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自己动手写iPhone wap浏览器之BSD Socket引擎篇(手把手教你iphon

2016-08-11 11:19:34 admin 返回上一页

作者:孙东风 2009-12-01(转载请注明出处)

 

在《自己动手写iPhone wap浏览器之预备篇》中笔者讲述了进行iPhone wap浏览器开发的主要流程如下:

²        封装BSD Socket进行HTTP请求。

²        将请求到的WML页面解析成XML数据结构。

²        渲染需要在界面上显示的WML标签(英文名tag)。

²        将渲染后的WML标签显示在界面上(UIView)。

 

在《html" target=_blank>自己动手写iPhone wap浏览器之预备篇》中已经讲述了利用tinyxml解析请求到的XML页面内容的知识,这个章节里主要讲述利用BSD Socket封装HTTP引擎的知识。在笔者的文章《玩转iPhone网络通讯之BSD Socket篇》中已经初步讲解了iPhone中利用BSD Socket进行网络通讯的关键技术点,但是笔者只是把请求的WML页面内容保存在一个缓冲区内。在实际应用中,大多数情况下需要解析请求到的WML页面内容从而区分开HTTP响应的包头、包体,有时候还需要解析HTTP包头的每行内容。要做到这些,首先需要BSD Socket引擎同步的解析请求到的数据,修改部分如下:

 

NSMutableString* readString = [[NSMutableString alloc] init];

char readBuffer[1];

 

int br = 0;

NSMutableString* readHeaderBufferStr = [[NSMutableString alloc] init];

while((br = recv(sockfd, readBuffer, sizeof(readBuffer), 0)))

{

[readHeaderBufferStr appendString:[NSString stringWithCString:readBuffer length:sizeof(readBuffer)]];

 

if([self RecvRespHeaderFinished:readHeaderBufferStr])

{

break;

}else

{

}

}

 

笔者把缓冲区的大小改为1,这样每次读取一个字符到缓冲内并把每次读取到的内容添加到readHeaderBufferStr内,之后调用RecvRespHeaderFinished:readHeaderBufferStr方法判断HTTP头部内容是否读取完成,这个方法的实现如下:

 

- (BOOL)RecvRespHeaderFinished:(NSString*) aReadBuffer

{

    int len = [aReadBuffer length];

    if(len < 12)

    {

        return NO;

    }

   

    if([aReadBuffer characterAtIndex:(len-4)] == (const unichar)&&

        [aReadBuffer characterAtIndex:(len-3)] == (const unichar) &&

        [aReadBuffer characterAtIndex:(len-2)] == (const unichar)&&

        [aReadBuffer characterAtIndex:(len-1)] == (const unichar) )

    {

        NSLog(@"ResponseHeader = %@",aReadBuffer);

        int nCode = [self GetResponseCode:aReadBuffer];

        NSLog(@"get http response code = %d",nCode);

       

        if(nCode > 299 || nCode < 200)

        {

            NSLog(@"ErrMsg:Server response code is %d.",nCode);

            close(sockfd);

        }

       

        contentlen = [[self GetHttpHdrFieldValue:aReadBuffer aField:EContentLength] intValue];

        NSLog(@"contentlen = %d",contentlen);

        return YES;

    }

   

    return NO;

}

 

笔者通过判断缓冲字符串的后四个字符是否依次为’’、’ ’、’’、’ ’来断定HTTP头部是否解析完成,如果解析完成则打印出来并返回YES,否则返回NO,最后并调用GetHttpHdrFieldValue:aReadBuffer:aField方法获取HTTP包头中指定行的value值,在这里笔者需要获取"Content-Length"的value值以便知道HTTP包体的长度,打印结果如下:

 

9-12-01 20:39:03.337 BSDHttpExample[253:207] getIpAddressForHost :220.181.37.183

2009-12-01 20:39:03.404 BSDHttpExample[253:207] Connect errno is :0

2009-12-01 20:39:03.404 BSDHttpExample[253:207] Then the conn is not -1!

2009-12-01 20:39:03.405 BSDHttpExample[253:207] httpCotent is :GET / HTTP/1.1

Host:wap.baidu.com

 

2009-12-01 20:39:03.406 BSDHttpExample[253:207] Sended content is :GET / HTTP/1.1

Host:wap.baidu.com

 

2009-12-01 20:39:03.406 BSDHttpExample[253:207] Datas have been sended over!

send 38 bytes to 220.181.37.183

2009-12-01 20:39:03.501 BSDHttpExample[253:207] ResponseHeader = HTTP/1.1 200 OK

Date: Tue, 01 Dec 2009 12:39:03 GMT

Server: Apache

Content-Length: 4638

Content-Type: text/vnd.wap.wml;charset=utf-8

Age: 0

Cache-Control: no-cache

Expires: -1

Set-Cookie: BAIDU_WISE_UID=frontui_1259671143_7379; Max-Age=800000000; expires=Sun, 08-Apr-35 18:52:23 GMT; path=/; domain=.baidu.com;

Vary: Accept-Encoding,User-Agent

Connection: close

 

 

可见,通过上面的方法成功的解析出来HTTP响应的头部内容并获取到HTTP包体的长度,那么接下来就需要解析HTTP包体的内容了,代码如下:

 

NSMutableString* readBodyBufferStr = [[NSMutableString alloc] init];

while((br = recv(sockfd, readBuffer, sizeof(readBuffer), 0)))

{

if(recLen < contentlen)

{

recLen++;

[readBodyBufferStr appendString:[NSString stringWithCString:readBuffer length:sizeof(readBuffer)]];

}else

{

}

}

NSLog(@"hava received all data = %@",readBodyBufferStr);

 

通过判断包体缓冲字符串的长度和“Content-Length”的值来决定HTTP包体内容是否已经解析完成,打印结果如下:

 

2009-12-01 20:39:03.503 BSDHttpExample[253:207] contentlen = 4638

2009-12-01 20:39:03.532 BSDHttpExample[253:207] hava received all data =

<?xml version="1.0" encoding="utf-8"?><!DOCTYPE wml PUBLIC "-//WAPFORUM//DTD WML 1.1//EN" "

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