Network and Multitasking

Networking
& Multitasking

孔祥波

12年12月23⽇日星期⽇日

network,tcp/ip,socket,CFNetWork

http, restful api

thread: posix thread,
NSThread,NSOperation,push notification

Block and GCD


tcp/ip

20世纪六十年代美国国防部

加州伯克利大学 BSD Unix

OSI 七层/TCP/IP四层模型

应用层http, pop3,smtp,ftp&


Socket
tcp/udp

tcp 三次握手

server/client 模型

server: open/bind/listen/connected/
(send,recv)/close

client: open/bind/connect/(send,recv)/
close


CFNetwork
CFStream

RUNLoop base

CFReadStream create stream, set
call back and runloop， call back
read bytes

CFWriteStream


http

http protocol

Web service,SOAP,XML-RPC

Get RSS and ATOM feeds

download file


web service restful
api


one more thing


debug network
package
tcpdump -A -s0 -i en1 host hostnameand
port 80

Wireshark network protocol dump


Multitasking


Why Concurrency?

With a single thread,long-running operations may
interfere with user interaction

Multiple threads allow you to load resources or
perform computations without locking
up your entire application


Threads on the iOS

Based on the POSIX threading API

/usr/include/pthread.h

Higher-level wrappers in the Foundation
framework(NSSThread)


NSThread Basics

Run loop automatically instantiated for each
thread

Each NSThread needs to create its own
autorelease pool

Convenience methods for messaging between
threads


Sample
- (void)someAction:(id)sender
{
// Fire up a new thread
[NSThread detachNewThreadSelector:@selector(doWork:)
withTarget:self object:someData];
}
- (void)doWork:(id)someData
{
NSAutoreleasePool *pool = [[NSAutoreleasePool alloc] init];
[someData doLotsOfWork];
// Message back to the main thread
[self performSelectorOnMainThread:@selector(allDone:)
withObject:[someData result] waitUntilDone:NO]; ／／同步主线程
[pool release];
}


UIKit and Threads

Unless otherwise noted, UIKit classes are not
threadsafe

Objects must be created and messaged from the
main thread


debug


build thread
- (void)threadDownload:(id)data
{
NSAutoreleasePool *pool=[[NSAutoreleasePool alloc] init];
NSString *urlStr=@"http://www.apple.com/home/images/t_hero.png";
NSData *imageData=[NSData dataWithContentsOfURL:[NSURL
URLWithString:urlStr]];

UIImage *image=[UIImage imageWithData:imageData];
[self performSelectorOnMainThread:@selector(freshUIWith:)
withObject:image waitUntilDone:YES];
[pool drain];
}
- (void)freshUIWith:(UIImage*)image
{

self.imageView.image = image;
}


NSOperation


basic

Abstract superclass

Manages thread creation and lifecycle

Encapsulate a unit of work in an object

•Specify priorities and dependencies


NSOperationQueue

Operations are typically scheduled by adding to a
queue

Choose a maximum number of concurrent
operations

Queue runs operations based on priority and
dependencies


KVC/KVO


Key-Value Coding (KVC)
•Access object values
■ NSString *name = person.name;
■ NSString *name = [person name];
■ NSString *name = [person valueForKey:@“name”];

•Set object values:
■ [person setName:@“Pee-Wee Herman”];
■ person.name = @“Pee-Wee Herman”;
■[person setValue:@“Pee-Wee Herman” forKey:@“name”];


Key-Value Coding (KVC)
•Get/set a value on an object by key (a string)
•First attempts to access via KVC-Compliant getters/setters
•If that fails, attempts to get to value directly

Key Paths
•Traverse objects using dot-separated keys
•Ex: @”person.address.street”
•Must use “keyPath” methods, instead of “key” methods to
automatically parse the string
- (id)valueForKeyPath:(NSString *)keyPath;
- (void)setValue:(id)value forKeyPath:(NSString *)keyPath;


Accessing Undefined Keys
•What if you try to access a key that is undefined?
■NSUndefinedKeyException
•But you can override!
-(id)valueForUndefinedKey:(NSString *)key;
-(void)setValue:(id)value forUndefinedKey:
(NSString *)key;


Key-Value Observing (KVO)

•Listen for changes to an object’s KVC-compliant values

•NSObject automatically broadcasts changes to observers

•No changes required to object being listened to



•To listen for changes:

