115 |
|
<---------- [{value}|ERROR]Returns the value of |
| 116 |
|
the requested config |
| 117 |
|
property |
| 118 |
|
eg, 120 |
| 119 |
|
If it is unable to |
| 120 |
< |
find the requested |
| 120 |
> |
find the requested |
| 121 |
|
property it returns |
| 122 |
|
ERROR to indicate |
| 123 |
< |
that fact |
| 124 |
< |
|
| 123 |
> |
that fact, but |
| 124 |
> |
communication still |
| 125 |
> |
proceeds |
| 126 |
> |
|
| 127 |
|
********** LOOP UNTIL ********** |
| 128 |
|
The loop continues until the host |
| 129 |
|
sends the following message |
| 130 |
< |
|
| 131 |
< |
[ENDCONFIG] ----------> Indicates that the |
| 130 |
> |
|
| 131 |
> |
[ENDCONFIG] ----------> Indicates that the |
| 132 |
|
host requires no |
| 133 |
|
more config |
| 134 |
< |
|
| 134 |
> |
|
| 135 |
|
********** LOOP END ********** |
| 136 |
|
Communication continues |
| 137 |
< |
|
| 137 |
> |
|
| 138 |
|
<---------- [OK] Indicates that the |
| 139 |
|
server is ready to |
| 140 |
|
proceed |
| 141 |
< |
|
| 141 |
> |
|
| 142 |
|
[FILTER] ----------> Asks the server to |
| 143 |
|
send it the host |
| 144 |
< |
information of a |
| 144 |
> |
information of a |
| 145 |
|
filter that it |
| 146 |
|
should connect to |
| 147 |
< |
|
| 147 |
> |
|
| 148 |
|
<---------- {filter} Returns a semi-colon |
| 149 |
< |
seperated list of |
| 149 |
> |
separated list of |
| 150 |
|
FQDN hostname, UDP |
| 151 |
|
port number and TCP |
| 152 |
< |
port number that a |
| 152 |
> |
port number that a |
| 153 |
|
configured Filter is |
| 154 |
|
running on and |
| 155 |
< |
assigned to the |
| 155 |
> |
assigned to the |
| 156 |
|
calling host |
| 157 |
|
eg, |
| 158 |
|
raptor.ukc.ac.uk; |
| 162 |
|
server that the host |
| 163 |
|
has finished an will |
| 164 |
|
disconnect |
| 165 |
< |
|
| 165 |
> |
|
| 166 |
|
<---------- [OK|ERROR] Indicates that the |
| 167 |
|
server is either ok |
| 168 |
|
or that it thought |
| 169 |
|
there was an error |
| 170 |
< |
|
| 170 |
> |
------------------------------------------------------------ |
| 171 |
> |
|
| 172 |
|
Host Heartbeat Protocol |
| 173 |
|
----------------------- |
| 174 |
|
When a host is configured after it has connected it should |
| 175 |
|
obtain a property TCPUpdateTime. This indicates how often |
| 176 |
< |
a host should send a "Heart Beat" which is a pro-active |
| 176 |
> |
a host should send a "Heart Beat", which is a pro-active |
| 177 |
|
connection to the server by the host to indicate that it is |
| 178 |
|
still alive. This "Heart Beat" also allows a host to see |
| 179 |
< |
its configuration has changed and act accordingly. In a |
| 179 |
> |
its configuration has changed and act accordingly. In a |
| 180 |
|
well written host this should just be a case of dropping out |
| 181 |
|
of a loop and heading back to the start (connecting to the |
| 182 |
|
filter manager). |
| 186 |
|
[HEARTBEAT] ----------> Starts the |
| 187 |
|
heartbeat protocol |
| 188 |
|
off |
| 189 |
< |
|
| 189 |
> |
|
| 190 |
|
<---------- [OK|ERROR] Indicates that the |
| 191 |
|
server is ok or not |
| 192 |
|
|
| 198 |
|
server is ok or not |
| 199 |
|
|
| 200 |
|
