WordPress前端自制拖放区域上传文件的轮子

PetitQ WordPress教程 2021-12-03 837 0 0

上个月写过一篇 WordPress 通过 Rest API 自定义附件上传接口，那篇文章主要介绍了如何打通前后端，利用 Rest API 保存“抓取”已知 URL 的文件。不过在更多的情况下，我们还是需要通过自己的表单上传文件。正好这个月有个项目，有个表单需要拖放文件到指定区域里，提交表单的时候上传文件。如果我用 Gravity Forms 给的文件上传域，它只有原生的点击选取本地的文件组件，并没有拖放选取文件的组件，所以这里就需要造一个轮子了。先说结果，最后实现出来是这样子的：

文件拖到区域上方，区域会变色；拖入后区域内显示文件名，判断文件格式和尺寸是否合规；点击清除，会重置区域。

HTML 结构

这里面#pro_document 这个就是真实的用来上传的输入项，把它隐藏，通过 JS 使.js-drag 整个区域可以接受拖放文件进来

也想出现在这里？联系我们吧

```
<div class="dragarea js-drag">
```
```
<p>DRAG A FILE HERE,<br/>OR</p>
```
```
<span class="js-drag-fileinfo"></span>
```

<a href="###" class="button">Choose a File</a>

<a href="###" class="js-drag-clear">x Clear</a>

<input type="file" value="" name="pro_document" id="pro_document" placeholder="" class="js-drag-file" />

```
</div>
```

JS 部分

```
$(function(){
```
```
	//允许的格式
```

	var fileTypeArray = ['JPG','PNG','CAD','RAR','ZIP'];

```
	function FileListItems (files) {
```

		var b = new ClipboardEvent("").clipboardData || new DataTransfer()

		for (var i = 0, len = files.length; i<len; i++) b.items.add(files[i])

```
		return b.files
```
```
	}
```
```
	function FileVerify(file){
```
```
		if(file.size > 2*1024*1024){
```
```
			alert("文件不能大于2M");
```
```
			return false;
```
```
		}else if(file.size <= 0){
```
```
			alert("文件大小不能小于0");
```
```
			return false;
```
```
		}else{
```
```
			var arr = file.name.split('.');
```

		    var suffix = arr[arr.length-1].toUpperCase();

		    if(fileTypeArray.includes(suffix)){

```
				return true;
```
```
		    }else {
```

		        alert("暂时不支持" + suffix + "格式文件");

```
		        return false;
```
```
		    }
```
```
		}
```
```
 
```
```
	}
```
```
 
```
```
	var dragElement = $('.js-drag');
```
```
	//拖入结束
```

	$('.js-drag').on("drop", function(event){

```
	    event.preventDefault();
```
```
	    event.stopPropagation();
```
```
 
```

	    var fileFieldDOM = $(this).find('.js-drag-file')[0];

	    var fileFieldDisplay = $(this).find('.js-drag-fileinfo');

```
	    console.log(event);
```
```
 
```

	    event.dataTransfer = event.originalEvent.dataTransfer;

		var firstFile = event.dataTransfer.files[0];

```
		var firstFileArr = [ firstFile ];
```

		var newfileList = new FileListItems(firstFileArr);

```
 
```
```
		if( FileVerify(firstFile)){
```

			console.log("file verified: "+ firstFile.name);

```
			console.log(firstFile);
```

			//.filled样式追加后，区域变成已添加文件的状态

```
			$(this).addClass("filled")
```

			fileFieldDisplay.html("selected file:</br>" + firstFile.name);

```
			fileFieldDOM.files= newfileList;
```
```
		}
```
```
		$(this).removeClass("dragenter");
```
```
 
```
```
	});
```
```
	//点击开启选择文件窗口
```

	$('.js-drag').on("click", function(event){

		var fileFieldDOM = $(this).find('.js-drag-file')[0];

		var fileFieldDisplay = $(this).find('.js-drag-fileinfo');

```
		fileFieldDOM.click();
```
```
	});
```
```
	//拖入
```

	$('.js-drag').on("dragenter", function(event){

```
		event.preventDefault();
```
```
		event.stopPropagation();
```
```
		//console.log('dragenter');
```

		//增加样式.dragenter，其实就是一个背景色，以提示用户有文件正在拖进来

```
		$(this).addClass("dragenter");
```
```
	});
```
```
	//文件正在区域上方
```

	$('.js-drag').on("dragover", function(event){

```
	    event.preventDefault();
```
```
	    event.stopPropagation();
```
```
	});
```
```
	//拖离
```

	$('.js-drag').on("dragleave", function(event){

```
		//console.log('dragleave');
```
```
		$(this).removeClass("dragenter");
```
```
	});
```
```
	//所选的文件改变
```

	$('.js-drag-file').on("change",function(event){

```
		var firstFile = $(this)[0].files[0];
```
```
		if( FileVerify(firstFile)){
```

			console.log("file verified: "+ firstFile.name);

```
			console.log(firstFile);
```
```
			$(this).parent().addClass("filled");
```

			$(this).siblings('.js-drag-fileinfo').html("selected file:</br>" + firstFile.name);

```
 
```
```
		}else{
```

			$(this)[0].files=new FileListItems("");

```
		}
```
```
	});
```
```
	//清空选定的文件
```

	$('.js-drag-clear').on("click",function(event){

```
		event.preventDefault();
```
```
	    event.stopPropagation();
```

		$(this).siblings('.js-drag-file')[0].files=new FileListItems("");

		$(this).siblings('.js-drag-fileinfo').html("");

		$(this).parent().removeClass("filled");

```
	});
```
```
 
```
```
});
```

CSS 样式

```
.form-regular .dragarea{
```
```
	box-sizing: border-box;
```
```
	width: 100%;
```
```
	height: 150px;
```
```
	background:#f7f7f7;
```
```
	border-radius: 6px;
```
```
	border:2px dashed #d3d3d3;
```
```
	display: flex;
```
```
	flex-direction: column;
```
```
	flex-wrap: nowrap;
```
```
	justify-content:center;
```
```
	font-size: 13px;
```
```
	text-align: center;
```
```
}
```
```
.form-regular .dragarea.dragenter{
```
```
	background:#dedede;
```
```
}
```
```
.form-regular .dragarea p{
```
```
	font-size: 13px;
```
```
	margin:0 auto 6px auto;
```
```
	line-height: 1.3;
```
```
}
```
```
.form-regular .dragarea .button{
```
```
	margin:0 auto;
```
```
}
```
```
.js-drag-file{
```
```
	overflow: hidden;
```
```
	width: 1px;
```
```
	height: 1px;
```
```
	opacity: 0;
```
```
}
```
```
.js-drag .js-drag-fileinfo,
```
```
.js-drag .js-drag-clear{
```
```
	display: none;
```
```
	color: #000;
```
```
	font-weight: 400;
```
```
	font-size: 15px;
```
```
	line-height: 1.5;
```
```
}
```
```
.js-drag .js-drag-clear{
```
```
	text-transform: uppercase;
```
```
	font-size: 13px;
```
```
	width: 80px;
```
```
	margin: 10px auto 0 auto;
```
```
}
```
```
.js-drag .js-drag-fileinfo:first-line{
```
```
	color: #b2b2b2;
```
```
}
```
```
.js-drag.filled .js-drag-fileinfo,
```
```
.js-drag.filled .js-drag-clear{
```
```
	display: block;
```
```
}
```
```
.js-drag.filled p,
```
```
.js-drag.filled .button{
```
```
	display: none;
```
```
}
```

表单处理

还是通过 Rest API 保存文件，保存后获取到文件地址以做后续其他工作。注意要上传文件就必须要身份验证，身份验证的接口上一篇文章也说了，先安装Basic-Auth插件。

```
//通过Rest API保存文件
```

function brain_wp_api_upload( $filedata ){

```
	$file_url = $filedata['tmp_name'];
```

	$file_content=file_get_contents($file_url);

	$url_api = site_url("/wp-json/wp/v2/media/");

```
	$file_name = $filedata['name'];
```
```
	$ch = curl_init();
```

	curl_setopt($ch, CURLOPT_URL,            $url_api );

	curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1 );

	curl_setopt($ch, CURLOPT_POST,           1 );

	curl_setopt($ch, CURLOPT_POSTFIELDS,     $file_content);

	curl_setopt($ch, CURLOPT_HTTPHEADER,     array(

		'content-disposition: attachment; filename="'.$file_name.'"',

		'authorization: Basic ' . base64_encode('username:password')

		//'authorization: ' . $_SERVER['HTTP_AUTHORIZATION']

```
		)
```
```
	); 
```
```
	$result=curl_exec($ch);
```
```
	if(json_decode($result)->id){
```

		return json_decode($result)->guid->rendered ;

```
	}else{
```

		return json_decode($result)->data->status . " " .json_decode($result)->message;

```
	}
```
```
}
```

//获取提交的内容，并调用brain_wp_api_upload这个函数返回的文件URL

if(!empty($_FILES['pro_document']['tmp_name'])){

	$pro_document = brain_wp_api_upload( $_FILES['pro_document'] );

	echo "pro_document: ".$pro_document. "<br/>";

```
}else{
```
```
	$pro_document = "";
```
```
}
```
```
...
```
```
//后续的一系列处理
```

最后，因为是对外使用的上传功能，还需要单独开设个子目录上传文件单独保存，以免和文章等其他附件混淆在一起。用 upload_dir 这个钩子，通过识别上传的用户 id 临时修改目录：

add_filter( 'upload_dir', 'brain_change_upload_dir_ct' );

function brain_change_upload_dir_ct( $upload ) {

	if( get_current_user_id()== 2 ){//basic认证的用户id

		$upload['subdir'] = '/subfolder'; //子目录名

		$upload['path'] = $upload['basedir'] . $upload['subdir'];

		$upload['url']  = $upload['baseurl'] . $upload['subdir'];

```
	}
```
```
	return $upload;
```
```
}
```

其实后来找了下 Gravity Forms 也有实现类似功能的外挂，比如这个，前端是原生的也有，比如这个。可惜这些都不完全符合我的应用场景。在提交表单之前，我只想让用户先选定本地文件，而并不是立即上传，我表单里还有很多其他选项以及用了验证码系统，在表单提交后通过验证，再上传文件，这样可以避免网站被滥传一些无用的文件甚至是木马。