json - 如何使用 MQL4 在 WebRequest() 调用中发送带有 JSON 的 POST？

Question

我想发送 POST 来自 MQL4 -script，使用 JSON 格式连接到节点服务器。

我试过 webRequest() MQL4 中的标准功能，基于以下文档，但没有成功。

From MQL4 Documentation:

Sending simple requests of type "key=value" using the header `Content-Type: application/x-www-form-urlencoded`.    

    int  WebRequest( const string  method,           // HTTP method  
                     const string  url,              // URL 
                     const string  cookie,           // cookie 
                     const string  referer,          // referer 
                     int           timeout,          // timeout 
                     const char   &data[],           // the array of the HTTP message body 
                     int           data_size,        // data[] array size in bytes 
                     char         &result[],         // an array containing server response data 
                      string      &result_headers    // headers of server response
                     );

和

Sending a request of any type specifying the custom set of headers for a more flexible interaction with various Web services.

    int  WebRequest( const string  method,           // HTTP method 
                     const string  url,              // URL 
                     const string  headers,          // headers  
                     int           timeout,          // timeout 
                     const char   &data[],           // the array of the HTTP message body 
                     char         &result[],         // an array containing server response data 
                     string       &result_headers    // headers of server response 
                     );


Parameters

    method          [in]  HTTP method.
    url             [in]  URL.
    headers         [in]  Request headers of type "key: value", separated by a line break "\r\n".
    cookie          [in]  Cookie value.
    referer         [in]  Value of the Referer header of the HTTP request.
    timeout         [in]  Timeout in milliseconds.
    data[]          [in]  Data array of the HTTP message body.
    data_size       [in]  Size of the data[] array.
    result[]       [out]  An array containing server response data.
    result_headers [out]  Server response headers. 

Returned value:
    HTTP server response code or -1 for an error.

有谁知道如何执行它？

更新:

这是 MQL4上的代码-脚本方面:

#include <Json\hash.mqh>
#include <Json\KoulJSONMgmt.mqh>
void OnStart()

    {
       string strParam = StringConcatenate("{","\"currency\"",":","\"",Symbol(),"\"",",","\"timeframe\"",":","\"",IntegerToString(Period()),"\"",",","\"ticktime\"",":","\"",TimeToString(TimeLocal(),TIME_DATE|TIME_SECONDS),"\"",",","\"bid\"",":",DoubleToString(MarketInfo(Symbol(),MODE_BID),4),",","\"ask\"",":",DoubleToString(MarketInfo(Symbol(),MODE_ASK),4),",","\"spread\"",":",DoubleToString(MarketInfo(Symbol(),MODE_SPREAD),0),"}");


        JSONParser *parser = new JSONParser();
        JSONValue *jv = parser.parse(strParam);
        string strJson = jv.toString();
        if (jv == NULL) {
            Print("error:"+(string)parser.getErrorCode()+parser.getErrorMessage());
        } else {
            Print("PARSED:"+strJson);
    //Example of json String :
    //EURUSD,M15: PARSED:{"bid" : 1.1152,"ask" : 1.1154,"spread" : 13,"ticktime" : "2016.10.10 16:24:01","currency" : "EURUSD","timeframe" : "15"}
        }

          string cookie=NULL,headers;
          char post[],result[];
          int res;
          string strResult,result_header;

          headers = "application/json";
          prmUrl=StringConcatenate("http://localhost/api"+"/"+"ticks");
          //--- Reset the last error code
          ResetLastError();
          int timeout=1000; //--- Timeout below 1000 (1 sec.) is not enough for slow Internet connection

          int intHostNameLength=StringLen(prmParameter);
          StringToCharArray(prmParameter,post,0,intHostNameLength);

          res=WebRequest("POST",prmUrl,headers,timeout,post,result,result_header);

          //--- Checking errors
          if(res==-1)
            {
             Print("Error in WebRequest. Error code  =",GetLastError());
             //--- Perhaps the URL is not listed, display a message about the necessity to add the address
             Print("Add the address '"+prmUrl+"' in the list of allowed URLs on tab 'Expert Advisors'","Error",MB_ICONINFORMATION);
            }
          else
           {
               for(int i=0;i<ArraySize(result);i++)
               {

                   if( (result[i] == 10) || (result[i] == 13)) {
                      continue;
                   } else {
                      strResult += CharToStr(result[i]);
                   }
               }
               ArrayCopy(strResult,result,0,0,WHOLE_ARRAY);

           }
           Print(strResult);

    }

节点端是:

