如何使用 CodeIgniter 在 Ajax 中对数组进行切片以进行分页？

Question

我的模块的视图页面中有一个 foreach 循环，它从控制器检索图像网格（数量由“items_top”确定）。问题是所有项目同时加载，因为此时没有设置分页。

这是我的视图的代码：

<div class="row row-sm padder-lg ">

        <?php
        foreach ($top->tracks->track as $key => $value) 
        {
            if($key >= $this->config->item("items_top"))
                return false;
            $image = $value->image[3]->text;
                if($image == '')
            $image = $value->image[2]->text;
                if($image == '')
            $image = base_url()."assets/images/no-cover.png";
        ?>       
        <div class="col-xs-6 col-sm-4 col-md-3 col-lg-2">
            <div class="item">
                <div class="pos-rlt">
                <a href="#">

                    <div class="item-overlay opacity r r-2x bg-black">
                        <div class="center text-center m-t-n">
                        <i class="icon-control-play i-2x"></i>                    
                        </div>

                    </div>
                    <a href="#">
                        <div class="r r-2x img-full" style="background:url('<?php echo $image; ?>') no-repeat top center; -webkit-background-size: cover; -moz-background-size: cover; -o-background-size: cover;  background-size: cover;">
                            <div style="height:180px;overflow:hidden;"></div>
                        </div>
                    </a>
                </div>
                <div class="padder-v">
                    <a href="#" class="text-ellipsis"><?php echo $value->name; ?></a>
                    <a href="#" class="text-ellipsis text-xs text-muted"><?php echo $value->artist->name; ?></a>
                </div>
            </div>
        </div>
        <?php
        }
        ?>

    <script>
    $(".nav-sidebar li").removeClass("active");
    $("#topTrack").addClass('active');
    </script>
</div> 

这是我的函数助手：

function _curl($url) {  
    $CI     =& get_instance();  
    $ch = curl_init(); 
    curl_setopt($ch,CURLOPT_RETURNTRANSFER,1);
    curl_setopt($ch,CURLOPT_CONNECTTIMEOUT,15);
    curl_setopt($ch,CURLOPT_FOLLOWLOCATION,1);    
    if(strtolower(parse_url($url, PHP_URL_SCHEME)) == 'https')
    {
        curl_setopt($ch,CURLOPT_SSL_VERIFYPEER,1);
        curl_setopt($ch,CURLOPT_SSL_VERIFYHOST,1);
    }
    if($CI->config->item("proxy") != '')
    {       
        curl_setopt($ch, CURLOPT_PROXY, $CI->config->item("proxy"));
    }
    curl_setopt($ch, CURLOPT_URL, $url); 
    $data = curl_exec($ch);
    curl_close($ch); 
    return $data;
}

function getTopTracks($artist = false)
{
$CI     =& get_instance();  
$artist = econde($artist);  

$url    = "http://ws.audioscrobbler.com/2.0/?method=chart.gettoptracks&api_key=".$CI->config->item("lastfm")."&format=json&limit=60&page=3";    
$file_cache = 'cache/tracks_'.sha1("toptracks").".cache";

if($cache)
    {   
        $json = $cache;
        if (time()-filemtime($file_cache) > 24 * 3600) {
          // file older than 24 hours
            @unlink($file_cache);
        }
    }
    else
    {       
        $json   = _curl($url);  
        if($CI->config->item("use_cache") == "1")
            write_file($file_cache, $json);
    }   

if(!$artist)
    $json   = str_ireplace("toptracks","tracks",$json);
else
    $json   = remove_banned($json,true) ;
$json   = str_ireplace("#text","text",$json);
$json   = str_ireplace(":totalResults","",$json);
return remove_banned($json) ;
}

这是我的控制器：

public function getTopTracks($return = false,$page = false)
{
    $data['page']   = $page;
    $data['top'] = json_decode(getTopTracks());
    if(count($data['top']->tracks->track) <=1)
            {                   
                $this->config->set_item("auto_country", '0');       
                $data['top'] = json_decode(getTopTracks());
            }
            return $this->load->view(getTemplate('topTracks'),$data,$return);   
 }

我需要对循环进行切片以对这些项目进行分页，我希望能够在底部添加一个“加载更多”按钮，但问题是 Ajax，我不能使用 $page = (int)getFromExternalInput();，因为循环调用公共功能不是网址。 分割这个循环的正确方法是什么？

