I have done everything needed to setup webservices on my moodle 3.11 instance, including roles/capabilities/user. However sending a test request always gives { "exception": "dml_missing_record_exception", "errorcode": "invalidrecord", "message": "Can't find data record in database table external_functions." }
The URL to access it is of the format https:///moodle/webservice/rest/server.php?wsfunction=core_user_create_user&service=mymoodleusermanage&moodlewsrestformat=json&users[0][username]=ABC&users[0][firstname]=VPTest&users[0][lastname]=None&users[0][email]=mail@xxx.com&users[0][password]=xxxxx&users[0][auth]=manual&wstoken=xxxxxxxxxxxxxx
The service parameter is correctly set to the shortname of the service. Does the service have to be defined anywhere additionally apart from Site Administration->Server->Web Services->External Services->Custom Services
Thanks for any help that can be given
The answer is very simple - you are trying to call a non-existent webservice function (hence the error message about being unable to find the database record for the function in the external_functions database table).
If you look in the Moodle code: https://github.com/moodle/moodle/blob/master/lib/db/services.php#L1717 you will see that the function is called core_user_create_users - with an "s" at the end of it.
If you add that extra "s" into the URL parameters you are using, then it should work.