Elavon Get Token, Postman convert to Lazarus TIdHTTP protocol unknown
/ missing
lazarus / 38-Networking and Web Programming

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RedOctober · 2021-05-21 17:26

Platform:  Lazarus 2.0.10,  FPC 3.2.0, Windows Server 2016, Indy
10.6.2.3662

I am trying to convert a working Postman request to a Lazarus TIdHTTP
request.  I'm getting a "Protocol unknown" error.  Can someone let me
know what I am doing wrong?  Thanks in advance.

Here is the Postman request:

Code: Text  [Select][+][-]window.onload = function(){var x1 =
document.getElementById("main_content_section"); if (x1) { var x =
document.getElementsByClassName("geshi");for (var i = 0; i {       
"info": {                "_postman_id":
"95a1529d-5dd5-4714-9a28-823f4c363fd3",                "name":
"transactionToken",                "schema": "https://schema.getpostma
n.com/json/collection/v2.1.0/collection.json"        },        "item":
[                {                        "name": "Transaction
Token",                        "request": {                          
    "method": "POST",                                "header": [     
                                 {                                   
           "key": "Content-Type",                                    
          "name": "Content-Type",                                    
          "value": "application/x-www-form-urlencoded",              
                                "type": "text"                       
               }                                ],                   
           "body": {                                        "mode":
"urlencoded",                                        "urlencoded": [ 
                                             {                       
                               "key": "ssl_merchant_id",             
                                         "value": "",                
                                      "type": "text"                 
                             },                                      
        {                                                       
"key": "ssl_user_id",                                                
      "value": "",                                                   
   "type": "text"                                                },  
                                            {                        
                              "key": "ssl_pin",                      
                                "value": "",                         
                             "type": "text"                          
                    },                                               
{                                                        "key":
"ssl_transaction_type",                                              
        "value": "ccsale",                                           
           "type": "text"                                            
  },                                                {                
                                      "key": "ssl_amount",           
                                           "value": "1.00",          
                                            "type": "text"           
                                   }                                 
     ]                                },                             
 "url": {                                        "raw":
"https://demo.convergepay.com/hosted-payments/transaction_token",    
                                  "protocol": "https",               
                       "host": [                                     
         "demo",                                               
"convergepay",                                                "com"  
                                    ],                               
       "path": [                                               
"hosted-payments",                                               
"transaction_token"                                        ]         
                     }                        },                     
 "response": []                }        ],       
"protocolProfileBehavior": {}} 

Here is my code:

Code: Pascal  [Select][+][-]window.onload = function(){var x1 =
document.getElementById("main_content_section"); if (x1) { var x =
document.getElementsByClassName("geshi");for (var i = 0; i procedure
TfrmMain.GetElavonToken;var  xHTTP: TidHTTP;  xHandler:
TIdSSLIOHandlerSocketOpenSSL;  xLogger: TIdLogDebug;     str_strm:
TStringStream;  xRequestBody: TStringList;  idx: Integer;  
https_post_cmd: String;    s: String;  snd_err: Boolean;begin 
memSndRcv.Lines.Clear;   Screen.Cursor := crHourGlass; 
Application.ProcessMessages;   //
 https://demo.convergepay.com/hosted-payments/transaction_token 
https_post_cmd := GV.Brook.Elavon.GetTokenURL;   xHTTP := nil; 
xHandler := nil;  xLogger := nil;  xRequestBody := nil;   snd_err :=
False;  xml_mem_strm := nil;  str_strm := nil;   try     xHTTP :=
TIdHttp.Create(Self);    xHandler :=
TIdSSLIOHandlerSocketOpenSSL.Create(Self);    xLogger :=
TIdLogDebug.Create(Self);    xLogger.OnReceive := @logElvReceive;   
xLogger.OnSend := @logElvSend;    xRequestBody :=
TStringList.Create;     xHTTP.IOHandler := xHandler;   
xHandler.Intercept := xLogger;    xHandler.SSLOptions.Method :=
sslvTLSv1_2;     xHTTP.AllowCookies := True;   
xHTTP.Request.BasicAuthentication := False;   
xHTTP.Request.CustomHeaders.AddValue('Content-Type',
'application/x-www-form-urlencoded');   
xHTTP.Request.CustomHeaders.AddValue('Accept', '*/*');   
xHTTP.Request.CustomHeaders.AddValue('Accept-Encoding', 'gzip,
deflate, br');    xHTTP.HTTPOptions := xHTTP.HTTPOptions +
[hoForceEncodeParams, hoKeepOrigProtocol];    xHTTP.ProtocolVersion :=
pv1_1;     xRequestBody.Add('ssl_merchant_id= (withheld for security
reasons)');    xRequestBody.Add('ssl_user_id=apiuser');   
xRequestBody.Add('ssl_pin= (withheld for security reasons)');   
xRequestBody.Add('ssl_transaction_type=ccsale');   
xRequestBody.Add('ssl_amount=26.00');     
memSndRcv.Lines.Add('Fetching Elavon token via HTTP');   
Application.ProcessMessages;        str_strm :=
TStringStream.Create('');     try      xHTTP.Post(https_post_cmd,
xRequestBody);    except      on E: Exception do        begin        
snd_err := True;          memSndRcv.Lines.Add('Error on xHTTP.Post(' +
GV.TxtMsg.https_get_cmd + ')');         
memSndRcv.Lines.Add(E.Message);          Screen.Cursor := crDefault; 
       Application.ProcessMessages;          Exit;        end;   
end;     xml_mem_strm.Position := 0;    memSndRcv.Lines.Add('Got
it.');    Application.ProcessMessages;     idx :=
memSndRcv.Lines.Add('Loading XMLDoc...');   
Application.ProcessMessages;    //ReadXMLFile(XMLDoc, xml_mem_strm); 
 memSndRcv.Lines[idx] := memSndRcv.Lines[idx] + 'Done.';   
Application.ProcessMessages;   finally    xHTTP.Free;   
xHandler.Free;     str_strm.Free;    xRequestBody.Free;    
Screen.Cursor := crDefault;    Application.ProcessMessages;  end; end;

