IOS网络开发（一）

1 简易的聊天工具

1.1 问题

Socket的英文原义是孔或者插座的意思，通常也称作套接字，用于描述IP地址和端口，是一个通信链的句柄，本案例使用第三方Socket编程框架AsyncSocket框架实现一个简易的聊天工具，并且能够进行文件传输，由于没有服务器本案例将服务器端和客户端写在一个程序中，如图-1所示：

图-1

1.2 方案

首先创建一个SingleViewApplication应用，导入AsyncSocket框架。在Storyboard中搭建聊天界面，上方的Textfield控件用于输入接受端IP地址，中间TextView控件用于展示聊天记录，下方的TextView用于接受用户输入的聊天内容，右下角有一个发送按钮。将这三个控件分别关联成ViewController的输出口属性IPTF、chatRecordTV、chatTV。

接下来首先实现聊天功能，在ViewController中定义三个属性severSocket、clientSocket以及myNewSocket。在viewDidLoad方法中创建服务器端severSocket，将端口号设置为8000，委托对象设置为self。将发送按钮关联成viewController的动作方法send:，实现send:方法，创建客户端对象，获取聊天输入框的内容转化成NSData类型的数据发送出去。

然后ViewController遵守AsyncSocketDelegate协议，分别实现关于socket连接，数据传输以及数据读取的协议方法，更新显示聊天记录内容。

最后实现传输文件功能，传输文件时为了确定所传输文件的类型需要拼接一个消息头，将传输文件的类型、名称和大小保存到消息头里，通常传输数据的开始的100个字节是消息头。在sender:方法中增加拼接消息头的代码。

接受端在接收到文件数据时首先对消息头进行解析，获取到接收文件的类型、大小以及名称，然后再持续接受文件数据，接受完成后将文件保存到本地路径。

1.3 步骤

实现此案例需要按照如下步骤进行。

步骤一：搭建聊天界面

首先创建一个SingleViewApplication应用，导入AsyncSocket框架。在Storyboard中搭建聊天界面，上方的Textfield控件用于输入接受端IP地址，中间TextView控件用于展示聊天记录，下方的TextView用于接受用户输入的聊天内容，如图-2所示：

图-2

然后将这三个控件分别关联成ViewController的输出口属性IPTF、chatRecordTV、chatTV，代码如下所示：

1. @interface ViewController ()
2. @property (weak, nonatomic) IBOutlet UITextField *IPTF;
3. @property (weak, nonatomic) IBOutlet UITextView *chatRecordTV;
4. @property (weak, nonatomic) IBOutlet UITextView *chatTV;
5. @end

步骤二：实现聊天功能

首先在ViewController中定义三个属性severSocket、clientSocket以及myNewSocket，代码如下所示：

1. @interface ViewController ()
2. @property (nonatomic, strong)AsyncSocket *serverSocket;
3. @property (nonatomic, strong)AsyncSocket *clientSocket;
4. @property (nonatomic, strong)AsyncSocket *myNewSocket;
5. @end

其次在viewDidLoad方法中创建服务器端severSocket，将端口号设置为8000，委托对象设置为self，代码如下所示：

1. - (void)viewDidLoad {
2. [super viewDidLoad];
3. self.serverSocket = [[AsyncSocket alloc]initWithDelegate:self];
4. [self.serverSocket acceptOnPort:8000 error:nil];
5. }

将发送按钮关联成viewController的动作方法send:，实现send:方法，创建客户端对象，获取聊天输入框的内容转化成NSData类型的数据发送出去，代码如下所示：

 

1. - (IBAction)send:(UIButton *)sender {
2. [self.chatTV resignFirstResponder];
3. //创建Socket客户端
4. self.clientSocket = [[AsyncSocket alloc]initWithDelegate:self];
5. [self.clientSocket connectToHost:self.IPTF.text onPort:8000 withTimeout:-1 error:nil];
6. //将聊天输入框的内容转化为NSData
7. NSData *data = [self.chatTV.text dataUsingEncoding:NSUTF8StringEncoding];
8. //发送数据
9. [self.clientSocket writeData:data withTimeout:-1 tag:0];
10. self.chatRecordTV.text = [NSString stringWithFormat:@"%@\n我说：%@",self.chatRecordTV.text,self.chatTV.text];
11. }

