The Question

How to get just the URL to a post author's avatar?

The Requirements

I want the url to the image that is hosted on my website.

Image will be called in the loop of a post.

The author of the post is the person whose avatar image I wish to display.

What I've Tried

A bunch of things, but mainly <?php echo get_avatar_url('user_email'); ?>

It returns a url to the default 'mystery man' image hosted by Gravatar despite their being an avatar uploaded to my site for this test user.

Clarification

I don't want a Gravatar hosted image.

To Reference

Wordpress code reference for get_avatar_url()

There is currently no completed Wordpress Codex entry for it

Concerns

I'm beginning to think with all the WP ambiguity between avatar and Gravatar that get_avatar_url is solely for Gravatar images which are of course only available to Gravatar registered users. Hopefully someone can tell me I am wrong.

Of Possible Interest

Website uses Buddypress
This websites Buddypress installation uses custom avatar sizes
This website uses its own custom theme
User has avatar uploaded to website
User does not have a gravatar account (testing without as most users wont have gravatar accounts. I dont want most users to have mystery men in place of their avatars)
The following code works fine to pull the website hosted avatar (but of course outputs the image tag and classes, not the pure url that i require)
```
<?php echo get_avatar( get_the_author_meta( 'ID' ), 180 ); ?>
```

回答1:

There doesn't seem to be an documentation around this, so no wonder it has been challenging.

In order to retrieve the BuddyPress avatar URL, use the function like so:

// Assuming $user_id is the id for the desired user
echo bp_core_fetch_avatar ( 
    array(  'item_id' => $user_id, // id of user for desired avatar
            'type'    => 'full',
            'html'   => FALSE     // FALSE = return url, TRUE (default) = return img html
    ) 
);

Here is the documentation (formatted a bit by me) from the source php file:

Documentation

bp_core_fetch_avatar( $args );

Return: string Formatted HTML <img> element, or raw avatar URL based on $html arg.

Description:

Get an avatar for a BuddyPress object. Supports avatars for users, groups, and blogs by default, but can be extended to support custom components as well.

This function gives precedence to locally-uploaded avatars. When a local avatar is not found, Gravatar is queried.

Usage

<?php  bp_core_fetch_avatar( $args ); ?>

Default Usage:

<?php  $args = array(
    'item_id'       => false,
    'object'        => 'user',
    'type'          => 'thumb',
    'avatar_dir'    => false,
    'width'         => false,
    'height'        => false,
    'class'         => 'avatar',
    'css_id'        => false,
    'title'         => false,
    'alt'           => '',
    'email'         => false,
    'no_grav'       => false,
    'html'          => true,
    'extra_attr'    => '',
    'scheme'        => null,
    'rating'        => {setting for 'avatar rating' option},
    'force_default' => false
);

bp_core_fetch_avatar( $args ); ?>

Parameters:

All arguments are technically optional; some will, if not provided, be auto-detected by bp_core_fetch_avatar(). This auto-detection is described more below, when discussing specific arguments.

item_id
(int|bool) The numeric ID of the item for which you're requesting an avatar (eg, a user ID). If no 'item_id' is present, the function attempts to infer an ID from the 'object' + the current context: if 'object' is 'user' and the current page is a user page, 'item_id' will default to the displayed user ID; if 'group' and on a group page, to the current group ID; if 'blog', to the current blog's ID. If no 'item_id' can be determined in this way, the function returns false. Default: false.

$object
(string) The kind of object for which you're getting an avatar. BuddyPress natively supports three options: 'user', 'group', 'blog'; a plugin may register more. Default: 'user'.

$type
(string) When a new avatar is uploaded to BP, 'thumb' and 'full' versions are saved. This parameter specifies whether you'd like the 'full' or smaller 'thumb' avatar. Default: 'thumb'.

$avatar_dir
(string|bool) (auto-detected) The name of the subdirectory where the requested avatar should be found. If no value is passed, 'avatar_dir' is inferred from 'object': 'user' becomes 'avatars', 'group' becomes 'group-avatars', 'blog' becomes 'blog-avatars'.

