将数组数据作为对象附加到json文件

Question

我有一个简单的json文件,它有一个直接的图像链接和每个json对象的文件夹名称:

[
        {
                "image": "http://placehold.it/350x150",
                "folder": "Small"
        },
        {
                "image": "http://placehold.it/450x250",
                "folder": "Medium"
        },
        {
                "image": "http://placehold.it/550x350",
                "folder": "Medium"
        }
]

我想从帖子中追加这两个值,但结果是一个未更改的json文件.这是PHP代码w/comments:

$directLink = $_POST['txtDirectLink'];
$category = $_POST['selectCategoriesImages'];
$util->addToJsonImageList($directLink, $category);

//decodes the json image list, merges to the decoded array a new image, then encodes back to a json file
function addToJsonImageList($link, $category) {
    $file = file_get_contents('./images_list.json', true);
    $data = json_decode($file);
    unset($file);

    $newImage = array('image' => $link, 'folder' => $category);
    //$newImage['image'] = $link;
    //$newImage['folder'] = $category;
    $result = array_merge((array)$data, (array)$newImage);

    json_encode($result);
    file_put_contents('./images_list.json', $result);
    unset($result);
}

逻辑是,将文件作为数组json_decode编码应该很简单,将新数组合并到该数组上,然后对结果进行编码并放入同一文件中.我也无法捕捉到任何错误.

Answer 1

$data = json_decode($file, true);
//When TRUE, returned objects will be converted into associative arrays.
unset($file);

$newImage = array('image' => $link, 'folder' => $category);
//$newImage['image'] = $link;
//$newImage['folder'] = $category;
$result = array_merge($data, $newImage);
//don't need to cast

参考PHP json_decode手册

编辑以下代码工作(测试)

function addToJsonImageList($link, $category) {
    $file = file_get_contents('./images_list.json', true);
    $data = json_decode($file,true);
    unset($file);
    //you need to add new data as next index of data.
    $data[] = array('image' => $link, 'folder' => $category);
    $result=json_encode($data);
    file_put_contents('./images_list.json', $result);
    unset($result);
}

编辑2添加了大量的错误报告和调试.请让我知道以下内容的输出.下面的代码未经过测试(只需输入此处).如果发现任何语法错误,请修复.在这里已经很晚了,明天只能查看我的时间,但可以回复.

<?php
//display all errors and warnings
error_reporting(-1);
addToJsonImageList('test link', 'test category');

function addToJsonImageList($link, $category) {
    $file = file_get_contents('./images_list.json', true);
    if ($file===false)die('unable to read file');
    $data = json_decode($file,true);
    if ($data ===NULL)die('Unable to decode');
    unset($file);
    echo "data before\n";
    var_dump ($data);
    //you need to add new data as next index of data.
    $data[] = array('image' => $link, 'folder' => $category);
    echo "data after\n";
    var_dump ($data);
    $result=json_encode($data);
    if (file_put_contents('./images_list.json', $result) === false){
        die('unable to write file');
    }
    unset($result);
}
?>