基于PHP的AJAX技术实现文件异步上传

＜?php
 $upload_dir = "/var/www/anyexample/aeu"; // 文件存储的路径
 $web_upload_dir = "/aeu"; // 文件在Web目录下的路径
 $tf =  $upload_dir.'/'.md5(rand()).".test";
 $f = @fopen( $tf, "w");
if ( $f == false)
die("Fatal error! { $upload_dir} is not writable. Set 'chmod 777 { $upload_dir}'
or something like this");
fclose( $f);
unlink( $tf);

//处理上传的文件
if (isset( $_POST['fileframe']))
{
　 $result = 'ERROR';
　 $result_msg = 'No FILE field found';

　if (isset( $_FILES['file'])) // 从浏览器接受文件
　{
　　if ( $_FILES['file']['error'] == UPLOAD_ERR_OK) // 没有错误
　　{
　　　 $filename =  $_FILES['file']['name']; // 文件名
　　　move_uploaded_file( $_FILES['file']['tmp_name'],  $upload_dir.'/'. $filename);
　　　// 处理的主过程-转移文件到  $upload_dir
　　　 $result = 'OK';
　　}
　　elseif ( $_FILES['file']['error'] == UPLOAD_ERR_INI_SIZE)
　　　 $result_msg = 'The uploaded file exceeds the upload_max_filesize directive in php.ini';
　　else
　　　 $result_msg = 'Unknown error';
　}

　echo '＜html＞＜head＞＜title＞-＜/title＞＜/head＞＜body＞';
　echo '＜script language="JavaScript" type="text/javascript"＞'."\n";
　echo 'var parDoc = window.parent.document;';
　'
　if ( $result == 'OK')
　{
　　echo 'parDoc.getElementById("upload_status").value = "file successfully uploaded";';
　　echo 'parDoc.getElementById("filename").value = "'. $filename.'";';
　　echo 'parDoc.getElementById("filenamei").value = "'. $filename.'";';
　　echo 'parDoc.getElementById("upload_button").disabled = false;';
　}
　else
　{
　　echo 'parDoc.getElementById("upload_status").value = "ERROR: '. $result_msg.'";';
　}

　echo "\n".'＜/script＞＜/body＞＜/html＞';
　exit();
}

function safehtml( $s)
{
　 $s=str_replace("&", "&",  $s);
　 $s=str_replace("＜", "<",  $s);
　 $s=str_replace("＞", ">",  $s);
　 $s=str_replace("'", "'",  $s);
　 $s=str_replace("\"", """,  $s);
　return  $s;
}

if (isset( $_POST['description']))
{
　 $filename =  $_POST['filename'];
　 $size = filesize( $upload_dir.'/'. $filename);
　 $date = date('r', filemtime( $upload_dir.'/'. $filename));
　 $description = safehtml( $_POST['description']);

　 $html =＜＜＜END
　＜html＞＜head＞＜title＞{ $filename} [uploaded by IFRAME Async file uploader]＜/title＞＜/head＞
　＜body＞
　　＜h1＞{ $filename}＜/h1＞
　　＜p＞This is a file information page for your uploaded file. Bookmark it, or send to anyone...＜/p＞
　　＜p＞Date: { $date}＜/p＞
　　＜p＞Size: { $size} bytes＜/p＞
　　＜p＞Description:
　　＜pre＞{ $description}＜/pre＞
　　＜/p＞
　　＜p＞＜a href="{ $web_upload_dir}/{ $filename}" style="font-size: large;"＞download file＜/a＞＜br＞
　　＜a href="{ $PHP_SELF}" style="font-size: small;"＞back to file uploading＜/a＞＜br＞
　　＜a href="{ $web_upload_dir}/upload-log.html" style="font-size: small;"＞upload-log＜/a＞＜/p＞
　　＜br＞＜br＞Example by ＜a href="http://www.anyexample.com/"＞AnyExample＜/a＞
　＜/body＞＜/html＞
　END;
　
　 $f = fopen( $upload_dir.'/'. $filename.'-desc.html', "w");
　fwrite( $f,  $html);
　fclose( $f);
　 $msg = "File { $filename} uploaded,
　＜a href='{ $web_upload_dir}/{ $filename}-desc.html'＞see file information page＜/a＞";

