Question

我在全球范围内定义了一个变量。我想修改一个存在于类中的函数内的相同变量，然后使用它作为json数据导出。

该函数由xataface api调用，所以我不确定我是否可以使用函数签名来执行像引用一样的操作。我以为我可能会在javascript嵌入式php中访问此动作类的实例，但我不知道如何向api请求它，我也不知道它的生命周期。似乎全局变量可能是要走的路。无论如何，我想知道：

为什么$ dataset1的全局实例不是在函数内修改的实例？
为什么对array_push的调用没有在任何一个数组上放置任何东西？

<?php
//non-dynamic data delcared in global scope. This is picked up later
//in a php block embedded into javascript
$dataset1 = array(array("label"=>"c120","data"=>"1"),
                  array("label"=>"c150","data"=>"10"),
                  array("label"=>"camp","data"=>"7"));
class actions_time_in_type
{
  function handle(&$params)
  {
    $this->app =& Dataface_Application::getInstance(); 
    //The Query
    $result = mysql_query("SELECT typeDes, total
                           FROM myTable", $this->app->db());
    //reserch leads me to believe that this *should* make all subsequent
    //references to $dataset1 use the global instance
    global $dataset1;
    //experimenting with appending more non-dynamic data
    //for some reason, this syntax does not seem to touch $dataset1 
    array_push($dataset1, array("label"=>"dv20","data"=>"1"));
    //This syntax is working, but $dataset1 is not the same as the global 
    //$dataset1. Prepending "global" here seems to crash the script
    $dataset1[] = array("label"=>"pa18","data"=>"5");
    while($row = mysql_fetch_assoc($result))
    {
       //append data to the array, again, this is not hitting
       //the global instance of $dataset1
       $dataset1[] = array("label"=>$row['typedes'],"data"=>$row['total']);
    }
    mysql_free_result($result); //Frees the result after finished using it           
    //diagnostic dump to see what we've got
    //This shows that we've constructed the dynamic data set, but it
    //seems to be scoped only to this function and does not make it into
    //javascript.
    var_dump($dataset1);
  }
}
?>
<script src="//ajax.googleapis.com/ajax/libs/jquery/1.11.0/jquery.min.js" ></script>
<script type="text/javascript">
$(function () {
   //This is getting only what was done original init of $dataset1, nothing that
   //happened in the function made a difference
   var dataset1 = <?php echo json_encode($dataset1); ?>;
});
</script>

Answer 1

看来这确实是执行顺序的问题。由于数据的操作发生在类定义中，而类定义又由api调用，因此似乎无法保证在操作数据时数据的全局定义将在范围内，或者它将会在重新使用数据时已被操纵。

对于感兴趣的读者，我能够让api开发人员演示将javascript与调用in-class函数的api集成的正确方法：

https://groups.google.com/forum/#!topic/xataface/l6qBzxF1vrc

为什么这个函数没有修改数组的全局版本？

1 个答案: