来源: 互联网  发布时间: 2013-11-30

确定重复出现

到现在为止，你已经知道如何去匹配一个字母或数字，但更多的情况下，可能要匹配一个单词或一组数字。一个单词有若干个字母组成，一组数字有若干个单数组成。跟在字符或字符簇后面的花括号({})用来确定前面的内容的重复出现的次数。

字符簇 含义
^[a-zA-Z_]$ 所有的字母和下划线
^[[:alpha:]]{3}$ 所有的3个字母的单词
^a$ 字母a
^a{4}$ aaaa
^a{2,4}$ aa,aaa或aaaa
^a{1,3}$ a,aa或aaa
^a{2,}$ 包含多于两个a的字符串
^a{2,} 如：aardvark和aaab，但apple不行
a{2,} 如：baad和aaa，但Nantucket不行
\t{2} 两个制表符
.{2} 所有的两个字符

这些例子描述了花括号的三种不同的用法。一个数字，{x}的意思是“前面的字符或字符簇只出现x次”；一个数字加逗号，{x,}的意思是“前面的内容出现x或更多的次数”；两个用逗号分隔的数字，{x,y}表示“前面的内容至少出现x次，但不超过y次”。我们可以把模式扩展到更多的单词或数字：

^[a-zA-Z0-9_]{1,}$ //所有包含一个以上的字母、数字或下划线的字符串
^[0-9]{1,}$ //所有的正数
^\-{0,1}[0-9]{1,}$ //所有的整数
^\-{0,1}[0-9]{0,}\.{0,1}[0-9]{0,}$ //所有的小数

最后一个例子不太好理解，是吗？这么看吧：与所有以一个可选的负号(\-{0,1})开头(^)、跟着0个或更多的数字([0-9]{0,})、和一个可选的小数点(\.{0,1})再跟上0个或多个数字([0-9]{0,})，并且没有其他任何东西($)。下面你将知道能够使用的更为简单的方法。

特殊字符"?"与{0,1}是相等的，它们都代表着：“0个或1个前面的内容”或“前面的内容是可选的”。所以刚才的例子可以简化为：

^\-?[0-9]{0,}\.?[0-9]{0,}$

特殊字符"*"与{0,}是相等的，它们都代表着“0个或多个前面的内容”。最后，字符"+"与 {1,}是相等的，表示“1个或多个前面的内容”，所以上面的4个例子可以写成：

^[a-zA-Z0-9_]+$ //所有包含一个以上的字母、数字或下划线的字符串
^[0-9]+$ //所有的正数
^\-?[0-9]+$ //所有的整数
^\-?[0-9]*\.?[0-9]*$ //所有的小数

当然这并不能从技术上降低正规表达式的复杂性，但可以使它们更容易阅读。

    

    来源: 互联网  发布时间: 2013-11-30

test_smtp.php

<?
require("smtp.php");

$smtp=new smtp_class;

$smtp->host_name="mail.xiaocui.com";
$smtp->localhost="localhost";
$from="webmaster@xiaocui.com";
$to="root@xiaocui.com";
if($smtp->SendMessage(
  $from,
  array(
   $to
  ),
  array(
   "From: $from",
   "To: $to",
   "Subject: Testing Manuel Lemos' SMTP class"
  ),
  "Hello $to,\n\nIt is just to let you know that your SMTP class is working just fine.\n\nBye.\n"))
  echo "Message sent to $to OK.\n";
else
  echo "Cound not send the message to $to.\nError: ".$smtp->error."\n"
?>

smtp.php

<?

class smtp_class
{
var $host_name="";
var $host_port=25;
var $localhost="";
var $timeout=0;
var $error="";
var $debug=1;
var $esmtp=1;
var $esmtp_host="";
var $esmtp_extensions=array();
var $maximum_piped_recipients=100;

/* private variables - DO NOT ACCESS */

var $state="Disconnected";
var $connection=0;
var $pending_recipients=0;

/* Private methods - DO NOT CALL */

Function OutputDebug($message)
{
  echo $message,"<br>\n";
}

Function GetLine()
{
  for($line="";;)
  {
   if(feof($this->connection))
   {
    $this->error="reached the end of stream while reading from socket";
    return(0);
   }
   if(($data=fgets($this->connection,100))==false)
   {
    $this->error="it was not possible to read line from socket";
    return(0);
   }
   $line.=$data;
   $length=strlen($line);
   if($length>=2
   && substr($line,$length-2,2)=="\r\n")
   {
    $line=substr($line,0,$length-2);
    if($this->debug)
     $this->OutputDebug("< $line");
    return($line);
   }
  }
}

