php - 使用 Angular 将 Post 发送到 PHP 文件

Question

我正在学习如何使用 HttpClient.post 更新 MySQL 数据库。我要插入的表是:

|id - 日志|

PHP文件如下，

<?php 
   header('Access-Control-Allow-Origin: *');    
    header('Access-Control-Allow-Headers: X-Requested-With');
    header('Access-Control-Allow-Methods: POST, GET, OPTIONS');
include 'db.php';

$postdata=file_get_contents("php://input");
$request = json_decode($postdata);
$message = $request->message;

// Create connection
$conn = new mysqli($server_name, $mysql_username, $mysql_password, $db_name);


 $sql = "INSERT INTO shootingchatlog (id, log) VALUES (NULL, '$message')";

 if($conn -> query($sql) === TRUE ){
 echo "message Uploaded Successfully";
 }else{
 echo "Error Uploading Image";
 }
 mysqli_close($conn);

我不断收到错误消息

$message = $request->message;

这让我认为问题与我的 Angular 代码有关。

   httpOptions = {
    headers: new HttpHeaders({
      'Content-Type': 'application/json'
    })
  };



  constructor(private http: HttpClient) { }


  public uploadService(mess: string): void {
    console.log(mess);
     this.http.post(this.url, JSON.stringify({"messasge": mess}), this.httpOptions)
           .subscribe((res: Response) => {
        console.log(res);
      },
      err => {
        console.log("Error occured", err);
      });
    }

我遇到的最常见错误是:

SyntaxError: Unexpected token < in JSON at position 0 at JSON.parse

我真的不确定我做错了什么。似乎没有任何关于此的文档。或者即使是这样，它通常也太抽象了。任何帮助将不胜感激!

Answer 1

来自 https://developer.mozilla.org/en-US/docs/Web/HTTP/Methods/POST

application/x-www-form-urlencoded: the keys and values are encoded in key-value tuples separated by '&', with a '=' between the key and the value. Non-alphanumeric characters in both keys and values are percent encoded: this is the reason why this type is not suitable to use with binary data (use multipart/form-data instead)

将内容类型从 application/x-www-form-urlencoded 更改为 multipart/form-data

还要检查这个非常有帮助的线程:application/x-www-form-urlencoded or multipart/form-data?