Remember that this string denotes a subdirectory of BP's main avatar directory (usually based on {@link wp_upload_dir()}); it's a string like 'group-avatars' rather than the full directory path. Generally, it'll only be necessary to override the default value if storing avatars in a non-default location. Default: false.

$width
(int|bool) (auto-detected) Requested avatar width. The unit is px. This value is used to build the 'width' attribute for the <img> element. If no value is passed, BP uses the global avatar width for this avatar type. Default: false.

$height
(int|bool) (auto-detected) Requested avatar height. The unit is px. This value is used to build the 'height' attribute for the <img> element. If no value is passed, BP uses the global avatar height for this avatar type. Default: false.

$class (string) The CSS class for the <img> element. Note that BP uses the 'avatar' class fairly extensively in its default styling, so if you plan to pass a custom value, consider appending it to 'avatar' (eg 'avatar foo') rather than replacing it altogether. Default: 'avatar'.

$css_id (string|bool) The CSS id for the <img> element. Default: false.

$title (string) The title attribute for the <img> element. Default: false.

$alt (string) The alt attribute for the <img> element. In BP, this value is generally passed by the wrapper functions, where the data necessary for concatenating the string is at hand; see {@link bp_get_activity_avatar()} for an example. Default: ''.

$email
(string|bool) An email to use in Gravatar queries. Unless otherwise configured, BP uses Gravatar as a fallback for avatars that are not provided locally. Gravatar's API requires using a hash of the user's email address; this argument provides it. If not provided, the function will infer it: for users, by getting the user's email from the database, for groups/blogs, by concatenating "{$item_id}-{$object}@{bp_get_root_domain()}". The user query adds overhead, so it's recommended that wrapper functions provide a value for 'email' when querying user IDs. Default: false.

$no_grav (bool) Whether to disable the default Gravatar fallback. By default, BP will fall back on Gravatar when it cannot find a local avatar. In some cases, this may be undesirable, in which case 'no_grav' should be set to true. To disable Gravatar fallbacks globally, see the 'bp_core_fetch_avatar_no_grav' filter. Default: false.

$html
(bool) Whether to return an <img> HTML element, vs a raw URL to an avatar. If false, <img>-specific arguments (like 'css_id') will be ignored. Default: true.

$extra_attr (string) HTML attributes to insert in the IMG element. Not sanitized. Default: ''.

$scheme
(string) URL scheme to use. See set_url_scheme() for accepted values. Default null.

$rating (string) What rating to display Gravatars for. Accepts 'G', 'PG', 'R', 'X'. Default is the value of the 'avatar_rating' option.

$force_default (bool) Used when creating the Gravatar URL. Whether to force the default image regardless if the Gravatar exists. Default: false.

Notes:

To disable Gravatar query fallbacks locally, add this filter:

add_filter( 'bp_core_fetch_avatar_no_grav', '__return_true' );

回答2:

I'm not sure this answer was incorporated into Cale's answer so I've undeleted it in case it's of use to anyone else.

in the loop (in say single.php)

<img class="" src="<?php 
$authorUserID = get_the_author_meta('ID');  // get the user id of the post author
echo bp_core_fetch_avatar ( 
    array(  'item_id'   => $authorUserID,       // output user id of post author
            'type'      => 'full',
            'html'      => FALSE               // FALSE = return url, TRUE (default) = return url wrapped with html and css classes
    ) 
); 
?>">

or call from functions.php file in theme folder

the call (from your loop in say single.php)

<?php custom_get_author_avatar_url(); ?>

the function (place in functions.php)

function custom_get_author_avatar_url() {
    $authorUserID = get_the_author_meta('ID');  // get the user id of the post author
    echo bp_core_fetch_avatar ( 
    array(  'item_id'   => $authorUserID,       // output user id of post author
            'type'      => 'full',
            'html'      => FALSE            // FALSE = return url, TRUE (default) = return url wrapped with html and css classes
    ) 
    ); 
}