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The author:(作者)归海一刀published in(发表于) 2014/2/10 6:52:50 基于PHP的AJAX技术实现文件异步上传_[PHP教程]
异步的文件上传是在现代的AJAX实现的Web应用里面经常要遇到,必须解决的问题。但是标准的AJAX类(XmlHttpRequest)无法实现传输文件的功能。因此,这里讨论的内容就是如何在AJAX的技术的基础之上构建异步的文件上传功能。在这个功能当中需要使用到内置的框及(IFRAME)来传输文件。这个功能实现的效果是页面在上传文件的时候,用户还可以使用该页面并且填写文件描述。 这个例子是我们引用AJAX的经典案例进行分析的。 系统环境 · 较新版本的浏览器。例如Opera,Firefox或者 Internet Explorer。 · PHP 4.3.0 或更高版本 · PHP 5 版本 · PHP 中的 'short_open_tag' 选项开启(否则会发生解析错误)。 功能分析 通过内置的IFRAME(框架)进行文件上传。具备包括三个部分组成。 · 在页面中间有一个简单的<form...表单,表单只包含了<input type="file" ... >控件。这个表单的目标链接就是一个隐藏得IFRAME(通过 CSS的风格" display: none;"实现)并且表单里面唯一一个控件的OnChange事件用来触发JavaScript函数。这个函数的作用是检查用户提交的扩展名,然后提交表单。 · 在服务器端用PHP编写了一个处理过程(用FILEFRAME坐注释了)。这个处理过程用来把从客户端上传的文件进行检查后保存在服务器,并且通过Javascript代码的形式返回给用户。返回给用户的Javascript脚本通过"parent.window.document"更改了用户现在正在查看的页面,设置了文件的名称并启用了让用户提交表单的按钮。启用按钮的操作是通过getElementById函数实现的。 · 在主页面还有一个表单,它包含了用户提交的描述和隐藏的文件名。用户可以在文件上传的同时填写文件的描述。当文件上传结束以后,用户点击按钮,就可以看上传以后返回给用户的文件信息了。(通过返回来的文件名和用户输入的描述构成文件信息)。 可能你会说这么操作不符合常理:文件在用户确认之前就已经被提交了。如果用户没有提交的话,情况会如何呢。你可以自己在扩展处理被用户放弃的文件。 这个例子把文件存储在一个文件系统的目录下。你需要在脚本开始运行的时候配置下这个目录,具体的包含这个目录信息的变量是upload_dir 和web_upload_dir。这里有一个对目录是否可写的权限检查。 这里我们用到了以下几个PHP函数: · move_uploaded_file - 转移一经上传到服务器的文件 · fopen - 打开文件 · fwrite - 把内容写入文件 · fclose - 关闭文件 · str_replace - 替换字符串 · filesize - 返回文件大小 · filemtime - 返回处理时间 你可以通过手册查到这些函数如果使用。请注意要把HTM(<, >, &)标记替换为(<, > 和 &).
源代码<?phpupload_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> 以上的讲解就是提供一种思路供大家参考。大家也可以根据自己的需求进行相应的优化
作者: hosander 出处: 天极开发
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