服务器.js

//Create new Tick
app.post('/api/ticks', function(req, res) {
    console.log('Inserting New Tick');

    var tick = req.body;
    console.log('>'+JSON.stringify(tick,null,4));

    Tick.addTick(tick, function(err, tick){
        if(err) res.json(err);
        res.json(tick);
    });
});

在模型 ticks.js 中

var mongoose = require('mongoose');


// User Schema
var TickSchema = mongoose.Schema({
    currency:{
        type: String
    },
    timeframe: {
        type: String
    },
    ticktime: {
        type: Date
    },
    bid: {
        type: Number
    },
    ask: {
        type: Number
    },
    spread: {
        type: Number
    },
    createddate :{
        type: Date,
        default:  Date.now
    }
}, {collection : 'fxTicks'});

var Tick = module.exports = mongoose.model('Tick', TickSchema);

//Create New Tick
module.exports.addTick = function(tick, callback){
    Tick.create(tick, callback);
};

// Get Ticks
module.exports.getTicks = function(callback, limit){
    Tick.find(callback).limit(limit);
};

Answer 1

所以，回到 1 号广场:

在 last-year's post ，有一个循序渐进的方法来进行基于 MCVE 的问题隔离方法。

在 内部重复相同的步骤MQL4 -代码，
添加 python - 基于模型的 WebSERVER，用于诊断实际工作的客户端/服务器 http 协议(protocol)交换和握手，( 不是 WebSERVER 端 解释 已交付的 POST 请求，即同样，就好像从 WebBROWSER 启动了 URL，所有相关详细信息引用:BaseHTTPServer.BaseHTTPRequestHandler)

>>> import BaseHTTPServer
>>> server_class  = BaseHTTPServer.HTTPServer
>>> handler_class = BaseHTTPServer.BaseHTTPRequestHandler
>>> httpd         = server_class( ( '', 8765 ), handler_class )
>>> httpd.handle_request()
127.0.0.1 - - [10/Oct/2016 09:46:45] code 501, message Unsupported method ('GET')
127.0.0.1 - - [10/Oct/2016 09:46:45] "GET /?test=123_from_Chrome HTTP/1.1" 501 -
>>> httpd.handle_request()
127.0.0.1 - - [10/Oct/2016 09:47:23] code 501, message Unsupported method ('GET')
127.0.0.1 - - [10/Oct/2016 09:47:23] "GET /favicon.ico HTTP/1.1" 501 -
>>>
>>>
>>>
>>> httpd = server_class( ( '', 80 ), handler_class )
>>> httpd.handle_request()
127.0.0.1 - - [10/Oct/2016 10:22:05] code 501, message Unsupported method ('GET')
127.0.0.1 - - [10/Oct/2016 10:22:05] "GET /?test=123_from_Chrome_on_port_80 HTTP/1.1" 501 -
>>> httpd.handle_request()
127.0.0.1 - - [10/Oct/2016 10:22:31] code 501, message Unsupported method ('GET')
127.0.0.1 - - [10/Oct/2016 10:22:31] "GET /?test=123_from_Chrome_on_port_80_again HTTP/1.1" 501 -
>>> httpd.handle_request()
127.0.0.1 - - [10/Oct/2016 10:22:34] code 501, message Unsupported method ('GET')
127.0.0.1 - - [10/Oct/2016 10:22:34] "GET /favicon.ico HTTP/1.1" 501 -
>>> httpd.handle_request()
127.0.0.1 - - [10/Oct/2016 11:25:56] code 501, message Unsupported method ('GET')
127.0.0.1 - - [10/Oct/2016 11:26:12] "GET /?test=123_from_Chrome_on_port_80_another_call HTTP/1.1" 501 -
>>>
>>>
127.0.0.1 - - [10/Oct/2016 12:03:03] code 501, message Unsupported method ('POST')
127.0.0.1 - - [10/Oct/2016 12:03:03] "POST / HTTP/1.1" 501 -
>>>

输出提供了最后一对行是由 MQL4 生成的证据。侧 WebRequest()已正确设置并且可以在此处和后面正常工作 [ MetaTrader 终端 4 ]-日志显示:

2016.10.10 12:03:03.921 ___StackOverflow_WebRequest_DEMO XAUUSD,H1:

           DATA:: <head><title>Error response</title></head>
                  <body>
                  <h1>Error response</h1><p>Error code 501.<p>
                  Message: Unsupported method ('POST').<p>
                  Error code explanation: 501 = Server does not support this operation.
                  </body>

2016.10.10 12:03:03.921 ___StackOverflow_WebRequest_DEMO XAUUSD,H1:

