iOS Learning notes-network programming

I. HTTP protocol
1. Interview questions: Talk about the HTTP protocol (express your view of the HTTP protocol)
* Full name of HTTP protocol: Hypertext Transfer Protocol, specification for custom transfer data (data transfer specification between client and server)
* Describe the HTTP protocol complete communication process

2. Communication process
1> Request
* Client-to-server
* Content of the request
A. " Request Line: Request method \ Request Resource Path \http protocol version
Get/mjserver/login?username=123&pwd=123&method=get&type=json http/1.1

B. " Request Header ": Client-side information
host:192.168.1.200:8080
User-agent:iphone Simulator; IPhone OS 7.1; en_US
Accept:text/html
accept-language:zh-cn,zh;q=0.8,en-us;q=0.5,en;q=0.3
Accept-encoding:gzip, deflate

C. " Request Body ": POST request only need to have, store specific data
* such as file data
* such as the parameter data of the POST request

2> response
* Server-to-client
* Content of the response
A. " Status line ": HTTP protocol version \ Status code \ Status information, also known as" response line "
http/1.1 OK

B. " Response Header ": Server information \ type of returned data \ length of returned data
server:apache-coyote/1.1
Content-type:application/json;charset=utf-8
content-length:248

C. " Entity content ": the specific content returned to the client, also known as the" response body "
* such as JSON data returned by the server
* such as file data returned by the server

3.HTTP method of Request
1> GET
* Parameters are stitched behind the URL
* Parameters are Limited

2> POST
* Parameters are in the request body
* No restrictions on parameters
* File upload can only be used post

3> head: Get response header information without getting the response body

The means of sending get\post requests in 4.iOS
1> nsurlconnection
* Apple native
* It's more complicated than Asi\afn.

2> ASI
* Based on Cfnetwork
* Provides a lot of powerful features, easy to use

3> AFN
* Based on Nsurlconnection
* Provides a common function, easy to use

4> recommendations
* In order to improve development efficiency and reduce the time spent debugging, try to use the famous simple third-party framework
* Therefore, to process HTTP requests, it is more recommended to use the ASI latter AFN

Two. nsurlconnection
1. Sending the request
1> Send a sync request
+ (NSData *) Sendsynchronousrequest: (nsurlrequest *) Request Returningresponse: (Nsurlresponse *) Response error: ( Nserror * *) error;

2> sending an asynchronous request (block)
+ (void) Sendasynchronousrequest: (nsurlrequest*) Request
Queue: (nsoperationqueue*) queue
Completionhandler: (void (^) (nsurlresponse* response, nsdata* data, nserror* connectionerror)) handler;

3> sending an asynchronous request (proxy method)
[Nsurlconnection connectionwithrequest:request delegate:self];
[[Nsurlconnection alloc] initwithrequest:request delegate:self];
[[Nsurlconnection alloc] initwithrequest:request delegate:self Startimmediately:yes];

Nsurlconnection *conn = [[Nsurlconnection alloc] initwithrequest:request delegate:self Startimmediately:no];
[Conn start];

2. File Download (large file download)
1> implementation scenario: Side Download Side writes (writes to a file in the sandbox)
2> Concrete Implementation Steps
A. When receiving a response from the server
Create an empty file-Nsfilemanager
[Mgr CreateFileAtPath:self.destPath Contents:nil Attributes:nil];

Creates a handle object associated with an empty file-Nsfilehandle
[Nsfilehandle FileHandleForWritingAtPath:self.destPath];

B. When receiving data from the server
Writes the data returned by the server to the end of the file using a handle object
Move to the end of a file
[Self.writehandle Seektoendoffile];
Writes data starting at the current moving position (end of file)
[Self.writehandle Writedata:data];

C. When the data returned by the server is received
Close handle
[Self.writehandle CloseFile];
Self.writehandle = nil;

3. Breakpoint Download
1> Key Technology points
* Set the request header range to tell the server which data to download

4. File Upload
1> Clear
* Can only be requested by post
* Request parameters are in the request body (file parameters \ non-file type of normal parameters)

2> implementation Steps
A. Stitching the request body (file parameters \ non-file type of normal parameters)
* File Parameters
Start tag of the parameter (split line)
--heima\r\n
Parameter description (parameter name ...)
Content-disposition:form-data; Name= "parameter name"; filename= "filename" \ r \ n
File type
Content-type: type of File mimetype\r\n
Binary data for files (parameter values)
\ r \ n
Binary data for files
\ r \ n