Answer 1

我用询问的代码编辑了我的问题中的函数助手 对于...希望这可能有助于回答。谢谢

好的，根据您的附加信息更新我的答案，我根据新信息创建了一个工作示例。但是，我确实必须为自己创建一个沙箱，它不会 100% 反映您的代码。我觉得你应该能够从这个答案中得到一些东西，你应该能够在你自己的代码中实现它。

代码确实需要一点优化

我将缓存文件保存在 /application/cache/lastfm

这里的缓存对于分页来说可能有点问题，但我尽我所能提出了一个可行的示例

application/config/lastfm.php

$config['url'] = 'http://ws.audioscrobbler.com/2.0/';
/**
 * 
 */
$config['API_KEY'] = '';
/**
 * 
 */
$config['limit'] = 12;
/**
 * 
 */
$config['cache_time'] = 24 * 3600;
/**
 * 
 */
$config['proxy'] = "";

---

应用程序/库/curl.php

class Curl
{
    protected $handle;

    public function __construct()
    {
        $this->_init();
    }
    /**
     * 
     * @return type
     */
    protected function _init()
    {
        if(!in_array('curl', get_loaded_extensions())) 
            return log_message('error', 'curl extension is not loaded!');

        $this->handle = curl_init();

        if(!$this->handle) {
            return log_message('error', 'could not create curl handle!');
        } 

    }
    /**
     * 
     * @param type $url
     * @return type
     */
    public function fetch($url)
    {
        $this->setOptions($url);

        $response = curl_exec($this->handle);

        if($errno = curl_errno($this->handle)){
            log_message('error', 'Curl Response Error: ' .  curl_strerror($errno));
        }

        curl_close($this->handle);

        return ($errno === 0) ? $response : false;
    }
    /**
     * 
     * @param type $url
     * @return type
     */
    protected function setOptions($url)
    {
        if(strtolower(parse_url($url, PHP_URL_SCHEME)) == "https"){
            curl_setopt($this->handle, CURLOPT_SSL_VERIFYPEER, 1);
            curl_setopt($this->handle, CURLOPT_SSL_VERIFYHOST, 1);
        }

        $proxy = $this->config->item('proxy', 'lastfm');

        if(!empty($proxy)){
            curl_setopt($this->handle, CURLOPT_PROXY, $proxy);
        }

        curl_setopt($this->handle,CURLOPT_FAILONERROR,true);
        curl_setopt($this->handle, CURLOPT_RETURNTRANSFER, true);
        curl_setopt($this->handle, CURLOPT_URL, $url);

        return;
    }
    /**
     * 
     * @param type $name
     * @return type
     */
    public function __get($name)
    {
        $instance =&get_instance();
        return $instance->$name;
    }
}

---

应用程序/控制器/tracks.php

class Tracks extends App_Controller 
{
    public function __construct()
    {
        parent::__construct();

        $this->load->config('lastfm', true);

        $this->load->model('lastfm_model');
    }

    public function index()
    {
        $tracks = $this->lastfm_model->getTracks(1);

        $this->load->view($this->template, array(
            'content'  =>  'lastfm/tracks',
            'tracks_view'  =>  $this->load->view('lastfm/partials/tracks', array(
                'tracks'   =>   $tracks,
                'statistics'    => $tracks['data']->tracks->attr
            ), true)         
        ));
    }

    public function get($pageId=0)
    {
        $tracks = $this->lastfm_model->getTracks($pageId, true);

        if($pageId > $tracks['data']->tracks->attr->totalPages){
            return;
        }

        $this->load->view('lastfm/partials/tracks', array(
            'tracks'   =>   $tracks,
            'statistics'    => $tracks['data']->tracks->attr 
        ));
    }
}

---

application/models/lastfm_model.php

class LastFM_Model extends CI_Model
{
    /**
     *
     * @var type 
     */
    protected $options;
    /**
     *
     * @var type 
     */
    protected $cache;
    /**
     *
     * @var type 
     */
    protected $method;
    /**
     *
     * @var type 
     */
    protected $byPassCache = false;

    public function __construct()
    {
        parent::__construct();

        $this->options = $this->config->config['lastfm'];
    }


    /**
     * 
     * @param type $page
     */
    public function getTracks($page=0, $bypass_cache=false, $method='chart.gettoptracks')
    {
        $this->method = $method;

        $this->cache = $this->_getCachePath();

        $this->byPassCache = $bypass_cache;