[{filelist}] ----------> Send a semi-colon |
| 201 |
< |
seperated list of |
| 201 |
> |
separated list of |
| 202 |
|
filenames |
| 203 |
|
eg, |
| 204 |
|
a.conf;b.conf;c.conf |
| 205 |
|
This should be |
| 206 |
|
identical to the one |
| 207 |
< |
recieved in the |
| 207 |
> |
received in the |
| 208 |
|
connection protocol |
| 209 |
|
|
| 210 |
|
<---------- [OK] Indicates that the |
| 211 |
|
server is ok |
| 212 |
|
|
| 213 |
|
[{lastmodified}]----------> Returns a long int |
| 214 |
< |
time since epoc |
| 214 |
> |
time since epoch |
| 215 |
|
eg, 123456789 |
| 216 |
|
This should be |
| 217 |
|
identical to the one |
| 218 |
< |
recieved in the |
| 218 |
> |
received in the |
| 219 |
|
connection protocol |
| 220 |
+ |
To indicate what |
| 221 |
+ |
format this is in, |
| 222 |
+ |
I quote from the |
| 223 |
+ |
Java 1.3 JDK API |
| 224 |
+ |
"measured in milli |
| 225 |
+ |
-seconds since the |
| 226 |
+ |
epoch" |
| 227 |
|
|
| 228 |
|
<---------- [OK|ERROR] The server then |
| 229 |
|
checks all the files |
| 231 |
|
see if they have |
| 232 |
|
been modified more |
| 233 |
|
recently than the |
| 234 |
< |
lastmodified value |
| 235 |
< |
if they HAVE that |
| 234 |
> |
lastmodified value. |
| 235 |
> |
If they HAVE that |
| 236 |
|
indicates that the |
| 237 |
|
configuration has |
| 238 |
|
changed and the host |
| 249 |
|
server that the host |
| 250 |
|
has finished an will |
| 251 |
|
disconnect |
| 252 |
< |
|
| 252 |
> |
|
| 253 |
|
<---------- [OK|ERROR] Indicates that the |
| 254 |
|
server is either ok |
| 255 |
|
or that it thought |
| 256 |
|
there was an error |
| 257 |
+ |
------------------------------------------------------------ |
| 258 |
|
|
| 259 |
|
Host Data Protocol |
| 260 |
|
------------------ |
| 267 |
|
Client Control Protocol |
| 268 |
|
----------------------- |
| 269 |
|
|
| 270 |
< |
<TODO> |
| 270 |
> |
The client control protocol channel is opened by the client |
| 271 |
> |
and allows a variety of actions to be carried out by the |
| 272 |
> |
client at anytime. Unlike previous protocols, this is NOT |
| 273 |
> |
sequential, all of the requests can be carried out in |
| 274 |
> |
any order. |
| 275 |
|
|
| 276 |
+ |
All client protocols are backwards compatible, and the |
| 277 |
+ |
version is shown by the protocol identifier. |
| 278 |
+ |
|
| 279 |
+ |
There are three sections to this protocol. |
| 280 |
+ |
|
| 281 |
+ |
1) Initialise (sent only at start) |
| 282 |
+ |
2) Send command(s) - unlimited number in any order |
| 283 |
+ |
3) Disconnect (sent only at end) |
| 284 |
+ |
|
| 285 |
+ |
If at anytime the client sends something the server does |
| 286 |
+ |
not understand, an [ERROR] will be sent |
| 287 |
+ |
|
| 288 |
+ |
All are indicated with <> brackets. |
| 289 |
+ |
|
| 290 |
+ |
v1.0 - Protocol identifier: "PROTOCOL 1.0" (without quotes) |
| 291 |
+ |
Supported commands: |
| 292 |
+ |
STARTCONFIG |
| 293 |
+ |
STARTDATA |
| 294 |
+ |
STOPDATA |
| 295 |
+ |
|
| 296 |
+ |
Host (direction) Server Comment |
| 297 |
+ |
------------------------------------------------------------ |
| 298 |
+ |
<initialise> |
| 299 |
