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php - 如何修复未定义的索引 $user = $_GET['user'];

问题描述

<?php
header('Access-Control-Allow-Origin: *');
header('Access-Control-Allow-Methods: GET, POST, PATCH, PUT, DELETE, OPTIONS');
header('Access-Control-Allow-Headers: Origin, Content-Type, X-Auth-Token');
header("Content-Type: application/json; charset=UTF-8");

include("global.php");

$conn = new mysqli(server, dbuser, dbpw, db);

$user = $_GET['user'];
//$customer = $_GET['customer'];
$querystring = "";
$querystring = "SELECT email, password, firstname, lastname from user ";
$result = $conn->query($querystring);



$outp = "[";
while($rs = $result->fetch_array(MYSQLI_ASSOC)) {
    if ($outp != "[") {$outp .= ",";}
    $outp .= '{"email":"'  . $rs["email"] . '",';
    $outp .= '"password":"'  . $rs["password"] . '",';
    $outp .= '"firstname":"'   . $rs["firstname"] . '",';   
    $outp .= '"lastname":"'   . $rs["lastname"]. '"}';
}
$outp .="]";

$conn->close();

echo($outp);
?>

这是数据库中的PHP代码，需要使用get方法。该错误显示未定义的索引：$user = $_GET['user'];当我运行它时显示此错误。如何解决？

标签： php

解决方案

我在下面的代码中添加了 IF 条件，您可以检查它。通过添加此条件，您可以解决未定义索引问题

<?php
header('Access-Control-Allow-Origin: *');
header('Access-Control-Allow-Methods: GET, POST, PATCH, PUT, DELETE, OPTIONS');
header('Access-Control-Allow-Headers: Origin, Content-Type, X-Auth-Token');
header("Content-Type: application/json; charset=UTF-8");

include("global.php");

$conn = new mysqli(server, dbuser, dbpw, db);
if(!isset($_GET['user']) && empty($_GET['user']))
return false;// this will send back if data or index is not found and also solve the undefine index problem
$user = $_GET['user'];
//$customer = $_GET['customer'];
$querystring = "";
$querystring = "SELECT email, password, firstname, lastname from user ";
$result = $conn->query($querystring);



$outp = "[";
while($rs = $result->fetch_array(MYSQLI_ASSOC)) {
    if ($outp != "[") {$outp .= ",";}
    $outp .= '{"email":"'  . $rs["email"] . '",';
    $outp .= '"password":"'  . $rs["password"] . '",';
    $outp .= '"firstname":"'   . $rs["firstname"] . '",';   
    $outp .= '"lastname":"'   . $rs["lastname"]. '"}';
}
$outp .="]";

$conn->close();

echo($outp);
?>

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