Function PutLine($line)
{
  if($this->debug)
   $this->OutputDebug("> $line");
  if(!fputs($this->connection,"$line\r\n"))
  {
   $this->error="it was not possible to write line to socket";
   return(0);
  }
  return(1);
}

Function PutData($data)
{
  if(strlen($data))
  {
   if($this->debug)
    $this->OutputDebug("> $data");
   if(!fputs($this->connection,$data))
   {
    $this->error="it was not possible to write data to socket";
    return(0);
   }
  }
  return(1);
}

Function VerifyResultLines($code,$responses="")
{
  if(GetType($responses)!="array")
   $responses=array();
  Unset($match_code);

  while(($line=$this->GetLine($this->connection)))
  {
   if(IsSet($match_code))
   {
    if(strcmp(strtok($line," -"),$match_code))
    {
     $this->error=$line;
     return(0);
    }
   }
   else
   {
    $match_code=strtok($line," -");
    if(GetType($code)=="array")
    {
     for($codes=0;$codes<count($code) && strcmp($match_code,$code[$codes]);$codes++);
     if($codes>=count($code))
     {
      $this->error=$line;
      return(0);
     }
    }
    else
    {
     if(strcmp($match_code,$code))
     {
      $this->error=$line;
      return(0);
     }
    }
   }
   $responses[]=strtok("");
   if(!strcmp($match_code,strtok($line," ")))
    return(1);
  }
  return(-1);
}

Function FlushRecipients()
{
  if($this->pending_sender)
  {
   if($this->VerifyResultLines("250")<=0)
    return(0);
   $this->pending_sender=0;
  }
  for(;$this->pending_recipients;$this->pending_recipients--)
  {
   if($this->VerifyResultLines(array("250","251"))<=0)
    return(0);
  }
  return(1);
}

/* Public methods */

Function Connect()
{
  $this->error=$error="";
   $this->esmtp_host="";
   $this->esmtp_extensions=array();
  if(!($this->connection=($this->timeout ? fsockopen($this->host_name,$this->host_port,&$errno,&$error,$this->timeout) : fsockopen($this->host_name,$this->host_port))))
  {
   switch($error)
   {
    case -3:
     $this->error="-3 socket could not be created";
     return(0);
    case -4:
     $this->error="-4 dns lookup on hostname \"".$host_name."\" failed";
     return(0);
    case -5:
     $this->error="-5 connection refused or timed out";
     return(0);
    case -6:
     $this->error="-6 fdopen() call failed";
     return(0);
    case -7:
     $this->error="-7 setvbuf() call failed";
     return(0);
    default:
     $this->error=$error." could not connect to the host \"".$this->host_name."\"";
     return(0);
   }
  }
  else
  {
   if(!strcmp($localhost=$this->localhost,"")
   && !strcmp($localhost=getenv("SERVER_NAME"),"")
   && !strcmp($localhost=getenv("HOST"),""))
     $localhost="localhost";
    $success=0;
    if($this->VerifyResultLines("220")>0)
    {
     if($this->esmtp)
     {
      $responses=array();
      if($this->PutLine("EHLO $localhost")
      && $this->VerifyResultLines("250",&$responses)>0)
      {
       $this->esmtp_host=strtok($responses[0]," ");
       for($response=1;$response<count($responses);$response++)
       {
        $extension=strtoupper(strtok($responses[$response]," "));
        $this->esmtp_extensions[$extension]=strtok("");
       }
       $success=1;
      }
     }
     if(!$success
     && $this->PutLine("HELO $localhost")
     && $this->VerifyResultLines("250")>0)
      $success=1;
   }
   if($success)
   {
    $this->state="Connected";
    return(1);
   }
   else
   {
    fclose($this->connection);
    $this->connection=0;
    $this->state="Disconnected";
    return(0);
   }
  }
}

