通过file文件函数来操作上传的图片,下面是转自zend.com上的一篇文章，有许多可取之处，但是却感觉到众多的目录很古怪，大家看了后可以相互讨论一下：
// file 1: display and process entry form and upload picture file to server
<?php
// full directory path
$filepath = "/home/httpd/html/tut/upload";
// 200k is the maximum (picture) file size to be accepted
define("max_file_size", 200*1024);
function print_error ($err) {
echo "<h1>$err</h1><hr>";
}
do {
// check if picture name variable has a value; if not, skip to the
// "while(false)" section of "do" statement
if(isset($picture)) {
// here is where the server transparently checks that the client picture file
// doesn't exceed maximum allowable size
if(getenv("content_length") > max_file_size) {
print_error("file too large: $picture_name");
break;
}
// open client picture file for read only; "@" prefix tells fopen not to print
// message if there is an error, since function print_error does that
// if there is an error, break out of "do" loop and continue at "while(false)"
$fp = @fopen($picture,"r");
if(!$fp) {
print_error("cannot open file: $picture_name");
break;
}
// generate unique name for session, use it to generate unique server
// directory name, and create the directory
srand((double) microtime() * 1000000);
$id = md5(uniqid(rand()));
$dirname = "$filepath/$id";
mkdir($dirname,0700);
// create the server picture file in the newly created server directory
$filename = $dirname . "/picture";
// open server picture file for write only; "@" prefix tells fopen not to
// print message if there is an error, since function print_error does that
// if there is an error, break out of "do" loop and continue at "while(false)"
$out = @fopen($filename,"w");
if(!$out) {
print_error("cannot open file: $filename");
break;
}
// copy client picture file to server picture file
while($buffer = fread($fp,8192)) {
fwrite($out,$buffer);
}
// close client picture file and server picture file
fclose($fp);
fclose($out);
// create server name file in picture file directory; this file will hold the
// name of the picture file
$filename = $dirname . "/name";
// open server name file for write only; "@" prefix tells fopen not to print
// message if there is an error, since function print_error does that
// if there is an error, break out of "do" loop and continue at "while(false)"
$out = @fopen($filename,"w");
if(!$out) {
print_error("cannot open file: $filename");
break;
}
// write the server picture name to the server name file, and close the server
// name file
fputs($out,$name);
fclose($out);
// display message that client picture file was successfully copied to the
// server, display a prompt to look at updated server photo gallery, and supply
// the html link
?>
picture added. thanks.<br>
<a href="upload_display.php">continue to the gallery</a>
<?php
// exit to the server photo gallery
exit();
}
} while(false);
// you get to here only when "if(isset($picture))" is false, which means that
// no picture name has been submitted, therefore go display the input form where
// the necessary information can be entered
?>
<!-- start upload form -->
<!doctype html public "-//ietf//dtd html//en">
<html>
<head>
<title>photo gallery - add</title>
</head>
<body bgcolor="white">
<h1>photo gallery add</h1>
<?php
// start of segment of code for displaying input form
// using $php_self for value of "form action" causes form to refer to itself
// when "submit" button is clicked
?>
<form action="<? echo $php_self ?>" method=post enctype="multipart/form-data">
<?php
// pass the php constant max_file_size to the html maximum file size
// constant max_file_size
?>
<input type="hidden" name="max_file_size" value="<? echo max_file_size ?>">
<?php
// display the text boxes for entering user name and picture name, and store
// the entered values in php variables; browsing is enabled
?>
your name is: <input name="name"><br>
your picture: <input name="picture" type="file"><br>
<?php
// display the "submit" button
?>
<input type="submit" value="add picture" name="send">
</form>
</body>
</html>
// ------------------------------------------------------
// file 2: display the server photo gallery
<!doctype html public "-//ietf//dtd html//en">
<html>
<head>
<title>photo gallery</title>
</head>
<body>
<h1>photo gallery</h1>
<?php
// full directory path
$filepath = "/home/httpd/html/tut/upload";
// user's path in browser -- same as full directory path
$url_path = "/tut/upload";
// get unique server directory used for this user session
$dir = dir($filepath);
// loop through all server subdirectories for this user session
while($entry=$dir->read()) {
// if entry is system file (doesn't have picture files), go to next entry in
// "while" loop
if($entry == "." || $entry == "..") {
continue;
}
// open server name file for read only; "@" prefix tells fopen not to print
// message if there is an error, since function print_error does that
// if there is an error, go to next entry in "while" loop
$fp = @fopen("$filepath/$entry/name","r");
if(!$fp) {
print "bad entry: $entry<br>";
continue;
}
// get name of the server picture file and close the server name file
$name = fgets($fp,4096);
fclose($fp);
// display each picture and its file name; in addition, "alt=" causes the file
// name to be displayed as tooltip text when mouse points to picture
?>
<img src="<? echo "$url_path/$entry/picture" ?>"
alt="<? echo $name ?>"> <b><? echo $name ?></b><br>
<?
}
?>
</body>
</html>
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