Wordpress function based on custom field

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Project Budget (USD)
$30 - $140

Project Description:
This project is pretty simple and straight forward for people with some knowledge in Wordpress and php. It includes 4 php snippets which are going to be used on a wordpress site:

(A) The "button"
(1) A form submit button "Associate" that is shown for logged-in users on single post page. When being clicked by a logged in user, the form will add this user's to the post's custom field of (which is going to be created by me).
(2) A form submit button "Unassociate" only showed for a logged-in user and that if his username is already exist within in the values of the custom field of current post, when clicked, the user's username will be removed from the custom field.
As you can see, the visibility of button (1) and (2) is depend on whether the current user's username exists in the cf . Neither of them will appear if the user is not logged-in.

(B) Number counter
Php snippet that can be put on single post page to show the number of values (how many usernames) in the custom filed of current post.

(C) Post Listing
Php snippet to list posts on condition that their cf contains the current logged-in user's username, and based on post category.
In your code you can use "examplecat" for the category, I will change it according to my needs.

(D) PHP condition snippet (to be put on single post page)
Content only show if current logged-in user's username is within the current post's custom field of .
i.e. I will handle the content and the message myself.
code if

//private content

code else echo //message

Hope they are light weight and efficient. You only need to deal with the codes, i will handle the rest myself. (I am a part-time web designer). The codes can be sent to me in text. Good luck! lol

Skills required:
PHP, Wordpress
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