　 $f = fopen( $upload_dir."/upload-log.html", "a");
　fwrite( $f, "＜p＞ $msg＜/p＞\n");
　fclose( $f);

　setcookie('msg',  $msg);
　header("Location: http://". $_SERVER['HTTP_HOST']. $PHP_SELF);
　exit();
}

if (isset( $_COOKIE['msg']) &&  $_COOKIE['msg'] != '')
{
　if (get_magic_quotes_gpc())
　　 $msg = stripslashes( $_COOKIE['msg']);
　else
　　 $msg =  $_COOKIE['msg'];
　　setcookie('msg', '');
}
?＞
＜!-- Beginning of main page --＞
＜html＞＜head＞
＜title＞IFRAME Async file uploader example＜/title＞
＜/head＞
＜body＞
＜?php
　if (isset( $msg))
　　echo '＜p style="font-weight: bold;"＞'. $msg.'＜/p＞';
?＞
＜h1＞Upload file:＜/h1＞
＜p＞File will begin to upload just after selection. ＜/p＞
＜p＞You may write file description, while you file is being uploaded.＜/p＞

＜form action="＜?= $PHP_SELF?＞" target="upload_iframe" method="post" enctype="multipart/form-data"＞
　＜input type="hidden" name="fileframe" value="true"＞
　＜!-- Target of the form is set to hidden iframe --＞
　＜!-- From will send its post data to fileframe section of this PHP script (see above) --＞

　＜label for="file"＞text file uploader:＜/label＞＜br＞
　＜!-- JavaScript is called by OnChange attribute --＞
　＜input type="file" name="file" id="file" onChange="jsUpload(this)"＞
＜/form＞
＜script type="text/javascript"＞
/* This function is called when user selects file in file dialog */
function jsUpload(upload_field)
{
　// this is just an example of checking file extensions
　// if you do not need extension checking, remove
　// everything down to line
　// upload_field.form.submit();
　
　var re_text = /\.txt|\.xml|\.zip/i;
　var filename = upload_field.value;

　/* Checking file type */
　if (filename.search(re_text) == -1)
　{
　　alert("File does not have text(txt, xml, zip) extension");
　　upload_field.form.reset();
　　return false;
　}

　upload_field.form.submit();
　document.getElementById('upload_status').value = "uploading file...";
　upload_field.disabled = true;
　return true;
}
＜/script＞
＜iframe name="upload_iframe" style="width: 400px; height: 100px; display: none;"＞
＜/iframe＞
＜!-- For debugging purposes, it's often useful to remove
"display: none" from style="" attribute --＞

＜br＞
Upload status:＜br＞
＜input type="text" name="upload_status" id="upload_status"
value="not uploaded" size="64" disabled＞
＜br＞＜br＞

File name:＜br＞
＜input type="text" name="filenamei" id="filenamei" value="none" disabled＞

＜form action="＜?= $PHP_SELF?＞" method="POST"＞
　＜!-- one field is "disabled" for displaying-only. Other, hidden one is for sending data --＞
　＜input type="hidden" name="filename" id="filename"＞
　＜br＞＜br＞

　＜label for="photo"＞File description:＜/label＞＜br＞
　＜textarea rows="5" cols="50" name="description"＞＜/textarea＞

　＜br＞＜br＞
　＜input type="submit" id="upload_button" value="save file" disabled＞
＜/form＞
＜br＞＜br＞
＜a href="＜?= $web_upload_dir?＞/upload-log.html"＞upload-log＜/a＞
＜br＞＜br＞＜br＞

Example by ＜a href="http://www.anyexample.com/"＞AnyExample＜/a＞
＜/body＞
＜/html＞