Question

如何读取通过POST方法从Dart服务器上的客户端发送的HttpRequest数据？

我从客户端发送类似这样的消息：

HttpRequest request = new HttpRequest(); 
var url = "http://127.0.0.1:8081"; 
request.open("POST", url, async: false); 

String data = 'hello from client'; 
request.send(data); 

在服务器我正在追赶的要求是这样的：

HttpServer.bind('127.0.0.1', 8081).then((server) { 
server.listen((HttpRequest request) { 

//DATA SHOULD BE READ HERE 



}); 
}); 

但我无法弄清楚如何实际读取数据。 ..在HttpRequest中没有数据属性也没有其他的东西...

编辑这是我现在如何得到答案：

HttpServer.bind('127.0.0.1', 8081).then((server) { 
server.listen((HttpRequest request) { 
    //DATA SHOULD BE READ HERE 
    print("got it"); 
    print(request.method); 
    if(request.method == "POST") { 
    print("got it 2"); 
    List<int> dataBody = new List<int>(); 
    request.listen(dataBody.addAll, onDone:() { 
     var postData = new String.fromCharCodes(dataBody); 
     print(postData); 
     }); 
    } 
}); 
}); 

但由于某些原因将request.method不是“POST”，而是“OPTIONS”，如果我改变if(request.method == "OPTIONS")，然后打印（POSTDATA）仍然会返回什么...

Answer 1

眼下，处理POST数据有点困难。但基本上HttpRequest本身必须被'听'。 HttpRequest is a stream itself。特别是它是一个Stream<List<int>>。所以基本上你的数据可以作为多个List<int>传递给你的HttpRequest。所以我们需要重建数据，然后将其转换为字符串（假设您期望字符串，而不是二进制数据等）。这里或多或少我做什么：

HttpServer.bind('127.0.0.1', 8081).then((server) { 
    server.listen((HttpRequest request) { 
    if(request.method == "POST") { 
    List<int> dataBody = new List<int>(); 
    request.listen(dataBody.addAll, onDone:() { 
     var postData = new String.fromCharCodes(dataBody); 
     // Do something with the data now. 
    }); 
    } 
    request.response.close(); 
}); 

注意，request.listen(dataBody.AddAll, ...)基本要求List.addAll()每一次数据到服务器（在更大的数据，或者可能不会一下子多部分形式的情况下）。这可以确保我们缓冲所有内容，直到流表明它已完成。在这种情况下，我们现在可以对收到的数据执行某些操作，例如将其转换为字符串。

Answer 2

您可以使用StringDecoder从HttpRequest中的“List of Int”转换为“String”。由于无论您发送json，纯文本还是png，Dart都始终以 “Int列表”的形式向服务器发送数据。另一种方法是使用在Heroku Steam v0.6.2 Dart Editor上测试的Streams（http://www.dartlang.org/articles/feet-wet-streams/） 0.4.3_r20602逸SDK 0.4.3.5_r26062

例如，

客户端：

import 'dart:html'; 
import 'dart:json' as Json; 
import 'dart:async'; 
import 'dart:uri'; 
final String data = 'Hello World!'; 
void _sendPNG(String pngData) { 
HttpRequest request = new HttpRequest(); // create a new XHR 
// add an event handler that is called when the request finishes 
request.onReadyStateChange.listen((_) 
{ 
if (request.readyState == HttpRequest.DONE && 
(request.status == 200 || request.status == 0)) { 
// data saved OK. 
print(request.responseText); // output the response from the server 
} 
        } 
); 
// POST the data to the server Async 
print('Sending Photos to the server...'); 
var url = "/png"; 
request.open("POST", url); 
request.setRequestHeader("Content-Type", "text/plain"); 
request.send(data); 
} 

服务器：

import 'dart:io'; 
import 'dart:async'; 
import 'dart:json' as Json; 
import "package:stream/stream.dart"; 
import 'package:xml/xml.dart' as xml; 
import 'package:unittest/unittest.dart'; 
import 'package:rikulo_commons/mirrors.dart'; 
void receivePNG(HttpConnect connect){ 
var request = connect.request; 
var response = connect.response; 
if(request.uri.path == '/png' && request.method == 'POST') 
    { 
    String png=''; 
    response.write('The server received png request!'); 
    //read incoming List<int> data from request and use StringDecoder to transform incoming data to string 
    var stream = request.transform(new StringDecoder()); 
    stream.listen((value){ 
    print(value); 
    //Hello World! 
    } 
    else 
    { 
    response.write('error'); 
    response.statusCode = HttpStatus.NOT_FOUND; 
    connect.close(); 
    } 
    } 

共nfigure.dart

var _mapping = { 
    "/": home, 
    "/png": receivePNG, 
}; 

Answer 3

我已经发现了与客户端/端代码

GitHub json send to server Example

// XXX: Dart Editor thinks this is OK, but I haven't run it. 

import 'dart:html'; 

String encodeMap(Map data) { 
    return data.keys.map((k) { 
    return '${Uri.encodeComponent(k)}=${Uri.encodeComponent(data[k])}'; 
    }).join('&'); 
} 

loadEnd(HttpRequest request) { 
    if (request.status != 200) { 
    print('Uh oh, there was an error of ${request.status}'); 
    return; 
    } else { 
    print('Data has been posted'); 
    } 
} 

main() { 
    var dataUrl = '/registrations/create'; 
    var data = {'dart': 'fun', 'editor': 'productive'}; 
    var encodedData = encodeMap(data); 

    var httpRequest = new HttpRequest(); 
    httpRequest.open('POST', dataUrl); 
    httpRequest.setRequestHeader('Content-type', 
           'application/x-www-form-urlencoded'); 
    httpRequest.onLoadEnd.listen((e) => loadEnd(httpRequest)); 
    httpRequest.send(encodedData); 
}