php - 序列化对象并缓存它们的奇怪行为

Question

我遇到了一个我似乎无法缩小范围的问题。在 Zend Framework 应用程序中，我使用 Zend Cache 来缓存自定义 Response 对象中包含的潮汐和天气数据。最初创建数据时，一切正常。我序列化它并缓存它。然后，当我点击刷新并从缓存中提取数据时，出现以下错误:

Message: String could not be parsed as XML

Stack trace:

0 /home/cillosis/mysites/tidely/application/views/scripts/tides/location.phtml(38): SimpleXMLElement->__construct('')

1 /home/cillosis/mysites/tidely/library/Zend/View.php(108): include('/home/cillosis/...')

2 /home/cillosis/mysites/tidely/library/Zend/View/Abstract.php(888): Zend_View->_run('/home/cillosis/...')

...

这发生在我的 View 中，我正在访问包含在我的自定义“响应对象”中的 XML:

<div class="data-box">

<h3>Current Weather</h3>
<hr>
<?php

// *** THIS IS LINE 38  ***                         
$weather_XML = new SimpleXMLElement($this->response->_weatherdata->weatherResults);
$params = $weather_XML->data->parameters;

$img_path = $params->{'conditions-icon'}->{'icon-link'};

echo("<img src='".$img_path."'>");

...

这是第一次运行时对象相关部分的转储(缓存之前):

["_weatherdata"]=>
  object(Tidely_WeatherData)#79 (6) {
    ["weatherResults"]=>
    string(6399) "<?xml version="1.0"?>
       <dwml version="1.0" xmlns:xsd="http://www.w3.org/2001/XMLSchema"
          xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
          xsi:noNamespaceSchemaLocation="http://graphical.weather.gov/xml/DWMLgen/schema/DWML.xsd">
          ...
       </dwml> "

在您看到“...”的地方有很多其他 XML 数据。 XML 来自 NWS(国家气象局)API，我已经通过 XML 验证器运行它，没有显示任何错误。一旦我序列化我的对象并缓存它，问题就会发生。以下是我的 Zend Cache 设置:

// Setup caching
$frontendOptions = array('lifeTime' => 30, 'automatic_seralization' => false);
$backendOptions = array('cache_dir' => '../application/cache');
$this->_cache = Zend_Cache::factory('Core', 'File', $frontendOptions, $backendOptions);

我正在用这个进行缓存和检索:

// Assign cache id
// Example query: "Chesapeake Bay Virginia"
$cache_id = 'request_results_' . $this->response->_querydata->query);
$cache_id = str_replace(' ', '_', $cache_id);
$cache_id = str_replace('-', '_', $cache_id);

// Check cache for this query
if ( ($results = $this->_cache->load($cache_id)) === false)
{
   // Cache not found, process request and generate response
   ...

   // Cache request output for specific query
   $serialized_data = serialize($this->response);
   $this->_cache->save($serialized_data, $cache_id);

   // Return processed request results
   return $this->response;
}
else
{
   // Return results from cache
   return unserialize($results);
}

一旦我发出请求并缓存它，$this->response 对象输出如下:

object(Tidely_ResponseData)#65 (7) { ["_querydata"]=> object(Tidely_QueryData)#66 (9) { ["query"]=> string(40) "bayou-la-batre-mississippi-sound alabama" ["source"]=> string(15) "TidesController" ["request_type"]=> string(3) "url" ["url_components"]=> array(2) { ["state"]=> string(7) "alabama" ["location"]=> string(32) "bayou-la-batre-mississippi-sound" } ["return_type"]=> string(4) "JSON" ["time_range"]=> array(2) { ["start"]=> object(DateTime)#64 (3) { ["date"]=> string(19) "2012-04-05 18:06:51" ["timezone_type"]=> int(3) ["timezone"]=> string(3) "UTC" } ["end"]=> object(DateTime)#63 (3) { ["date"]=> string(19) "2012-04-06 18:06:51" ["timezone_type"]=> int(3) ["timezone"]=> string(3) "UTC" } } ["hasError"]=> bool(false) ["userMessage"]=> NULL ["logMessage"]=> NULL } ["_locationdata"]=> object(Tidely_LocationData)#80 (31) { ["location_id"]=> string(5) "18921" ["station_name"]=> string(33) "Bayou La Batre, Mississippi Sound" ["station_url_name"]=> string(32) "bayou-la-batre-mississippi-sound" ["station_type"]=> string(11) "Subordinate" ["station_id"]=> string(7) "8739051" ["station_lat"]=> string(8) "+30.3717" ["station_lon"]=> string(8) "-88.2750" ["station_height_offset_high"]=> string(5) "*1.23" ["station_height_offset_low"]=> string(5) "*1.23" ["station_time_offset_high"]=> string(3) "112" ["station_time_offset_low"]=> string(2) "74" ["station_ref_station_id"]=> string(7) "8760551" ["state_id"]=> string(1) "1" ["state_name"]=> string(7) "Alabama" ["state_url_name"]=> string(7) "alabama" ["timezone"]=> string(2) "-6" ["dst"]=> string(1) "1" ["city_name"]=> string(14) "Bayou La Batre" ["city_zip"]=> string(5) "36509" ["city_lat"]=> string(7) "30.4014" ["city_lon"]=> string(8) "-88.2467" ["adjacentStations"]=> string(321) "a:10:{i:8739051;d:2.6562027890531361;s:7:"TEC4393";d:8.0529290086617618;i:8740448;d:11.564338218805837;i:8735180;d:14.637787569358004;i:8741196;d:17.602722038773138;i:8734635;d:17.824002491920826;i:8733810;d:19.474837234444919;i:8737048;d:24.414028460259932;i:8742221;d:27.466706516499691;i:8731952;d:31.251405048051701;}" ["city_distance"]=> string(15) "2.6562027890531" ["multipleResults"]=> string(0) "" ["multipleCount"]=> int(0) ["hasMultiple"]=> bool(false) ["showStates"]=> bool(false) ["showLocations"]=> bool(false) ["hasError"]=> bool(false) ["userMessage"]=> NULL ["logMessage"]=> NULL } ["_tidedata"]=> object(Tidely_TideData)#68 (6) { ["tideResults"]=> NULL ["queryStart"]=> NULL ["queryEnd"]=> NULL ["hasError"]=> bool(false) ["userMessage"]=> NULL ["logMessage"]=> NULL } ["_weatherdata"]=> object(Tidely_WeatherData)#79 (6) { ["weatherResults"]=> string(6399) " meteorological forecast 2012-04-05T18:06:57Z http://graphical.weather.gov/xml/ Meteorological Development LaboratoryProduct Generation Branch http://www.nws.noaa.gov/disclaimer.html http://www.weather.gov/ http://www.weather.gov/images/xml_logo.gif http://www.weather.gov/feedback.php point1 http://forecast.weather.gov/MapClick.php?textField1=30.37&textField2=-88.28 k-p24h-n1-1 2012-04-05T08:00:00-05:00 2012-04-05T20:00:00-05:00 k-p24h-n1-2 2012-04-05T20:00:00-05:00 2012-04-06T09:00:00-05:00 k-p3h-n5-3 2012-04-05T13:00:00-05:00 2012-04-05T16:00:00-05:00 2012-04-05T19:00:00-05:00 2012-04-05T22:00:00-05:00 2012-04-06T01:00:00-05:00 Daily Maximum Temperature 81 Daily Minimum Temperature 63 Temperature 79 79 74 69 67 Dew Point Temperature 66 65 64 64 61 Wind Speed 12 11 11 13 14 Wind Direction 240 260 280 300 330 Relative Humidity 64 63 71 84 81 Weather Type, Coverage, and Intensity Conditions Icons http://forecast.weather.gov/images/wtf/tsra60.jpg http://forecast.weather.gov/images/wtf/tsra60.jpg http://forecast.weather.gov/images/wtf/scttsra60.jpg http://forecast.weather.gov/images/wtf/nscttsra20.jpg http://forecast.weather.gov/images/wtf/nsct.jpg " ["queryStart"]=> float(1333649211.6989) ["queryEnd"]=> float(1333649217.2038) ["hasError"]=> bool(false) ["userMessage"]=> NULL ["logMessage"]=> NULL } ["hasError"]=> bool(false) ["userMessage"]=> NULL ["logMessage"]=> NULL }

