Add validation to startATMode, post and get

Added validation and retries to the startATMode handshake as well as
timeouts if the handshake fails entirely.

Also added a disconnect method which disconnects TCP connections and
placed this at the end of the get and post methods as these are already
using the Connection: close method.

Finally, made it so get and post examine the return code from their HTTP
requests and use that as the return value, using negative numbers for
error codes.

DigiFi.cpp

@@ -121,26 +121,61 @@ void DigiFi::begin(int aBaud, bool en)
 }
 void DigiFi::startATMode()
 {
+    bool ATsuccess = false;
+	// ensure the module properly acknowledges
+	// our request for AT mode. Otherwise retry.
+	int retries = 0; // TODO: make constant
+    do {
+	  if (retries > 5) {
+	    debug("Retried 5 times, bailing");
+		// need to change return-types perhaps to
+		// trigger some kind of reset higher up.
+		return;
+	  }
+	  ATsuccess = startATSequence();
+	  retries += 1;
+	} while (!ATsuccess);
+	debug("Send client acknowledge AT mode");
+    Serial1.print("a"); 
+    debug(readResponse(0));
+    debug("echo off");
+    Serial1.print("AT+E\r");
+    debug(readResponse(0));
+}
+bool DigiFi::startATSequence(){
     //silly init sequence for wifi module
-    delay(100);
+    delay(50); // changed from 100
+	// clear the incoming buffer
     while(Serial1.available()){Serial1.read();} 
     debug("start at mode");
     debug("next");
     Serial1.write("+++");
     debug("wait for a");
-    while(!Serial1.available()){delay(1);}
-    debug("clear buffer");
-    while(Serial1.available()){Serial1.read();}
-    Serial1.print("A"); 
-    debug(readResponse(0));
-
-    debug("echo off");
-    Serial1.print("AT+E\r");
-    debug(readResponse(0));
+	// there's a ~4s (see datasheet for newer G2 module)
+	// time within which the handshake must complete
+	// if time is longer than that, it's failed.
+	// TODO: turn the timeout into a constant
+	unsigned long timeout = millis() + (4*1000);
+    while(!Serial1.available()){
+	  delay(1);
+      if (millis() > timeout) {
+	    debug("FAILED: AT handshake timeout");
+	    return false;
+	  }
+	}
+    debug("check for a");
+    char resp = Serial1.read();
+	if (resp == 'a') {
+	  debug("OK: module acknowledge AT mode");
+	  return true;
+	}
+    // otherwise it's failed.
+	debug("FAILED: module acknowledge AT mode");
+	return false;
 }
 void DigiFi::endATMode()
 {
-    //back to trasparent mode
+    //back to transparent mode
     Serial1.print("AT+E\r");
     debug(readResponse(0)); 
     Serial1.print("AT+ENTM\r");
@@ -362,7 +397,7 @@ int DigiFi::connect(IPAddress ip, uint16_t port = 80){
     return connect(server.c_str(),port);
 }
 int DigiFi::connect(const char *host, uint16_t port = 80){
-
+    debug("::connect(*char host, uint port)");
     uint8_t lastMode = TCP;
     debug("Connect");
     startATMode();
@@ -401,11 +436,9 @@ int DigiFi::connect(const char *host, uint16_t port = 80){
         delay(3000);
         startATMode();
         setTCPConn("off");
-
     }
 
     setTCPConn("On");
-
     uint32_t linkStart = millis();
     if(digiFiMode == TCP){
 
@@ -448,6 +481,14 @@ int DigiFi::connect(const char *host, uint16_t port = 80){
 
     return 1;
 }
+
+int DigiFi::disconnect() {
+    debug("::disconnect(*char host, uint port)");
+    startATMode();
+    setTCPConn("off");
+	endATMode();
+	return 1;
+}
 String DigiFi::body(){
     return aBody;
 }
@@ -470,7 +511,14 @@ void DigiFi::debugWrite(char output){
         Serial.write(output);
 
 }
-bool DigiFi::get(char *aHost, char *aPath){
+/*
+Return value should be the HTTP return code (i.e. 100 and above).
+If something else fails, the non-HTTP error codes are negative numbers.
+-1 - connect failure
+-2 - connect successful, but request failed
+-3 - invalid HTTP return-code returned
+*/
+int DigiFi::get(char *aHost, char *aPath){
     if(connect(aHost) == 1){
         //delay(500);
         Serial1.print("GET ");
@@ -496,7 +544,7 @@ bool DigiFi::get(char *aHost, char *aPath){
         }
         debug("get header");
         if(success == false)
-            return 0;
+            return -2;
         aHeader = readResponse(0);
         debug(aHeader);
 