运行程序发现，点击聊天输入框弹出的键盘会挡住聊天输入框，因此需要在接受用户输入的时候屏幕界面上移，viewController遵守UITextFieldDelegate和UITextViewDelegate协议，当进入输入状况的时候屏幕界面上移，代码如下所示：

1. -(BOOL)textViewShouldBeginEditing:(UITextView *)textView {
2. [UIView beginAnimations:nil context:nil];
3. [UIView setAnimationCurve:UIViewAnimationCurveEaseIn];
4. [UIView setAnimationDuration:0.2];
5. self.view.center = CGPointMake(160, self.view.center.y-200);
6. [UIView commitAnimations];
7. return YES;
8. }

添加一个单击手势。当单击屏幕或者点击发送按钮时键盘收回，屏幕界面恢复正常位置，代码如下所示：

1. //点击发送按钮是
2. - (IBAction)send:(UIButton *)sender {
3. [self.chatTV resignFirstResponder];
4. [UIView beginAnimations:nil context:nil];
5. [UIView setAnimationCurve:UIViewAnimationCurveEaseIn];
6. [UIView setAnimationDuration:0.2];
7. self.view.center = CGPointMake(160, point.y);
8. [UIView commitAnimations];
9. //创建Socket客户端
10. self.clientSocket = [[AsyncSocket alloc]initWithDelegate:self];
11. [self.clientSocket connectToHost:self.IPTF.text onPort:8000 withTimeout:-1 error:nil];
12. //将聊天输入框的内容转化为NSData
13. NSData *data = [self.chatTV.text dataUsingEncoding:NSUTF8StringEncoding];
14. //发送数据
15. [self.clientSocket writeData:data withTimeout:-1 tag:0];
16. self.chatRecordTV.text = [NSString stringWithFormat:@"%@\n我说：%@",self.chatRecordTV.text,self.chatTV.text];
17. }
18. //单击屏幕时
19. - (IBAction)resign:(UITapGestureRecognizer *)sender {
20. if (self.view.center.y!=point.y) {
21. [self.chatTV resignFirstResponder];
22. [UIView beginAnimations:nil context:nil];
23. [UIView setAnimationCurve:UIViewAnimationCurveEaseIn];
24. [UIView setAnimationDuration:0.2];
25. self.view.center = point;
26. [UIView commitAnimations];
27. }
28. }

最后ViewController遵守AsyncSocketDelegate协议，分别实现关于socket连接，数据传输以及数据读取的协议方法，代码如下所示：

1. //当Socket接受一个连接的时候被调用
2. -(void)onSocket:(AsyncSocket *)sock didAcceptNewSocket:(AsyncSocket *)newSocket{
3. //将新接受的socket持有
4. self.myNewSocket = newSocket;
5. }
6. //当Socket连接并准备读和写调用
7. -(void)onSocket:(AsyncSocket *)sock didConnectToHost:(NSString *)host port:(UInt16)port {
8. //持续读取数据
9. [self.myNewSocket readDataWithTimeout:-1 tag:0];
10. }
11. //当Socket读取数据时调用
12. -(void)onSocket:(AsyncSocket *)sock didReadData:(NSData *)data withTag:(long)tag {
13. NSString *chatStr = [[NSString alloc]initWithData:data encoding:NSUTF8StringEncoding];
14. self.chatRecordTV.text = [NSString stringWithFormat:@"%@\n对方说：%@",self.chatRecordTV.text,chatStr];
15. [self.myNewSocket readDataWithTimeout:-1 tag:0];
16. }
17. //持续发送数据
18. -(void)onSocket:(AsyncSocket *)sock didWriteDataWithTag:(long)tag {
19. NSLog(@"发送成功");
20. [self.myNewSocket readDataWithTimeout:-1 tag:0];
21. }

运行程序，聊天效果如图-3所示：

图-3

步骤三：实现文件传输功能

首先定义三个属性用于记录传输文件的数据、名称和大小，代码如下所示：

1. @property (strong,nonatomic) NSMutableData *allData;
2. @property (nonatomic, copy)NSString *reciveFileName;
3. @property (nonatomic, assign)int reciveFileLength;

文件传输需要拼接头文件，将传输文件的类型、大小和名称放进消息头里面，因此在sender:方法中增加拼接消息头的代码，本案例以路径开头区分是发送文件还是聊天，代码如下所示：

