WordPress用戶資料添加自定義用戶頭像功能

一般情況下，WordPress默認都是使用Gravatar頭像，如果用戶沒有注冊過Gravatar頭像，那就使用網站設置的默認頭像，這樣用戶體驗不是很好；再則，如果直接調用遠程Gravatar頭像，還會影響網站的加載速度（WordPress緩存Gravatar頭像到本地，提高加載速度）。所以，作為一個開放注冊的WordPress網站而言，在用戶資料頁面添加自定義用戶頭像功能是極為重要的。

自定義用戶頭像，只需要安裝 Simple Local Avatars 插件即可，建議在后臺插件安裝頁面搜索 Simple Local Avatars 在線安裝，或者在此下載 Simple Local Avatars 。啟用該插件后，你就可以在后臺 >用戶>我的個人資料 下看到自定義頭像上傳功能了，如下圖所示

Simple Local Avatars 是英文的，只有一個主文件 simple-local-avatars.php，你也可以將這個功能直接集成到你的主題中，只需將該插件的 simple-local-avatars.php 放到正在使用的主題的根目錄，然后在 functions.php文件中使用下面的代碼引入該文件即可：

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

通過以上的兩種方式，你的網站已經具備了自定義用戶頭像功能。那么，如何調用自定義頭像？很簡單，可以調用get_simple_local_avatar 或 get_avatar 函數即可，例如：

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

注：如果你已設置了Gravatar頭像，也上傳了自定義頭像，優(yōu)先顯示自定義頭像

附：simple-local-avatars.php 完整代碼

<?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');
}

參考資料：http://www.oome.org/wordpress-custom-user-avatar.html