WordPress用户资料添加自定义用户头像功能

一般情况下，WordPress默认都是使用Gravatar头像，如果用户没有注册过Gravatar头像，那就使用网站设置的默认头像，这样用户体验不是很好；再则，如果直接调用远程Gravatar头像，还会影响网站的加载速度（WordPress缓存Gravatar头像到本地，提高加载速度）。所以，作为一个开放注册的WordPress网站而言，在用户资料页面添加自定义用户头像功能是极为重要的。

自定义用户头像，只需要安装 Simple Local Avatars 插件即可，建议在后台插件安装页面搜索 Simple Local Avatars 在线安装，或者在此下载 Simple Local Avatars 。启用该插件后，你就可以在后台 >用户>我的个人资料 下看到自定义头像上传功能了，如下图所示

Simple Local Avatars 是英文的，只有一个主文件 simple-local-avatars.php，你也可以将这个功能直接集成到你的主题中，只需将该插件的 simple-local-avatars.php 放到正在使用的主题的根目录，然后在 functions.php文件中使用下面的代码引入该文件即可：

require_once(TEMPLATEPATH . '/simple-local-avatars.php');

通过以上的两种方式，你的网站已经具备了自定义用户头像功能。那么，如何调用自定义头像？很简单，可以调用get_simple_local_avatar 或 get_avatar 函数即可，例如：

