llRequestURL

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Revision as of 20:47, 9 January 2014 by Strife Onizuka (talk | contribs)
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Summary

Function: key llRequestURL( );
0.0 Forced Delay
10.0 Energy

Requests one HTTP:// url for use by this object. The http_request event is triggered with the result of the request. HTTP-in uses port 12046.
Returns a handle (a key) used for identifying the result of the request in the http_request event.

Caveats

  • HTTP-in uses port 12046.
  • When a region is (re)started all HTTP server URLs are automatically released and invalidated.
  • The number of available URLs is a limited resource, that is to say, a script can only have so many open URLs. See LSL http_server#Resource Limitations for details.
  • When abandoning a URL, always release it with llReleaseURL, otherwise it will leak.
KBcaution.png Important: Never ever forget to release a URL again which you have requested! URLs are region resources just like prims. If you take them all you can get into big trouble with the sim owner and/or estate managers.

Examples

This script requests a new URL after region restart: <lsl> string url; key urlRequestId; key selfCheckRequestId;

reset_script() {

   llReleaseURL(url);
   llResetScript();

}

request_url() {

   llReleaseURL(url);
   url = "";
   urlRequestId = llRequestURL();

}

throw_exception(string inputString) {

   key owner = llGetOwner();
   llInstantMessage(owner, inputString);
   // yeah, bad way to handle exceptions by restarting.
   // However this is just a demo script...
   reset_script();

}

default {

   on_rez(integer start_param)
   {
       reset_script();
   }
   changed(integer change)
   {
if (change & (CHANGED_OWNER

Notes

Another comment on resilient programming: getting a global resource, an HTTP listener in this case, should always be considered an operation that can fail for transitory reasons (as well as permanent ones). In this case, LSL folds retryable and permanent errors into the same error status and there's no opportunity for a script writer to distinguish the two cases. But a reasonable way to handle this is sleeping with limited retries before failing hard in the LSL code.
Monty Linden

See Also

Functions

•  llRequestSecureURL
•  llGetFreeURLs
•  llReleaseURL
•  llHTTPResponse
•  llGetHTTPHeader

Articles

•  LSL http server

Deep Notes

History

Signature

function key llRequestURL();