使用 JQuery/Ajax 将图像从输入上传到服务器答案

【问题标题】：Upload an image from input to server using JQuery/Ajax使用 JQuery/Ajax 将图像从输入上传到服务器
【发布时间】：2022-01-19 20:42:09
【问题描述】：

我有这样的输入：
<input type="file" accept="image/*">

现在我想将图像发送到服务器（我想 ajax 是要走的路？）
我想从服务器将图像保存到 aws-s3 存储（实际上不是我的问题）
问题是如何将图像发送到 php，以便以后将其存储在对象存储中？

【问题讨论】：

标签： javascript php jquery ajax amazon-s3

【解决方案1】：

此代码复制自以下网页：https://www.w3schools.com/PHP/php_file_upload.asp

请注意，使用 AJAX/jQuery 更难，因此您可以使用此代码。

首先检查您的 php.ini 文件（它在 C:/php-install-path/php.ini 中）并搜索以下行：

file_uploads = On

它可能显示为

file_uploads = Off

所以您需要转至On。如果 Web 服务器已关闭，请重新启动它。

接下来，创建表单。

<!DOCTYPE html>
<html>
<body>

<form action="upload.php" method="post" enctype="multipart/form-data">
  Select image to upload:
  <input type="file" name="fileToUpload" id="fileToUpload">
  <input type="submit" value="Upload Image" name="submit">
</form>

</body>
</html>

它需要重定向到一个 PHP 文件，因为 PHP 可以接收元素。

对于 PHP 文件，输入如下代码：

<?php
$target_dir = "uploads/";
$target_file = $target_dir . basename($_FILES["fileToUpload"]["name"]);
$uploadOk = 1;
$imageFileType = strtolower(pathinfo($target_file,PATHINFO_EXTENSION));

// Check if image file is a actual image or fake image
if(isset($_POST["submit"])) {
  $check = getimagesize($_FILES["fileToUpload"]["tmp_name"]);
  if($check !== false) {
    echo "File is an image - " . $check["mime"] . ".";
    $uploadOk = 1;
  } else {
    echo "File is not an image.";
    $uploadOk = 0;
  }
}

// Check if file already exists
if (file_exists($target_file)) {
  echo "Sorry, file already exists.";
  $uploadOk = 0;
}

// Check file size
if ($_FILES["fileToUpload"]["size"] > 500000) {
  echo "Sorry, your file is too large.";
  $uploadOk = 0;
}

// Allow certain file formats
if($imageFileType != "jpg" && $imageFileType != "png" && $imageFileType != "jpeg"
&& $imageFileType != "gif" ) {
  echo "Sorry, only JPG, JPEG, PNG & GIF files are allowed.";
  $uploadOk = 0;
}

// Check if $uploadOk is set to 0 by an error
if ($uploadOk == 0) {
  echo "Sorry, your file was not uploaded.";
// if everything is ok, try to upload file
} else {
  if (move_uploaded_file($_FILES["fileToUpload"]["tmp_name"], $target_file)) {
    echo "The file ". htmlspecialchars( basename( $_FILES["fileToUpload"]["name"])). " has been uploaded.";
  } else {
    echo "Sorry, there was an error uploading your file.";
  }
}
?>

奖励：如果你想为此创建一个函数，你可以。

<?php
function uploadFile($names, $button) {
  $file = $_FILES[$names];
  $target_dir = "uploads/";
  $target_file = $target_dir . basename($file["name"]);
  $uploadOk = 1;
  $imageFileType = strtolower(pathinfo($target_file,PATHINFO_EXTENSION));

  // Check if image file is a actual image or fake image
  if(!empty($button)) {
    $check = getimagesize($file["fileToUpload"]["tmp_name"]);
    if($check !== false) {
    echo "File is an image - " . $check["mime"] . ".";
    $uploadOk = 1;
  } else {
    echo "File is not an image.";
    $uploadOk = 0;
  }

  // Check if file already exists
  if (file_exists($target_file)) {
    echo "Sorry, file already exists.";
    $uploadOk = 0;
  }

  // Check file size
  if ($_FILES["fileToUpload"]["size"] > 500000) {
    echo "Sorry, your file is too large.";
    $uploadOk = 0;
  }

  // Allow certain file formats
  if($imageFileType != "jpg" && $imageFileType != "png" && $imageFileType != "jpeg"
&& $imageFileType != "gif" ) {
    echo "Sorry, only JPG, JPEG, PNG & GIF files are allowed.";
    $uploadOk = 0;
  }

  // Check if $uploadOk is set to 0 by an error
  if ($uploadOk == 0) {
    echo "Sorry, your file was not uploaded.";
  // if everything is ok, try to upload file
  } else {
    if (move_uploaded_file($file["fileToUpload"]["tmp_name"], $target_file)) {
      echo "The file ". htmlspecialchars( basename( $file["fileToUpload"] ["name"])). " has been uploaded.";
    } else {
      echo "Sorry, there was an error uploading your file.";
    }
  }
}
?>

然后在接收文件上传的 PHP 文件中包含或要求该文件。

<?php
include_once("file_upload_fn.php");
uploadFile("fileToUpload", $_POST['submit']);
?>

给你。这就是你使用 PHP 上传图片的方式。

【讨论】：