将值发布到php文件中以执行sql查询并以json格式获取数据 [英] Post value to a php file to execute sql query and get back data in json format
问题描述
我正在学习Flutter,并试图构建一个可以显示我今天的课程的移动应用程序.而且我想了解有关数据处理的更多信息,所以我尝试使用php并从数据库中获取数据.
I am learning Flutter and trying to build a mobile application that can display my today courses. And I want to learn more about data handling so I try to use php and get data from database.
我的目标是我想将日期值发布到php文件中,然后执行sql查询并以json格式获取数据.最后,数据将显示在Flutter应用中.
My target is that I want to post the date value to the php file, then execute the sql query and get the data in json format. Finally, the data will be displayed in a Flutter app.
我的php文件的一部分如下:
A part of my php file is as follow:
$date = $_POST["date"];
$sql = "SELECT * FROM Table WHERE Date = '$date'";
$response=array();
$final=array();
$response["status"] = "fail";
$result = mysqli_query($con, $sql);
while($row=mysqli_fetch_assoc($result)){
$response["status"] = "success";
$final[] = $row;
}
$response["result"]=$final;
echo json_encode($response);
从服务器获取数据的apiProvider.dart文件.
The apiProvider.dart file to get data from the server.
import 'dart:async';
import 'dart:convert';
import 'package:http/http.dart' show Client;
import 'package:http/http.dart' as http;
class ApiProvider {
Client client = Client();
final String apiURL = "my.php";
final String today = '2019-06-18';
// Use to fetch today courses.
Future<CourseListModel> getCourses() async {
http.post(apiURL, body: {"date": today});
final response = await client.get(apiURL);
if (response.statusCode == 200) {
// If the API call to the server was successful, parse the course list in JSON format
return CourseListModel.fromJson(json.decode(response.body));
}
else {
// If the API call was fail, throw an error.
throw Exception('Response content length is ${response.statusCode}, failed to get today courses.');
}
}
}
运行Flutter应用程序时无法显示课程数据.我认为"today"值无法正确解析到php文件.我已经完成了Google搜索并尝试了其他方法,但仍然无法正常工作.我不太了解如何处理POST方法.因此,有人可以给我一些解决问题的提示或建议吗?谢谢.
The course data cannot be shown when I run the Flutter app. I think the "today" value cannot be parse to the php file correctly. I have done Google search and tried different methods but it still not work. I am not quite understand how to handle the POST method. So can anyone give me some hints or suggestions to solve the problem? Thanks.
===========更新========
=========== Updated ==========
我已经使用 Ephenodrom 的方法解决了我的问题.更新后的dart文件如下:
I have solved my problem by using the Ephenodrom's method. Updated dart file is as follow:
class ApiProvider {
...
Future<CourseListModel> getCourses() async {
final response = await http.post(apiURL, body:{"date": today});
...
}
谢谢大家:D
推荐答案
您的问题
您发出POST请求,然后发出GET请求.您应该在POST请求中从您的php脚本获得响应.此后不必发出GET请求.
更改此内容:
http.post(apiURL, body: {"date": today});
final response = await client.get(apiURL);
对此:
final response = http.post(apiURL, body: {"date": today});
我强烈建议您查看以下信息!
I would highly recommend to check out the information below!
有一个dart程序包,它为http请求提供了一些帮助程序类.
There is a dart package that provides some helper classes for http requests.
Github: https://github.com/Ephenodrom/Dart-Basic-Utils一个>安装:
Github : https://github.com/Ephenodrom/Dart-Basic-Utils Install it with:
dependencies:
basic_utils: ^1.5.1
用法
Map<String, String> headers = {
"Some": "Header"
};
Map<String, String> queryParameters = {
"Some": "Parameter"
};
String url = "";
String payloadAsString = "{\"date\": \"2019-06-18\"}";
Future<CourseListModel> getCourses() async {
Map<String, dynamic> body;
try {
body = await HttpUtils.postForJson(url, payloadAsString,
queryParameters: queryParameters, headers: headers);
} catch (e) {
// Handle exception, for example if response status code != 200-299
}
return CourseListModel.fromJson(body);
}
其他信息:
这些都是HttpUtils类中的所有方法.
These are all methods from the HttpUtils class.
Future<Map<Response> getForFullResponse(String url,{Map<String, dynamic> queryParameters,Map<String, String> headers});
Future<Map<String, dynamic>> getForJson(String url,{Map<String, dynamic> queryParameters,Map<String, String> headers});
Future<String> getForString(String url,{Map<String, dynamic> queryParameters,Map<String, String> headers});
Future<Map<Response> postForFullResponse(String url, String body,{Map<String, String> queryParameters,Map<String, String> headers});
Future<Map<String, dynamic>> postForJson(String url, String body,{Map<String, String> queryParameters,Map<String, String> headers});
Future<String> postForString(String url, String body,{Map<String, String> queryParameters,Map<String, String> headers});
Future<Response> putForFullResponse(String url, String body,{Map<String, String> queryParameters,Map<String, String> headers});
Future<Map<String, dynamic>> putForJson(String url, String body,{Map<String, String> queryParameters,Map<String, String> headers});
Future<String> putForString(String url, String body,{Map<String, String> queryParameters,Map<String, String> headers});
Future<Response deleteForFullResponse(String url,{Map<String, String> queryParameters,Map<String, String> headers});
Future<Map<String, dynamic>> deleteForJson(String url,{Map<String, String> queryParameters,Map<String, String> headers});
Future<String> deleteForString(String url,{Map<String, String> queryParameters,Map<String, String> headers});
Map<String, dynamic> getQueryParameterFromUrl(String url);
String addQueryParameterToUrl(String url, Map<String, dynamic> queryParameters);
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