Adding and posting custom field values using WHMCS API

Yes, It's another achievement, another milestone for someone who are getting tired by searching solution for sending input values of client custom fields ( Eg. from a registration form) or submitting product/service custom fields (eg. from an order form)  through WHMCS API. It was good to play with the API until some confusion arose while submitting custom fields from input forms.

WHMCS has a well documentation around the API Functions. It specifies that custom fields can be posted as a base64 encoded serialized array of custom field values. Like all other attributes it has to be bind with a post field variable, something like $postfields["customfields"]. So according to one WHMCS API Function: Add Order has the sample:

$postfields["customfields"] = base64_encode(serialize(array("1"=>"Google")));


But confusion may come with these array values (array("1"=>"Google")). What does that "1" mean and why "Google" is assigned as a value of "1"?  It's clear that they are key value pairs in array. But how we can set those keys and values? We may think that this "1" might be a "Field Name" that can be setup through WHMCS admin panel (Setup->Custom Client Fields). For example, if we setup a custom field by name 'VAT' from the panel and want to use it in the customized order form or in registration form then $postfields["customfields"] need that key value pairs. How we can specify that? That's the point where article will explain.

Suppose we added two client custom fields named "VAT" and "DLN" It may come in our mind that the custom fields should write as key value pairs and the array for the custom fields should look like the following:

$customfields = array(
    'VAT' => "value1",
    'DLN' => "value2"
);

$postfields["customfields"] = base64_encode(serialize($customfields));

Does it submit VAT and DLN value either? No, it doesn't. It won't find any reference with VAT and DLN (which was setup from admin panel) with the action ($postfields["action"]) we are performing. All these keys refer to the ids of the individual custom fields. So how can we find that id? The steps are:

1. Login to your WHMCS admin panel.
2. Navigate Setup->Client Custom Fields
3. If there is no custom fields yet create a new one; say named "VAT".
4. After creating the field, see the HTML source from the page by right clicking on page and click view source (in Firefox).
5. Find the text "VAT".
6. You will find something like this line of HTML code (<input type="text" size="30" value="VAT" name="fieldname[11]">)
7. This fieldname[] with id may vary by users admin panel. So track the id from fieldname[11] and yes it's 11. If you find something like <input type="text" size="30" value="VAT" name="fieldname[xx]"> then 'xx' will be the id you have to use in your $customfields array. The array now should look like:

$customfields = array(
    "11" => "123456",
    "12" => "678945"
);

$postfields["customfields"] = base64_encode(serialize($customfields));

Now the reference built up and you will have those values in the WHMCS panel while you are viewing the client details. Similarly, custom fields for Products/Services the similar way should work.

If you find 11, 12, 33, 34, 35, 50 as an ID of custom fields from the view source then process them into array and use it in base64 encoded serialized array and call API functions to perform the rest of the task.

Those who have Firebug installed with their firefox browser they can easily inspect that field using 'inspect element' and can see the id from there. I am not sure if there is another way to track this id, I mean still couldn't find it.

If this article doesn't cover anyone's need please feel free to contact me.

Cheers.