docusign php sdk: Call to a member function read() on string in ObjectSerializer.php:285

TL;DR

Upgrade with composer require docusign/esign-client:^5.3.0 (or newer). This was a confirmed SDK bug (DCM-4285), fixed in the 5.3.0 release.

Steps

1. This was a confirmed SDK bug (DCM-4285), fixed in the 5.3.0 release. Upgrade with composer require docusign/esign-client:^5.3.0 (or newer). The fix changed getDocument handling so a string response is written directly to the file instead of calling ->read() on it. If you cannot upgrade, patch ObjectSerializer.php around line 285 with the reporter's guard: if (is_string($data)) { fwrite($file, $data); } else { while ($chunk = $data->read(200)) { fwrite($file, $chunk); } }.

When to use

You are seeing this: Calling EnvelopeApi\getDocument in the DocuSign eSign PHP client (docusign/esign-client) crashed with this fatal error. Use this skill when you run into "docusign php sdk: Call to a member function read() on string in ObjectSerializer.php:285".

When not to use

If your error message or symptom does not match what is described above, this is probably not your fix. Search for your exact error text instead of forcing this one to fit.

Versions

Versions mentioned in the source: before 5.3.0. If you are on something much newer or older, the details may have shifted.

Why this happens

The original report does not dig into a root cause. It documents the symptom and the fix that resolved it.

A user asked: Calling EnvelopeApi\getDocument in the DocuSign eSign PHP client (docusign/esign-client) crashed with this fatal error. In ObjectSerializer.php line 285 the code called $data->read(200) on the response, but getDocument returns the file contents as a plain string, not a stream object. This hit any code path that downloads envelope documents via the SDK on versions before 5.3.0. Reporter confirmed the failure and provided the workaround of guarding with isstring(). The verified answer: This was a confirmed SDK bug (DCM-4285), fixed in the 5.3.0 release. Upgrade with composer require docusign/esign-client:^5.3.0 (or newer). The fix changed getDocument handling so a string response is written directly to the file instead of calling ->read() on it. If you cannot upgrade, patch ObjectSerializer.php around line 285 with the reporter's guard: if (isstring($data)) { fwrite($file, $data); } else { while ($chunk = $data->read(200)) { fwrite($file, $chunk); } }. Thread: https://vectle.com/threads/thr_CyxK3QaoWyZquSBFvwPgbg