当我收到 gsm 调制解调器异常时如何实现重试机制：没有从 phone 收到数据？
how to implement retry mechanism when I got gsm modem Exception: No data received from phone?
public class GSMModemConnection
{
我使用 Wavecom Gsm 调制解调器 1306B 创建了一个接收 SMS 的 windows 服务。但是过了一会儿我得到了一个
异常：未从 phone 收到数据。我在 Whosebug 中搜索过，我发现了这个 link Exception: No data received from phone
有人指出要创建重试机制，但我不知道如何实现它。
static void Main(string[] args)
{
GSMModemConnection gsm = new GSMModemConnection();
var result = gsm.OpenPort();
Console.WriteLine(result.PortName);
while (true)
{
Stopwatch stopwatch = new Stopwatch();
stopwatch.Start();
ShortMessage execResult = gsm.ReadSMS(result, "AT+CMGL=\"ALL\"");
Console.WriteLine(execResult.Message);
Console.WriteLine(execResult.Status);
}
}
public class GSMModemConnection
{
public AutoResetEvent receiveNow;
//string strPortName, string strBaudRate
public SerialPort OpenPort()
{
receiveNow = new AutoResetEvent(false);
SerialPort port = new SerialPort();
port.PortName = "COM3";
port.BaudRate = 115200 /*Convert.ToInt32(strBaudRate)*/; //updated by Anila (9600)
port.DataBits = 8;
port.StopBits = StopBits.One;
port.Parity = Parity.None;
port.ReadTimeout = 300;
port.WriteTimeout = 300;
port.Encoding = Encoding.GetEncoding("iso-8859-1");
port.DataReceived += new SerialDataReceivedEventHandler(port_DataReceived);
port.Open();
port.DtrEnable = true;
port.RtsEnable = true;
return port;
}
//Close Port
public void ClosePort(SerialPort port)
{
port.Close();
port.DataReceived -= new SerialDataReceivedEventHandler(port_DataReceived);
port = null;
}
//Execute AT Command
public string ExecCommand(SerialPort port, string command, int responseTimeout, string errorMessage)
{
try
{
//receiveNow = new AutoResetEvent();
port.DiscardOutBuffer();
port.DiscardInBuffer();
receiveNow.Reset();
port.Write(command + "\r");
//Thread.Sleep(3000); //3 seconds
string input = ReadResponse(port, responseTimeout);
if ((input.Length == 0) || ((!input.EndsWith("\r\n> ")) && (!input.EndsWith("\r\nOK\r\n"))))
throw new ApplicationException("No success message was received.");
return input;
}
catch (Exception ex)
{
throw new ApplicationException(errorMessage, ex);
}
}
//Receive data from port
public void port_DataReceived(object sender, SerialDataReceivedEventArgs e)
{
if (e.EventType == SerialData.Chars)
receiveNow.Set();
}
public string ReadResponse(SerialPort port, int timeout)
{
string buffer = string.Empty;
do
{
if (receiveNow.WaitOne(timeout, false))
{
string t = port.ReadExisting();
buffer += t;
}
else
{
if (buffer.Length > 0)
throw new ApplicationException("Response received is incomplete.");
else
throw new ApplicationException("No data received from phone.");
}
}
while (!buffer.EndsWith("\r\nOK\r\n") && !buffer.EndsWith("\r\n> ") && !buffer.EndsWith("\r\nERROR\r\n"));
return buffer;
}
public ShortMessage ReadSMS(SerialPort port, string p_strCommand)
{
// Set up the phone and read the messages
ShortMessage messages = null;
try
{
#region Execute Command
// Check connection
var a = ExecCommand(port, "AT", 300, "No phone connected");
// Use message format "Text mode"
var b = ExecCommand(port, "AT+CMGF=1\r", 300, "Failed to set message format.");
// Use character set "PCCP437"
//var c = ExecCommand(port, "AT+CSCS=\"PCCP437\"", 300, "Failed to set character set.");
// Select SIM storage
//var d = ExecCommand(port, "AT+CPMS=\"SM\"", 300, "Failed to select message storage.");
// Read the messages
string input = ExecCommand(port, p_strCommand, 5000, "Failed to read the messages.");
#endregion
#region Parse messages
messages = ParseMessages(input);
#endregion
}
catch (Exception ex)
{
throw ex;
}
if (messages != null)
return messages;
else
return null;
}
public ShortMessage ParseMessages(string input)
{
ShortMessage msg = new ShortMessage();
//ShortMessageCollection messages = new ShortMessageCollection();
try
{
Regex r = new Regex(@"\+CMGL: (\d+),""(.+)"",""(.+)"",(.*),""(.+)""\r\n(.+)\r\n");
Match m = r.Match(input);
while (m.Success)
{
//msg.Index = int.Parse(m.Groups[1].Value);
msg.Index = int.Parse(m.Groups[1].Value);
msg.Status = m.Groups[2].Value;
msg.Sender = m.Groups[3].Value;