•To stop listening for changes:
-(void)addObserver:(NSObject *)anObserver
forKeyPath:(NSString *)keyPath
options:(NSKeyValueObservingOptions)options
context:(void *)context;

-(void)removeObserver:(NSObject *)anObserver
forKeyPath:(NSString *)keyPath;


•Observing a value change:
-(void)observeValueForKeyPath:(NSString *)keyPath
ofObject:(id)object
change:(NSDictionary *)change
context:(void *)context
{
if (context == myContext)
{
// Do something
}
else
{
// Don’t forget to call super
}
}


Demo


NSInvocationOperation

Concrete subclass of NSOperation

For lightweight tasks where creating a subclass
is overkill
- (void)someAction:(id)sender
{
NSInvocationOperation *operation =
[[NSInvocationOperation alloc]
initWithTarget:self selector:@selector(doWork:)
object:someObject];
[queue addObject:operation];
[operation release];
}


Apple Push Notiﬁcation
Service


工作流


Block and GCD


Block定义

int (^oneFrom)(int);
!
! oneFrom = ^(int anInt) {
! ! return anInt - 1;
! };
!
! NSLog(@"%d",oneFrom(10));


Writing to Local Variables


typedef void (^ScheduleFetcherResultBlock)(NSArray *classes,
! ! ! ! ! ! ! ! ! ! NSError *error);

- (void)fetchClassesWithBlock:
(ScheduleFetcherResultBlock)theBlock;


- (void)fetchClassesWithBlock:(ScheduleFetcherResultBlock)theBlock {
! // Copy the block to ensure that it is not kept on the stack:
! resultBlock = [theBlock copy];
!
! NSURL *xmlURL = [NSURL URLWithString:
! ! ! ! ! @"http://bignerdranch.com/xml/schedule"];
! NSURLRequest *req = [NSURLRequest requestWithURL:xmlURL
! ! ! ! ! ! ! ! ! !
cachePolicy:NSURLRequestReturnCacheDataElseLoad
! ! ! ! ! ! ! ! ! timeoutInterval:30];
! connection = [[NSURLConnection alloc] initWithRequest:req
! ! ! ! ! ! ! ! ! ! ! ! delegate:self];
! if (connection)
! {
! ! responseData = [[NSMutableData alloc] init];
! }
resultBlock(nil, error);
}


UIViewAnimation style Animation

- (void)setSelectedVeg:(id)sender
{
[selectedVegetableIcon setAlpha:0.0];
! [UIView beginAnimations:@"setSelectedVeg" context:nil];
! float angle = [self spinnerAngleForVegetable:sender];
! [vegetableSpinner
setTransform:CGAffineTransformMakeRotation(angle)];
! [UIView setAnimationDuration:0.4];
! [UIView setAnimationDelegate:self];
! [UIView setAnimationDidStopSelector:@selector(done)];
! [UIView commitAnimations];
!
}
-(void)done
{
! [selectedVegetableIcon setAlpha:1.0];
}


- (void)setSelectedVeg:(id)sender
{

[UIView animateWithDuration:0.4
   animations: ^{
   float angle = [self spinnerAngleForVegetable:sender];
   [vegetableSpinner setTransform:CGAffineTransformMakeRotation(angle)];
   }
   completion:^(BOOL finished) {
   }];

}
以上代码来⾃自WWDC2010 iPlant PlantCareViem.m


NSNotification
! void (^block)(NSNotification *);
! block=^(NSNotification *noti){
! ! NSLog(@"%@",[noti object]);
! };
! queue =[[NSOperationQueue alloc] init];
! [[NSNotificationCenter defaultCenter] addObserverForName:@"Blocktest"
! ! ! ! ! ! ! ! ! ! ! ! ! object:self
! ! ! ! ! ! ! ! ! ! ! ! ! queue:queue
! ! ! ! ! ! ! ! ! ! ! ! usingBlock:block];

[[NSNotificationCenter defaultCenter] postNotificationName:@"Blocktest" object:self];


NSOperation

! void (^oneFrom)(void);
!
! oneFrom = ^(void) {
! ! NSLog(@"from opt");
! };
! NSOperation *opt=[[NSOperation alloc] init];
! [opt setCompletionBlock:oneFrom];
! [queue addOperation:opt];


