Chapter 7

thepianoguy · March 22nd, 2011, 01:02 PM

Some comments on NetworkServer-Mac

On p. 236 the

Code:

if ([self netService] != nil) {
            NSLog(@"Service was not started");
        }

seems backwards to me. Shouldn't it be

Code:

if ([self netService] == nil) {
            NSLog(@"Service was not started");
        }

?
Once the [self startService]; method is called successfully, the netService is not nil.

In general there is an issue with the -postMessage method. Most of the messages never make it to the window.The window does not appear on screen until after the
-netServiceDidPublish method has returned, so the messages in -startService and -netServiceWillPublish have no where to go. It seems to make more sense to post them to the console. In order to make use of these messages, I added a toggleService method

Code:

- (IBAction)toggleService:(id)sender {
    if (self.netService != nil) {
        [self stopService];
        [sender setTitle:@"Start Service"];
    }
    else
    {
        [self startService];
        [sender setTitle:@"Stop Service"];
    }
}

to the class with a push button in the Interface. With this invoked, the startService, netServiceDidPublish, and stopService methods do show. For some reason, the messages from the -netServiceWillPublish and -netServiceDidStop methods do not make it to the window even with this added method. They can be logged to the console and the messageLabel stringValue as well, but they never appear in the window. Thinking it may be occurring too quickly to see, I added breakpoints to try to catch the messages being displayed, but though they are logged they do not appear on the interface.

On p 239 in the -viewWillAppear method, the *browser variable is instantiated to search for browsable domains yet never is released anywhere. Should it be? I redid this with an instance variable. Is there a particular reason to not use the *localBrowser for both the domain search and the service search?

With the ability to start and stop services it is necessary to add

Code:

-(void)netServiceBrowser:(NSNetServiceBrowser *)aNetServiceBrowser didRemoveService:(NSNetService *)aNetService moreComing:(BOOL)moreComing
{
    [self.services removeObject:aNetService];
    [self.tableView reloadData];
}

so that the view is updated.

The two BOOL variables domainsFound and servicesFound are never used.

Bob

gbacklin · March 25th, 2011, 11:22 PM

As always Bob, thank you for your time and effort with my book.

I will get back on your questions, I am currently swamped !

Take care,
Gene

gbacklin · March 26th, 2011, 08:40 AM

Ok, here is updated code to address your browser question. It should be stored in an instance variable, because if your release it as the way it is currently written, no values will be displayed in the table view. This memory leak will not come up in Build and Analyze in Xcode 3.x nor in 4.x, but you are correct that any alloc and init should be released, so below is an updated listing.

Code:

//
//  RootViewController.h
//  NetServiceBrowser-iPhone
//
//  Created by Gene Backlin on 6/14/10.
//  Copyright MariZack Consulting 2010. All rights reserved.
//

#import <UIKit/UIKit.h>

@interface RootViewController : UITableViewController <NSNetServiceBrowserDelegate, NSNetServiceDelegate> {
	NSNetServiceBrowser *netDomainBrowser;
	NSNetServiceBrowser *netServiceBrowser;
	NSMutableArray *domains;
	NSMutableArray *services;
}

@property (nonatomic, retain) NSNetServiceBrowser *netDomainBrowser;
@property (nonatomic, retain) NSNetServiceBrowser *netServiceBrowser;
@property (nonatomic, retain) NSMutableArray *domains;
@property (nonatomic, retain) NSMutableArray *services;

@end

Code:

//
//  RootViewController.m
//  NetServiceBrowser-iPhone
//
//  Created by Gene Backlin on 6/14/10.
//  Copyright MariZack Consulting 2010. All rights reserved.
//

#import "RootViewController.h"


@implementation RootViewController

@synthesize netDomainBrowser;
@synthesize netServiceBrowser;
@synthesize domains;
@synthesize services;


#pragma mark -
#pragma mark View lifecycle

- (void)viewDidLoad {
	[super viewDidLoad];
	[self setTitle:@"Networks"];
}

- (void)viewWillAppear:(BOOL)animated {
	NSNetServiceBrowser* browser = [[NSNetServiceBrowser alloc] init]; 
	[browser setDelegate:self];
	[self setNetDomainBrowser:browser];
	
	[[self netDomainBrowser] searchForBrowsableDomains];
	
	NSNetServiceBrowser *localBrowser = [[NSNetServiceBrowser alloc] init];
	[localBrowser setDelegate:self];
	[self setNetServiceBrowser:localBrowser];
	
	[[self netServiceBrowser] searchForServicesOfType:@"_hab._tcp." 
											 inDomain:@"local"];
	
	[browser release];
	[localBrowser release];
	
    [super viewWillAppear:animated];
}

- (void)viewWillDisappear:(BOOL)animated {
	[[self netServiceBrowser] stop];
	[[self netServiceBrowser] setDelegate:nil];
	[self setNetServiceBrowser:nil];
	
	[[self netDomainBrowser] stop];
	[[self netDomainBrowser] setDelegate:nil];
	[self setNetDomainBrowser:nil];
	