        $url= $this->_buildUrl($page);

        if($bypass_cache){
            return array(
                'src'  =>  'curl',
                'data'  =>  $this->_parseContent($this->_fetch($url), false)
            );
        }

        if($cache = $this->_getCache()){
            return array(
                'src'  =>  'cache',
                'data'  =>  $this->_parseContent($cache)
            );
        }

        return array(
            'src'  =>  'curl',
            'data'  =>  $this->_parseContent($this->_fetch($url), false)
        );
    }
    /**
     * 
     * @param type $page
     * @return type
     */
    protected function _buildUrl($page=0)
    {
        $query_data = array(
            'method'    =>  $this->method,
            'format'    =>  'json',
            'page'      =>  $page,                     
            'limit'     =>  $this->options['limit'],
            'api_key'   =>  $this->options['API_KEY']
        );

        $query = http_build_query($query_data);

        return $this->options['url'] . '?' . $query;
    }
    /**
     * 
     * @param type $url
     * @return type
     */
    protected function _fetch($url)
    {
        $this->load->library('curl');

        $data = $this->curl->fetch($url);

        $data = str_ireplace(array('#text', '@attr'), array('text', 'attr'), $data);

        if(!$this->byPassCache){
            $this->_setCache($data);
        }


        return ($data) ? $data : false;
    }
    /**
     * 
     * @return type
     */
    protected function _getCachePath()
    {
        return APPPATH . "cache/lastfm/{$this->method}.cache";
    }
    /**
     * 
     * @param type $data
     * @return type
     */
    protected function _setCache($data)
    {
        if(file_exists($this->cache)){
            unlink($this->cache);
        }

        if(!empty($data)){
            return file_put_contents($this->cache, $data);
        }
    }
    /**
     * 
     * @return type
     */
    protected function _getCache()
    {
        return ( file_exists($this->cache) && ( time() - filemtime($this->cache) ) < $this->options['cache_time']  )
            ? $this->cache
            : false;
    }
    /**
     * 
     * @param type $content
     * @param type $cache
     * @return type
     */
    protected function _parseContent($content, $cache=true)
    {
        if($cache)
            $content = file_get_contents($content);

        return json_decode($content);
    }
}

---

application/views/lastfm/tracks.php

<div id="track_list">
    <?php echo $tracks_view; ?>
</div>

<script>
var SITE_URL = "<?php echo site_url();?>"; 
</script>
<script>
/** LastFm **/
(function($){  

    var lastFm = {
        /**
         * 
         * @type type
         */
        options : {
            cache : false,
            url   : undefined,
            type  : "GET",
            dataType : "html",
            data : {}
        },
        /**
         * 
         * @returns {undefined}
         */
        init : function(){
            this.More = $("a#more");

            this.trackList = $("#track_list");

            this.trackList.on('click', this.More, $.proxy(this.handleEventClick, this));
        },
        /**
         * 
         * @param {type} event
         * @returns {undefined}
         */
        handleEventClick : function(event){

            event.preventDefault();

            var target, pageId;

            target = event.target;

            pageId = parseInt($(target).attr('data-pageId'));

            $(target).remove();

            this.pageID = pageId+1;

            this.fetch(this.pageID);

        },
        /**
         * 
         * @returns {undefined}
         */
        fetch : function(pageId){

            this.options.url = SITE_URL + "/tracks/get/"+pageId;

            this.dojax().then(
                $.proxy(this.handleResponse, this),
                $.proxy(this.handleErrors, this)
            );
        },
        /**
         * 
         * @returns {unresolved}
         */
        dojax : function(){
            return $.ajax(this.options).promise();
        },
        /**
         * 
         * @param {type} response
         * @returns {undefined}
         */
        handleResponse : function(response){

            this.More.remove();

            this.trackList.append(response);

            $("html, body").animate({
                scrollTop : $("[data-pageSlideId="+this.pageID+"]").filter(':last').offset().top
            });
        },
        /**
         * 
         * @param {type} error
         * @returns {undefined}
         */
        handleErrors : function(error){

        }
    };

    lastFm.init();

}(jQuery));
</script>

---

application/views/lastfm/partials/tracks.php

    <div id="page_<?php echo $statistics->page;?>">
    <?php 
    $columnsPerRow = 4;

    foreach(array_chunk($tracks['data']->tracks->track, $columnsPerRow) as $track): ?>

    <div class="row" data-pageSlideId="<?php echo $statistics->page;?>">

        <?php foreach($track as $trac):?>

            <?php $image = (!empty($trac->image[2]->text)) ? $trac->image[2]->text : false;?>

