src/Bundle/Common/File/FileUpload.php
public function read()
    {
        $data = '';
        $fileObj = $this->openFile();
        while (!$fileObj->eof()) {
            $data .= $fileObj->fread(4096);
        }
        $fileObj = null;
        return $data;
    }
public function read()
    {
        $data = '';
        $fileObj = $this->openFile();
        while (!$fileObj->eof()) {
            $data .= $fileObj->fread(4096);
        }
        $fileObj = null;
        return $data;
    }
Get file content.

@return string|mixed