title: FPDFI - setSourceFile as string and not file
body: <p>I am using FPDFI to manipulate an existing PDF. I get this PDF back in the form of a base64 encoding string from an external API. I then create a PDF and then use the following code to manipulate it:</p>
  
  <pre><code>$pdf = new FPDI();
  $sourceFileName = 'label.pdf';
  $pdf-&gt;setSourceFile($sourceFileName);
  </code></pre>
  
  <p>Is it possible to bypass the process of creating the file and just send the base64 decoded string straight into setSourceFile, e.g:</p>
  
  <pre><code>$pdf = new FPDI();
  $pdf-&gt;setSourceString(base64_encode($labelString));
  </code></pre>
  
  <p>I can't find anything in the docs.</p>
  
  <p>EDIT: </p>
  
  <p>I seem to have been able to solve this by using the tempnam() function in PHP:</p>
  
  <pre><code>$tmpfname = tempnam("/tmp", "ABC");
  
  $handle = fopen($tmpfname, "w");
  fwrite($handle, $label);
  fclose($handle);
  </code></pre>
  
  <p>And then referring to $tmpfname as $sourceFileName</p>