           HDRs:: HTTP/1.0 501 Unsupported method ('POST')
                  Server: BaseHTTP/0.3 Python/2.7.6
                  Date: Mon, 10 Oct 2016 20:03:03 GMT
                  Content-Type: text/html
                  Connection: close

一个生的 MQL4 -snippet 但使用风险自负! (强烈建议不要在任何生产级代码中使用任何 BLOCKING WebRequest() 调用... for NON-BLOCKING tools see my other posts 和 how to 或阅读用于分布式异构系统的高性能、低延迟、非阻塞集成工具的内部详细信息处理类似 ZeroMQ 或 nanomsg )

所有人都被警告过，所以:

去年的设置图片仍然有效:


模型 WebSERVER 在虚线表单字段输入内具有:

http://localhost/

还应记住，尝试在 URL 中设置特定端口名称将违反 MetaQuotes Inc. 设计规则，即端口是从 URL 声明开头的协议(protocol)编译指示派生的，因此:

http://localhost:8765/

将不起作用，因为 MQL4 WebRequest()不能 使用除 之外的其他端口{ 80 | 443 } ，由 URL 中所述的协议(protocol)编译指示给出: { http: | https: }

因此，对于任何端口编号体操，都必须设置和调整一组适当的端口转发服务，这将使 MetaTrader 终端 4 在这个设计笼中存活，只使用 { 80 | 443 } 中的任何一个.

最简单的 MQL4 -脚本 OnStart()演示者看起来是这样的:

//+------------------------------------------------------------------+
//|                             ___StackOverflow_WebRequest_DEMO.mq4 |
//|                                       Copyright © 1987-2016 [MS] |
//|                                                       nowhere.no |
//+------------------------------------------------------------------+ >>> https://stackoverflow.com/questions/39954177/how-to-send-a-post-with-a-json-in-a-webrequest-call-using-mql4
#property copyright "Copyright © 1987-2016 [MS]"
#property link      "nowhere.no"
#property version   "1.00"
#property strict
//+------------------------------------------------------------------+
//| Script program start function                                    |
//+------------------------------------------------------------------+
void  OnStart(){

      /* A BRIGHTER WAY:

         string JSON_string = StringFormat( "{\"currency\": \"%s\", \"timeframe\": \"%d\", \"ticktime\": \"%s\", \"bid\": %f, \"ask\": %f, \"spread\": %s }",  _Symbol,
                                                                                                                                                               Period(),
                                                                                                                                                               TimeToString( TimeLocal(), TIME_DATE | TIME_SECONDS ),
                                                                                                                                                               MarketInfo( _Symbol, MODE_BID ),
                                                                                                                                                               MarketInfo( _Symbol, MODE_ASK ),
                                                                                                                                                               MarketInfo( _Symbol, MODE_SPREAD )
                                                                                                                                                               );
      // A SMARTER WAY & THE FASTEST PROCESSING TIMES:
      // --------------

#define MQL4_COMPILE_TIME_JSON_TEMPLATE     "{\"currency\": \"%s\", \"timeframe\": \"%d\", \"ticktime\": \"%s\", \"bid\": %f, \"ask\": %f, \"spread\": %s }"   // CONSTANT TEMPLATE TO FILL-IN AD-HOC VALUES:
      // +
         string JSON_string = StringFormat( MQL4_COMPILE_TIME_JSON_TEMPLATE",                                                                                  _Symbol,
                                                                                                                                                               Period(),
                                                                                                                                                               TimeToString( TimeLocal(), TIME_DATE | TIME_SECONDS ),
                                                                                                                                                               MarketInfo( _Symbol, MODE_BID ),
                                                                                                                                                               MarketInfo( _Symbol, MODE_ASK ),
                                                                                                                                                               MarketInfo( _Symbol, MODE_SPREAD )
                                                                                                                                                               );
         */
      string JSON_string = StringConcatenate( "{",                                                    // **** MQL4 can concat max 63 items
                                              "\"currency\"",
                                              ":",
                                              "\"",
                                              Symbol(),
                                              "\"",
                                              ",",
                                              "\"timeframe\"",
                                              ":",
                                              "\"",
                                              IntegerToString( Period() ),
                                              "\"",
                                              ",",
                                              "\"ticktime\"",
                                              ":",
                                              "\"",
                                              TimeToString( TimeLocal(), TIME_DATE | TIME_SECONDS ),
                                              "\"",
                                              ",",
                                              "\"bid\"",
                                              ":",
                                              DoubleToString( MarketInfo( Symbol(), MODE_BID ), 4 ),
                                              ",",
                                              "\"ask\"",
                                              ":",
                                              DoubleToString( MarketInfo( Symbol(), MODE_ASK ), 4 ),
                                              ",",
                                              "\"spread\"",
                                              ":",
                                              DoubleToString( MarketInfo( Symbol(), MODE_SPREAD ), 0 ),
                                              "}"
                                              );
   // */
   /* off-topic: a JSON-string VALIDATOR -----------------------------------------------------------------------------------------------------------------------------------

