Why doesn't my custom download manager get launched by Safari?

Question

Hi all,
I'm working on a download manager for Leopard, Snow Leopard and possibly Tiger. It's a single window app that should get launched when the browser downloads a file with a custom extension, similar to the way the Amazon MP3 Downloader works with *.amz files.
My test app is set up to handle ".mytype" files and gets launched as expected when you double-click a ".mytype" file in the Finder or download one with Firefox.
Unfortunately, Safari just downloads the file and never launches my app. I can double-click on the file in Safari's Downloads window and it launches my app, but I need it to launch automatically.
Any hints or advice would be greatly appreciated.
Thanks,
Tom
Code below built with Xcode 3.1.2, target 10.5|Release|i386
Document type section of Info.plist:
<key>CFBundleDocumentTypes</key>
<array>
<dict>
<key>CFBundleTypeExtensions</key>
<array>
<string>mytype</string>
</array>
<key>CFBundleTypeIconFile</key>
<string>Icon</string>
<key>CFBundleTypeMIMETypes</key>
<array>
<string>application/x-mytype</string>
</array>
<key>CFBundleTypeName</key>
<string>mytype Doc</string>
<key>CFBundleTypeRole</key>
<string>Editor</string>
</dict>
</array>
Application delegate functions:
// this one gets called when downloading in FF, no luck in Safari
- (void)application:(NSApplication *)sender openFiles:(NSArray *)filenames
NSLog(@"in application:openFiles");
[sender replyToOpenOrPrint: NSApplicationDelegateReplySuccess];
// this one works in FF if I remove application:openFiles above
// I tried both methods in case it made a difference
- (BOOL)application:(NSApplication *)theApplication openFile:(NSString *)filename
NSLog(@"in application:openFile: %@", filename);
return YES;
testfile.mytype (served as PHP by apache):
<?
header('Content-Disposition: filename="testfile.mytype"');
header("Content-Type: application/x-mytype");
$body = "
sample file contents
header("Content-Length: " . strlen($body));
echo $body;
?>

Answer 1

Ray,
Thanks for the folder monitoring idea. I'd still like to get the original problem solved, but that might be an acceptable workaround.
The download manager is for a commercial product. All the examples of folder actions that I found involved the user selecting the folder and the script that gets executed. Is this process scriptable by my install program, even if the user has folder actions disabled?
Another option might be using the WatchPaths option in LaunchAgents and have it launch my program when a new ".mytype" file is detected.
I'm pretty new to Mac programming (unix background) - what would be the pros and cons of LaunchAgents vs. Folder Actions?
Also, I know that "~/Downloads" is the standard location to save downloaded files, but what if the user changes it to a different folder in Safari Preferences?
Regarding the original problem...
"Open safe files after downloading" is checked in my Safari preferences.
Since I will be distributing the program I don't want to go mucking about with overriding the built-in list of safe file types.
Would it make sense to write a Safari plugin to handle the custom file types? The sample plugins that I looked at all deal with the custom types in the context of the browser page (like a movie viewer), but I want to launch an external application to handle the file. Is that possible? Or is watching the Downloads folder for new files a better approach?
Thanks,
Tom