            <div class="large-3 medium-6 columns text-center" >
                <div class="panel" style="background: url('<?php echo $image;?>') no-repeat;background-size: cover;">
                    <h6><?php echo $trac->name;?></h6>
                    <h5><?php echo $trac->artist->name;?></h5>
                </div>
            </div>

        <?php endforeach;?>

    </div>

    <?php endforeach; ?>

    </div>


<div class="row">
    <div class="large-12 columns text-center">
        <a href="" class="button" id="more" data-pageId="<?php echo $statistics->page;?>">Load More...</a>
    </div>
</div>

Answer 2

我认为您需要做的是将代码分解为函数，而不是直接在视图上使用它。这个问题有点令人困惑，但让我们看看我是否可以帮助你。我将使用我在 codeigniter 中使用的分页列表代码和数据表。

<?php
#model fuction that take the list data from db
public function listSomething($listStart, $numberOfRows)
{
    $this->db->select('login, nome');
    $this->db->from('list');
    $this->db->limit($numberOfRows, $listStart);
    $queryUsuario = $this->db->get();
    return $queryUsuario->result();
}

#controller fuction
public function listSomething ()
{
    #pego as váriaveis do datatables via post.
    $numeroDeRegistros = intval($this->input->post('length'));
    $listStart = $this->input->post('start');

    #Carega o model de usuario.
    $this->load->model('UsuarioModel');

    #Cria uma váriavel para armazenar o resultado já no formato do DataTables.

    #Pega uma lista de usuário com parâmetros de paginação.
    $list = listSomething($listStart, $numberOfRows);
    #Conta os usuário registrados no banco.
    $listCount = count($list);

    #Pega o tamanho que a lista deve ter, passado pelo Datatables.
    $listLength = intval($this->input->post('length'));
    #Se o tamanho da lista for maior que a propria lista, o total é o tamanho.
    if ( $listLength > $listCount ) {
       $listLength = $listCount;
    }

    #Se o fim da lista é maior que o total da lista, então o fim da lista é o total.
    $listEnd = $listStart + $listLength;
    if ( $listEnd > $listCount ) {
       $listEnd = $listCount;
    }
    #Formata os dados antes de passar para json.
    for($i = 0; $i < $listEnd-$listStart; $i++) {
        foreach($list[$i] as $var => $value) {
            $list["data"][$i][] = $value;
        }
        $list["data"][$i][] =
        '
        <a href="javascript:;" class="btn btn-xs default blue" id="editaUsuarioBnt"><i class="fa fa-pencil"></i> Editar</a>
        <a href="javascript:;" class="btn default btn-xs red" id="excluiUsuario"><i class="fa fa-trash-o"></i> Excluir </a>
        <a href="javascript:;" class="btn btn-xs default yellow"><i class="fa fa-times"></i> Redefinir Senha</a>
        ';                
    }

    #Envia a lista para formatar em json.
    $this->jsonDataTables($list, $listCount);
}

#library function that append some datatables data and output json.
public function jsonDataTables (&$list, $totalDaLista) 
{

    #Gravo na variável o valor de quantas 
    $sEcho = intval($this->input->post('draw'));

    if ( $list != null ) {

        if (isset($_REQUEST["customActionType"]) && $_REQUEST["customActionType"] == "group_action") {
              $list["customActionStatus"] = "OK"; // pass custom message(useful for getting status of group actions)
              $list["customActionMessage"] = "Group action successfully has been completed. Well done!"; // pass custom message(useful for getting status of group actions)
        }

        $list["draw"] = $sEcho;
        $list["recordsTotal"] = $totalDaLista;
        $list["recordsFiltered"] = $totalDaLista;

        echo json_encode($list);
    }
    else {
        echo json_encode("");
    }
}

所以您只需要创建一个数据表或将其调整为您自己的表。每当您更新表格时，我都需要发布变量，因此 codeigniter 控制器可以跟踪 listStart、listLength 等的更改。

因此，假设您知道 DataTables 的工作原理，就不难弄清楚代码的作用。正如你所说的数据，我假设你会从你的外部源得到一个数组，比如 $list[0],...,$list[$i]。

所以不是从数据库中获取它，而是在你的模型/任何功能列表中你可能会有类似的东西：

#model fuction that take the list data from db
public function listSomething($listStart, $numberOfRows)
{
    $list = getMyExternalImages();
    return array_slice($list, $listStart, $numberOfRows);
}

#I'll probably need this to count how many results you have
public function countExternalImages()
{
    $list = getMyExternalImages();
    return count($list);
}

如果您可以阅读代码和解释，我认为您可以根据自己的需要进行调整。如果您有任何问题，请询问。