Function MailFrom($sender)
{
  if(strcmp($this->state,"Connected"))
  {
   $this->error="connection is not in the initial state";
   return(0);
  }
  $this->error="";
  if(!$this->PutLine("MAIL FROM: <".$sender.">"))
   return(0);
  if(!IsSet($this->esmtp_extensions["PIPELINING"])
  && $this->VerifyResultLines("250")<=0)
   return(0);
  $this->state="SenderSet";
  if(IsSet($this->esmtp_extensions["PIPELINING"]))
   $this->pending_sender=1;
  $this->pending_recipients=0;
  return(1);
}

Function SetRecipient($recipient)
{
  switch($this->state)
  {
   case "SenderSet":
   case "RecipientSet":
    break;
   default:
    $this->error="connection is not in the recipient setting state";
    return(0);
  }
  $this->error="";
  if(!$this->PutLine("RCPT TO:<".$recipient.">"))
   return(0);
  if(IsSet($this->esmtp_extensions["PIPELINING"]))
  {
   $this->pending_recipients++;
   if($this->pending_recipients>=$this->maximum_piped_recipients)
   {
    if(!$this->FlushRecipients())
     return(0);
   }
  }
  else
  {
   if($this->VerifyResultLines(array("250","251"))<=0)
    return(0);
  }
  $this->state="RecipientSet";
  return(1);
}

Function StartData()
{
  if(strcmp($this->state,"RecipientSet"))
  {
   $this->error="connection is not in the start sending data state";
   return(0);
  }
  $this->error="";
  if(!$this->PutLine("DATA"))
   return(0);
  if($this->pending_recipients)
  {
   if(!$this->FlushRecipients())
    return(0);
  }
  if($this->VerifyResultLines("354")<=0)
   return(0);
  $this->state="SendingData";
  return(1);
}

Function PrepareData($data,&$output)
{
  $length=strlen(&$data);
  for($output="",$position=0;$position<$length;)
  {
   $next_position=$length;
   for($current=$position;$current<$length;$current++)
   {
    switch($data[$current])
    {
     case "\n":
      $next_position=$current+1;
      break 2;
     case "\r":
      $next_position=$current+1;
      if($data[$next_position]=="\n")
       $next_position++;
      break 2;
    }
   }
   if($data[$position]==".")
    $output.=".";
   $output.=substr(&$data,$position,$current-$position)."\r\n";
   $position=$next_position;
  }
}

Function SendData($data)
{
  if(strcmp($this->state,"SendingData"))
  {
   $this->error="connection is not in the sending data state";
   return(0);
  }
  $this->error="";
  return($this->PutData(&$data));
}

Function EndSendingData()
{
  if(strcmp($this->state,"SendingData"))
  {
   $this->error="connection is not in the sending data state";
   return(0);
  }
  $this->error="";
  if(!$this->PutLine("\r\n.")
  || $this->VerifyResultLines("250")<=0)
   return(0);
  $this->state="Connected";
  return(1);
}

Function ResetConnection()
{
  switch($this->state)
  {
   case "Connected":
    return(1);
   case "SendingData":
    $this->error="can not reset the connection while sending data";
    return(0);
   case "Disconnected":
    $this->error="can not reset the connection before it is established";
    return(0);
  }
  $this->error="";
  if(!$this->PutLine("RSET")
  || $this->VerifyResultLines("250")<=0)
   return(0);
  $this->state="Connected";
  return(1);
}

Function Disconnect($quit=1)
{
  if(!strcmp($this->state,"Disconnected"))
  {
   $this->error="it was not previously established a SMTP connection";
   return(0);
  }
  $this->error="";
  if(!strcmp($this->state,"Connected")
  && $quit
  && (!$this->PutLine("QUIT")
  || $this->VerifyResultLines("221")<=0))
   return(0);
  fclose($this->connection);
  $this->connection=0;
  $this->state="Disconnected";
  return(1);
}

Function SendMessage($sender,$recipients,$headers,$body)
{
  if(($success=$this->Connect()))
  {
   if(($success=$this->MailFrom($sender)))
   {
    for($recipient=0;$recipient<count($recipients);$recipient++)
    {
     if(!($success=$this->SetRecipient($recipients[$recipient])))
      break;
    }
    if($success
    && ($success=$this->StartData()))
    {
     for($header_data="",$header=0;$header<count($headers);$header++)
      $header_data.=$headers[$header]."\r\n";
     if(($success=$this->SendData($header_data."\r\n")))
     {
      $this->PrepareData($body,&$body_data);
      $success=$this->SendData($body_data);
     }
     if($success)
      $success=$this->EndSendingData();
    }
   }
   $disconnect_success=$this->Disconnect($success);
   if($success)
    $success=$disconnect_success;
  }
  return($success);
}