msg.Alphabet = m.Groups[4].Value;
msg.Sent = m.Groups[5].Value;
msg.Message = m.Groups[6].Value;
//messages.Add(msg);
m = m.NextMatch();
}
}
catch (Exception ex)
{
throw ex;
}
return msg;
}
}
您确实有一个重试机制，使用来自以下表达式的 DO-WHILE 循环：
public string ReadResponse(SerialPort port, int timeout)
{
string buffer = string.Empty;
do
{
if (receiveNow.WaitOne(timeout, false))
{
string t = port.ReadExisting();
buffer += t;
}
else
{
if (buffer.Length > 0)
throw new ApplicationException("Response received is incomplete.");
else
throw new ApplicationException("No data received from phone.");
}
}
while (!buffer.EndsWith("\r\nOK\r\n") && !buffer.EndsWith("\r\n> ") && !buffer.EndsWith("\r\nERROR\r\n"));
return buffer;
}
您可以做的是降低错误报告机制的粒度。
在这种情况下，例如，行 throw new ApplicationException() 将中断循环并在 Exec() 函数中被捕获，然后再次抛出。如果你只是想等待循环结束和 DO-WHILE 循环被执行，我会替换代码的以下部分：
else
{
if (buffer.Length > 0)
throw new ApplicationException("Response received is incomplete.");
else
throw new ApplicationException("No data received from phone.");
}
有：
else
{
if (buffer.Length > 0)
bufferError += "Response received is incomplete.\n";
else
bufferError += "No data received from phone.\n";
}
为什么？
在 DO-WHILE 循环之后，缓冲区将 return string.Empty 或某个值。
在代码中，您有：
string input = ReadResponse(port, responseTimeout);
if ((input.Length == 0) || ((!input.EndsWith("\r\n> ")) && (!input.EndsWith("\r\nOK\r\n"))))
throw new ApplicationException("No success message was received.");
return input;
基本上，如果 returned 缓冲区是 string.Empty，将再次抛出异常。
通过 return 缓冲区错误，您可以稍后决定如何处理它，但是 DO-WHILE 循环将 运行 至少一次，直到 WHILE 表达式的条件为遇见了。
其余代码应如下所示：
//Thread.Sleep(3000); //3 seconds
string bufferErrors = string.Empty;
string input = ReadResponse(port, responseTimeout, bufferErrors);
if ((input.Length == 0) || ((!input.EndsWith("\r\n> ")) && (!input.EndsWith("\r\nOK\r\n"))))
throw new ApplicationException("No success message was received.");
if (!string.IsNullOrWhiteSpace(bufferErrors))
{
//Handle bufferErrors
}
return input;
记得在ReadResponse中声明out参数
public string ReadResponse(SerialPort port, int timeout, out string bufferError)
{
string buffer = string.Empty;
bufferError = string.Empty;
public class GSMModemConnection { 我使用 Wavecom Gsm 调制解调器 1306B 创建了一个接收 SMS 的 windows 服务。但是过了一会儿我得到了一个 异常：未从 phone 收到数据。我在 Whosebug 中搜索过，我发现了这个 link Exception: No data received from phone
有人指出要创建重试机制，但我不知道如何实现它。
static void Main(string[] args)
{
GSMModemConnection gsm = new GSMModemConnection();
var result = gsm.OpenPort();
Console.WriteLine(result.PortName);
while (true)
{
Stopwatch stopwatch = new Stopwatch();
stopwatch.Start();
ShortMessage execResult = gsm.ReadSMS(result, "AT+CMGL=\"ALL\"");
Console.WriteLine(execResult.Message);
Console.WriteLine(execResult.Status);
}
}
public class GSMModemConnection
{
public AutoResetEvent receiveNow;
//string strPortName, string strBaudRate
public SerialPort OpenPort()
{
receiveNow = new AutoResetEvent(false);
SerialPort port = new SerialPort();
port.PortName = "COM3";
port.BaudRate = 115200 /*Convert.ToInt32(strBaudRate)*/; //updated by Anila (9600)
port.DataBits = 8;
port.StopBits = StopBits.One;
port.Parity = Parity.None;
port.ReadTimeout = 300;
port.WriteTimeout = 300;
port.Encoding = Encoding.GetEncoding("iso-8859-1");
port.DataReceived += new SerialDataReceivedEventHandler(port_DataReceived);
port.Open();
port.DtrEnable = true;
port.RtsEnable = true;
return port;
}
//Close Port
public void ClosePort(SerialPort port)
{
port.Close();
port.DataReceived -= new SerialDataReceivedEventHandler(port_DataReceived);
port = null;
}
//Execute AT Command
public string ExecCommand(SerialPort port, string command, int responseTimeout, string errorMessage)
{
try
{
//receiveNow = new AutoResetEvent();
port.DiscardOutBuffer();
port.DiscardInBuffer();
receiveNow.Reset();
port.Write(command + "\r");
//Thread.Sleep(3000); //3 seconds
string input = ReadResponse(port, responseTimeout);
if ((input.Length == 0) || ((!input.EndsWith("\r\n> ")) && (!input.EndsWith("\r\nOK\r\n"))))
throw new ApplicationException("No success message was received.");
return input;
}
catch (Exception ex)
{
throw new ApplicationException(errorMessage, ex);
