javascript Ajax 发送并保存 Base64 编码的图像到服务器
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Ajax send & Save Base64 encoded image to server
提问by David
I am passing a base64 url through jquery ajax and want to save onto the server. But the code below is giving me a empty file. I have tried writing the decoded string and createimage from string but with both variables, 0 bites have been written. When i test the value being worked on it outputs [object FileReader]......i think either i am missing a step or making a mistake some where.
我正在通过 jquery ajax 传递 base64 url 并希望保存到服务器上。但是下面的代码给了我一个空文件。我尝试从字符串中编写解码的字符串和 createimage，但是使用这两个变量，已写入 0 个字节。当我测试正在处理的值时，它会输出 [object FileReader] ......我想要么我错过了一个步骤，要么在某些地方犯了错误。
Also is there a way to convert the image to a $_FILE type object? reason being id like to using a wordpress function to save the file if possible.
还有一种方法可以将图像转换为 $_FILE 类型的对象吗？原因是我喜欢使用 wordpress 函数来保存文件，如果可能的话。
Php code:
代码：
function uploadimg() {
$error = false;
//if ( ! function_exists( 'wp_handle_upload' ) ) require_once( ABSPATH . 'wp-admin/includes/file.php' );
//$upload_overrides = array( 'test_form' => false );
$images=array();
$a=0;
unset ($_POST['action']);
foreach($_POST as $basefile){
$upload_dir = wp_upload_dir();
$upload_path = str_replace( '/', DIRECTORY_SEPARATOR, $upload_dir['path'] ) . DIRECTORY_SEPARATOR;
$base64_string = $basefile;
echo $basefile;
$base64_string = preg_replace( '/data:image\/.*;base64,/', '', $base64_string );
$decoded_string= base64_decode($base64_string); // 0 bytes written in fwrite
$source = imagecreatefromstring($decoded_string); // 0 bytes written in fwrite
$output_file = $upload_path.'myfilef'.$a.'.jpg';
$images[]=$output_file;
$a++;
$image = fopen( $output_file, 'wb' );
$bytes=fwrite( $image, $source);
echo $bytes;
fclose( $image );
}
echo json_encode($images);
exit;
}
add_action('wp_ajax_uploadimg', 'uploadimg');
add_action('wp_ajax_nopriv_uploadimg', 'uploadimg');
jQuery sample code
jQuery 示例代码
jQuery(document).on('change', '.imageup', function(event){
errors= [];
errnum=0;
numberofimages=jQuery("#selectedimages > div").length; //get number of images
if(numberofimages<10){
var id= jQuery(this).attr('id');
var length= this.files.length;
if(length>1) {// if a multiple file upload
var images = new FormData();
images.append('action', 'uploadimg'); //wordpress specific
jQuery.each(event.target.files, function(key, value ){
var size= value.size;
var extension= value.name.substring(value.name.lastIndexOf('.') + 1).toLowerCase();
var allowedExtensions = ['png', 'jpg', 'jpeg', 'gif'];
if( allowedExtensions.indexOf(extension) !== -1 ) {
if(numberofimages<10){
var file=value;
console.log(file);
var fileReader = new FileReader();
fileReader.onload = function (e) {
var img = new Image();
img.onload = function () {
var MAX_WIDTH = 100;
var MAX_HEIGHT = 100;
var width = img.width;
var height = img.height;
if (width > height) {
if (width > MAX_WIDTH) {
height *= MAX_WIDTH / width;
width = MAX_WIDTH;
}
} else {
if (height > MAX_HEIGHT) {
width *= MAX_HEIGHT / height;
height = MAX_HEIGHT;
}
}
var canvas = document.createElement("canvas");
canvas.width = width;
canvas.height = height;
canvas.getContext("2d").drawImage(this, 0, 0, width, height);
this.src = canvas.toDataURL('image/png');
} // end on load function
img.src = e.target.result;
} //end filereader function
fileReader.readAsDataURL(file);
console.log(fileReader);
images.append(key, fileReader);
numberofimages++;
} else {
errnum++;
errors[errnum]= value=' is a illegal file type';
}
}
});
//image holder finished, remove
jQuery('#'+id).remove();
jQuery.ajax({
url: '/wp-admin/admin-ajax.php',
type: 'POST',
data: images,
cache: false,
processData: false,
contentType: false,
success: function(data) {
console.log(data);
}//end of success function
});
回答by David
ok thanks to PaulS for pointing me in the right direction....updated jQuery below........the php up top wont work with this (im cutting out the ajax even though i have included a note below to show where it goes) the array is different as i added in the filename as well as the base64 url.
好的，感谢 PaulS 为我指出了正确的方向......下面更新了 jQuery......顶部的 php 无法使用这个（我删除了 ajax，即使我在下面包含了一个注释来显示它去哪里）数组是不同的，因为我在文件名和 base64 url 中添加了。
jsfiddle http://jsfiddle.net/dheffernan/6Ut59/
jsfiddle http://jsfiddle.net/dheffernan/6Ut59/
Basically the flow is,
1.Check max files allowed
2 & then for each file check it does not exceed it.
3 Call filereader, when loaded, call resizeBase64img (thanks to the person who submitted that)
4. if on the last file to be processed -- submit FormData via Ajax
5.When file returns input div to show image & if full remove file input
基本上流程是，1.Check max files allowed 2 & 然后对于每个文件检查它不超过它。
3 调用filereader，加载时调用resizeBase64img（感谢提交那个的人） 4. 如果在最后一个要处理的文件上——通过Ajax 提交FormData 5.当文件返回输入div 以显示图像时，如果完整删除文件输入
function resizeBase64Img(base64, width, height) {
var canvas = document.createElement("canvas");
canvas.width = width;
canvas.height = height;
var context = canvas.getContext("2d");
var deferred = $.Deferred();
$("<img/>").attr("src", base64).load(function() {
context.scale(width/this.width, height/this.height);
context.drawImage(this, 0, 0);
deferred.resolve($("<img/>").attr("src", canvas.toDataURL('image/jpg')));
});
return deferred.promise();
}
function readFile(file) {
var reader = new FileReader();
var deferred = $.Deferred();
reader.onload = function(event) {
deferred.resolve(event.target.result);
};
reader.onerror = function() {
deferred.reject(this);
};
if (/^image/.test(file.type)) {
reader.readAsDataURL(file);
} else {
reader.readAsText(file);
}
return deferred.promise();
}
jQuery(document).on('change', '.imageup', function(event){
var maximages=4;
var imagecount=jQuery("#imagesholder > div").length;
var length= this.files.length;
var images= new FormData;
var processKey=0;
var i=1;
jQuery.each(event.target.files, function(key, value){
// number of images control.
imagecount++;
if(imagecount > maximages) {
var full=true;
jQuery('.imageup').remove();
jQuery('#imageinput').html("Image Quota Full, Please delete some images if you wish to change them");
return;
} else if (imagecount == maximages) {
var full=true;
jQuery('.imageup').remove();
jQuery('#imageinput').html('<div class="image-box-full">Image Quota Full: delete images to change them</div>');
}
//call resize functions
var name=value;
$.when( readFile(value) ).done(function(value) {
resizeBase64Img(value, 300, 200).done(function(newImg){
images[processKey]=[];
images[processKey]['url']=newImg[0].src;
images[processKey]['name']=name.name;
processKey++;
if(length===processKey) {
//----------------INSERT AJAX TO RUN HERE SUBMITTING IMAGES (THE FORMDATA) E.G
jQuery.ajax({
url: '/wp-admin/admin-ajax.php',
type: 'POST',
data: images,
cache: false,
processData: false,
contentType: false,
success: function(data) {
console.log(data);
}
});
}
$('#imagesholder').append('<div id="delete'+i+'">'+'<div class="image-box"><div class="box-image"><img src="'+newImg[0].src+'" style="width:50px;"/></div><div class="image-box-text">'+name.name+'</div><input type="image" src="http://testserverdavideec.mx.nf/wp-content/uploads/2014/04/success_close.png" class="deletebutton" id="delete/i'+i+'"/></div> </div>');
i++;
if(full === true) {
jQuery('.image-box-full').show();
}
});
});//end when
});//end each
jQuery(this).val('');
});//end on change
