用PHP将JSON数据写入文本文件

问题：

我有一个脚本，它以这种方式将JSON数据发送到PHP文件：

var xmlhttp = new XMLHttpRequest();
xmlhttp.open("POST", "process-survey.php");
xmlhttp.setRequestHeader("Content-Type", "application/json;charset=UTF-8");
xmlhttp.send(JSON.stringify({uid, selected}));

问题是未使用PHP函数file_put_contents()将JSON数据写入文本文件。

最小(工作)示例：

控制台日志中的JSON

{
  "uid":1,
  "selected":[
     {
        "questionsid":1,
        "val":"1"
     },
     {
        "questionsid":2,
        "val":"1"
     }
  ]
}

PHP

<?php
  $uid = json_decode($_POST['uid'], true);
  $answers = json_decode($_POST['selected'], true);

  $file = $_SERVER['DOCUMENT_ROOT'] . '/association/data.txt';

  // Open the file to get existing content
  $current = file_get_contents($file);

  // Append a new id to the file
  $current .= $uid . "
";

  foreach ($answers as $item) {
    $current .= $item . "
";
  }

  // Write the contents back to the file
  file_put_contents($file, $current);
?>

权限

添加了以下读/写功能：chmod 644 data.txt

所需输出：

uid: 1
questionid: 1, val: 1
questionid: 2, val: 1

---

解决方案

您的输入是json，所以它还没有被分成uid，selected，所以下面的代码将获取您的json并输出您预期的结果(我想这就是您的意思，将其放在$_POST中)。

<?php
$json = '{
  "uid":1,
  "selected":[
     {
        "questionsid":1,
        "val":"1"
     },
     {
        "questionsid":2,
        "val":"1"
     }
  ]
}';

$_POST = json_decode($json, true);

$uid = $_POST['uid'];
$answers = $_POST['selected'];

$current = ''; // fgc 

// start building your expected output
$current .= "uid: $uid
";
foreach ($answers as $item) {
    $line = '';
    foreach ($item as $key => $value) {
        $line .= "$key: $value, ";
    }
    $current .= rtrim($line, ', ')."
";
}

https://3v4l.org/ekAUB

结果：

uid: 1
questionsid: 1, val: 1
questionsid: 2, val: 1