}
}
//Receive data from port
public void port_DataReceived(object sender, SerialDataReceivedEventArgs e)
{
if (e.EventType == SerialData.Chars)
receiveNow.Set();
}
public string ReadResponse(SerialPort port, int timeout)
{
string buffer = string.Empty;
do
{
if (receiveNow.WaitOne(timeout, false))
{
string t = port.ReadExisting();
buffer += t;
}
else
{
if (buffer.Length > 0)
throw new ApplicationException("Response received is incomplete.");
else
throw new ApplicationException("No data received from phone.");
}
}
while (!buffer.EndsWith("\r\nOK\r\n") && !buffer.EndsWith("\r\n> ") && !buffer.EndsWith("\r\nERROR\r\n"));
return buffer;
}
public ShortMessage ReadSMS(SerialPort port, string p_strCommand)
{
// Set up the phone and read the messages
ShortMessage messages = null;
try
{
#region Execute Command
// Check connection
var a = ExecCommand(port, "AT", 300, "No phone connected");
// Use message format "Text mode"
var b = ExecCommand(port, "AT+CMGF=1\r", 300, "Failed to set message format.");
// Use character set "PCCP437"
//var c = ExecCommand(port, "AT+CSCS=\"PCCP437\"", 300, "Failed to set character set.");
// Select SIM storage
//var d = ExecCommand(port, "AT+CPMS=\"SM\"", 300, "Failed to select message storage.");
// Read the messages
string input = ExecCommand(port, p_strCommand, 5000, "Failed to read the messages.");
#endregion
#region Parse messages
messages = ParseMessages(input);
#endregion
}
catch (Exception ex)
{
throw ex;
}
if (messages != null)
return messages;
else
return null;
}
public ShortMessage ParseMessages(string input)
{
ShortMessage msg = new ShortMessage();
//ShortMessageCollection messages = new ShortMessageCollection();
try
{
Regex r = new Regex(@"\+CMGL: (\d+),""(.+)"",""(.+)"",(.*),""(.+)""\r\n(.+)\r\n");
Match m = r.Match(input);
while (m.Success)
{
//msg.Index = int.Parse(m.Groups[1].Value);
msg.Index = int.Parse(m.Groups[1].Value);
msg.Status = m.Groups[2].Value;
msg.Sender = m.Groups[3].Value;
msg.Alphabet = m.Groups[4].Value;
msg.Sent = m.Groups[5].Value;
msg.Message = m.Groups[6].Value;
//messages.Add(msg);
m = m.NextMatch();
}
}
catch (Exception ex)
{
throw ex;
}
return msg;
}
}
您确实有一个重试机制，使用来自以下表达式的 DO-WHILE 循环：
public string ReadResponse(SerialPort port, int timeout)
{
string buffer = string.Empty;
do
{
if (receiveNow.WaitOne(timeout, false))
{
string t = port.ReadExisting();
buffer += t;
}
else
{
if (buffer.Length > 0)
throw new ApplicationException("Response received is incomplete.");
else
throw new ApplicationException("No data received from phone.");
}
}
while (!buffer.EndsWith("\r\nOK\r\n") && !buffer.EndsWith("\r\n> ") && !buffer.EndsWith("\r\nERROR\r\n"));
return buffer;
}
您可以做的是降低错误报告机制的粒度。
在这种情况下，例如，行 throw new ApplicationException() 将中断循环并在 Exec() 函数中被捕获，然后再次抛出。如果你只是想等待循环结束和 DO-WHILE 循环被执行，我会替换代码的以下部分：
else
{
if (buffer.Length > 0)
throw new ApplicationException("Response received is incomplete.");
else
throw new ApplicationException("No data received from phone.");
}
有：
else
{
if (buffer.Length > 0)
bufferError += "Response received is incomplete.\n";
else
bufferError += "No data received from phone.\n";
}
为什么？ 在 DO-WHILE 循环之后，缓冲区将 return string.Empty 或某个值。 在代码中，您有：
string input = ReadResponse(port, responseTimeout);
if ((input.Length == 0) || ((!input.EndsWith("\r\n> ")) && (!input.EndsWith("\r\nOK\r\n"))))
throw new ApplicationException("No success message was received.");
return input;
基本上，如果 returned 缓冲区是 string.Empty，将再次抛出异常。
通过 return 缓冲区错误，您可以稍后决定如何处理它，但是 DO-WHILE 循环将 运行 至少一次，直到 WHILE 表达式的条件为遇见了。 其余代码应如下所示：
//Thread.Sleep(3000); //3 seconds
string bufferErrors = string.Empty;
string input = ReadResponse(port, responseTimeout, bufferErrors);
if ((input.Length == 0) || ((!input.EndsWith("\r\n> ")) && (!input.EndsWith("\r\nOK\r\n"))))
throw new ApplicationException("No success message was received.");
if (!string.IsNullOrWhiteSpace(bufferErrors))
{
//Handle bufferErrors
}
return input;
记得在ReadResponse中声明out参数
public string ReadResponse(SerialPort port, int timeout, out string bufferError)
{
string buffer = string.Empty;
bufferError = string.Empty;