* Non-file parameters (normal parameters)
Start tag of the parameter (split line)
--heima\r\n
Parameter description (parameter name ...)
Content-disposition:form-data; Name= "parameter name" \ r \ n
Parameter values
\ r \ n
Parameter values
\ r \ n

* Mark end of all parameters
--heima--\r\n

B. Setting the request header
* Length of the request body
Content-length: Length of the request body (bytes length)

* Type of request data
Content-type:
Normal POST request: application/x-www-form-urlencoded
Post request to upload file: multipart/form-data; Boundary=--heima

5.JSON and XML
1>. JSON conversion to OC data type
In iOS, there are 4 common parsing scenarios for JSON
Third-party frameworks: Jsonkit, Sbjson, Touchjson (performance from left to right, worse)
Apple native (comes with): Nsjsonserialization (Best performance)
Common methods of Nsjsonserialization
OC object, JSON data
+ (ID) jsonobjectwithdata: (NSData *) Data options: (nsjsonreadingoptions) opt error: (NSERROR *) error;
OC Object--JSON data
+ (NSData *) Datawithjsonobject: (ID) obj options: (nsjsonwritingoptions) opt error: (NSERROR *) error;
2>. Convert XML to OC data type
There are 2 ways to parse XML
DOM: Loading an entire XML document into memory at once, which is more suitable for parsing small files
SAX: Starting from the root element, in order to parse an element down, it is more suitable for parsing large files
Apple native
Nsxmlparser:sax method analysis, easy to use
Third-party frameworks
LIBXML2: pure C language, which is included by default in the iOS SDK while supporting DOM and sax parsing
Gdataxml:dom method Analysis, developed by Google, based on LIBXML2
A. Nsxmlparser
Incoming XML data, creating a parser
Nsxmlparser *parser = [[Nsxmlparser alloc] initwithdata:data];
Set up the agent to listen to the parsing process
Parser.delegate = self;
Start parsing
[Parser parse];
Nsxmlparserdelegate
Called when scanning to the beginning of a document (parsing is started)
-(void) Parserdidstartdocument: (Nsxmlparser *) parser
Called when scanning to the end of a document (parsing is complete)
-(void) Parserdidenddocument: (Nsxmlparser *) parser
Called when scanning to the beginning of an element (Attributedict holds the attributes of the element)
-(void) Parser: (Nsxmlparser *) parser didstartelement: (NSString *) elementname NamespaceURI: (NSString *) NamespaceURI QualifiedName: (NSString *) QName attributes: (nsdictionary *) attributedict
Called when scanning to the end of an element
-(void) Parser: (Nsxmlparser *) parser didendelement: (NSString *) elementname NamespaceURI: (NSString *) NamespaceURI QualifiedName: (NSString *) qName

Three. Nsurlcache
Steps to use the cache
Get a global cache object
Nsurlcache *cache = [Nsurlcache Sharedurlcache];

Set Cache capacity
cache.memorycapacity = 1024 * 1024;
cache.diskcapacity = 20 * 1024 * 1024;

Set the requested cache policy
Request.cachepolicy = Nsurlrequestreturncachedataelseload;

Four. ASI
1. Steps to use the cache
1> Caching Individual requests
1. Get a global cache object (determines where the cache is stored and where to store it)
Asidownloadcache *cache = [Asidownloadcache Sharedcache];
Set the default cache load policy
Cache.defaultcachepolicy = Asidonotreadfromcachecachepolicy;

2. Set the cache object for the request object (which cache object to use)
Request.downloadcache = cache;

3. Set the cache load policy for the request object
Request.cachepolicy = Asionlyloadifnotcachedcachepolicy;
Send a request if there is no cache

4. Set the cache storage policy for the request object (length of storage)
Request.cachestoragepolicy = Asicachepermanentlycachestoragepolicy;
Permanent storage

Note the priority of the cache load policy: request.cachepolicy > Cache.defaultcachepolicy

2> Cache all requests
1. Get a global cache object (determines where the cache is stored and where to store it)
Asidownloadcache *cache = [Asidownloadcache Sharedcache];
Set the default cache load policy
Cache.defaultcachepolicy = Asionlyloadifnotcachedcachepolicy;

2. Setting the global Cache object
[ASIHTTPRequest Setdefaultcache:cache];

2. Sending the request
1> Sync Request
[Request startsynchronous];

2> Asynchronous requests
[Request startasynchronous];

3.get\post
1> GET Request
ASIHTTPRequest *request = [ASIHTTPRequest Requestwithurl:url];

2> POST Request
Asiformdatarequest *request = [Asiformdatarequest Requestwithurl:url];
Add normal parameter (non-file parameter)
[Request setpostvalue:@ "Zhangsan" forkey:@ "username"];
[Request setpostvalue:@ "123" forkey:@ "pwd"];

4. File download
The path to where files are stored (where files are downloaded)
Request.downloaddestinationpath = filepath;
Set up Download agent (listen for download progress)
Request.downloadprogressdelegate = Self.circleview;
Support Breakpoint Download
Request.allowresumeforfiledownloads = YES;

5. File Upload
Add File parameter (file: path to upload files)
[Request Setfile:file forkey:@ "file"];
[Request Setfile:file withfilename:@ "123.txt" andcontenttype:@ "Text/plain" forkey:@ "file"];
[Request Setdata:data withfilename:@ "Minion.png" andcontenttype:@ "image/png" forkey:@ "file"];

Set up upload agent (listen for upload progress)
Request.uploadprogressdelegate = Self.circleview;

6. The process of listening for requests
1> Proxy method
Set up Proxy
Request.delegate = self;
Compliance Agreement
Asihttprequestdelegate
Implementing proxy methods in the Protocol
-(void) requeststarted: (asihttprequest *) request;
-(void) Request: (ASIHTTPRequest *) Request Didreceivedata: (NSData *) data
-(void) requestfinished: (asihttprequest *) request;
-(void) requestfailed: (asihttprequest *) request;

2> SEL
Set up Proxy
Request.delegate = self;
Set method Name
[Request Setdidstartselector: @selector (start)]; Starts sending the request, the proxy's Start method is invoked
// ....

3> Block
[Request setstartedblock:^{
NSLog (@ "setstartedblock----");
}];

[Request setdatareceivedblock:^ (NSData *data) {
NSLog (@ "setdatareceivedblock----");
}];

[Request setcompletionblock:^{
NSLog (@ "setcompletionblock----");
}];

[Self setfailedblock:^{
NSLog (@ "setfailedblock----");
}];

7. Get the server's response through the request object
1> Getting response header information
@property (Atomic, retain) Nsdictionary *responseheaders;

2> Get response Body (entity content)
-(NSData *) responsedata; Returns binary data directly to the server
-(NSString *) responsestring; Convert binary data to strings (easy debugging)

Five. AFN
1.get\post
1> GET Request
1. Obtaining the Request Manager
Afhttprequestoperationmanager *mgr = [Afhttprequestoperationmanager manager];

2. Package Request Parameters
Nsmutabledictionary *params = [Nsmutabledictionary dictionary];
params[@ "username"] = @ "123";
params[@ "pwd"] = @ "123";

3. Send a GET request
[Mgr get:@ "Http://192.168.1.200:8080/MJServer/login" Parameters:params
success:^ (afhttprequestoperation *operation, id responseobject) {
NSLog (@ "Request successfully---%@", responseobject);
}
failure:^ (afhttprequestoperation *operation, Nserror *error) {
NSLog (@ "Request failed---%@", error);
}];

2> POST Request
1. Obtaining the Request Manager
Afhttprequestoperationmanager *mgr = [Afhttprequestoperationmanager manager];

2. Package Request Parameters
Nsmutabledictionary *params = [Nsmutabledictionary dictionary];
params[@ "username"] = @ "123";
params[@ "pwd"] = @ "123";

3. Send a POST request
[Mgr post:@ "Http://192.168.1.200:8080/MJServer/login" Parameters:params
success:^ (afhttprequestoperation *operation, id responseobject) {
NSLog (@ "Request successfully---%@", responseobject);
}
failure:^ (afhttprequestoperation *operation, Nserror *error) {
NSLog (@ "Request failed---%@", error);
}];

2. File Upload
1. Obtaining the Request Manager
Afhttprequestoperationmanager *mgr = [Afhttprequestoperationmanager manager];

2. Send the request (do file upload)
#warning parameters: Only non-file parameters can be placed
Nsmutabledictionary *params = [Nsmutabledictionary dictionary];
params[@ "username"] = @ "Zhangsan";