	[super viewWillDisappear:animated];
}

#pragma mark -
#pragma mark NSNetServiceBrowserDelegate

- (void)netServiceBrowser:(NSNetServiceBrowser *)aNetServiceBrowser 
		   didFindService:(NSNetService *)netService 
			   moreComing:(BOOL)moreServicesComing {
	NSLog(@"didFindService %@", netService);
	if ([self services] == nil)
		[self setServices:[[NSMutableArray alloc] init]];
	
	[[self services] addObject:netService];
	
	[self.tableView reloadData];
}

- (void)netServiceBrowser:(NSNetServiceBrowser *)aNetServiceBrowser 
		 didRemoveService:(NSNetService *)netService 
			   moreComing:(BOOL)moreServicesComing {
	[[self services] removeObject:netService];
	[[self tableView] reloadData];
}

- (void)netServiceBrowserDidStopSearch:(NSNetServiceBrowser *)aNetServiceBrowser {
	[[self services] removeAllObjects];
}

- (void)netServiceBrowser:(NSNetServiceBrowser*)aNetServiceBrowser 
			didFindDomain:(NSString*)domain 
			   moreComing:(BOOL)moreComing {
	NSLog(@"didFindDomain - Domain = %@ more = %d", domain, moreComing);
	if ([self domains] == nil)
		[self setDomains:[[NSMutableArray alloc] init]];
	
	[[self domains] addObject:domain];
	
	if(moreComing == 0) {
		[[self tableView] reloadData];
	}
}

- (void)netServiceBrowser:(NSNetServiceBrowser*)aNetServiceBrowser 
		  didRemoveDomain:(NSString*)domain 
			   moreComing:(BOOL)moreComing {
	NSLog(@"didRemoveDomain - Domain = %@ more = %d", domain, moreComing);
	if([self domains] != nil) {
		[[self domains] removeObject:domain];
		
		if(moreComing == 0) {
			[[self tableView] reloadData];
		}
	}
}

#pragma mark -
#pragma mark NSNetServiceDelegate

- (void)netService:(NSNetService *)sender 
	 didNotResolve:(NSDictionary *)errorDict {
	NSLog(@"didNotResolve - errorDict = %@", errorDict);
}

- (void)netServiceDidResolveAddress:(NSNetService *)service {
	NSLog(@"netServiceDidResolveAddress - name = %@", [service name]);
	NSString *msg = [NSString stringWithFormat:@"%@", [service name]];
	[self setTitle:msg];
}


#pragma mark -
#pragma mark Table view data source

// Customize the number of sections in the table view.
- (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView {
    return 2;
}

// Customize the number of rows in the table view.
- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section {
	switch (section) {
		case 0:
			return [domains count];
			break;
		case 1:
			return [services count];
			break;
		default:
			return 0;
			break;
	}
}

// Customize the Header Titles of the table view.
- (NSString *)tableView:(UITableView *)tableView titleForHeaderInSection:(NSInteger)section {
	switch (section) {
		case 0:
			return @"Domains";
			break;
		case 1:
			return @"Services";
			break;
		default:
			return @"Unknown";
			break;
	}
}

// Customize the appearance of table view cells.
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
    
    static NSString *CellIdentifier = @"Cell";
	NSString *cellText = @"Unknown";
	NSNetService *service = nil;
    
    UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];
    if (cell == nil) {
        cell = [[[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:CellIdentifier] autorelease];
		[cell setSelectionStyle:UITableViewCellSelectionStyleNone];
    }
    
	switch ([indexPath section]) {
		case 0:
			cellText = [[self domains] objectAtIndex:indexPath.row];
			break;
		case 1:
			service = [[self services] objectAtIndex:indexPath.row];
			cellText = [service name];
			break;
		default:
			break;
	}
	// Configure the cell.
	[[cell textLabel]setText: cellText];
	
    return cell;
}

#pragma mark -
#pragma mark Table view delegate

- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath {
	NSNetService *service = nil;
	
	switch ([indexPath section]) {
		case 1:
			service = [[self services] objectAtIndex:indexPath.row];
			[service setDelegate:self];
			[service resolveWithTimeout:5];
			break;
		default:
			break;
	}
}

#pragma mark -
#pragma mark Memory management

- (void)didReceiveMemoryWarning {
    [super didReceiveMemoryWarning];
}

- (void)viewDidUnload {
    // Relinquish ownership of anything that can be recreated in viewDidLoad or on demand.
    // For example: self.myOutlet = nil;
	[self setNetDomainBrowser:nil];
	[self setNetServiceBrowser:nil];
	[self setDomains:nil];
	[self setServices:nil];
}


- (void)dealloc {
	[netDomainBrowser release];
	[netServiceBrowser release];
	[domains release];
	[services release];
    [super dealloc];
}

@end

thepianoguy · March 26th, 2011, 11:41 AM

That is how I redid the program, including completing the didRemoveDomain method.
Bob