Watch applications send and receive Apple Events
Fri, Mar 21 2003 at 9:54AM PST • Contributed by: noworryz
Fri, Mar 21 2003 at 9:54AM PST • Contributed by: noworryz
Applications use Apple Events to communicate among themselves. If you've ever wondered what they're saying behind your back, just open the Terminal and type:
% setenv AEDebugSends 1
% setenv AEDebugReceives 1
% /usr/bin/osascript -e 'quit application "Finder"'
% /usr/bin/open -a "Finder"For example, suppose you use the Finder to open Safari, then you double-click on a
.webloc file on the
desktop. In the Console, you will see the Finder send the "go to URL" event and Safari receive it:
AE2000 (474): Sending an event:
------oo start of event oo------
{ 1 } 'aevt': GURL/GURL {
return id: 31064065 (0x1da0001)
transaction id: 0 (0x0)
interaction level: 112 (0x70)
reply required: 0 (0x0)
target:
{ 2 } 'psn ': 8 bytes {
{ 0x0, 0x2e0001 } (Safari)
}
optional attributes:
< empty record >
event data:
{ 1 } 'aevt': - 1 items {
key '----' -
{ 1 } 'TEXT': 21 bytes {
"http://www.apple.com/"
}
}
}
------oo end of event oo------
AE2000 (477): Received an event:
------oo start of event oo------
{ 1 } 'aevt': GURL/GURL {
return id: 31064065 (0x1da0001)
transaction id: 0 (0x0)
interaction level: 112 (0x70)
reply required: 0 (0x0)
target:
{ 1 } 'psn ': 8 bytes {
{ 0x0, 0x2c0001 } (Finder)
}
optional attributes:
< empty record >
event data:
{ 1 } 'aevt': - 1 items {
key '----' -
{ 1 } 'TEXT': 21 bytes {
"http://www.apple.com/"
}
}
}
------oo end of event oo------
In the above, the Unix process IDs are in parentheses, in this case (474) and (477). The tag
psn indicates the Process Serial Number, in hexadecimal. (When sending, the event target is the receiving process; when receiving, the target is the sending process.) The URL being opened is http://www.apple.com/.
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