1. - (IBAction)send:(UIButton *)sender {
2. [self.chatTV resignFirstResponder];
3. [UIView beginAnimations:nil context:nil];
4. [UIView setAnimationCurve:UIViewAnimationCurveEaseIn];
5. [UIView setAnimationDuration:0.2];
6. self.view.center = CGPointMake(160, point.y);
7. [UIView commitAnimations];
8. self.clientSocket = [[AsyncSocket alloc]initWithDelegate:self];
9. [self.clientSocket connectToHost:self.IPTF.text onPort:8000 withTimeout:-1 error:nil];
10. if (![self.chatTV.text hasPrefix:@"/Users"]) {
11. NSData *data = [self.chatTV.text dataUsingEncoding:NSUTF8StringEncoding];
12. [self.clientSocket writeData:data withTimeout:-1 tag:0];
13. self.chatRecordTV.text = [NSString stringWithFormat:@"%@\n我说：%@",self.chatRecordTV.text,self.chatTV.text];
14. }else {
15. NSString *filePath = self.chatTV.text;
16. NSData *fileData = [NSData dataWithContentsOfFile:filePath];
17. //把头信息添加到文件Data的前面
18. NSString *header = [NSString stringWithFormat:@"file&&%@&&%d",[filePath lastPathComponent],fileData.length];
19. //把头字符串转成data
20. NSData *headerData = [header dataUsingEncoding:NSUTF8StringEncoding];
21. //把头替换进100个字节的data里面
22. NSMutableData *sendAllData = [NSMutableData dataWithLength:100];
23. [sendAllData replaceBytesInRange:NSMakeRange(0, headerData.length) withBytes:headerData.bytes];
24. [sendAllData appendData:fileData];
25. NSLog(@"%@",header);
26. NSLog(@"SendLength = %d",sendAllData.length);
27. [self.clientSocket writeData:sendAllData withTimeout:-1 tag:0];
28. self.chatRecordTV.text = [NSString stringWithFormat:@"%@\n我说：%@正在发送",self.chatRecordTV.text,self.chatTV.text];
29. }
30. }

在读取数据的方法中首先获取消息头信息，如果传递过来的是文件则获取到传输文件的类型、大小和名称，持续读取文件数据，将文件保存到本地路径，接受完成更新聊天记录，代码如下所示：

1. -(void)onSocket:(AsyncSocket *)sock didReadData:(NSData *)data withTag:(long)tag {
2. if (data.length>=100) {
3. NSData *headerData = [data subdataWithRange:NSMakeRange(0, 100)];
4. NSString *headerStr = [[NSString alloc]initWithData:headerData encoding:NSUTF8StringEncoding];
5. if (headerStr&& [headerStr componentsSeparatedByString:@"&&"].count==3) {
6. isFile = YES;
7. }
8. }
9. if (isFile == NO) {
10. NSString *chatStr = [[NSString alloc]initWithData:data encoding:NSUTF8StringEncoding];
11. self.chatRecordTV.text = [NSString stringWithFormat:@"%@\n对方说：%@",self.chatRecordTV.text,chatStr];
12. }
13. if (isFile==YES) {
14. if (data.length>=100) {
15. NSData *headerData = [data subdataWithRange:NSMakeRange(0, 100)];
16. NSString *headerStr = [[NSString alloc]initWithData:headerData encoding:NSUTF8StringEncoding];
17. if (headerStr&& [headerStr componentsSeparatedByString:@"&&"].count==3) {
18. NSArray *headers = [headerStr componentsSeparatedByString:@"&&"];
19. NSString *type = [headers objectAtIndex:0];
20. if ([type isEqualToString:@"file"]) {
21. self.reciveFileName = [headers objectAtIndex:1];
22. self.reciveFileLength = [[headers objectAtIndex:2] intValue];
23. NSData *subFileData = [data subdataWithRange:NSMakeRange(100, data.length-100)];
24. if (!self.allData) {
25. self.allData = [NSMutableData data];
26. }
27. [self.allData appendData:subFileData];
28. }
29. }else {//没有消息头的情况下
30. [self.allData appendData:data];
31. }
32. }else {//没有消息头的情况下
33. [self.allData appendData:data];
34. }
35. NSLog(@"%d,%d",self.allData.length,self.reciveFileLength);
36. if (self.allData.length == self.reciveFileLength ) {
37. NSLog(@"接受完成");
38. NSString *filePath = [@"/Users/Vivian/Documents" stringByAppendingPathComponent:self.reciveFileName];
39. [self.allData writeToFile:filePath atomically:YES];
40. self.chatRecordTV.text = [NSString stringWithFormat:@"%@\n对方说：成功接收文件%@",self.chatRecordTV.text,self.reciveFileName];
41. self.allData = nil;
42. isFile = NO;
43. }
44. if (isFile == YES) {
45. //如果有数据能够持续接受
46. [self.myNewSocket readDataWithTimeout:-1 tag:0];
47. }
48. }
49. }

