如何通过cURL实现图片上传？
我正在使用zamzar沙箱api将pdf文件转换为.txt文件。如果我为$sourceFile variable使用pdf的“ https://s3.amazonaws.com/zamzar-samples/sample.pdf”路径，则其工作正常。但是，如果我使用系统路径“ test.pdf”，则它不起作用。

我试图通过curl_file_create，但出现以下错误：

  

可恢复的致命错误：不能为类CURLFile的对象   转换为字符串。

我正在使用PHP版本7.3.0

<?php
error_reporting(E_ALL);
$endpoint = "https://api.zamzar.com/v1/jobs";
$apiKey = "GiVUYsF4A8ssq93FR48H";
$sourceFile = "https://s3.amazonaws.com/zamzar-samples/sample.pdf";//new CurlFile("test.pdf");
$targetFormat = "txt";


$postData = array(
  "source_file" => $sourceFile,"target_format" => $targetFormat
);
$ch = curl_init();
curl_setopt($ch,CURLOPT_URL,$endpoint);
curl_setopt($ch,CURLOPT_CUSTOMREQUEST,'POST');
curl_setopt($ch,CURLOPT_SAFE_UPLOAD,false);
curl_setopt($ch,CURLOPT_POSTFIELDS,$postData);
curl_setopt($ch,CURLOPT_RETURNTRANSFER,true);
curl_setopt($ch,CURLOPT_SSL_VERIFYPEER,CURLOPT_USERPWD,$apiKey . ":");
$body = curl_exec($ch);
curl_close($ch);
$response = json_decode($body,true);
echo "Response:\n---------\n";
echo"<pre>";
print_r($response);
?>

Response: ---------
Array
(
    [id] => 8442473
    [key] => GiVUYsF4A8ssq93FR48H
    [status] => initialising
    [sandbox] => 
    [created_at] => 2019-11-12T10:35:01Z
    [finished_at] => 
    [import] => Array
        (
            [id] => 671784
            [url] => https://s3.amazonaws.com/zamzar-samples/sample.pdf
            [status] => initialising
        )

    [target_files] => Array
        (
        )

    [target_format] => txt
    [credit_cost] => 0
)

上面的例子也给了我很好的输出。如果我将amazonaws中的system path替换为空白，则不会给出任何响应。