当我查看源代码 时，“weatherResults”部分有 XML，我没有复制和粘贴它，因为它相当长。下面是当我按下刷新时会发生什么，它使用了上述对象的缓存副本:

object(Tidely_ResponseData)#65 (7) { ["_querydata"]=> object(Tidely_QueryData)#66 (9) { ["query"]=> string(40) "bayou-la-batre-mississippi-sound alabama" ["source"]=> string(15) "TidesController" ["request_type"]=> string(3) "url" ["url_components"]=> array(2) { ["state"]=> string(7) "alabama" ["location"]=> string(32) "bayou-la-batre-mississippi-sound" } ["return_type"]=> string(4) "JSON" ["time_range"]=> array(2) { ["start"]=> object(DateTime)#64 (3) { ["date"]=> string(19) "2012-04-05 18:10:30" ["timezone_type"]=> int(3) ["timezone"]=> string(3) "UTC" } ["end"]=> object(DateTime)#63 (3) { ["date"]=> string(19) "2012-04-06 18:10:30" ["timezone_type"]=> int(3) ["timezone"]=> string(3) "UTC" } } ["hasError"]=> bool(false) ["userMessage"]=> NULL ["logMessage"]=> NULL } ["_locationdata"]=> object(Tidely_LocationData)#67 (31) { ["location_id"]=> string(0) "" ["station_name"]=> string(0) "" ["station_url_name"]=> string(0) "" ["station_type"]=> string(0) "" ["station_id"]=> string(0) "" ["station_lat"]=> string(0) "" ["station_lon"]=> string(0) "" ["station_height_offset_high"]=> string(0) "" ["station_height_offset_low"]=> string(0) "" ["station_time_offset_high"]=> string(0) "" ["station_time_offset_low"]=> string(0) "" ["station_ref_station_id"]=> string(0) "" ["state_id"]=> string(0) "" ["state_name"]=> string(0) "" ["state_url_name"]=> string(0) "" ["timezone"]=> string(0) "" ["dst"]=> string(0) "" ["city_name"]=> string(0) "" ["city_zip"]=> string(0) "" ["city_lat"]=> string(0) "" ["city_lon"]=> string(0) "" ["adjacentStations"]=> string(0) "" ["city_distance"]=> string(0) "" ["multipleResults"]=> string(0) "" ["multipleCount"]=> int(0) ["hasMultiple"]=> bool(false) ["showStates"]=> bool(false) ["showLocations"]=> bool(false) ["hasError"]=> bool(false) ["userMessage"]=> NULL ["logMessage"]=> NULL } ["_tidedata"]=> object(Tidely_TideData)#68 (6) { ["tideResults"]=> NULL ["queryStart"]=> NULL ["queryEnd"]=> NULL ["hasError"]=> bool(false) ["userMessage"]=> NULL ["logMessage"]=> NULL } ["_weatherdata"]=> object(Tidely_WeatherData)#69 (6) { ["weatherResults"]=> NULL ["queryStart"]=> NULL ["queryEnd"]=> NULL ["hasError"]=> bool(false) ["userMessage"]=> NULL ["logMessage"]=> NULL } ["hasError"]=> bool(false) ["userMessage"]=> NULL ["logMessage"]=> NULL }

在序列化/反序列化和保存缓存的过程中，它以某种方式将所有字符串设置为空或 NULL!所以当然，我收到了 XML 错误，因为它是空的。

有没有其他人在使用 Zend Cache(或与此相关的任何其他缓存库)缓存对象时遇到问题？这与序列化有关吗？我缺少缓存设置吗？抱歉解释冗长，提前感谢您的帮助!

Answer 1

PHP 资源不能被序列化，这就是为什么你不能序列化你的对象(这将间接序列化一个 SimpleXML 对象)。

在序列化之前，您需要将您的对象转换为格式良好的 XML 字符串 (SimpleXMLElement::asXML())，一旦您的对象被反序列化，将您的字符串重新转换为 SimpleXML 对象 (simplexml_load_string()).

See here了解更多信息。 This question也很有用。

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根据新的细节进行编辑:根据您问题中的这些新元素，我了解到您的问题并非来自序列化的 SimpleXML 对象。你有什么理由不使用 automatic_serialization 吗？ (顺便说一句，有一个“i”，我猜你拼错了)而不是让 Zend_Cache 自动序列化/反序列化你的对象。

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编辑 #2:阅读下面来自 cillosis 的评论以获得最终解决方案。