Disable freeform if user has submitted details and returns to the site

Question

Is there a way to disable a freeform form if a user has already submitted their details? There is a plugin that can pull the users IP but how do I compare to that to the list of IP addresses of submitted freeform entries?

{if "{exp:get_post_var type='user_ip'}" == "127.0.0.1"}
    YES, it is 127.0.0.1
{if:else}
    NO, it is not 127.0.0.1
{/if} 

Answer 1

Freeform has built in duplicate detection. https://solspace.com/legacy_docs/freeform-4/form/#prevent_duplicate_on

Answer 2

You could check if an entry with a certain ip address is submitted with the entries function:

{exp:freeform:entries search:ip_address="127.0.0.1" form_id="your-form-id" dynamic="off" limit='1'}
{if freeform:no_results}
No, 127.0.0.1 has not submitted an entry
{/if}

Yes, 127.0.0.1 has submitted an entry
{/exp:freeform:entries}