将DateTime从PHP返回到JS的良好实践 [英] Good practice to return DateTime from PHP to JS

问题描述

我创建了文件api.php

I've created file api.php

<?php
// Prevent caching.
header('Cache-Control: no-cache, must-revalidate');

// The JSON standard MIME header.
header('Content-type: application/json');   

//mssql_select_db("**", mssql_connect(**));
$conn=mssql_connect(***);    

$query = "SELECT ROUND([AirTemp_C],1) as [T]
                ,[DT]
            FROM [ASUTP].[dbo].[Temperature_ER]
            WHERE [Place] = 'ER06' AND [DT] > '26.05.2015 11:00'";

$qwr_res = mssql_query($query);

while ($row=mssql_fetch_array($qwr_res))
{
    $temps[] = array (
        'x' => $row['DT'],
        'y' => $row['T']
                );
}
echo json_encode($temps);   
?>

它返回JSON，例如[{ x： 2015-05-26 11:02:04 ， y：26.3}]和我的测量值。

It returns JSON like [{"x":"2015-05-26 11:02:04","y":26.3}] with my measurments.

我想使用此数据通过canvasjs-1.6.2绘制图形。这是我的代码：
window.onload = function（）{

I want to use this data to draw graph using canvasjs-1.6.2. Here is my code: window.onload = function () {

    $.getJSON("api.php",function(data1)
                        {                               
                            var chart = new CanvasJS.Chart("chartContainer",
                            {

                                title:{
                                    text: "Title",
                                    fontSize: 30
                                },
                                animationEnabled: true,
                                zoomEnabled:true,
                                height: 500,
                                axisX:{

                                    gridColor: "Silver",
                                    tickColor: "silver",
                                    labelAngle: -80,
                                    valueFormatString: "DD.MM HH:mm"

                                },                        
                                            toolTip:{
                                            shared:true
                                            },
                                theme: "theme2",
                                axisY: {
                                    gridColor: "Silver",
                                    tickColor: "silver"
                                },
                                legend:{
                                    verticalAlign: "center",
                                    horizontalAlign: "right"
                                },
                                data: [
                                {        
                                    type: "line",
                                    showInLegend: true,
                                    lineThickness: 2,
                                    name: "T",
                                    //markerType: "square",
                                    color: "#F08080",
                                    dataPoints: data1
                                }
                                ],
                            legend:{
                                cursor:"pointer",
                                itemclick:function(e){
                                if (typeof(e.dataSeries.visible) === "undefined" || e.dataSeries.visible) {
                                    e.dataSeries.visible = false;
                                }
                                else{
                                    e.dataSeries.visible = true;
                                }
                                chart.render();
                                }
                            }
                            });

                            chart.render();
                        });

但是，似乎这张图表（或根本没有JS）不能使用我的Date值作为正确的DateTime因此，图表无法呈现。

But it seems that this chart (or JS at all) cant use my Date value as a correct DateTime so chart can't render.

我已通过以下循环修复了此问题：

I've fixed this issue with such loop:

for(var i=0;i<data1.length;i++)
{
   data1[i].x = new Date(data1[i].x);
}

我应该注意，我使用的是PHP 5.2，但我不允许升级它。
所以我的问题是：

I should notice that I'm using PHP 5.2 and I'm not allowed to upgrade it. So my questions are:

1. 通过api.php获取图表数据的方法是否正确？


2. 有没有办法在不进行循环转换的情况下将正确的DateTime值从php传递到JS？

推荐答案

如注释中所述，最可靠的跨浏览器传输日期的方式是使用时间值。从1970-01-01T00：00：00Z开始，UNIX时间值以秒为单位。 Javascript时间值来自同一纪元，但是使用毫秒，因此您只需将UNIX时间值乘以1000，然后直接传递给Date构造函数即可。

As noted in comments, the most reliable cross-browser way to transfer dates is using a time value. UNIX time values are in seconds since 1970-01-01T00:00:00Z. Javascript time values are from the same epoch, but use milliseconds so you just multiply UNIX time values by 1000 and pass directly to the Date constructor.

因此JSON可能类似于：

So the JSON might be like:

'[{x:"1432788147300", y:26.3}]'

，如果将 x 值读入名为 unixTimeValue 的变量，则代码为像这样：

and if the x value is read into a variable called unixTimeValue, the code would be like:

var javascriptDate = new Date(unixTimeValue * 1000);

但是，如果无法执行此操作，则可以解析'2015-05-26 11:02:04'相当容易。假设日期为世界标准时间，则可以使用 Date.UTC 将其转换为日期对象：

However, if you can't do that, you can parse strings like '2015-05-26 11:02:04' fairly easily. Assuming that the date is UTC, you can use Date.UTC to convert it to a date object:

function parseISOUTC(s) {
  var b = s.split(/\D/);
  return new Date(Date.UTC(b[0],b[1],b[2],b[3],b[4],b[5]));
}

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