[Mgr post:@ "Http://192.168.1.200:8080/MJServer/upload" Parameters:params
constructingbodywithblock:^ (id<afmultipartformdata> formData) {
Be sure to add the file parameter to this block

Loading file data
NSString *file = [[NSBundle mainbundle] pathforresource:@ "test.txt" oftype:nil];
NSData *data = [NSData datawithcontentsoffile:file];

Stitching file Parameters
[FormData appendpartwithfiledata:data name:@ "file" filename:@ "123.txt" mimetype:@ "Text/plain"];
}
success:^ (afhttprequestoperation *operation, id responseobject) {
NSLog (@ "Upload successful----%@", responseobject);
} failure:^ (Afhttprequestoperation *operation, Nserror *error) {
NSLog (@ "Upload failed----%@", error);
}];

Six. Network Status monitoring
1.Reachability
Notification of monitoring network status changes
[[Nsnotificationcenter Defaultcenter] addobserver:self selector: @selector (networkstatechange) Name: Kreachabilitychangednotification Object:nil];

Create reachability
Self.conn = [reachability reachabilityforinternetconnection];
Start monitoring the network (notify Kreachabilitychangednotification once the network status changes)
[Self.conn Startnotifier];

Handling Network status changes
-(void) Networkstatechange
{
1. Detect WiFi Status
reachability *wifi = [reachability Reachabilityforlocalwifi];

2. Check whether the mobile phone can be on the network (wifi\3g\2.5g)
reachability *conn = [reachability reachabilityforinternetconnection];

3. Determine network status
if ([WiFi currentreachabilitystatus]! = notreachable) {//WiFi available
NSLog (@ "WiFi");
} else if ([conn currentreachabilitystatus]! = notreachable) {//not using WiFi, use your phone to bring your own network to the Internet
NSLog (@ "Use your phone to bring your own network to the Internet");
} else {//no network
NSLog (@ "no network");
}
}

2.AFN
1. Managers who have access to network monitoring
Afnetworkreachabilitymanager *mgr = [Afnetworkreachabilitymanager Sharedmanager];

2. Set up the processing after the network status change
[Mgr setreachabilitystatuschangeblock:^ (afnetworkreachabilitystatus status) {
When the network state changes, the block is called
Switch (status) {
Case Afnetworkreachabilitystatusunknown://Unknown network
NSLog (@ "Unknown network");
Break

Case afnetworkreachabilitystatusnotreachable://No network (off-grid)
NSLog (@ "No network (off-Grid)");
Break

Case Afnetworkreachabilitystatusreachableviawwan://Phone comes with network
NSLog (@ "Mobile phone comes with network");
Break

Case Afnetworkreachabilitystatusreachableviawifi://WIFI
NSLog (@ "WIFI");
Break
}
}];

3. Start monitoring
[Mgr Startmonitoring];

Seven. What is the difference between ASI and AFN?
1. Performance (Focus)
* ASI based on the underlying cfnetwork framework
* AFN based on nsurlconnection
* Operating performance: ASI > ASN

2. Processing server data
1> AFN: Automatic parsing based on data returned by the server
* The server returns JSON data, automatically converted to nsdictionary or Nsarray
* The server returns XML data and is automatically converted to Nsxmlparser

2> ASI: Does not parse the server data, directly returns the NSData binary data

3. Process of processing requests
1> afn:success and failure two blocks
2> ASI: There are 3 ways to handle the request process (proxy method \sel\block)

Features of 3.ASI (emphasis)
1> Cache

2> Download and upload
* Easy monitoring of Request progress
* Easy to implement breakpoint download (ASI does not have breakpoint upload function, breakpoint upload to use socket technology)

3> provides a number of expansion interfaces (such as data compression)
* ASIDataCompressor.h
* ASIDataDecompressor.h

4> asihttprequest inherit from Nsoperation
* All requests can be managed uniformly by queue
* Requests can depend on each other

5> Asinetworkqueue
* Unified management of all requests
* 5 downloads \ Upload Request-Asinetworkqueue: Monitor total progress of 5 requests
* Listen for all requests start \ Fail \ Complete
* Shouldcancelallrequestsonfailure
YES: A request in the queue failed and all other requests were canceled
No: One of the requests in the queue failed, the other requests are not affected, and the request continues

Features of 4.AFN
1> Easy to use
2> comes with a network monitoring function