Hello all,
I need to show different layers in my map depending on whether the user is
public/anonymous or has login credentials. I'm using geoserver.
I can log in and out using forms with j_spring_security_check. The difficulty
is in trying to sense whether the user is logged in or not.
I've come up with a way to do it by attempting to query one of the secure
layers, and setting the login flag to yes if it succeeds and no if it fails.
The problem is that javascript just blows right on past my protocol.read()
command without setting the flag, unless I force it to wait with an alert,
which is pretty ugly and not ideal.
Does OpenLayers have an event listener I can call for the script protocol so
that the rest of the code won't fire until the login flag is set? From
googling around, it looks like there may once have been plans for this, but no
one has been discussing it much recently...
Alternately, does anyone have a creative suggestion for nesting callback
functions so this will work smoothly without recourse to alert()? I've tried a
few different ways but nothing really works.
Any suggestions greatly appreciated!
Code:
Ext.onReady(function init() {
//Start with login = no
login = "no";
//function to parse and test the response - are there any features?
var test = function(resp) {
if (resp.features) {
login = "yes"; //change login to yes
} else {
login = "no";
//Do nothing. It never actually gets here -
//if not logged in, it can't get a json response
//and errors out trying to parse the xml fail response
//But that's ok, that's why login defaults to no
}
}
var filter = new OpenLayers.Filter.Comparison({
type: OpenLayers.Filter.Comparison.EQUAL_TO,
property: 'ID',
value: 'TESTAREA'
});
protocol = new OpenLayers.Protocol.Script({
url:geoserver_url + '/wfs',
callbackKey: 'format_options',
callbackPrefix: 'callback:',
params: {
service: 'WFS',
version: '1.1.0',
srsName: 'EPSG:3857',
request: 'GetFeature',
typeName: 'Areas',
outputFormat: 'json',
cql_filter: filter
},
callback: test,
});
protocol.read();
//have to do an alert here so login=yes has a chance to catch up
alert ("Checking login credentials ...");
//construct a logout button or a login form - reload the page
after logging in or out, which will rerun the test protocol above and reset the
login flag
if (login == 'yes') { //only gets here if we wait with the
alert
document.getElementById('login').innerHTML='<center><font
style="font-size:8pt; font-family:sans-serif;"><form name="logout"
method="post" action="'+ geoserver_url+ '/j_spring_security_logout"
target="_blank"><input type="submit" value="Logout"
onclick="location.reload();"></form></font></center>';
} else { //always goes here without the alert, even if
protocol succeeds
document.getElementById('login').innerHTML='<font
style="font-size:8pt; font-family:sans-serif;"><form name="login" method="post"
action="' + geoserver_url + '/j_spring_security_check" target="_blank"><label
for="username">Username: </label><input id="username" type="text"
name="username" value=""><br/><label for="password">Password: </label><input
id="password" type="password" name="password"><input type="submit"
value="Login" onclick="location.reload();"></form></font>';
}
//..... all the rest of the map code, do it slightly differently if login = yes
or login = no
}); //end init
Kathryn Catlin
GIS Supervisor
Massachusetts Historical Commission
220 Morrissey Blvd
Boston, MA 02125
(617) 727-8470
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