正则匹配

NSRegularExpression* regex2=nil;
regex2 =[[NSRegularExpression alloc] initWithPattern:@"(?<=>).*?(?=</a>)"
! ! ! ! ! ! ! ! ! ! options:NSRegularExpressionCaseInsensitive error:nil];

[regex enumerateMatchesInString:src options:0 range:NSMakeRange(0, [src length])
! ! usingBlock:^(NSTextCheckingResult *result, NSMatchingFlags flags, BOOL *stop)
{
! ! NSString*resultString = [src substringWithRange:[result range]];
NSRange range0= NSMakeRange(0,[resultString length]);
NSRange range1= [[regex2 firstMatchInString:resultString options:0 range:range0] range];
! ! NSString*link=[resultString substringWithRange:range1];
! ! ! ! ! ! ! !
}];


GCD

Grand Central DIspatch

-(IBAction)extractCurAll:(id)sender
{
! [indicator setHidden:NO];
! [indicator startAnimation:sender];
! NSLog(@"extractCurAll");
!

!
! dispatch_queue_t queue;
! queue = dispatch_queue_create("com.example.operation", NULL);
! dispatch_async(queue, ^{
! ! // Create a CGPDFDocumentRef from the input PDF file.
! ! CGPDFDocumentRef pdfDoc = NULL;
! ! pdfDoc = CGPDFDocumentCreateWithURL((CFURLRef)pdfURL);
! ! [[PDFImageExtrator sharedPDFImageExtrator] setUrl:pdfURL];
! ! [[PDFImageExtrator sharedPDFImageExtrator] ExtratorWithPDF:pdfDoc];
! ! dispatch_async(dispatch_get_main_queue(),^{
! ! ! [indicator stopAnimation:sender];
! ! ! [indicator setHidden:YES];
! ! ! [openBtn setEnabled:YES];
! ! });
! });
! dispatch_release(queue);!
}


use block and GCD

-(void)blockwork
{
dispatch_queue_t queue;
! queue = dispatch_queue_create("com.example.operation", NULL);
! dispatch_async(queue, ^{
! ! // Create a CGPDFDocumentRef from the input PDF file.
NSString *urlStr=@"http://www.apple.com/home/images/
t_hero.png";
NSData *imageData=[NSData dataWithContentsOfURL:[NSURL
URLWithString:urlStr]];

UIImage *image=[UIImage imageWithData:imageData];
! ! dispatch_async(dispatch_get_main_queue(),^{
! ! ! self.imageView.image = image;
! ! });
! });
! dispatch_release(queue);!
}


use GCD change our NSThread Code!


Resource
Session 102 - What's New in Foundation for
iOS 4

Session 110 - Advanced Text Handling for
iPhone OS

Session 206 - Introducing Blocks and
Grand Central Dispatch on iPhone

Session 211 - Simplifying iPhone App
Development with Grand Central Dispatch


Queues Objects Sources
dispatch_queue_t dispatch_object_t dispatch_source_t

dispatch_queue_create dispatch_retain dispatch_source_create
dispatch_queue_get_label dispatch_release dispatch_source_cancel
dispatch_get_main_queue dispatch_suspend dispatch_source_testcancel
dispatch_get_global_queue dispatch_resume dispatch_source_merge_data
dispatch_get_current_queue dispatch_debug dispatch_source_get_handle
dispatch_main dispatch_get_context dispatch_source_get_mask
dispatch_async dispatch_set_context dispatch_source_get_data
dispatch_async_f dispatch_set_finalizer_f dispatch_source_set_timer
dispatch_sync dispatch_set_target_queue dispatch_source_set_event_handler
dispatch_sync_f dispatch_source_set_event_handler_f
dispatch_after dispatch_source_set_cancel_handler
dispatch_after_f dispatch_source_set_cancel_handler_f
dispatch_apply
dispatch_apply_f Groups
dispatch_group_t

dispatch_group_create
Not Objects
dispatch_group_enter
Semaphores dispatch_group_leave
dispatch_semaphore_t dispatch_group_wait Time Once
dispatch_group_notify dispatch_time_t dispatch_once_t
dispatch_semaphore_create dispatch_group_notify_f
dispatch_semaphore_signal dispatch_group_async dispatch_time dispatch_once
dispatch_semaphore_wait dispatch_group_async_f dispatch_walltime dispatch_once_f


Q&A


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