WordPress pre_get_posts不起作用 [英] WordPress pre_get_posts not working
问题描述
一些背景:
- 我正在尝试替换存档模板的默认主查询，并返回自定义帖子类型(天")的子集，其中相对于键日期"的元值在某个值之间
- 天"的自定义帖子类型具有日期"的自定义变量字段，用于将与该帖子相关联的每个日期的各个数据库行存储在标准wp_postmeta表中，并以纪元格式(U)存储
- 我非常有信心SQL查询能够正常运行.在每种情况下，返回的帖子ID在查询的日期范围内都是正确的.
- I'm trying to replace the default main query for archive templates, and to return a subset of a custom post type ('days') where meta values against the key 'dates' is between a certain value
- The 'days' custom post type has a custom variable field of 'dates' which stores individual database rows in the standard wp_postmeta table for each date associated with that post, stored in Epoch format ('U')
- I'm fairly confident that the SQL query is functioning correctly; the post IDs it returns appear to be correct in each case for the date range queried.
我正在函数文件中运行以下查询:
I'm running the following query in my functions file:
function modify_queries( $query ) {
global $wpdb;
if ( $query->is_post_type_archive('days') && $query->is_main_query() ) {
// Get Days with a date within the archive range
$year = substr($query->query_vars['m'],0,4);
$month = substr($query->query_vars['m'],4,2);
$day = substr($query->query_vars['m'],6,2);
if (is_year()) {
$startDate = date('U', mktime(0, 0, 0, 1, 1, $year));
$endDate = date('U', mktime(0, 0, 0, 12, 31, $year));
}
if (is_month()) {
$startDate = date('U', mktime(0, 0, 0, $month, 1, $year));
$endDate = date('U', mktime(0, 0, 0, $month, cal_days_in_month(CAL_GREGORIAN, $month, $year), $year));
}
if (is_day()) {
$startDate = date('U', mktime(0, 0, 0, $month, $day, $year));
$endDate = date('U', mktime(0, 0, 0, $month, $day, $year));
}
$request = "SELECT ID FROM $wpdb->posts, $wpdb->postmeta";
$request .= " WHERE $wpdb->posts.ID = $wpdb->postmeta.post_id";
$request .= " AND post_status='publish' AND post_type='days'";
$request .= " AND $wpdb->postmeta.meta_key = 'dates' AND $wpdb->postmeta.meta_value >= $startDate AND $wpdb->postmeta.meta_value <= $endDate LIMIT 0 , 30";
$postsList = $wpdb->get_results($request,ARRAY_N);
if ($postsList) {
foreach ($postsList as $thePost) {
$thePostList[] = $thePost[0];
}
$query->set( 'post__in', $thePostList);
$query->set( 'post_type', 'days');
return;
} else {
return false;
}
}
add_action( 'pre_get_posts', 'modify_queries',1 );
我的理解是，这应该获取查询的输出，并使用从SQL查询返回的ID替换为普通查询，但是，它只是返回5个最近的"days"帖子.
My understanding is that this should take the output of the query and simply replace the normal query with one using the IDs returned from the SQL query - however, it's just returning the 5 most recent 'days' posts.
目前，archive.php文件仅包含以下内容，因此我们可以排除任何干扰:
At present, the archive.php file consists purely of the following, so we can rule out any interference:
<?
while ( have_posts() ) : the_post();
global $post;
the_title();
endwhile;
?>
我收到了5条最近发布的天"帖子，似乎忽略了pre_get_posts过滤器应该已经通过的ID.
I get the 5 most recently published 'days' posts, and it seems to ignore the IDs that the pre_get_posts filter should have passed it.
我暗中怀疑该问题的一部分与在主查询上设置"post_id"有关，而不是与"p"有关，但是我似乎根本没有得到任何结果.
I have a sneaky suspicion that part of the problem relates to setting 'post_id' on the main query, rather than 'p', but I don't seem to get any results at all with the latter.
我已经四处搜寻，但是除了作为替代query_posts的有用和有益之处之外，找不到关于pre_get_posts的大量文档.
I've hunted around, but can't find much documentation about pre_get_posts other than how useful and beneficial it is as a replacement to query_posts.
实时调试输出: http://dev.daysoftheyear.com/days/2012/10
推荐答案
您可以在pre_get_post过滤器上找到文档. rel ="nofollow"> http://codex.wordpress.org/Plugin_API/Action_Reference/pre_get_posts
You can find the documentation on the pre_get_post filter here http://codex.wordpress.org/Plugin_API/Action_Reference/pre_get_posts
在我看来，问题实际上是您如何设置要检索的post_id.如果您参考上面的链接，则可以看到可以在传递给过滤器的$query对象上设置的不同值，而post_id不是其中之一，这就是为什么它在以下情况下起作用"的原因设置它，而设置p则不起作用".后者用于单个帖子ID，因此如果您只想使用100，则可以使用$query->set('p', 100).如果要返回帖子ID在数组中的结果，请使用$query->set('post__in', array(100, 120)).您的SQL代码只是返回ID，因此您可以直接获取一个数组，而不必返回对象，而是直接获取一个数组-我假设回显标题和print_r行只是调试:
It looks to me like the problem is in fact how you are setting the post_ids that you want to retrive. If you refer to the link above, you can see the different values that can be set on the $query object that is passed to the filter, and post_id isn't one of them, which is why it "works" when you set it, and "doesn't work" when you set p. The latter is for a single post ID, so if you just wanted 100, you would use $query->set('p', 100). If you want to return results where the post ID is in an array, you use $query->set('post__in', array(100, 120)). Your SQL code is just returning the ID, so rather than returning objects, you can just get an array directly - I'm assuming that echoing the title and print_r lines are just debugging:
// get results as a numeric array
$post_ids = $wpdb->get_results($request, ARRAY_N);
// pass post id array to $query
$query->set( 'post__in', $post_ids );
如果在$query上设置了现有的冲突参数，您也可能无法获得结果.您可以使用var_dump($query->query_vars)检查这些值，并将任何可能冲突的值设置为空字符串-在您的情况下$query->set( 'm', '' );
You may also not get results if there are existing conflicting parameters set on the $query. You can check these values with var_dump($query->query_vars) and set any that may be in conflict to an empty string - in your case $query->set( 'm', '' );
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