};

?>

    

    来源: 互联网  发布时间: 2013-11-30

注意本程序使用的表结构为:
    use test;
    create table image(
                       id int unsigned auto_increment primary key,
                       description text,
                       filename varchar(50),
                       filesize int,
                       filetype varchar(50),
                       filedata longblob
                      );
*/

//?cmd={read|list|form|store}

//检查cmd参数的合法性
switch($cmd){
   case 'read':
      break;
   case 'list':
      break;
   case 'form':
      break;
   Case 'store':
      break;
   default:
      $cmd = 'list';
      break;
}

switch($cmd){
   case 'read':
      //?cmd=read&id={}
      //读一个图片
      $server = mysql_connect("localhost","test","") or die("无法连接数据库服务器");
      mysql_select_db("test",$server) or die("无法连接数据库");
      $sql = "select filetype,filedata from image where id='$id'";
      $rst = mysql_query($sql,$server) or die("$sql查询出错");
      if($row=mysql_fetch_row($rst)){
         header("Content-Type:" . $row[0]);
         echo $row[1];
      }
      else{
         echo "没有找到该记录";
      }
      mysql_free_result($rst);
      mysql_close($server) or die("无法与数据库服务器断开连接");
      break;
   case 'list':
      //?cmd=list
      //显示所有图片
      echo '<html>';
      echo '<head><title>图片存储与浏览一例</title></head>';
      echo '<body>';
      echo '<a href="' . $PHP_SELF . '?cmd=list">显示所有图片</a>';
      echo "    ";
      echo '<a href="' . $PHP_SELF . '?cmd=form">上传图片</a>';
      $server = mysql_connect("localhost","test","") or die("无法连接数据库服务器");
      mysql_select_db("test",$server) or die("无法连接数据库");
      $sql = "select id,description,filename,filetype,filesize from image";
      $rst = mysql_query($sql,$server) or die("$sql查询出错");
      while($row=mysql_fetch_row($rst)){
         echo "<hr>";
         echo "描述:" . $row[1] . "<br>";
         echo "文件名:" . $row[2] . "<br>";
         echo "类型:" . $row[3] . "<br>";
         echo "大小:" . $row[4] . "<br>";
         echo '<img src="' . $PHP_SELF . '?cmd=read&id=' . $row[0] . '">';
      }
      mysql_free_result($rst);
      mysql_close($server) or die("无法与数据库服务器断开连接");
      echo '</body>';
      echo '</html>';
      break;
   case 'form':
?>

<html>
<head><title>图片存储与浏览一例</title></head>
<body>
<form action="/blog_article/</echo $PHP_SELF;/gt;cmd/store.html" method="post" enctype="multipart/form-data">
<input type="hidden" name="MAX_FILE_SIZE" value="2097152">
描述:<br>
<textarea name="description" rows="5" cols="100"></textarea><br>
文件:<input type="file" name="file"><br>
<input type="submit" value="上传">
</form>
</body>
</html>

<?
      break;
   case 'store':
      //?cmd=store&description={}&file={}&file_size={}&file_type={}&file_name={}
      //存储图片
      echo '<html>';
      echo '<head><title>图片存储与浏览一例</title></head>';
      echo '<body>';
      echo '<a href="' . $PHP_SELF . '?cmd=list">显示所有图片</a>';
      echo "    ";
      echo '<a href="' . $PHP_SELF . '?cmd=form">上传图片</a>';
      $server = mysql_connect("localhost","test","") or die("无法连接数据库服务器");
      mysql_select_db("test",$server) or die("无法连接数据库");
      $data = addslashes(fread(fopen($file,"r"),filesize($file)));
      $sql = "insert into image(description,filename,filetype,filesize,filedata)
              values('$description','" . basename($file_name) . "','$file_type',$file_size,'$data')";
      mysql_query($sql,$server) or die("$sql执行出错");
      $id = mysql_insert_id();
      echo "<hr>你上传的图片效果:<br>";
      echo '<img src="' . $PHP_SELF . '?cmd=read&id=' . $id . '">';
      mysql_close($server) or die("无法与数据库服务器断开连接");
      echo '</body>';
      echo '</html>';
      break;
}
?>