<?php echo get_avatar(get_the_author_meta('ID')); ?>

注：如果你已设置了Gravatar头像，也上传了自定义头像，优先显示自定义头像

附：simple-local-avatars.php 完整代码

<?php
/**
Plugin Name: Simple Local Avatars
Plugin URI: http://get10up.com/plugins/simple-local-avatars-wordpress/
Description: Adds an avatar upload field to user profiles if the current user has media permissions. Generates requested sizes on demand just like Gravatar! Simple and lightweight.
Version: 1.3.1
Author: Jake Goldman (10up LLC), Oomph Inc
Author URI: http://get10up.com
Plugin: Copyright 2011 Jake Goldman (email : jake@get10up.com)
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
NOTE: Previous versions may have accidentally and incorrectly attributed the 
copyright to employers of Mr. Goldman. While credit is given to all contributors
to the current version, including Mr. Goldman's employers, the copyright belongs
- and has always belonged - to Mr. Goldman, personally.
*/
/**
* add field to user profiles
*/
class Simple_Local_Avatars {
private $user_id_being_edited;
public function __construct() {
add_filter( 'get_avatar', array( $this, 'get_avatar' ), 10, 5 );
add_action( 'admin_init', array( $this, 'admin_init' ) );
add_action( 'show_user_profile', array( $this, 'edit_user_profile' ) );
add_action( 'edit_user_profile', array( $this, 'edit_user_profile' ) );
add_action( 'personal_options_update', array( $this, 'edit_user_profile_update' ) );
add_action( 'edit_user_profile_update', array( $this, 'edit_user_profile_update' ) );
add_filter( 'avatar_defaults', array( $this, 'avatar_defaults' ) );
}
public function get_avatar( $avatar = '', $id_or_email, $size = 96, $default = '', $alt = false ) {
if ( is_numeric($id_or_email) )
$user_id = (int) $id_or_email;
elseif ( is_string( $id_or_email ) && ( $user = get_user_by( 'email', $id_or_email ) ) )
$user_id = $user->ID;
elseif ( is_object( $id_or_email ) && ! empty( $id_or_email->user_id ) )
$user_id = (int) $id_or_email->user_id;
if ( empty( $user_id ) )
return $avatar;
$local_avatars = get_user_meta( $user_id, 'simple_local_avatar', true );
if ( empty( $local_avatars ) || empty( $local_avatars['full'] ) )
return $avatar;
$size = (int) $size;
if ( empty( $alt ) )
$alt = get_the_author_meta( 'display_name', $user_id );
// generate a new size
if ( empty( $local_avatars[$size] ) ) {
$upload_path = wp_upload_dir();
$avatar_full_path = str_replace( $upload_path['baseurl'], $upload_path['basedir'], $local_avatars['full'] );
$image_sized = image_resize( $avatar_full_path, $size, $size, true );		
// deal with original being >= to original image (or lack of sizing ability)
$local_avatars[$size] = is_wp_error($image_sized) ? $local_avatars[$size] = $local_avatars['full'] : str_replace( $upload_path['basedir'], $upload_path['baseurl'], $image_sized );	
// save updated avatar sizes
update_user_meta( $user_id, 'simple_local_avatar', $local_avatars );
} elseif ( substr( $local_avatars[$size], 0, 4 ) != 'http' ) {
$local_avatars[$size] = home_url( $local_avatars[$size] );
}
$author_class = is_author( $user_id ) ? ' current-author' : '' ;
$avatar = "<img alt='" . esc_attr( $alt ) . "' src='" . $local_avatars[$size] . "' class='avatar avatar-{$size}{$author_class} photo' height='{$size}' width='{$size}' />";
return apply_filters( 'simple_local_avatar', $avatar );
}
public function admin_init() {
load_plugin_textdomain( 'simple-local-avatars', false, dirname( plugin_basename( __FILE__ ) ) . '/localization/' );
register_setting( 'discussion', 'simple_local_avatars_caps', array( $this, 'sanitize_options' ) );
add_settings_field( 'simple-local-avatars-caps', __('Local Avatar Permissions','simple-local-avatars'), array( $this, 'avatar_settings_field' ), 'discussion', 'avatars' );
}
public function sanitize_options( $input ) {
$new_input['simple_local_avatars_caps'] = empty( $input['simple_local_avatars_caps'] ) ? 0 : 1;
return $new_input;
}
public function avatar_settings_field( $args ) {		
$options = get_option('simple_local_avatars_caps');
echo '
<label for="simple_local_avatars_caps">
<input type="checkbox" name="simple_local_avatars_caps" id="simple_local_avatars_caps" value="1" ' . @checked( $options['simple_local_avatars_caps'], 1, false ) . ' />
' . __('Only allow users with file upload capabilities to upload local avatars (Authors and above)','simple-local-avatars') . '
</label>
';
}
public function edit_user_profile( $profileuser ) {
?>
<h3><?php _e( 'Avatar','simple-local-avatars' ); ?></h3>
<table class="form-table">
<tr>
<th><label for="simple-local-avatar"><?php _e('Upload Avatar','simple-local-avatars'); ?></label></th>
<td style="width: 50px;" valign="top">
<?php echo get_avatar( $profileuser->ID ); ?>
</td>
<td>
<?php
$options = get_option('simple_local_avatars_caps');
if ( empty($options['simple_local_avatars_caps']) || current_user_can('upload_files') ) {
do_action( 'simple_local_avatar_notices' ); 
wp_nonce_field( 'simple_local_avatar_nonce', '_simple_local_avatar_nonce', false ); 
?>
<input type="file" name="simple-local-avatar" id="simple-local-avatar" /><br />
<?php
if ( empty( $profileuser->simple_local_avatar ) )
echo '<span class="description">' . __('No local avatar is set. Use the upload field to add a local avatar.','simple-local-avatars') . '</span>';