#include <Json\hash.mqh>
#include <Json\KoulJSONMgmt.mqh>

        JSONParser *parser = new JSONParser();
        JSONValue  *jv     =         parser.parse(strParam);

        string strJson = jv.toString();

        if ( jv == NULL ) Print( "ERROR:"  + (string) parser.getErrorCode()
                                                    + parser.getErrorMessage()
                                 );
        else              Print( "PARSED:" + strJson );

                          // Example of a journalled Print() for an above setup JSON String :
                          // EURUSD,M15: PARSED:{"bid" : 1.1152,"ask" : 1.1154,"spread" : 13,"ticktime" : "2016.10.10 16:24:01","currency" : "EURUSD","timeframe" : "15"}
*/ // off-topic: a JSON-string VALIDATOR -----------------------------------------------------------------------------------------------------------------------------------

       // string  ReqSERVER_URL = "http://localhost:8765/",         // **** MQL4 WebRequest CANNOT use other port but either of { 80 | 443 } given by protocol pragma stated in URL: { http: | https: }
          string  ReqSERVER_URL = "http://localhost/",              // ---- MQL4 WebRequst
                  ReqCOOKIE     =  NULL,
               // ReqHEADERs    =               "application/json"; // **** MQL4 WebRequest MUST   use [in]  Request headers of type "key: value", separated by a line break "\r\n".
                  ReqHEADERs    = "Content-Type: application/json\r\n";
          int     ReqTIMEOUT    =  5000;                            // ---- MQL4 WebRequest SHALL  use [in]  Timeouts below 1000 (1 sec.) are not enough for slow Internet connection;
               // ================================================= // ~~~~ MQL4 WebRequest SHALL be AVOIDED as an un-control-able BLOCKING-SHOW-STOPPER, any professional need shall use NON-BLOCKING tools
          char    POSTed_DATA[],
                  result_RECVed_DATA_FromSERVER[];
          int     result_RetCODE;
          string  result_DecodedFromSERVER,
                  result_RECVed_HDRs_FromSERVER;

       // int     intHostNameLength                       = StringLen(  ReqSERVER_URL );
       // StringToCharArray( ReqSERVER_URL, POSTed_DATA, 0, StringLen(  ReqSERVER_URL ) );
       // StringToCharArray( prmParameter,  post,        0, intHostNameLength );
          StringToCharArray( JSON_string,   POSTed_DATA, 0, StringLen(  JSON_string   ) );

          ResetLastError();

          result_RetCODE = WebRequest( "POST",
                                       ReqSERVER_URL,
                                       ReqHEADERs,
                                       ReqTIMEOUT,
                                       POSTed_DATA,
                                       result_RECVed_DATA_FromSERVER,
                                       result_RECVed_HDRs_FromSERVER
                                       );
          if (  result_RetCODE == -1 ) Print( "Error in WebRequest. Error code  =", GetLastError() ); // returns error 4060 – "Function is not allowed for call" unless permitted -- ref. Picture in >>> https://stackoverflow.com/questions/39954177/how-to-send-a-post-with-a-json-in-a-webrequest-call-using-mql4
          else {
                for (  int i = 0; i < ArraySize( result_RECVed_DATA_FromSERVER ); i++ ) {
                       if (  ( result_RECVed_DATA_FromSERVER[i] == 10 ) // == '\n'  // <LF>
                          || ( result_RECVed_DATA_FromSERVER[i] == 13 ) // == '\r'  // <CR>
                          ) 
                          continue;
                       else     result_DecodedFromSERVER += CharToStr( result_RECVed_DATA_FromSERVER[i] );
                }
                Print( "DATA:: ", result_DecodedFromSERVER );
                Print( "HDRs:: ", result_RECVed_HDRs_FromSERVER );
          }
      }
//+------------------------------------------------------------------+

Deviations from documented steps are easily visible in the source and were left for clarity.

结语:

如果文档说明了什么，那么值得保留该建议(当然，通过一些测试)。

如果赞助的社区建议说了些什么，那么在要求更多之前，至少值得一试。