PHP数组中的对象转换为字符串（据我所知）

Question

I'm developing front-end code for a web application, and ran into an odd piece of trouble with a custom object. When I request the object and use print_r() I get this (the object is a lot bigger; just cut it to the relevant code):

MemberInfo Object
(
    [meta_data] => Array
    (
        [email_recommendations] => true
        [email_updates] => false
    )
)

To change something in the MemberInfo object, I just update its properties and send it back to the backend with a second function. So for instance, the page is loaded once (which gives us the object shown above), then I send a POST request with changes on a second load of the page. During the second load, I fetch the object above, set one field differently based on the POST with something like $memberInfo->meta_data['email_recommendations'] = 'false'; and then use that version of the object to populate the page after running the update function (which is something like updateMember($memberInfo); ). However, once I've changed the object property value print_r() shows me something different:

MemberInfo Object
(
    [meta_data] => {\"email_recommendations\":\"false\",\"email_updates\":\"false\"}

)

I'm sure I'm overlooking something very stupid; does anyone have a good idea of what I should be looking for? I checked, and the backend code isn't passing by reference (the function call is updateMember(MemberInfo $memberInfo); ) but I'm a little shaky on my PHP 5 object handling so I'm not sure what might be going wrong.

I don't expect in-depth debugging; I just need to know the general direction I should be looking for what is causing this change in a property that by all rights should be an array.

Thanks in advance!

Answer 1

so are you using the object after calling updateMember() ? PHP5 objects are passed by reference by default, so if you're calling json_encode() on the meta_data property, it'll exhibit the behaviour you describe.

you may want to post the updateMember() function to confirm, but it sounds like that's what's going on.

ie:

class MemberInfo {
    function __construct()  {
        $this->meta_data = array(
            'email_recommendations' => true,
            'email_updates' => false,
        );
    } 
}

function updateMember($meminfo) {
    $meminfo->meta_data = json_encode($meminfo->meta_data);
    // do stuff
}

$meminfo = new MemberInfo();

updateMember($meminfo);

print_r($meminfo); // you'll see the json encoded value for "meta_data"