else 
echo '
<input type="checkbox" name="simple-local-avatar-erase" value="1" /> ' . __('Delete local avatar','simple-local-avatars') . '<br />
<span class="description">' . __('Replace the local avatar by uploading a new avatar, or erase the local avatar (falling back to a gravatar) by checking the delete option.','simple-local-avatars') . '</span>
';		
} else {
if ( empty( $profileuser->simple_local_avatar ) )
echo '<span class="description">' . __('No local avatar is set. Set up your avatar at Gravatar.com.','simple-local-avatars') . '</span>';
else 
echo '<span class="description">' . __('You do not have media management permissions. To change your local avatar, contact the blog administrator.','simple-local-avatars') . '</span>';
}
?>
</td>
</tr>
</table>
<script type="text/javascript">var form = document.getElementById('your-profile');form.encoding = 'multipart/form-data';form.setAttribute('enctype', 'multipart/form-data');</script>
<?php		
}
public function edit_user_profile_update( $user_id ) {
if ( ! isset( $_POST['_simple_local_avatar_nonce'] ) || ! wp_verify_nonce( $_POST['_simple_local_avatar_nonce'], 'simple_local_avatar_nonce' ) )			//security
return;
if ( ! empty( $_FILES['simple-local-avatar']['name'] ) ) {
$mimes = array(
'jpg|jpeg|jpe' => 'image/jpeg',
'gif' => 'image/gif',
'png' => 'image/png',
'bmp' => 'image/bmp',
'tif|tiff' => 'image/tiff'
);
// front end (theme my profile etc) support
if ( ! function_exists( 'wp_handle_upload' ) )
require_once( ABSPATH . 'wp-admin/includes/file.php' );
$this->avatar_delete( $user_id );	// delete old images if successful
// need to be more secure since low privelege users can upload
if ( strstr( $_FILES['simple-local-avatar']['name'], '.php' ) )
wp_die('For security reasons, the extension ".php" cannot be in your file name.');
$this->user_id_being_edited = $user_id; // make user_id known to unique_filename_callback function
$avatar = wp_handle_upload( $_FILES['simple-local-avatar'], array( 'mimes' => $mimes, 'test_form' => false, 'unique_filename_callback' => array( $this, 'unique_filename_callback' ) ) );
if ( empty($avatar['file']) ) {		// handle failures
switch ( $avatar['error'] ) {
case 'File type does not meet security guidelines. Try another.' :
add_action( 'user_profile_update_errors', create_function('$a','$a->add("avatar_error",__("Please upload a valid image file for the avatar.","simple-local-avatars"));') );				
break;
default :
add_action( 'user_profile_update_errors', create_function('$a','$a->add("avatar_error","<strong>".__("There was an error uploading the avatar:","simple-local-avatars")."</strong> ' . esc_attr( $avatar['error'] ) . '");') );
}
return;
}
update_user_meta( $user_id, 'simple_local_avatar', array( 'full' => $avatar['url'] ) );		// save user information (overwriting old)
} elseif ( ! empty( $_POST['simple-local-avatar-erase'] ) ) {
$this->avatar_delete( $user_id );
}
}
/**
* remove the custom get_avatar hook for the default avatar list output on options-discussion.php
*/
public function avatar_defaults( $avatar_defaults ) {
remove_action( 'get_avatar', array( $this, 'get_avatar' ) );
return $avatar_defaults;
}
/**
* delete avatars based on user_id
*/
public function avatar_delete( $user_id ) {
$old_avatars = get_user_meta( $user_id, 'simple_local_avatar', true );
$upload_path = wp_upload_dir();
if ( is_array($old_avatars) ) {
foreach ($old_avatars as $old_avatar ) {
$old_avatar_path = str_replace( $upload_path['baseurl'], $upload_path['basedir'], $old_avatar );
@unlink( $old_avatar_path );	
}
}
delete_user_meta( $user_id, 'simple_local_avatar' );
}
public function unique_filename_callback( $dir, $name, $ext ) {
$user = get_user_by( 'id', (int) $this->user_id_being_edited ); 
$name = $base_name = sanitize_file_name( $user->display_name . '_avatar' );
$number = 1;
while ( file_exists( $dir . "/$name$ext" ) ) {
$name = $base_name . '_' . $number;
$number++;
}
return $name . $ext;
}
}
$simple_local_avatars = new Simple_Local_Avatars;
/**
* more efficient to call simple local avatar directly in theme and avoid gravatar setup
* 
* @param int|string|object $id_or_email A user ID,  email address, or comment object
* @param int $size Size of the avatar image
* @param string $default URL to a default image to use if no avatar is available
* @param string $alt Alternate text to use in image tag. Defaults to blank
* @return string <img> tag for the user's avatar
*/
function get_simple_local_avatar( $id_or_email, $size = '96', $default = '', $alt = false ) {
global $simple_local_avatars;
$avatar = $simple_local_avatars->get_avatar( '', $id_or_email, $size, $default, $alt );
if ( empty ( $avatar ) )
$avatar = get_avatar( $id_or_email, $size, $default, $alt );
return $avatar;
}
/**
* on uninstallation, remove the custom field from the users and delete the local avatars
*/
register_uninstall_hook( __FILE__, 'simple_local_avatars_uninstall' );
function simple_local_avatars_uninstall() {
$simple_local_avatars = new Simple_Local_Avatars;
$users = get_users_of_blog();
foreach ( $users as $user )
$simple_local_avatars->avatar_delete( $user->user_id );
delete_option('simple_local_avatars_caps');
}

参考资料：http://www.oome.org/wordpress-custom-user-avatar.html