+ |
<---------- [{protocol}] The server sends the |
| 300 |
+ |
protocol identifier |
| 301 |
+ |
|
| 302 |
+ |
[{name}] ----------> The client sends its |
| 303 |
+ |
"name". This name |
| 304 |
+ |
is used to identify |
| 305 |
+ |
the type of client |
| 306 |
+ |
to the system and |
| 307 |
+ |
obtain its config |
| 308 |
+ |
eg, Conient |
| 309 |
+ |
|
| 310 |
+ |
<---------- [OK] Indicates the server |
| 311 |
+ |
is ok to proceed |
| 312 |
+ |
|
| 313 |
+ |
|
| 314 |
+ |
<command #1> (allows client to obtain its configuration) |
| 315 |
+ |
[STARTCONFIG]----------> Tell the server we |
| 316 |
+ |
want to start this |
| 317 |
+ |
command |
| 318 |
+ |
|
| 319 |
+ |
<---------- [OK] Indicates the server |
| 320 |
+ |
is ok to proceed |
| 321 |
+ |
|
| 322 |
+ |
********** LOOP START ********** |
| 323 |
+ |
This loop reads configuration |
| 324 |
+ |
properties from the config |
| 325 |
+ |
|
| 326 |
+ |
[{property}] ----------> Sends the name of a |
| 327 |
+ |
property to be |
| 328 |
+ |
retrieved from the |
| 329 |
+ |
config file |
| 330 |
+ |
Clients can obtain |
| 331 |
+ |
host information |
| 332 |
+ |
eg, |
| 333 |
+ |
Host.UDPUpdateTime |
| 334 |
+ |
Otherwise it must |
| 335 |
+ |
prefix requests |
| 336 |
+ |
with "Client." |
| 337 |
+ |
All other requests |
| 338 |
+ |
will be ignored as |
| 339 |
+ |
if it was unable to |
| 340 |
+ |
retrieve the |
| 341 |
+ |
property |
| 342 |
+ |
|
| 343 |
+ |
<---------- [{value}|ERROR]Returns the value of |
| 344 |
+ |
the requested config |
| 345 |
+ |
property |
| 346 |
+ |
eg, 120 |
| 347 |
+ |
If it is unable to |
| 348 |
+ |
find the requested |
| 349 |
+ |
property it returns |
| 350 |
+ |
ERROR to indicate |
| 351 |
+ |
that fact |
| 352 |
+ |
|
| 353 |
+ |
********** LOOP UNTIL ********** |
| 354 |
+ |
The loop continues until the client |
| 355 |
+ |
sends the following message |
| 356 |
+ |
|
| 357 |
+ |
[ENDCONFIG] ----------> Indicates that the |
| 358 |
+ |
client requires no |
| 359 |
+ |
more config |
| 360 |
+ |
|
| 361 |
+ |
********** LOOP END ********** |
| 362 |
+ |
Communication continues |
| 363 |
+ |
|
| 364 |
+ |
<---------- [OK] Indicates that the |
| 365 |
+ |
server is ready to |
| 366 |
+ |
proceed |
| 367 |
+ |
|
| 368 |
+ |
<command #2> (tells the server to start the data link) |
| 369 |
+ |
[STARTDATA] ----------> Tell the server we |
| 370 |
+ |
want to start this |
| 371 |
+ |
command |
| 372 |
+ |
|
| 373 |
+ |
<---------- [{portnumber} The server then sets |
| 374 |
+ |
|ERROR] itself listening for |
| 375 |
+ |
a connection on its |
| 376 |
+ |
data link socket for |
| 377 |
+ |
this client. It |
| 378 |
+ |
returns the port no. |
| 379 |
+ |
that it is listening |
| 380 |
+ |
on eg, 12367 |
| 381 |
+ |
If the data link is |
| 382 |
+ |
already started the |
| 383 |
+ |
server will return |
| 384 |
+ |
ERROR |
| 385 |
+ |
|
| 386 |
+ |
<---------- [OK] Indicates the client |
| 387 |
+ |
has successfully |
| 388 |
+ |
connected to the |
| 389 |
+ |
data socket. |
| 390 |
+ |
|
| 391 |
+ |
<command #3> (tells the server to stop the data link) |
| 392 |
+ |
[STOPDATA] ----------> Tell the server we |