运行程序，传输文件效果如图-4所示：

图-4

1.4 完整代码

本案例中，ViewController.m文件中的完整代码如下所示：

 

1. #import "ViewController.h"
2. @interface ViewController () <AsyncSocketDelegate,UITextFieldDelegate,UITextViewDelegate> {
3. BOOL isFile;
4. CGPoint point;
5. }
6. @property (weak, nonatomic) IBOutlet UITextField *IPTF;
7. @property (weak, nonatomic) IBOutlet UITextView *chatRecordTV;
8. @property (weak, nonatomic) IBOutlet UITextView *chatTV;
9. @property (nonatomic, strong)AsyncSocket *serverSocket;
10. @property (nonatomic, strong)AsyncSocket *clientSocket;
11. @property (nonatomic, strong)AsyncSocket *myNewSocket;
12. @property (strong,nonatomic) NSMutableData *allData;
13. @property (nonatomic, copy)NSString *reciveFileName;
14. @property (nonatomic, assign)int reciveFileLength;
15. @end
16. @implementation ViewController
17. - (void)viewDidLoad {
18. [super viewDidLoad];
19. self.serverSocket = [[AsyncSocket alloc]initWithDelegate:self];
20. [self.serverSocket acceptOnPort:8000 error:nil];
21. point = self.view.center;
22. self.allData = [NSMutableData data];
23. isFile = NO;
24. }
25. -(void)onSocket:(AsyncSocket *)sock didAcceptNewSocket:(AsyncSocket *)newSocket{
26. //将新接受的socket持有
27. self.myNewSocket = newSocket;
28. }
29. -(void)onSocket:(AsyncSocket *)sock didConnectToHost:(NSString *)host port:(UInt16)port {
30. [self.myNewSocket readDataWithTimeout:-1 tag:0];
31. }
32. -(void)onSocket:(AsyncSocket *)sock didReadData:(NSData *)data withTag:(long)tag {
33. if (data.length>=100) {
34. NSData *headerData = [data subdataWithRange:NSMakeRange(0, 100)];
35. NSString *headerStr = [[NSString alloc]initWithData:headerData encoding:NSUTF8StringEncoding];
36. if (headerStr&& [headerStr componentsSeparatedByString:@"&&"].count==3) {
37. isFile = YES;
38. }
39. }
40. if (isFile == NO) {
41. NSString *chatStr = [[NSString alloc]initWithData:data encoding:NSUTF8StringEncoding];
42. self.chatRecordTV.text = [NSString stringWithFormat:@"%@\n对方说：%@",self.chatRecordTV.text,chatStr];
43. }
44. if (isFile==YES) {
45. if (data.length>=100) {
46. NSData *headerData = [data subdataWithRange:NSMakeRange(0, 100)];
47. NSString *headerStr = [[NSString alloc]initWithData:headerData encoding:NSUTF8StringEncoding];
48. if (headerStr&& [headerStr componentsSeparatedByString:@"&&"].count==3) {
49. NSArray *headers = [headerStr componentsSeparatedByString:@"&&"];
50. NSString *type = [headers objectAtIndex:0];
51. if ([type isEqualToString:@"file"]) {
52. self.reciveFileName = [headers objectAtIndex:1];
53. self.reciveFileLength = [[headers objectAtIndex:2] intValue];
54. NSData *subFileData = [data subdataWithRange:NSMakeRange(100, data.length-100)];
55. if (!self.allData) {
56. self.allData = [NSMutableData data];
57. }
58. [self.allData appendData:subFileData];
59. }
60. }else {//没有消息头的情况下
61. [self.allData appendData:data];
62. }
63. }else {//没有消息头的情况下
64. [self.allData appendData:data];
65. }
66. NSLog(@"%d,%d",self.allData.length,self.reciveFileLength);
67. if (self.allData.length == self.reciveFileLength ) {
