404

Question

这是我第一次在Php中使用API。它用id找到一个产品。如果数据库中存在产品，则->代码200 (如果不是->代码404 )。但404不起作用

我做错了什么？

1.代码200的输出：

/get_id2.php?id=39

records 0   
id  "39"
caption     "Product1"
filename    "Image01.jpg"

2.代码404没有工作输出：

/get_id2.php?id=39999 (there is no product)

SyntaxError: JSON.parse: unexpected end of data at line 3 column 1 of the JSON data

代码：

header("Content-Type: application/json; charset=UTF-8");

include_once('config_setup.php');

$id = $_GET['id'];

$sql = "SELECT * ";
$sql .= "FROM photographs ";
$sql .= "WHERE id='" . db_escape($db, $id) . "'";

$result = mysqli_query($db, $sql);
confirm_db_connect($result);

// products array
$products_arr=array();
$products_arr["records"]=array();
$message = [];


      while($photo = mysqli_fetch_assoc($result)) { 

      if($photo['caption']!=null){  

      extract($photo); 

            $product_item = array(

            "id"            => $id,
            "caption"       => $caption,
            "filename"      => $filename,

        );
          // set response code - 200 OK
          http_response_code(200);
          array_push($products_arr["records"], $product_item);
          echo(json_encode($products_arr));

      } else {
          // set response code - 404 Not found
          http_response_code(404);
         // tell the user product does not exist
         echo json_encode(array("message" => "Product does not exist."));
      }   
 } 

mysqli_free_result($result);

db_disconnect($db);

Answer 1

在mysqli_fetch_assoc之前，您检查结果是true还是false。如果没有记录，mysqli_query将返回一个布尔值false。

你可以有这样的东西：

    if(!$result) {
              http_response_code(404);
              //response message
        }
        else {
              //process result 
    }

Answer 2

现在一切都正常了。我解决了问题：)

header("Content-Type: application/json; charset=UTF-8");

    include_once('config_setup.php');

    $id = $_GET['id'];

    $sql = "SELECT * ";
    $sql .= "FROM photographs ";
    $sql .= "WHERE id='" . db_escape( $db, $id ) . "'";

    $result = mysqli_query( $db, $sql );
    confirm_db_connect( $result );

    $photo = mysqli_fetch_assoc( $result );

    $id = $photo['id'];
    $caption = $photo['caption'];
    $filename = $photo['filename'];

    if ($photo['caption'] != null) {

        // create array
        $product_arr = array(
            "id" => $photo['id'],
            "caption" => $photo['caption'],
            "filename" => $photo['filename']
        );


        // set response code - 200 OK
        http_response_code(200);
        echo json_encode( $product_arr );

    } else {
        // set response code - 404 Not found
        http_response_code(404);
        // tell the user product does not exist
        echo json_encode(array("message" => "Product does not exist."));
    }

    mysqli_free_result( $result );

    db_disconnect( $db );