| 393 |
+ |
want to start this |
| 394 |
+ |
command |
| 395 |
+ |
The server then |
| 396 |
+ |
shuts down the |
| 397 |
+ |
data link to the |
| 398 |
+ |
client |
| 399 |
+ |
|
| 400 |
+ |
<---------- [OK|ERROR] Returns OK is the |
| 401 |
+ |
server is ready to |
| 402 |
+ |
proceed, or ERROR |
| 403 |
+ |
if the data link |
| 404 |
+ |
was not open in the |
| 405 |
+ |
first place |
| 406 |
+ |
|
| 407 |
+ |
<disconnect> |
| 408 |
+ |
[DISCONNECT] ----------> Tells the server the |
| 409 |
+ |
client wants to |
| 410 |
+ |
close the control |
| 411 |
+ |
link |
| 412 |
+ |
|
| 413 |
+ |
<---------- [OK] The last word from |
| 414 |
+ |
the server, it will |
| 415 |
+ |
disappear after |
| 416 |
+ |
this, and close the |
| 417 |
+ |
data link if |
| 418 |
+ |
required |
| 419 |
+ |
------------------------------------------------------------ |
| 420 |
+ |
|
| 421 |
+ |
v1.1 - Protocol identifier: "PROTOCOL 1.1" (without quotes) |
| 422 |
+ |
Supported commands: |
| 423 |
+ |
SETHOSTLIST |
| 424 |
+ |
|
| 425 |
+ |
Host (direction) Server Comment |
| 426 |
+ |
------------------------------------------------------------ |
| 427 |
+ |
<command #4> (indicates to the server which hosts the client |
| 428 |
+ |
wants data from) |
| 429 |
+ |
[SETHOSTLIST]----------> Tell the server we |
| 430 |
+ |
want to start this |
| 431 |
+ |
command |
| 432 |
+ |
|
| 433 |
+ |
<---------- [OK|ERROR] The server will |
| 434 |
+ |
return an ERROR if |
| 435 |
+ |
the data link is |
| 436 |
+ |
open, as a host list |
| 437 |
+ |
must ONLY be set |
| 438 |
+ |
if the data link is |
| 439 |
+ |
closed |
| 440 |
+ |
If the server is |
| 441 |
+ |
ok to proceed with |
| 442 |
+ |
the command it says |
| 443 |
+ |
[OK] |
| 444 |
+ |
|
| 445 |
+ |
[{hostlist}] ----------> This is a semi-colon |
| 446 |
+ |
seperated list of |
| 447 |
+ |
FQDN hostnames that |
| 448 |
+ |
the client wishes to |
| 449 |
+ |
recieve data from |
| 450 |
+ |
eg, |
| 451 |
+ |
raptor.ukc.ac.uk;killigrew.ukc.ac.uk;chalk.ukc.ac.uk |
| 452 |
+ |
|
| 453 |
+ |
If the list is sent |
| 454 |
+ |
blank (or if no list |
| 455 |
+ |
is set at all) then |
| 456 |
+ |
data from ALL hosts |
| 457 |
+ |
will be sent to the |
| 458 |
+ |
client (this is the |
| 459 |
+ |
default if no |
| 460 |
+ |
SETHOSTLIST is not |
| 461 |
+ |
run by the client |
| 462 |
+ |
|
| 463 |
+ |
<---------- [OK] Indicates the server |
| 464 |
+ |
is ok to proceed and |
| 465 |
+ |
the host list has |
| 466 |
+ |
been accepted |
| 467 |
+ |
------------------------------------------------------------ |
| 468 |
+ |
|
| 469 |
|
Client Data Protocol |
| 470 |
|
-------------------- |
| 471 |
+ |
Once the data link has been opened by the control link, the |
| 472 |
+ |
server will send XML formatted data packets separated by the |
| 473 |
+ |
\n (newline) character. For information on the format of |
| 474 |
+ |
this data see the XML via UDP specification document at: |
| 475 |
|
|
| 476 |
< |
<TODO> |
| 476 |
> |
http://www.i-scream.org.uk/cgi-bin/docs.cgi?doc=specification/xml_via_udp.txt |
| 477 |
|
|
| 478 |
|
About |
| 479 |
|
----- |
