# Customizing create topic form to add more custom fields, what does add\_to\_serializer or register\_custom\_field\_type do?

**URL:** <https://meta.discourse.org/t/customizing-create-topic-form-to-add-more-custom-fields-what-does-add-to-serializer-or-register-custom-field-type-do/57774>\
**Category:** Extras\
**Created:** [2017 年2 月 22 日 10:24 UTC](https://meta.discourse.org/t/customizing-create-topic-form-to-add-more-custom-fields-what-does-add-to-serializer-or-register-custom-field-type-do/57774 "2017-02-22T10:24:50Z")\
**Posts on this page:** 1\
**Showing post:** 1

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作者： ![net\_deamon](https://sea3.discourse-cdn.com/meta/user_avatar/meta.discourse.org/net_deamon/32/70126_2.png) [@net\_deamon](https://meta.discourse.org/u/net_deamon)\
发布日期： [2017 年2 月 22 日 10:24 UTC](https://meta.discourse.org/t/customizing-create-topic-form-to-add-more-custom-fields-what-does-add-to-serializer-or-register-custom-field-type-do/57774/1 "2017-02-22T10:24:50Z")

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Hi I was looking into customizing create topic form.

1. Removing the category option all together
2. Adding custom field to the form.

Now I was able to add custom field using the plugin outlet composer-fields-below,  
but how to integrate it with topic ? When the user clicks on “+ Create Topic” button, how to save the custom field along with the form?

 ![](https://global.discourse-cdn.com/meta/original/3X/c/c/ccb26375d3f872b587a77c71d5bc4ab1a10c6817.png)

Then I came to know about  
User.register\_custom\_field\_type(‘see\_signatures’, :boolean)  
in [discourse-signatures/plugin.rb at master · xfalcox/discourse-signatures · GitHub](https://github.com/xfalcox/discourse-signatures/blob/master/plugin.rb#L15).

I tried doing  
Topic.register\_custom\_field\_type(‘custom\_field’, :string)  
But no result.

I just dont know how to pass the custom field value to the backend .  
I tried browsing many discourse plugin in github, but could not understand.  
what does add\_to\_serializer or register\_custom\_field\_type do? Can you point me to its documentation?

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_[View the full topic](https://meta.discourse.org/t/customizing-create-topic-form-to-add-more-custom-fields-what-does-add-to-serializer-or-register-custom-field-type-do/57774)._