反序列化后PHP类公共(public)变量未定义

Question

所以在某个时候，ajax 调用会发送一个 JSON，我将其转换为对象并存储在 session 中:

    if ( $deps = json_decode( $raw_json, true ) )
    {   
        $pkgs = array();

        foreach ( $deps['vector'] as $key )
        {
            if ( strcasecmp( $key['package'], $key['component'] ) == 0 )
            {
                $package = new Package();
                $package->name = $key['package'];
                $package->version = $key['version'];
                $package->cxx_include = $key['cxx_inc'];
                $package->cxx_link = $key['cxx_link'];
                $pkgs[] = $package;
            }
            else
            {
                foreach( $pkgs as $package ) 
                {
                    if ( $package->name == $key['package'] )
                    {
                        $component = new Component();
                        $component->name = $key['component'];
                        $component->cxx_link = $key['cxx_link'];
                        $package->components[] = $component;
                    }
                }
            }
        }

        $_SESSION['pkgs'] = serialize( $pkgs );

实际的类很简单:

class Component
{
    public $name;
    public $cxx_link;
}

class Package
{
    public $name;
    public $version;
    public $cxx_inclue;
    public $cxx_link;
    public $components = array();
}

稍后，我反序列化并尝试解析它们:

    $pkgs = isset( $_SESSION['pkgs'] ) ? unserialize($_SESSION['pkgs']) : array();

    foreach ( $pkgs as $package )
    {
        fwrite( $cmake, "find_package(" . $package->name . " " . $package->version . " " );
        if ( count( $package->components ) > 0 )
        {
            fwrite( $cmake, "COMPONENTS " );
            foreach ( $package->components as $component )
                fwrite( $cmake, $component->name. " " );

            fwrite( $cmake, "REQUIRED )\r\n" );
        }

        if ( isset( $package->cxx_include ) )
            // ERROR here: undefined variable
            fwrite( $cmake, "include_directories(${".$package->cxx_include."})\r\n" );

        if ( isset( $package->cxx_link ) )
            // ERROR here: undefined variable
            fwrite( $cmake, "target_link_libraries($rapp_name ${".$package->cxx_link."})\r\n" );
        foreach ( $package->components as $component )
        {
            if ( isset($component->cxx_link) )
                // ERROR here: undefined variable
                fwrite( $cmake, "target_link_libraries($rapp_name ${".$component->cxx_link."})\r\n" );
        }
    }

真正让我困惑的不是 undefined variable 是 $component->cxx_link 或 $package->cxx_link，而是我看到的是来自 JSON 的实际值。

例如，如果 JSON 是:

{
    "vector": [
        {
            "package": "Boost",
            "version": "1.54",
            "component": "Boost",
            "cxx_inc": "Boost_INCLUDE_DIRS",
            "cxx_link": "Boost_LIBRARIES"
        },
        {
            "package": "Boost",
            "version": "1.54",
            "component": "date_time",
            "cxx_inc": "",
            "cxx_link": "Boost_DATE_TIME_LIBRARY"
        },
        {
            "package": "Boost",
            "version": "1.54",
            "component": "filesystem",
            "cxx_inc": "",
            "cxx_link": "Boost_FILESYSTEM_LIBRARY"
        },
        {
            "package": "Opencv",
            "version": "3.0",
            "component": "OpenCV",
            "cxx_inc": "OpenCV_INCLUDE_DIRS",
            "cxx_link": "OpenCV_LIBS"
        },
        {
            "package": "Eigen3",
            "version": "3.0",
            "component": "Eigen3",
            "cxx_inc": "EIGEN3_INCLUDE_DIR",
            "cxx_link": ""
        }
    ]
}

我收到错误:

PHP Notice:  Undefined variable: .Boost_INCLUDE_DIRS.
PHP Notice:  Undefined variable: .Boost_LIBRARIES.
PHP Notice:  Undefined variable: .OpenCV_INCLUDE_DIRS.

哪些是我为类成员设置的值。如果我理解正确的话，JSON 迭代期间的赋值操作会进行某种浅拷贝吗？

编辑 根据 Barmar 的评论，我删除了序列化/反序列化，并将类定义移动到每个使用这些类的文件的顶部。我不再收到自动加载错误，但我仍然收到完全相同的 undefined variable 错误。

Answer 1

更正:

所以问题是您使用双引号而不是单引号作为字符串。 PHP 有一个叫做可变变量的东西，你会无意中使用它(参见 http://php.net/manual/en/language.variables.variable.php )。

将包含 "${something}" 之类内容的每个字符串切换为单引号(或像 Alex 提到的那样转义美元符号)，你会没事的，即:

fwrite( $cmake, "include_directories(${".$package->cxx_include."})\r\n");

会是

fwrite( $cmake, 'include_directories(${'.$package->cxx_include.'})'."\r\n");

(请注意，您不能在单引号字符串中使用 \r 或 \n。)

旧答案:

您的 Package 类中有错字。

您将其分配给 $package->cxx_include 但实际名称缺少“d”。

class Package
{
    public $name;
    public $version;
    public $cxx_inclue; // typo
    public $cxx_link;
    public $components = array();
}