Question

我想从POST脚本发送 MQL4 ，使用JSON格式发送到节点服务器。

我已根据以下文档在webRequest()中尝试了 MQL4 标准功能，但未成功。

来自MQL4文档：

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.

有谁知道如何表演它？

UPDATE：

以下是MQL4 - 脚本端的代码：

#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);

    }

节点方面是：

server.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);
    });
});

和模型ticks.js

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

对我来说效果很好，我有这样的人：

string response = SendResquest("POST", "GetPrediction", "[4, 7]", "Content-Type: application/json", 5000);

string SendResquest(string httpType, string methodName, string bodyData = "", string headers = "", int timeout)
{
    uchar bodyDataCharArray[];
    ArrayResize(bodyDataCharArray, StringToCharArray(bodyData, bodyDataCharArray)-1);

    int response = WebRequest(httpType, this.address+methodName, headers, timeout, bodyDataCharArray, this.resultDataCharArray, this.resultHeader);

    string result = CharArrayToString(this.resultDataCharArray); 

    if(response == 200)
        return result;
    Print("Error when trying to call API : ", response);
    return "";
}

Answer 2

所以，回到1号广场：

在last-year's post中，有一个循序渐进的方法来继续使用基于MCVE的问题隔离方法。

在此处重复相同的步骤，在 MQL4 - 代码中，执行添加基于 python 的模型WebSERVER，以诊断实际工作的客户端/服务器http协议交换＆amp;握手，（ > - 传递的POST请求的WebSERVER端解释，就像所有相关细节都是从WebBROWSER启动了URL一样参考：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 -
>>>

输出结果是提供证据表明最后一对行是由MQL4 - 侧 WebRequest()生成的，这些行已正确设置并在那里正常工作
[ MetaTrader Terminal 4 ] - 日志读取：

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

原始`MQL4` - 代码段但使用风险自负！

_{（强烈建议不要使用任何阻止WebRequest()在任何生产级代码中调用
... for NON-BLOCKING tools see my other posts和how to或阅读有关高性能，低延迟，非阻塞集成工具的内部详细信息，以便分布式异构系统处理ZeroMQ或nanomsg）}

所有人都被警告过，所以：

去年设置图片仍然有效：

模拟WebSERVER在点缀的表单字段输入中包含：

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，即端口是在URL声明开头从协议编译指示派生的，因此：

http://localhost:8765/

不起作用，因为 MQL4 WebRequest()不能使用其他端口，但 { 80 | 443 } ，由URL中声明的协议编译指示： { http: | https: }

因此，对于任何端口编号体操，必须设置和调整一组适当的端口转发服务，这样就可以使用{ 80 | 443 }中的任何一个将MetaTrader Terminal 4保留在此设计框内。 / p>
最简单的MQL4 - 脚本OnStart()演示器就是这样的：

//+------------------------------------------------------------------+ //| ___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 ); } } //+------------------------------------------------------------------+

在源中可以很容易地看到与记录步骤的偏差，并且为了清楚起见而留下了。

尾声：

如果文档说了些什么，那么值得保留这些建议（肯定会有一些测试）。

如果赞助的社区建议说了些什么，在要求更多之前，至少值得尝试一下。

Answer 3

您是否尝试过像这样设置标题：

headers = "Content-Type: application/json\r\n";

Answer 4

允许您的[ MetaTrader Terminal 4 ]通过菜单与网址进行通信：

工具 - ＆gt; 选项 - ＆gt; Expert Advisors - ＆gt;

<强> 1。标记在“允许WebReq ....”前面的复选框 [ X ] ＆安培;
的 2。使用表单中的绿色 (+) 图标键入复选框下方的网址名称。

如果这没有帮助 - 尝试添加Print()语句以查看可能的错误（错误的MQL4代码或不正确的JSON格式文件）。

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

UPDATE：

4 个答案:

所以，回到1号广场：

尾声：