python - 如何编写在Flask服务器上进行Ajax调用的Dart HttpRequest？

Question

我试图了解如何从Dart进行Ajax调用。我对Web编程的了解非常有限。

我的简单服务器ajax.py:-

#!/usr/bin/env python

from datetime import timedelta  
from flask import Flask, make_response, request, current_app, jsonify
from functools import update_wrapper
app = Flask(__name__)

#Decorator for CORS request
def crossdomain(origin=None, methods=None, headers=None, max_age=21600, attach_to_all=True, automatic_options=True):  
    if methods is not None:
        methods = ', '.join(sorted(x.upper() for x in methods))
    if headers is not None and not isinstance(headers, basestring):
        headers = ', '.join(x.upper() for x in headers)
    if not isinstance(origin, basestring):
        origin = ', '.join(origin)
    if isinstance(max_age, timedelta):
        max_age = max_age.total_seconds()

    def get_methods():
        if methods is not None:
            return methods

        options_resp = current_app.make_default_options_response()
        return options_resp.headers['allow']

    def decorator(f):
        def wrapped_function(*args, **kwargs):
            if automatic_options and request.method == 'OPTIONS':
                resp = current_app.make_default_options_response()
            else:
                resp = make_response(f(*args, **kwargs))
            if not attach_to_all and request.method != 'OPTIONS':
                return resp

            h = resp.headers

            h['Access-Control-Allow-Origin'] = origin
            h['Access-Control-Allow-Methods'] = get_methods()
            h['Access-Control-Max-Age'] = str(max_age)
            if headers is not None:
                h['Access-Control-Allow-Headers'] = headers
            return resp

        f.provide_automatic_options = False
        return update_wrapper(wrapped_function, f)
    return decorator

@app.route('/index')
@crossdomain(origin='*')
def index():
#    print request.json()
    return "Hello World"

@app.route('/sum')
@crossdomain(origin='*')
def add_numbers():
    a = request.args.get('a', 0, type=int)
    b = request.args.get('b', 0, type=int)
    return jsonify(result = a + b)

if __name__ == '__main__':
    app.run()

客户端上的Dart代码:-

import 'dart:html';
//import 'package:http/http.dart' as http;

void main() {
  String url = 'http://localhost:5000/index';
  HttpRequest.getString(url).then((val) => print("received::$val"));
  HttpRequest.request(url).then((val) => print("received33::${val.response}"));
  String url2 = 'http://localhost:5000/sum';
  HttpRequest.request(url2, sendData:"{'a':1, 'b':2}", responseType:'json').then((val) =>   print("received33::${val.response}"));
}

这是我的输出:

received::Hello World
received33::{result: 0}
received33::Hello World

如何编写Dart Httprequest来调用a = 1和b = 2的add_numbers(sum)？

Answer 1

我仍然不确定是否应该这样做。但是，这是代码更新，可以进行通信。如果有人可以评论一些更惯用的方式，我将不胜感激。

Ajax服务器( flask ):-

#!/usr/bin/env python

from datetime import timedelta  
from flask import Flask, make_response, request, current_app, jsonify
from functools import update_wrapper
app = Flask(__name__)

def crossdomain(origin=None, methods=None, headers=None, max_age=21600, attach_to_all=True, automatic_options=True):  
    if methods is not None:
        methods = ', '.join(sorted(x.upper() for x in methods))
    if headers is not None and not isinstance(headers, basestring):
        headers = ', '.join(x.upper() for x in headers)
    if not isinstance(origin, basestring):
        origin = ', '.join(origin)
    if isinstance(max_age, timedelta):
        max_age = max_age.total_seconds()

    def get_methods():
        if methods is not None:
            return methods

        options_resp = current_app.make_default_options_response()
        return options_resp.headers['allow']

    def decorator(f):
        def wrapped_function(*args, **kwargs):
            if automatic_options and request.method == 'OPTIONS':
                resp = current_app.make_default_options_response()
            else:
                resp = make_response(f(*args, **kwargs))
            if not attach_to_all and request.method != 'OPTIONS':
                return resp

            h = resp.headers

            h['Access-Control-Allow-Origin'] = origin
            h['Access-Control-Allow-Methods'] = get_methods()
            h['Access-Control-Max-Age'] = str(max_age)
            if headers is not None:
                h['Access-Control-Allow-Headers'] = headers
            #print h
            return resp

        f.provide_automatic_options = False
        return update_wrapper(wrapped_function, f)
    return decorator

@app.route('/index')
@crossdomain(origin='*')
def index():
#    print request.json()
    return "Hello World"

@app.route('/sum', methods = ['GET', 'POST'])
@crossdomain(origin='*', methods=['POST','GET'])
def add_numbers():
#     print request.headers
#     print request.get_data()
#     print request.get_json()
#     print request.environ
#     print request.get_json(True)
#     print request.args
#     a = request.args.get('a', 0, type=int)
#     b = request.args.get('b', 0, type=int)
    data = request.get_json(True)
    a = data['a']
    b = data['b']
    return jsonify(result = a + b)

if __name__ == '__main__':
    app.run()

Dart httprequest(flask.dart):-

import 'dart:html';
//import 'package:http/http.dart' as http;
//import 'package:http/browser_client.dart';
import 'dart:convert' show JSON;

void main() {
  String url = 'http://localhost:5000/index';
  HttpRequest.getString(url).then((val) => print("received::$val"));
  HttpRequest.request(url).then((val) => print("received33::${val.response}"));
  String url2 = 'http://localhost:5000/sum';
  var data = JSON.encode({'a':6, 'b':2});
  HttpRequest.request(url2, method:'POST', mimeType:'application/json', sendData: data, responseType:'json').then((val) => print("received33::${val.response['result']}")).catchError((e)=> e.toString());

//  var client = new BrowserClient();
//  client.get(url).then((response) => print(" My server says: ${response.body}"));
//  client.get(url2).then((response) => print(" My server says: ${response.body}"));
//  client.close();
}

使用http包dart(Flask_io.dart)发出的HTTP请求:-

import 'package:http/http.dart' as http;
import 'dart:convert' show JSON;


void main(){
  String url = 'http://localhost:5000/index';
  String url2 = 'http://localhost:5000/sum';
  var client = new http.Client();
  client.get(url).then((response) => print(" My server says: ${response.body}"));

  var data = JSON.encode({'a':2,'b':3});
  client.post(url2, body:data ).then((response) => print(" My server says: ${JSON.decode(response.body)['result']}"));
//  client.close();
}