The communication between IOS app local Socket_ios

I've seen an article about five ways to communicate between apps, which have URL Scheme,keychain,uipastedboard,uidocumentinteractioncontroller and use sockets for local communication. The first 4 kinds of things have been useful, but also relatively simple, a few lines of code. For the last one has never been used before (forgive me is a little white), so try to write today, here is recorded here and share with you.

Okay, nonsense don't say much, start:

First of all, the principle of it, in fact, is very simple, an app in the local port for TCP bind and listen, and another app on the local same port to connect, so that a normal TCP connection, you can want to pass any data on what data. The following starts by creating a service-side:

1, first use the socket () function to create a socket

* * Socket returns an int value,-1 for Create failure
* The first parameter indicates the protocol family/domain, usually with af_inet (IPV4), Af_inet6 (IPV6), af_local
* The second parameter specifies a set of interface types: Sock_stream,sock_dgram, Sock_seqpacket, and so on
* The third parameter specifies the corresponding transport protocol, such as TCP/UDP, which is generally set to 0来 using this default value.
int sock = socket (af_inet, sock_stream, 0);
if (sock = = 1) {Close
(sock);
NSLog (@ "Socket error:%d", sock);<br> return;
}
 * * Socket returns an int value,-1 for Create failure
 * The first parameter indicates the protocol family/domain, usually with af_inet (IPV4), Af_inet6 (IPV6), af_local
 * The second parameter specifies a set of interface types: Sock_stream,sock_dgram, Sock_seqpacket, and so on
 * The third parameter specifies the corresponding transport protocol, such as TCP/UDP, which is generally set to 0来 using this default value.
int sock = socket (af_inet, sock_stream, 0);
if (sock = = 1) {Close
 (sock);
 NSLog (@ "Socket error:%d", sock);<br> return;

}

2, binding this machine address and port number

Address structure body data, recording IP and port number
struct sockaddr_in sockaddr;
The protocol used by the declaration
sockaddr.sin_family = af_inet;
Gets the native IP, converts to a char-type
const char *IP = [[self getipaddress] cstringusingencoding:nsasciistringencoding];
assigning IP to a struct, the inet_addr () function converts a dotted decimal IP to a long integer number
sockAddr.sin_addr.s_addr = inet_addr (IP);
Set the port number, htons () is the conversion of integer variables from host byte order to network byte order
sockaddr.sin_port = htons (12345);
 /* * Bind function to associate a socket with an address, return an int value,-1 for failure
 * The first parameter specifies a socket, that is, the front socket function call return socket
 * The second parameter is the specified address
 * The third parameter is the size of the address data
 *
/INT bd = bind (sock, (struct sockaddr *) &sockaddr, sizeof (SOCKADDR));
if (BD = = 1) {Close
 (sock);
 NSLog (@ "Bind error:%d", BD);
 return;

}

3, listen to the binding address

 * * Listen function uses the active connection socket interface to become the connected interface, so that it can accept requests from other processes, return an int value,-1 is a failure
 * The first parameter is the socket returned by the socket function
 * The second parameter can be understood as the maximum limit of the connection
 *
/int ls = listen (sock,20);
if (ls = = = 1) {Close
 (sock);
 NSLog (@ "Listen error:%d", ls);
 return;
}

4, the following is waiting for the client connection, using accept () (because the Accept function will block the thread, in the process of waiting for the connection will always be stuck, so it is recommended to put it in the child thread)  

1. Open a child thread

nstread *recvthread = [[Nsthread alloc] initwithtarget:self selector: @selector (RecvData) Object:nil];
[Recvthread start];

-(void) recvdata{
 

//2. Wait for the client to connect

//Declare an address structure that is used to receive the address returned by the client after 
 struct sockaddr_in recvaddr;
Address size
 socklen_t recv_size = sizeof (struct sockaddr_in);
 * * Accept () function returns a new socket (Self.newsock) After the connection is successful, used to send and receive data before and after the client
 * The first parameter is the socket that was previously listening, the local variable, and now it needs to be changed to the global

 * The second parameter is a result parameter that is used to receive a return value that specifies the address of the client
 * The third parameter is also a result parameter, which is used to receive the consignment of the RECVADDR structure, indicating the number
of bytes it occupies. Self.newsock = Accept (Self.sock, (struct sockaddr *) &recvaddr, &recv_size);
3. Come here on behalf of already connected to a new client, the following can send and receive data, mainly used to send () and recv () function
 ssize_t bytesrecv =-1;//return data byte size
 Char RECVDATA[128] = ""; Return data buffer
//If one end is disconnected, RECV returns immediately, Bytesrecv equals 0, then the while loop executes, so the judgment equals 0 is skipped while
 (1) {
 BYTESRECV = Recv (self.newsocket,recvdata,128,0); RecvData for received data
 if (Bytesrecv = = 0) {break
 ; 

 }

}}

5, send data

-(void) sendmessage{ 

 char senddata[32] = "Hello client";

 ssize_t size_t = Send (Self.newsocket, SendData, strlen (SendData), 0);

 

The client side is mainly divided into: Create sockets, according to IP and port number to obtain the server's host address, and then connect, after successful connection to the server to send and receive data, the following we look at the code.

1, and the service end with the socket function to create sockets

int sock = socket (af_inet, sock_stream,0);

if (sock = = 1) {

 

 NSLog (@ "Socket error:%d", sock);

 return;

}

2, get the address of the host

NSString *host = [self getipaddress]; Gets the native IP address
//Returns the hostent structure pointer that contains the host name and address information for a given host name
struct hostent *remotehostent = gethostbyname ([host Utf8string]);
if (remotehostent = = NULL) {Close
 (sock);

 NSLog (@ "Unable to resolve server host name");
 return;
} <br>//configures the IP address and port number that the socket will connect to the host, for the Connect () function
struct in_addr *remoteinaddr = (struct in_addr *) remotehost->h _ADDR_LIST[0];
struct sockaddr_in socktpram;
socketpram.sin_family = Af_int;
Socketpram.sin_addr = *remoteinaddr;

Socketpram.sin_port = htons ([port Intvalue]);

3. Connect the host with Connect () function

 /* * Connect function is usually used for client resume TCP connection, connect the host of the specified address, function return an int value,-1 for failure
 * The first parameter is a socket created by the socket function to connect to the specified host
 * The second parameter is the socket sock the host address and port number to which you want to connect
 * The third parameter is host address size/
int con = connect (sock, (struct sockaddr *) & Socketpram, sizeof (Socketpram));
if (con = = 1) {Close
 (sock);
 NSLog (@ "Connection failed");
 return;

}

NSLog ("connected successfully"); Come to this represents the connection success;

4, after the successful connection can send and receive data

-(Ibaction) SendData: (ID) Sender {
 //Send data
 char senddata[32] = "Hello service";
 ssize_t size_t = Send (Self.sock, SendData, strlen (SendData), 0);
 NSLog (@ "%zd", size_t);
}
 

-(void) recvdata{
 //acceptance data, placed in the child thread
 ssize_t bytesrecv =-1;
 Char recvdata[32] = "";
 while (1) {
 
  bytesrecv = recv (self.sock, RecvData, 0);
  NSLog (@ "%zd%s", bytesrecv,recvdata);
  if (Bytesrecv = = 0) {break
   ;
  }}

 }

All right, I'm going to use the socket for two apps on the local phone. The first time to write a blog, one is to record their own experience, and the second is to share with you, the text has the wrong place I hope you can point out. Finally attach demo address, two items, interested everyone can come down to try:

The above is the entire content of this article, I hope to help you learn, but also hope that we support the cloud habitat community.