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engkin · 2021-05-21 18:45

I search for 'Protocol unknown' in Indy's source files, and I found:
Code: Pascal  [Select][+][-]window.onload = function(){var x1 =
document.getElementById("main_content_section"); if (x1) { var x =
document.getElementsByClassName("geshi");for (var i = 0; i  
RSHTTPUnknownProtocol = 'Unknown Protocol';
I did another search for 'RSHTTPUnknownProtocol'. I found it in two
places. This one seems related:
Code: Pascal  [Select][+][-]window.onload = function(){var x1 =
document.getElementById("main_content_section"); if (x1) { var x =
document.getElementsByClassName("geshi");for (var i = 0; i procedure
TIdCustomHTTP.PrepareRequest(ARequest: TIdHTTPRequest);...    if
Length(LURI.Port) > 0 then begin      FURI.Port := LURI.Port;    end 
 else if TextIsSame(LURI.Protocol, 'http') then begin     {do not
localize}      FURI.Port := IntToStr(IdPORT_HTTP);    end    else if
TextIsSame(LURI.Protocol, 'https') then begin  {do not localize}     
FURI.Port := IntToStr(IdPORT_https);    end    else if
Length(FURI.Port) = 0 then begin      raise
EIdUnknownProtocol.Create(RSHTTPUnknownProtocol);    end;
There must be a port, or 'http' or 'https' otherwise some unknown
protocol?

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Remy Lebeau · 2021-05-21 19:58

Quote from: RedOctober on May 21, 2021, 07:26:27 pmI'm getting a
"Protocol unknown" error.  Can someone let me know what I am doing
wrong?

That error typically means you attempted to request a URL that does
not begin with 'http:' or 'https:'.  Double-check that
GV.Brook.Elavon.GetTokenURL returns a full URL.

On a side note...

Quote from: RedOctober on May 21, 2021, 07:26:27 pmCode: Pascal
 [Select][+][-]window.onload = function(){var x1 =
document.getElementById("main_content_section"); if (x1) { var x =
document.getElementsByClassName("geshi");for (var i = 0; i
xHandler.SSLOptions.Method := sslvTLSv1_2;
You should be using the SSLVersions property instead of the Method
property:

Code: Pascal  [Select][+][-]window.onload = function(){var x1 =
document.getElementById("main_content_section"); if (x1) { var x =
document.getElementsByClassName("geshi");for (var i = 0; i
xHandler.SSLOptions.SSLVersions := [sslvTLSv1_2];
Quote from: RedOctober on May 21, 2021, 07:26:27 pmCode: Pascal
 [Select][+][-]window.onload = function(){var x1 =
document.getElementById("main_content_section"); if (x1) { var x =
document.getElementsByClassName("geshi");for (var i = 0; i
xHTTP.Request.CustomHeaders.AddValue('Content-Type',
'application/x-www-form-
urlencoded');xHTTP.Request.CustomHeaders.AddValue('Accept',
'*/*');xHTTP.Request.CustomHeaders.AddValue('Accept-Encoding', 'gzip,
deflate, br');
You should be using the Request's own sub-properties for those values,
not the CustomHeaders property:

Code: Pascal  [Select][+][-]window.onload = function(){var x1 =
document.getElementById("main_content_section"); if (x1) { var x =
document.getElementsByClassName("geshi");for (var i = 0; i
xHTTP.Request.ContentType := 'application/x-www-form-
urlencoded';xHTTP.Request.Accept := '*/*';xHTTP.Request.AcceptEncoding
:= 'gzip, deflate, br';
However, for the Content-Type header, the TStrings version of
TIdHTTP.Post() will set that value for you, so you can safely omit it.

But more importantly, you really should not be sending a custom
Accept-Encoding header at all, unless you are actually prepared to
handle those specific data types yourself manually should the server
decide to send them (in which case, you should not be using
TStringStream for that, not that it matters since you are not
capturing the server's response body at all).  Indy does not implement
any built-in support for 'br' at this time, and TIdHTTP's support for
'gzip' and 'deflate' is disabled by default, you have to assign a
TIdZLibCompressorBase-derived component to the TIdHTTP.Compressor
property, such as TIdCompressorZLib.  So, you should typically just
let TIdHTTP handle the Accept-Encoding header for you, based on how
TIdHTTP is actually configured.

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RedOctober · 2021-05-22 00:17

After making all the changes suggested, the code works now, and I can
retrieve a token. Thanks all!