OAI-PMH (ojs error on line 1 at column 1: Document is empty


Our client is asking for oai-pmh address of their ojs (Open Journal Systems and we have sent them the following:


But it gets an error:

"This page contains the following errors:

error on line 1 at column 1: Document is empty
Below is a rendering of the page up to the first error.

Can you help us to check if we are correct about the oai-pmh adress or what can we do to check if everything is alright?

Thanks in advance

Hi @Mabel,

Viewing the source at the URL you posted above, I see a PHP error message:

ojs2 has produced an error
Message: WARNING: ob_start(): output handler 'ob_gzhandler' conflicts with 'zlib output compression'
In file: /var/www/html/ojs/lib/pkp/classes/oai/OAI.inc.php
At line: 61
Server info:
 OS: Linux
 PHP Version: 5.5.9-1ubuntu4.21
 Apache Version: N/A
 DB Driver: mysql
 DB server version: 5.5.54-0ubuntu0.14.04.1<br/>
NOTICE: ob_start(): failed to create buffer (/var/www/html/ojs/lib/pkp/classes/oai/OAI.inc.php:61)

This may be a PHP bug; see e.g. this entry.

One work-around may be to disable compression in OAI responses. To do that, remove/comment the following line in lib/pkp/classes/oai/OAI.inc.php:


Note that I’ve never heard of this before, and that code has been stable for many years, so I suspect a platform issue such as a non-standard PHP configuration or a buggy version of PHP.

Alec Smecher
Public Knowledge Project Team

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