Question

我想从浏览器窗口将图像上传到我的服务器。但是，每个人都可以看到上传字段，因此我需要设置一些限制。我只发现w3schools文件上传（从w3fools.com开始我不信任它）。我希望限制为：

最大尺寸为2,5M

图片类型jpg，jpeg，png，gif

所以这是w3schools提供的代码，但它实际上不会将文件保存在任何地方？我已经修改了一下以满足我的需求。

<?php
$allowedExts = array("jpg", "jpeg", "gif", "png");
$extension = end(explode(".", $_FILES["file"]["name"]));
if ((($_FILES["file"]["type"] == "image/gif")
|| ($_FILES["file"]["type"] == "image/jpg")
|| ($_FILES["file"]["type"] == "image/jpeg"))
|| ($_FILES["file"]["type"] == "image/png"))
&& ($_FILES["file"]["size"] < 2500000)
&& in_array($extension, $allowedExts))
  {
  if ($_FILES["file"]["error"] > 0)
    {
    echo "Error: " . $_FILES["file"]["error"] . "<br />";
    }
  else
    {
    echo "Upload: " . $_FILES["file"]["name"] . "<br />";
    echo "Type: " . $_FILES["file"]["type"] . "<br />";
    echo "Size: " . ($_FILES["file"]["size"] / 1024) . " Kb<br />";
    echo "Stored in: " . $_FILES["file"]["tmp_name"];
    }
  }
else
  {
  echo "Invalid file";
  }
?>

由于我不希望我的网站被黑客攻击，我想要一个安全的解决方案，对此有任何帮助吗？

修改

代码甚至没有做任何事情。那我该怎么做呢？

Answer 1

你需要使用php move_upload_file函数，并且我已经对你的if语句进行了更改，这里是工作和测试的例子：

<?php

if (isset($_REQUEST["submit"])) {

    $allowedExts = array("jpg", "jpeg", "gif", "png");
    $extension = end(explode(".", $_FILES["file"]["name"]));

    if ($_FILES["file"]["type"] == "image/gif" || $_FILES["file"]["type"] == "image/jpg" || $_FILES["file"]["type"] == "image/jpeg" || $_FILES["file"]["type"] == "image/png" && $_FILES["file"]["size"] < 2500000 && in_array($extension, $allowedExts)) {

      if ($_FILES["file"]["error"] > 0) {

        echo "Error: " . $_FILES["file"]["error"] . "<br />";

      }
      else {

        $fname = $_FILES["file"]["name"];
        move_uploaded_file($_FILES["file"]["tmp_name"], $fname);

        echo "Upload: " . $_FILES["file"]["name"] . "<br />";
        echo "Type: " . $_FILES["file"]["type"] . "<br />";
        echo "Size: " . ($_FILES["file"]["size"] / 1024) . " Kb<br />";
        echo "Stored in: " . $fname;

      }

    }
    else {

      echo "Invalid file type";

    }

}
?>
<form action="" method="post" enctype="multipart/form-data">
<input type="file" name="file" />
<input type="submit" name="submit" value="submit" />
</form>

你也可以按照下一步的建议使用getimagesize功能：

$size = getimagesize("http://www.simplestudio.rs/060620121945.jpg");

$file_format = $size['mime'];

$ file_format将表示为例如“image / jpeg”，因此您可以轻松检查这样的图像类型：

foreach($allowedExts as $allowed) {

$chk_types = strpos($file_format, $allowed);

if($chk_types > -1) {
$type_is_good = true;
break;
}

}

Answer 2

使用：move_uploaded_file，参见Manual

还有一件事，

$_FILES["file"]["type"]变量不适合使用，因为浏览器设置可以更改它。

请改用getimagesize，参见Manual

Answer 3

$ ratio2）{$ thumb_w = $ new_w; $ thumb_h = $ old_y / $比1; } else {$ thumb_h = $ new_h; $ thumb_w = $ old_x / $比* 2; }

    $dst_img=ImageCreateTrueColor($thumb_w,$thumb_h);

    imagecopyresampled($dst_img,$src_img,0,0,0,0,$thumb_w,$thumb_h,$old_x,$old_y);

            if(!strcmp("png",$ext))             imagepng($dst_img,$filename);       else            imagejpeg($dst_img,$filename); 
        imagegif($dst_img,$filename);
            imagedestroy($dst_img);         imagedestroy($src_img);   }  }  if(!function_exists('getExtension'))    {       function

getExtension（$ str）{ $ i = strrpos（$ str，“。”）; if（！$ i）{return“”; } $ l = strlen（$ str） - $ i; $ ext = substr（$ str，$ i + 1，$ l）; 返回$ ext; }}

$image=$_FILES["$imagename"]['name'];   if($image)      {  
    $filename = stripslashes($_FILES["$imagename"]['name']); 
    $extension = getExtension($filename);       $extension =

