php的文件上传

文件上传

php的文件上传放在了$_FILES数组里，单文件和多文件上传的区别在于$_FILES['userfile']['name']是否为数组，
不熟悉的可以读一下官方文档 单文件上传、 多文件上传

阿里云oss web直传实践

这里采用的是服务端签名后上传，没有使用回调。

阿里云提供了一个php和前端的示例，不过有点坑人，前端采用的是plupload插件，这种demo应该使用原生js更合适啊，毕竟上传的js插件各不相同。
使用jquery的ajax上传时，始终上传失败，于是用fiddler抓包demo，才知道了上传给oss的详细参数格式。

吐槽完毕，下面才是正式上菜。

• 服务端生成policy，这里使用php
  下面的代码是从官方demo修改而来，可以通过Facade模式增加静态方法，方便调用。
  注意dir目录不能使用"/"开始。下面的签名算法来自阿里云的demo。

<?php
class OssPolicy
{private $oss_bucket ;private $oss_host;private $oss_appid;private $oss_appsecret;private $oss_expire ;//过期时间/*** OssPolicy constructor.* @param $bucket 阿里云oss的bucket* @param $host 对应bucket的host* @param $appId app_id* @param $appSecret app_secret* @param int $expire 过期时间*/public function __construct($bucket,$host,$appId,$appSecret,$expire=900) {$this->oss_expire = $expire;$this->oss_bucket = $bucket;$this->oss_host = $host;$this->oss_appid = $appId;$this->oss_appsecret = $appSecret;}private function gmt_iso8601($time) {$dtStr = date("c", $time); //格式为2016-12-27T09:10:11+08:00$mydatetime = new DateTime($dtStr);$expiration = $mydatetime->format(DateTime::ISO8601); //格式为2016-12-27T09:12:32+0800$pos = strpos($expiration, '+');$expiration = substr($expiration, 0, $pos);//格式为2016-12-27T09:12:32return $expiration."Z";}/*** @function getPolicy 获取policy* @author * @version 1.0* @date* @param $dir 上传目录* @param $maxSize 最大文件大小 单位M* @param int $expireTime 过期时间* @return $array policy*/public function getPolicy($dir,$maxSize=100,$expireTime=null){$expireTime = isset($expireTime) ? $expireTime : $this->oss_expire;$end = time() + $expireTime;$expiration = $this->gmt_iso8601($end);$conditions = [];$conditions[] = array(0=>'content-length-range', 1=>0, 2=>1024*1024*$maxSize); // 最大文件大小.用户可以自己设置 100M$start = array(0=>'starts-with', 1=>'$key', 2=>$dir); //表示用户上传的数据,必须是以$dir开始, 不然上传会失败,这一步不是必须项,只是为了安全起见,防止用户通过policy上传到别人的目录$conditions[] = $start;$arr = array('expiration'=>$expiration,'conditions'=>$conditions);$policy = json_encode($arr);$base64_policy = base64_encode($policy);$string_to_sign = $base64_policy;$signature = base64_encode(hash_hmac('sha1', $string_to_sign, $this->oss_appsecret, true));$response = array();$response['accessid'] = $this->oss_appid;$response['host'] = $this->oss_host;$response['policy'] = $base64_policy;$response['signature'] = $signature;$response['expire'] = $end;$response['bucket'] = $this->oss_bucket;$response['dir'] = $dir;  //这个参数是设置用户上传指定的前缀return $response;}
}

• 前端
  过程 想后端请求policy，上传到阿里云，成功后通知后端
  不要问我代码为啥这么乱，我不生产代码，我只是代码的搬运工(从阿里云demo里搬出来，稍加修改)
  在用表单提交时，注册一下提交处理的函数，取出文件，然后OssUpload()即可。

oss_accessid = ''
oss_accessoss_key = ''
oss_host = ''
oss_policyBase64 = ''
oss_signature = ''
oss_callbackbody = ''
oss_filename = ''
oss_key = ''
oss_expire = 0
g_object_name = ''
g_object_name_type = 'local_name'
OSS_FILE_NAME_TYPE_LOCAL = "local_name"
OSS_FILE_NAME_TYPE_RANDOM = "random_name"oss_now = oss_timestamp = Date.parse(new Date()) / 1000;//向服务端请求policy
function send_request() {}
//生成签名
function get_oss_signature() {//可以判断当前oss_expire是否超过了当前时间,如果超过了当前时间,就重新取一下.3s 做为缓冲oss_now = oss_timestamp = Date.parse(new Date()) / 1000;if (oss_expire < oss_now + 3) {body = send_request()var obj = eval("(" + body + ")");oss_host = obj['host']oss_policyBase64 = obj['policy']oss_accessid = obj['accessid']oss_signature = obj['signature']oss_expire = parseInt(obj['expire'])oss_callbackbody = obj['callback']oss_key = obj['dir']}}//随机字符串
function random_string(len) {len = len || 32;var chars = 'ABCDEFGHJKMNPQRSTWXYZabcdefhijkmnprstwxyz2345678';var maxPos = chars.length;var str = '';for (i = 0; i < len; i++) {str += chars.charAt(Math.floor(Math.random() * maxPos));}return str;
}
//获取文件名后缀
function get_suffix(filename) {pos = filename.lastIndexOf('.')suffix = ''if (pos != -1) {suffix = filename.substring(pos)}return suffix;
}
//根据文件名类型 临时文件还是原始文件名，返回文件名
function calculate_object_name(filename) {if (g_object_name_type == 'local_name') {g_object_name = oss_key + "${filename}"}else if (g_object_name_type == 'random_name') {suffix = get_suffix(filename)g_object_name = oss_key + random_string(10) + suffix}return ''
}//把policy填充到Formdata里
function set_upload_param(file) {get_oss_signature()if (file) {calculate_object_name(file.name);var res = {'key': g_object_name,'policy': oss_policyBase64,'OSSAccessKeyId': oss_accessid,'success_action_status': '200', //让服务端返回200,不然，默认会返回204
//                'callback': oss_callbackbody,'signature': oss_signature,};var form_data = new FormData();for ( var key in res ) {form_data.append(key, res[key]);}form_data.append("file",file);return res;}return false;}//上传到阿里云 callBack 是用来在上传成功后通知服务端
function OssUpload( file,fileNameType,callBack) {g_object_name_type = fileNameType;var form_data = set_upload_param(file.name);if(!form_data){alert("form_data error")return}var fileFullName = oss_host+form_data.get("key");$.ajax({url: oss_host,data: form_data,processData: false,cache: false,async: false,type:'POST',contentType: false,//这个就是了success: function (data, textStatus, request) {//textStatus === "success" 表示成功if(typeof callBack === "function") {callBack(fileFullName,form_data.get("policy"),textStatus);}},error : function(responseStr) {if(typeof callBack === "function") {callBack(fileFullName,form_data.get("policy"),responseStr.responseText);}}});
}