如何从数据库中下载画布映像

Question

我有一个保存在MYSQL数据库中的画布图像，它可以在使用可数据和PHP的表中看到，但我无法下载该映像。

下面是我的JS文件，它将ajax请求发送到服务器：

$(document).ready(function(){
  var data = $('#dataList').DataTable({
    "lengthChange": false,
    "processing":true,
    "order":[],
    "ajax":{
        url:"/php/process.php",
        type:"POST",
        data:{action:'listData'},
        dataType:"json"
    },
    "columnDefs":[
        {
            "targets":[0, 5, 6],
            "orderable":true,
        },
    ],
    "pageLength": 10
  });

这是process.php

$sqlQuery = "SELECT * FROM table1 AS a LEFT JOIN sketch AS s ON a.id= s.id";

$auftragData = array();
$result = $this->dbc -> prepare($sqlQuery);
$result -> execute();

 while ( $tableResult= $result->fetch(PDO::FETCH_ASSOC) ) {
  $resultRows = array();
  $resultRows[] = $tableResult['id'];
  $resultRows[] = ucfirst($tableResult['cust_id']);
  $resultRows[] = $tableResult['typ'];
  $resultRows[] = $tableResult['status'];
  $resultRows[] = $tableResult['sketch'];
  if ($tableResult['sketch']) {
      $resultRows[] = '<a id="download" download="sketch.png"><button type="button">Download Image</button></a>';
        }
   $resultRows[] = '<button type="button" name="update" id="'.$tableResult["id"].'" class="btn btn-warning btn-xs update">update</button>';
   $resultRows[] = '<button type="button" name="delete" id="'.$tableResult["id"].'" class="btn btn-danger btn-xs delete" >delete</button>';
 $finalData[] = $auftragRows;
        }
$numRows = $result -> rowCount();

    $output = array(
        "draw"          =>  $numRows,
        "recordsTotal"      =>  $numRows,
        "recordsFiltered"   =>  $numRows,
        "data"          =>  $finalData
        );
        echo json_encode($output);
      $this->dbc = NULL;
      exit;
    }

Img url是: data:image/png;base64 64，iVBORw0KGgoAAAANSUhEUgAAA4QAAAH0CAYAAABl8+PTAAAgAElEQVR4Xu3dB9glZ103/u8LJCHhpQkYCUWlWwAFFZDQO0F6lUAkFEEpghQpvuArRboUAaU36YYWpBMhFP1Lk1clIhZAOoIgCUko/+uHs/pks7vPmTkzZ2bOfOa6zrULue

如何用上面的代码下载图像？

Answer 1

发现了问题。MySQL DB中的字段正在切割字符，同时将图像保存在服务器上。解决了这个问题。