用strtolower（$扩展）; if（（$ extension！=“jpg”）＆amp;＆amp;（$ extension ！=“jpeg”）＆amp;＆amp; （$ extension！=“png”）＆amp;＆amp; （$ extension！=“gif”）＆amp;＆amp; （$ extension！=“bmp”））{

        $obj->set_flash("Unknown extension...!");           header("Location: $filename ");             exit;       }       else        {

        $size=getimagesize($_FILES["$imagename"]['tmp_name']);
        $sizekb=filesize($_FILES["$imagename"]['tmp_name']);

        if ($sizekb > MAX_SIZE*1024)
        {
            $obj->set_flash("You have exceeded the size limit...!");
            header("Location: $filename");
            exit;
        }

    $select_max = $obj->sql_query("select max($fieldname) as MaxID from  ".$tablename."");
                    if($action=="Add")          {
            $Max = $select_max[0]['MaxID'];
            $image_name = $Max + 1;
            $new_name = $image_name.".".$extension;//the new name will be containing the full path where will be stored (images folder)
            $$imagename = $new_name;//New Name of Image same as Image Field Name
            $thumbfilename = $new_name;
            $newname="$uploadpath/large/".$new_name;

            $copied = copy($_FILES["$imagename"]['tmp_name'], $newname);
            //we verify if the image has been uploaded, and print error instead
            if (!$copied) 
            { 
                $obj->set_flash("Copy unsuccessfull...!");
                header("Location: $filename");
                exit;
            }
            else
            {
                $thumb_name="$uploadpath/thumb/".$thumbfilename;
                $thumb=make_thumb($newname,$thumb_name,$WIDTH,$HEIGHT);
            }           }           if($action=="Update")           {

            $new_name=$ID.".".$extension;
            $$imagename = $new_name;//New Name of Image same as Image Field Name
            $newname = "$uploadpath/large/".$new_name;
            $thumbfilename = $new_name;
            $copied = copy($_FILES["$imagename"]['tmp_name'], $newname);

            if (!$copied) 
            {
                $obj->set_flash("Copy unsuccessfull...!");
                header("Location: $filename");
                exit;
            }
            else
            {
                $thumb_name="$uploadpath/thumb/".$thumbfilename;
                $thumb=make_thumb($newname,$thumb_name,$WIDTH,$HEIGHT);
            }           }       }   }       if($action=="Delete")   {       $SelectImage = $obj->sql_query("select $imagename from  $tablename where $fieldname

=“。$$ fieldname。” “）; $ ThisImage = $ SelectImage [0] [”$ imagename“]; unlink（”$ uploadpath / thumb /".$ ThisImage）; 取消链接（“$ uploadpath /大/".$ ThisImage）; }？＆gt;

列表项

Answer 4

<?php

          $file_name   = $_FILES['file']['name'];
          $file_size   = $_FILES['file']['size'];
          $file_tmp    = $_FILES['file']['tmp_name'];
          $file_type   = $_FILES['file']['type'];

          /* variable array for store errors */
          $errors   = [];                   


          /* Check if file already exists in location file save */
          $file_dir  = "uploads";
          /** if folder not exists, then create it **/
          if (!file_exists($file_dir)) {
            mkdir($file_dir, 0777, true);
          }

          $file_target = $file_dir . $file_name;
          if (file_exists($file_target)) {
            //$errors[] = "Sorry, <strong>{$file_name}</strong> already exists.";
          }


             /* Check file size */
          if ($file_size > 2500000) {
            $errors[] = "Sorry, <strong>{$file_name}</strong> is too large. It size is {$file_size} > 2500000 bytes";
          }


          /* Check current file formats with file secure */
          $file_secure  = array('jpg', 'jpeg', 'png', 'gif');                   
          $file_current = strtolower(pathinfo($file_name, PATHINFO_EXTENSION)); /* (end(explode('.', $file_name) */

          if (in_array($file_current, $file_secure) === false) {
            $errors[] = "Sorry, <strong>{$file_current}</strong> extension not allowed";            
          }


          /* Check if Errors exist, then not upload. Or if Errors NOT exist, then try upload */
          if (!empty($errors)) {                            

            /* display error */                 
            foreach ($errors as $keyError => $valueError) {
              echo "$keyError = $valueError <br />";
            }

            echo "<br />";
            echo "<strong>{$file_name}</strong> could not uploaded. <hr />";                            

          } else {

            if (move_uploaded_file($file_tmp, $file_target)) {

              echo "Upload: "    . $file_name . "<br />";
              echo "Type: "      . $file_type . "<br />";
              echo "Size: "      . ($file_size / 1024) . " Kb<br />";
              echo "Stored in: " . $file_tmp;

            } else {

              echo "Invalid file";

            }

          }

?>

使用PHP保护图像上传？

4 个答案: