File: http://svn.grimore.org/corrade-lsl-templates/source/heads-up-display/recall/recall.lsl -

///////////////////////////////////////////////////////////////////////////
//  Copyright (C) Wizardry and Steamworks 2016 - License: CC BY 2.0      //
///////////////////////////////////////////////////////////////////////////
//
// This is a recall device that will make Corrade send you a teleport lure
// such that you can teleport to Corrade's location.
//
// For more information on Corrade, please see:
//     http://grimore.org/secondlife/scripted_agents/corrade
//
///////////////////////////////////////////////////////////////////////////
 
///////////////////////////////////////////////////////////////////////////
//    Copyright (C) 2015 Wizardry and Steamworks - License: CC BY 2.0    //
///////////////////////////////////////////////////////////////////////////
string wasKeyValueGet(string k, string data) {
    if(llStringLength(data) == 0) return "";
    if(llStringLength(k) == 0) return "";
    list a = llParseString2List(data, ["&", "="], []);
    integer i = llListFindList(llList2ListStrided(a, 0, -1, 2), [ k ]);
    if(i != -1) return llList2String(a, 2*i+1);
    return "";
}
 
///////////////////////////////////////////////////////////////////////////
//    Copyright (C) 2013 Wizardry and Steamworks - License: CC BY 2.0    //
///////////////////////////////////////////////////////////////////////////
string wasKeyValueEncode(list data) {
    list k = llList2ListStrided(data, 0, -1, 2);
    list v = llList2ListStrided(llDeleteSubList(data, 0, 0), 0, -1, 2);
    data = [];
    do {
        data += llList2String(k, 0) + "=" + llList2String(v, 0);
        k = llDeleteSubList(k, 0, 0);
        v = llDeleteSubList(v, 0, 0);
    } while(llGetListLength(k) != 0);
    return llDumpList2String(data, "&");
}
 
///////////////////////////////////////////////////////////////////////////
//    Copyright (C) 2015 Wizardry and Steamworks - License: CC BY 2.0    //
///////////////////////////////////////////////////////////////////////////
// escapes a string in conformance with RFC1738
string wasURLEscape(string i) {
    string o = "";
    do {
        string c = llGetSubString(i, 0, 0);
        i = llDeleteSubString(i, 0, 0);
        if(c == "") jump continue;
        if(c == " ") {
            o += "+";
            jump continue;
        }
        if(c == "\n") {
            o += "%0D" + llEscapeURL(c);
            jump continue;
        }
        o += llEscapeURL(c);
@continue;
    } while(i != "");
    return o;
}
 
// callback URL
string callback = "";
 
// configuration data
string configuration = "";
 
 
default {
    state_entry() {
        llSetTimerEvent(1);
    }
    link_message(integer sender, integer num, string message, key id) {
        if(sender != 1 || id != "configuration") return;
        configuration = message;
        state off;
    }
    timer() {
        llMessageLinked(LINK_ROOT, 0, "configuration", NULL_KEY);
    }
    attach(key id) {
        llResetScript();
    }
    on_rez(integer num) {
        llResetScript();
    }
    changed(integer change) {
        if((change & CHANGED_INVENTORY) || (change & CHANGED_REGION_START) || (change & CHANGED_OWNER)) {
            llResetScript();
        }
    }
    state_exit() {
        llSetTimerEvent(0);
    }
}
 
state off {
    state_entry() {
        llReleaseControls();
        llSetColor(<.5,0,0>, ALL_SIDES);
    }
    touch_end(integer num) {
        state on;
    }
    attach(key id) {
        llResetScript();
    }
    on_rez(integer num) {
        llResetScript();
    }
    changed(integer change) {
        if((change & CHANGED_INVENTORY) || (change & CHANGED_REGION_START) || (change & CHANGED_OWNER)) {
            llResetScript();
        }
    }
}
 
state on {
    state_entry() {
        llSetColor(<0,.5,0>, ALL_SIDES);
        state url;
    }
    attach(key id) {
        llResetScript();
    }
    on_rez(integer num) {
        llResetScript();
    }
    changed(integer change) {
        if((change & CHANGED_INVENTORY) || (change & CHANGED_REGION_START) || (change & CHANGED_OWNER)) {
            llResetScript();
        }
    }
}
 
state url {
    state_entry() {
        // DEBUG
        llOwnerSay("Requesting URL...");
        llRequestURL();
    }
    touch_end(integer num) {
        llSetColor(<.5,0,0>, ALL_SIDES);
        llResetScript();
    }
    http_request(key id, string method, string body) {
        if(method != URL_REQUEST_GRANTED) return;
        callback = body;
        // DEBUG
        llOwnerSay("Got URL...");
        state recall;
    }
    attach(key id) {
        llResetScript();
    }
    on_rez(integer num) {
        llResetScript();
    }
    changed(integer change) {
        if((change & CHANGED_INVENTORY) || (change & CHANGED_REGION_START) || (change & CHANGED_OWNER)) {
            llResetScript();
        }
    }
}
 
state recall {
    state_entry() {
        // DEBUG
        llOwnerSay("Recalling...");
        llInstantMessage(
            (key)wasKeyValueGet(
                "corrade", 
                configuration
            ),
            wasKeyValueEncode(
                [
                    "command", "lure",
                    "group", wasURLEscape(
                        wasKeyValueGet(
                            "group", 
                            configuration
                        )
                    ),
                    "password", wasURLEscape(
                        wasKeyValueGet(
                            "password", 
                            configuration
                        )
                    ),
                    "agent", llGetOwner(),
                    "callback", wasURLEscape(callback)
                 ]
            )
        );
        llSetTimerEvent(30);
    }
    timer() {
        // DEBUG
        llOwnerSay("Recall failed...");
        llSetColor(<.5,0,0>, ALL_SIDES);
        llResetScript();
    }
    touch_end(integer num) {
        llSetColor(<.5,0,0>, ALL_SIDES);
        llResetScript();
    }
    http_request(key id, string method, string body) {
        llHTTPResponse(id, 200, "OK");
        if(wasKeyValueGet("command", body) != "lure" ||
            wasKeyValueGet("success", body) != "True") {
            // DEBUG
            llOwnerSay("Recall failed...");
            llSetColor(<.5,0,0>, ALL_SIDES);
            llResetScript();
        }
        // DEBUG
        llOwnerSay("Recall succeeded...");
        llSetColor(<.5,0,0>, ALL_SIDES);
        llResetScript();
    }
    attach(key id) {
        llResetScript();
    }
    on_rez(integer num) {
        llResetScript();
    }
    changed(integer change) {
        if((change & CHANGED_INVENTORY) || (change & CHANGED_REGION_START) || (change & CHANGED_OWNER)) {
            llResetScript();
        }
    }
    state_exit() {
        llSetTimerEvent(0);
    }
}