问题
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.
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.
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);
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.');
}
}
}
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.
=========== Updated ==========
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});
...
}
Thanks everyone :D
回答1:
Your Problem
You make a POST request and after that you make a GET request. Your should get the response from your php script within the POST request. It is not necessary to make a GET request after that.
Change this :
http.post(apiURL, body: {"date": today});
final response = await client.get(apiURL);
To this :
final response = http.post(apiURL, body: {"date": today});
I would highly recommend to check out the information below!
Additional Information
There is a dart package that provides some helper classes for http requests.
Github : https://github.com/Ephenodrom/Dart-Basic-Utils Install it with:
dependencies:
basic_utils: ^1.5.1
Usage
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);
}
Additional information :
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);
回答2:
flutter:
http.get('http://project.php?date=today');
php :
<?php
function fetchDataa(){
include 'connect.php';
$date = $_GET['date'];
$conn = connect();
$sql = 'SELECT * FROM areas Where date = $date';
$result = mysqli_query($conn, $sql);
$i=0;
if (mysqli_num_rows($result) > 0) {
while($row = mysqli_fetch_assoc($result)) {
$arrA[$i]=array('area_id'=>$row['id'], 'name' => $row['name']);
$i++;
}
} else {
echo "0 results";
}
$conn->close();
return json_encode($arrA);
}
print_r(fetchDataa());
?>
This is how you can send a GET request to your server and the get the Json data in the response.
If you use a local server (e.g., wamp) then go to wamp's configuration and change the permission so that it permits access from itself (i.e., localhost).
来源：https://stackoverflow.com/questions/57371762/post-value-to-a-php-file-to-execute-sql-query-and-get-back-data-in-json-format