服务器上传文件会有一定的限制。避免内存消耗过大影响性能，在 php.ini 配置文件中，有几个影响参数：
upload_max_filesize = 2M //PHP最大能接受的文件大小
post_max_size = 8M //PHP能收到的最大POST值'
memory_limit = 128M //内存上限
max_execution_time = 30 //最大执行时间
为了满足需求，可适量调整配置参数。但遇到超大文件上传，比如视频时，就需要在技术层面解决这一问题。
以下利用 html5 可直接操作二进制文件的新特性，用 PHP + JS 实现将大文件分割上传后再合并的办法，实现大文件上传。
前端代码：
<!doctype html>
<head>
<title>slide-upload</title>
</head>
<body> <input type="file" name="file" id="file"> <script>
var fileForm = document.getElementById("file");
var upload = new Upload(); fileForm.onchange = function(){
upload.addFileAndSend(this);
} function Upload(){
var xhr = new XMLHttpRequest();
var form_data = new FormData();
const LENGTH = 1024 * 1024 * 1;
var start = 0;
var end = start + LENGTH;
var blob;
var blob_num = 1;
var is_stop = 0 //传入文件对象
this.addFileAndSend = function(that){
var file = that.files[0];
blob = cutFile(file);
sendFile(blob,file);
blob_num += 1;
}
//切割文件
function cutFile(file){
var file_blob = file.slice(start,end);
start = end;
end = start + LENGTH;
return file_blob;
};
//发送文件
function sendFile(blob,file){
var total_blob_num = Math.ceil(file.size / LENGTH);
form_data.append('file',blob);
form_data.append('blob_num',blob_num);
form_data.append('total_blob_num',total_blob_num);
form_data.append('file_name',file.name); xhr.open('POST','./slice_upload.php',true);
xhr.onreadystatechange = function () {
var progress;
if(total_blob_num == 1){
progress = '100%';
}else{
progress = Math.min(100,(blob_num/total_blob_num)* 100 ) +'%';
}
var t = setTimeout(function(){
if(start < file.size){
blob = cutFile(file);
sendFile(blob,file);
blob_num += 1;
}else{
setTimeout(t);
}
},1000);
}
xhr.send(form_data);
}
} </script>
</body>
</html>
后台文件上传代码：
<?php //实例化并获取系统变量传参
$upload = new Upload($_FILES['file']['tmp_name'],$_POST['blob_num'],$_POST['total_blob_num'],$_POST['file_name']);
//调用方法，返回结果
$upload->apiReturn(); class Upload{
private $filepath = './upload'; //上传目录
private $tmpPath; //PHP文件临时目录
private $blobNum; //第几个文件块
private $totalBlobNum; //文件块总数
private $fileName; //文件名 public function __construct($tmpPath, $blobNum, $totalBlobNum, $fileName){
$this->tmpPath = $tmpPath;
$this->blobNum = $blobNum;
$this->totalBlobNum = $totalBlobNum;
$this->fileName = $fileName; $this->moveFile();
$this->fileMerge();
} //判断是否是最后一块，如果是则进行文件合成并且删除文件块
private function fileMerge(){
if($this->blobNum == $this->totalBlobNum){
$blob = ''; for($i=1; $i<= $this->totalBlobNum; $i++){
$blob .= file_get_contents($this->filepath.'/'. $this->fileName.'__'.$i);
}
file_put_contents($this->filepath.'/'. $this->fileName,$blob);
$this->deleteFileBlob();
}
} //删除文件块
private function deleteFileBlob(){
for($i=1; $i<= $this->totalBlobNum; $i++){
@unlink($this->filepath.'/'. $this->fileName.'__'.$i);
}
} //移动文件
private function moveFile(){
$this->touchDir();
$filename = $this->filepath.'/'. $this->fileName.'__'.$this->blobNum;
move_uploaded_file($this->tmpPath,$filename);
} //API返回数据
public function apiReturn(){
if($this->blobNum == $this->totalBlobNum){
if(file_exists($this->filepath.'/'. $this->fileName)){
$data['code'] = 2;
$data['msg'] = 'success';
$data['file_path'] = 'http://'.$_SERVER['HTTP_HOST'].dirname($_SERVER['DOCUMENT_URI']).str_replace('.','',$this->filepath).'/'. $this->fileName;
}
}else{
if(file_exists($this->filepath.'/'. $this->fileName.'__'.$this->blobNum)){
$data['code'] = 1;
$data['msg'] = 'waiting for all';
$data['file_path'] = '';
}
}
header('Content-type: application/json');
echo json_encode($data);
} //建立上传文件夹
private function touchDir(){
if(!file_exists($this->filepath)){
return mkdir($this->filepath);
}
}
}
以上只是实现了简单的上传功能，很多情况下文件传输之前需要加密，或者实现端点传输。