GPRS or Edge Howto?

Hello all, I started writing a driver for the SIM900A today based on the ESP8266 driver.

1. init is working
   
2. connect is working
   
3. getIP is working
   
4. reset is just calling init currently because I didn't find a way to reset the SIM900 by using an AT-command (for ESP8266 there is AT+RST)
   
   

I got stuck at sending a HTTP-Request through NetworkJS. What happens is, that the send-method is called over and over and after a few retries it stops. I can not see any response from the server currently. I assume that there are subtle differences in the use of the AT+CIPSEND command for ESP8266 and SIM900A. Any ideas?

Here you find the code:

Serial1.setup(115200, { rx: B7, tx : B6 });


var at;
var socks = [];
var sockData = ["","","","",""];
var MAXSOCKETS = 5;

var netCallbacks = {
  create : function(host, port) {
    /* Create a socket and return its index, host is a string, port is an integer.
    If host isn't defined, create a server socket */  
    if (host===undefined) {
      sckt = MAXSOCKETS;
      socks[sckt] = "Wait";
      sockData[sckt] = "";
      at.cmd("AT+CIPSERVER=1,"+port+"\r\n", 10000, function(d) {
        if (d=="OK") {
          socks[sckt] = true;
        } else {
          socks[sckt] = undefined;
          throw new Error("CIPSERVER failed");
        }
      });
      return MAXSOCKETS;
    } else {
      var sckt = 0;
      while (socks[sckt]!==undefined) sckt++; // find free socket
      if (sckt>=MAXSOCKETS) throw new Error("No free sockets");
      socks[sckt] = "Wait";
      sockData[sckt] = "";
      at.cmd('AT+CIPSTART='+sckt+',"TCP",'+JSON.stringify(host)+','+port+'\r\n',10000, function(d) {
        if (d=="OK") {
          at.registerLine(sckt + ', CONNECT OK', function() {
            at.unregisterLine(sckt + ', CONNECT OK');
            socks[sckt] = true;
          });
          at.registerLine(sckt + ', CLOSED', function() {
            at.unregisterLine(sckt + ', CLOSED');
            socks[sckt] = undefined;
          });
        } else {
          socks[sckt] = undefined;
          throw new Error("CIPSTART failed");
        }
      });
    }
    return sckt;
  },
  /* Close the socket. returns nothing */
  close : function(sckt) {    
    at.cmd('AT+CIPCLOSE='+sckt+"\r\n",1000, function(/*d*/) {
      socks[sckt] = undefined;
      //console.log("?"+JSON.stringify(d));
    });
  },
  /* Accept the connection on the server socket. Returns socket number or -1 if no connection */
  accept : function(sckt) {
    // console.log("Accept",sckt);
    for (var i=0;i<MAXSOCKETS;i++)
      if (sockData[i] && socks[i]===undefined) {
        //console.log("Socket accept "+i,JSON.stringify(sockData[i]),socks[i]);
        socks[i] = true;
        return i;
      }
    return -1;
  },
  /* Receive data. Returns a string (even if empty).
  If non-string returned, socket is then closed */
  recv : function(sckt, maxLen) {    
    if (at.isBusy() || socks[sckt]=="Wait") return "";
    if (sockData[sckt]) {
      var r;
      if (sockData[sckt].length > maxLen) {
        r = sockData[sckt].substr(0,maxLen);
        sockData[sckt] = sockData[sckt].substr(maxLen);
      } else {
        r = sockData[sckt];
        sockData[sckt] = "";
      }
      return r;
    }
    if (!socks[sckt]) return -1; // close it
    return "";
  },
  /* Send data. Returns the number of bytes sent - 0 is ok.
  Less than 0  */
  send : function(sckt, data) {
    console.log(data);
    if (at.isBusy() || socks[sckt]=="Wait") return 0;
    if (!socks[sckt]) return -1; // error - close it
    console.log("Send: " + data);
    var f = function(d) {
      // TODO: register for '>'
      //console.log("?"+JSON.stringify(d));
      if (d=="> ") {
        return f;
      }
    };
    at.cmd('AT+CIPSEND='+sckt+','+data.length+'\r\n' + data , 10000, f);
    return data.length;
  }
};


//Handle +IPD input data from SIM900A
function ipdHandler(line) {
  var colon = line.indexOf(":");
  if (colon<0) return line; // not enough data here at the moment
  var parms = line.substring(5,colon).split(",");
  parms[1] = 0|parms[1];
  var len = line.length-(colon+1);
  if (len>=parms[1]) {
   // we have everything
   sockData[parms[0]] += line.substr(colon+1,parms[1]);
   return line.substr(colon+parms[1]+1); // return anything else
  } else { 
   // still some to get
   sockData[parms[0]] += line.substr(colon+1,len);
   return "+IPD,"+parms[0]+","+(parms[1]-len)+":"; // return IPD so we get called next time    
  }
}

var gprsFuncs = {
  ipdHandler:ipdHandler,
  "debug" : function() {
    return {
      socks:socks,
      sockData:sockData
    };
  },
  // initialise the SIM900A
  "init" : function(callback) { 
    var s = 0;
    var cb = function(r) {
      console.log(r);
      switch(s) {
        case 0:
          if(r === 'ATE0' || r === 'OK') return cb;
          else if(r) {
            callback('Error in ' + s + ': ' + r);
          } else {
            s = 1;
            at.cmd('AT+CPIN?\r\n', 100, cb);
          }
          break;
        case 1:
          if(r === '+CPIN: READY' || r === 'OK') return cb;
          else if(r) {
            callback('Error in ' + s + ': ' + r);
          } else {
            s = 2;
            at.cmd('AT+CGATT?\r\n', 100, cb);
          }
          break;
        case 2:
          if(r === '+CGATT: 1' || r === 'OK') return cb;
          else if(r) {
            callback('Error in ' + s + ': ' + r);
          } else {
            s = 3;
            at.cmd('AT+CIPSHUT\r\n', 100, cb);
          }
          break;
        case 3:
          if(r === 'SHUT OK') return cb;
          else if(r) {
            callback('Error in ' + s + ': ' + r);
          } else {
            s = 4;
            at.cmd('AT+CIPSTATUS\r\n', 100, cb);
          }
          break;
        case 4:
          if(r === 'STATE: IP INITIAL' || r === 'OK') return cb;
          else if(r) {
            callback('Error in ' + s + ': ' + r);
          } else {
            s = 5;
            at.cmd('AT+CIPMUX=1\r\n', 100, cb);
          }
          break;
        case 5:
          if(r === 'OK') return cb;
          else if(r) {
            callback('Error in ' + s + ': ' + r);
          } else {
            callback(null);
          }
          break;
      }
      return cb;
    };
    at.cmd("ATE0\r\n",1000,cb);
  },
  "reset" : function(callback) {
    gprsFuncs.init(callback);
  },
  "getVersion" : function(callback) {
    at.cmd("AT+GMR\r\n", 1000, function(d) {
      callback(null,d);
    });
  },
  "connect" : function(apn, username, password, callback) {
    var s = 0;
    var cb = function(r) {
      switch(s) {
        case 0:
          if(r === 'OK') return cb;
          else if(r) {
            callback('Error in ' + s + ': ' + r);
          } else {
            s = 1;
            at.cmd('AT+CIICR\r\n', 2000, cb);
          }
          break;
        case 1:
          if(r === 'OK') return cb;
          else if(r) {
            callback('Error in ' + s + ': ' + r);
          } else {
            callback(null);
          }
          break;
      }
    };
    at.cmd('AT+CSTT="' + apn + '", "' + username + '", "' + password + '"\r\n', 1000, cb);
  },
  "getIP" : function(callback) {
    var ip;
    var cb = function(r) {
      if(r && r != 'ERROR') {
        ip = r;
        return cb;
      } else if(r === 'ERROR') {
        callback('CIFSR Error');
      } else if(!r) {
        callback(null, ip);
      }
    };
    at.cmd('AT+CIFSR\r\n', 2000, cb);
  }
};
var connect = function(usart, connectedCallback) {
  gprsFuncs.at = at = require("AT").connect(usart);
  require("NetworkJS").create(netCallbacks);
  at.register("+IPD", ipdHandler);
  gprsFuncs.reset(connectedCallback);
  return gprsFuncs;
};

connect(Serial1, function() {
  gprsFuncs.connect('pinternet.interkom.de', '', '', function(err) {
    console.log(err);
    gprsFuncs.getIP(function(err, ip) {
      console.log('IP:' + ip);
      require("http").get("http://www.pur3.co.uk/hello.txt", function(res) {
        console.log("Response: ",res);
        res.on('data', function(d) {
          console.log("--->"+d);
        });
      });
    });
  });
});