68. NSLog(@"接受完成");
69. NSString *filePath = [@"/Users/Vivian/Documents" stringByAppendingPathComponent:self.reciveFileName];
70. [self.allData writeToFile:filePath atomically:YES];
71. self.chatRecordTV.text = [NSString stringWithFormat:@"%@\n对方说：成功接收文件%@",self.chatRecordTV.text,self.reciveFileName];
72. self.allData = nil;
73. isFile = NO;
74. }
75. if (isFile == YES) {
76. //如果有数据能够持续接受
77. [self.myNewSocket readDataWithTimeout:-1 tag:0];
78. }
79. }
80. }
81. -(void)onSocket:(AsyncSocket *)sock didWriteDataWithTag:(long)tag {
82. NSLog(@"发送成功");
83. [self.myNewSocket readDataWithTimeout:-1 tag:0];
84. }
85. -(BOOL)textViewShouldBeginEditing:(UITextView *)textView {
86. [UIView beginAnimations:nil context:nil];
87. [UIView setAnimationCurve:UIViewAnimationCurveEaseIn];
88. [UIView setAnimationDuration:0.2];
89. self.view.center = CGPointMake(160, self.view.center.y-200);
90. [UIView commitAnimations];
91. return YES;
92. }
93. - (IBAction)send:(UIButton *)sender {
94. [self.chatTV resignFirstResponder];
95. [UIView beginAnimations:nil context:nil];
96. [UIView setAnimationCurve:UIViewAnimationCurveEaseIn];
97. [UIView setAnimationDuration:0.2];
98. self.view.center = CGPointMake(160, point.y);
99. [UIView commitAnimations];
100. self.clientSocket = [[AsyncSocket alloc]initWithDelegate:self];
101. [self.clientSocket connectToHost:self.IPTF.text onPort:8000 withTimeout:-1 error:nil];
102. if (![self.chatTV.text hasPrefix:@"/Users"]) {
103. NSData *data = [self.chatTV.text dataUsingEncoding:NSUTF8StringEncoding];
104. [self.clientSocket writeData:data withTimeout:-1 tag:0];
105. self.chatRecordTV.text = [NSString stringWithFormat:@"%@\n我说：%@",self.chatRecordTV.text,self.chatTV.text];
106. }else {
107. NSString *filePath = self.chatTV.text;
108. NSData *fileData = [NSData dataWithContentsOfFile:filePath];
109. //把头信息添加到文件Data的前面
110. NSString *header = [NSString stringWithFormat:@"file&&%@&&%d",[filePath lastPathComponent],fileData.length];
111. //把头字符串转成data
112. NSData *headerData = [header dataUsingEncoding:NSUTF8StringEncoding];
113. //把头替换进100个字节的data里面
114. NSMutableData *sendAllData = [NSMutableData dataWithLength:100];
115. [sendAllData replaceBytesInRange:NSMakeRange(0, headerData.length) withBytes:headerData.bytes];
116. [sendAllData appendData:fileData];
117. NSLog(@"%@",header);
118. NSLog(@"SendLength = %d",sendAllData.length);
119. [self.clientSocket writeData:sendAllData withTimeout:-1 tag:0];
120. self.chatRecordTV.text = [NSString stringWithFormat:@"%@\n我说：%@正在发送",self.chatRecordTV.text,self.chatTV.text];
121. }
122. }
123. - (IBAction)done:(UITextField *)sender {
124. [self.IPTF resignFirstResponder];
125. }
126. - (IBAction)resign:(UITapGestureRecognizer *)sender {
127. if (self.view.center.y!=point.y) {
128. [self.chatTV resignFirstResponder];
129. [UIView beginAnimations:nil context:nil];
130. [UIView setAnimationCurve:UIViewAnimationCurveEaseIn];
131. [UIView setAnimationDuration:0.2];
132. self.view.center = point;
133. [UIView commitAnimations];
134. }
135. }
136. @end