Php 为什么GTFS如此困难？

我正在尝试创建一个基于Arduino的显示器，显示纽约地铁北站下几趟列车的时间。Metro North由MTA运营，MTA是纽约市地铁和公交局，但是，列车数据非常困难。无法通过URL中的GET命令对其进行筛选。我必须自己解析数据才能得到停止级别的数据。它是由火车组织的

我有一个网页，可以运行简单的PHP、java等。我想我需要创建一个页面来解析MTA中的json/XML文件。然后Arduino可以使用简化的数据。我可以使用URL和api密钥获取实时数据。这就是它看起来的样子：

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就像用消防水龙带喝水一样

它是一种叫做GTFS的格式，应该是通用的，但我发现很难找到任何可以使用它的东西

Arduinos不适合解析文本。我不能强迫Arduino做所有的工作

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我应该学什么方法？我对我的服务器没有太多的控制权。我不能轻易改变PHP在我的服务器上运行的方式。到目前为止，我发现的方法似乎需要扩展和其他我无法做到的事情。

是的，从消防水龙带喝水是处理GTFS数据的一个很好的比喻。GTFS的一个方面是将运输机构的系统负载降至最低，并让应用程序开发人员的系统尽可能多地完成工作。包含当前路由信息的静态GTFS文件和GTFS实时文件都可以是从哑web服务器提供的静态数据文件，无需web应用程序代码，这使得提供数据非常可伸缩

一些交通机构，如MTA，在他们的公交线路方面很好，为您做一些工作，提供XML或JSON API，为您提供特定线路的当前实时状态。但是，如果您学会了如何在您的终端处理GTFS数据，您就不需要依赖他们的API，您的系统将变得通用，能够处理任何提供GTFS实时信息的机构

我猜你已经看过这些文件了，但为了以防万一，这里有参考资料：

通常，您将使用包含日历、路线、行程、站点和停车时间的GTFS文件和GTFS实时文件（具体而言，是tripUpdate文件）的组合来确定车辆当前状态与其当前行程中的站点的关系。他们可能只会给您提供车辆在其当前行程上的延迟时间，然后您需要查找目标停车的每次行程的停车时间，并根据相应的延迟进行调整

然而，MTA再次表现得很好，他们在实时提要中为您提供了足够的信息，以显示车辆（如1586次列车）何时到达车站（如每次停车144次，如unix时间1442890020=Tue，2015年9月22日02:47:00 GMT）和延迟（如60秒）

因此，如果您的PHP进程试图为目标站点创建即将出发时间的列表，您应该：

将实时提要解析到一个对象集合中，我假设您可以在PHP中这样做，正如上面提到的Twisty使用json_解码 遍历trip_update对象数组 在stop_time_update对象下，遍历离开对象数组 对于具有与您希望设备显示信息的站点相匹配的站点id的每次出发，将其时间值unix time添加到集合中。 对结果集合进行排序，并将其从unix时间转换为PHP的本地datetime对象，并将其格式化为文本 将下两次出发时间发送到您的设备

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对于这种情况，这将是一个快速解决方案。

看起来很像JSON。它不是XML。试试json_解码，我打赌你会成功的。而且，你的目标是什么还不清楚。对于Arduino，您希望将其简化为什么？具体的输入数据是什么？有样品吗？