@@ -509,20 +557,24 @@ bool DigiFi::get(char *aHost, char *aPath){
             aBody = readResponse(contentLength.toInt());
 
         debug("return from get");
-
-        return 1;
+
+		// work out the returncode
+		int iRetCode = aHeader.substring(9,12).toInt();
+		if (iRetCode == 0) {
+			debug("Invalid return code");
+			return -3;
+		}
+        return iRetCode;
     }
     else
-        return 0;
+        return -1;
 
     //To do:
     /*
     User agent!
     Better handle timeouts/other errors
-    Actually look at returned header for status
     Efficiency!
     */
-
 }
 String DigiFi::URLEncode(String smsg)
 {
@@ -544,11 +596,15 @@ String DigiFi::URLEncode(String smsg)
     }
     return encodedMsg;
 }
-bool DigiFi::post(char *aHost, char *aPath, String postData){
+/*
+Return value should be the HTTP return code (i.e. 100 and above).
+If something else fails, the non-HTTP error codes are negative numbers.
+-1 - connect failure
+-2 - connect successful, but request failed
+-3 - invalid HTTP return-code returned
+*/
+int DigiFi::post(char *aHost, char *aPath, String postData) {
     if(connect(aHost) == 1){
-
-
-
         Serial1.print("POST ");
         Serial1.print(aPath);
         Serial1.print(" HTTP/1.1\r\nHost: ");
@@ -561,7 +617,6 @@ bool DigiFi::post(char *aHost, char *aPath, String postData){
         Serial1.print("\r\n\r\n");
         Serial1.flush();
 
-
         debug("wait for response...");
         bool success = true;
         int i=0;
@@ -577,31 +632,45 @@ bool DigiFi::post(char *aHost, char *aPath, String postData){
         }
 
         if(success == false)
-            return 0;
+            return -2;
 
         debug("get header");
         aHeader = readResponse(0);
-        debug(aHeader);
 
+        debug(aHeader);
 
         String contentLength = aHeader.substring(aHeader.lastIndexOf("Content-Length: "));
         contentLength = contentLength.substring(16,contentLength.indexOf("\n"));
         debug(contentLength);
 
         debug("get body");
         aBody = readResponse(contentLength.toInt());
-
-        return 1;
+		// connection: close hard-coded, so disconnect here.
+		disconnect();
+		// TODO: 
+		// + make connection: close header optional
+		//   and run disconnect dependent on that option
+		// + remove the disconnect command (TCPDIS=off)
+		//   from the start of the connect command.
+		//   but need to have connection checking upfront
+		//   first.
+
+		// work out the returncode
+		int iRetCode = aHeader.substring(9,12).toInt();
+		if (iRetCode == 0) {
+			debug("Invalid return code");
+			return -3;
+		}
+        return iRetCode;
     }
     else
-        return 0;
+        return -1;
 
     //To do:
     /*
     User agent!
     accept post data as array or array or string, etc
     Better handle timeouts/other errors
-    Actually look at returned header for status
     Efficiency!
     */
 
@@ -629,7 +698,7 @@ String DigiFi::readResponse(int contentLength) //0 = cmd, 1 = header, 2=body
         {
             inByte = Serial1.read();
             curLength++;
-            debugWrite(inByte);
+            //debugWrite(inByte);// disabled, leads to lots of duplicate debug logging
 
             if(contentLength == 0){
                 if (inByte == '\n' && rCount == 2 && nCount == 1)

DigiFi.h

@@ -32,8 +32,9 @@ class DigiFi : public Client
         String serverRequestPath();
         virtual int connect(IPAddress ip, uint16_t port);
         virtual int connect(const char *host, uint16_t port);
-        bool get(char *aHost, char *aPath);
-        bool post(char *aHost, char *aPath, String postData);
+		virtual int disconnect();
+        int get(char *aHost, char *aPath);
+        int post(char *aHost, char *aPath, String postData);
         void startATMode();
         void endATMode();
         void close();
@@ -149,11 +150,13 @@ class DigiFi : public Client
         void setWifiCfgPassword(char *aswd);
     private:
         String readResponse(int contentLength);
+		bool startATSequence();
         String aHeader;
         String aBody;
         //String lastHost;
         int lastErr;
         bool debugState;
+
 };
 
 #endif