Function and usage of get_metadata_raw() in wordpress

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    2024-01-07T12:15:33+00:00

    The get_metadata_raw() function in WordPress is a utility for retrieving raw metadata values associated with various types of objects like posts, comments, terms, and users. It's part of the WordPress metadata API that allows developers to interact with the site's data layer. Here's a detailed explanation of its functionality and usage:

    Function:

    get_metadata_raw( string $meta_type, int $object_id, string $meta_key = '', bool $single = false ): mixed

    Purpose:

    This function is used to retrieve the raw metadata value for a specified object in WordPress.

    Parameters:

    1. $meta_type (string, required): This parameter defines the type of object for which the metadata is being retrieved. It accepts values like 'post', 'comment', 'term', 'user', or any other object type with an associated metadata table.

    2. $object_id (int, required): The ID of the object for which the metadata is being retrieved. It should be a valid ID corresponding to the $meta_type.

    3. $meta_key (string, optional): The specific metadata key to retrieve. If this parameter is not specified (or is an empty string), the function will retrieve all metadata associated with the specified object. Its default value is an empty string ('').

    4. $single (bool, optional): Determines the format of the return value. If set to true, the function returns only the first value of the specified $meta_key. This parameter has no effect if $meta_key is not specified. The default is false.

    Return Values:

    • Mixed: The return type is mixed, meaning it can vary based on the input and the state of the metadata:
      • An array of values if $single is false.
      • The value of the meta field if $single is true.
      • False for an invalid $object_id (non-numeric, zero, or negative values), or if $meta_type is not specified.
      • Null if the specified meta key value does not exist.

    Sample Usage:

    Example 1: Retrieve All Metadata for a Post

    $metadata = get_metadata_raw('post', 123); // 123 is the post ID
    

    This code retrieves all metadata associated with the post having ID 123.

    Example 2: Retrieve Specific Metadata for a User

    $user_meta = get_metadata_raw('user', 456, 'user_meta_key', true); // 456 is the user ID
    

    Here, it retrieves the value of 'user_meta_key' for the user with ID 456. Since $single is true, only the first value is returned.

    Example 3: Error Handling

    $meta = get_metadata_raw('term', -1);
    if ($meta === false) {
        // Handle error for invalid object ID
    }
    

    This code tries to fetch metadata for a term with an invalid ID (-1) and handles the error when false is returned.

    Using get_metadata_raw() is particularly useful when you need the unfiltered, raw metadata values, as it bypasses the usual metadata filters applied in other get_meta functions.

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