main.cpp

00001 #include "mbed.h"
00002 #include "EthernetNetIf.h"
00003 #include "HTTPClient.h"
00004 #include "spdomparser.hpp"
00005 #include "spxmlnode.hpp"
00006 #include "spxmlhandle.hpp"
00007 #include "NokiaLCD.h"
00008 #include <string>
00009 // Internet of Things weather display example: LCD displays LA current weather via internet Google API
00010 // Adapted for LCD from http://mbed.org/users/hlipka/programs/spxmltest_weather/lif782
00011 
00012 NokiaLCD lcd(p5, p7, p8, p9, NokiaLCD::LCD6610); // mosi, sclk, cs, rst, type
00013 DigitalIn but1(p13);
00014 DigitalIn but2(p14);
00015 EthernetNetIf eth;
00016 HTTPClient http;
00017 HTTPResult result;
00018 bool completed = false;
00019 void request_callback(HTTPResult r) {
00020     result = r;
00021     completed = true;
00022 }
00023 
00024 void parseWeather(SP_XmlElementNode *node, string loc) {
00025     //extracts current weather XML data fields for LCD
00026     SP_XmlHandle handle(node);
00027     SP_XmlElementNode * condition = handle.getChild( "item" ).getChild("yweather:condition").toElement();
00028     lcd.cls();
00029     // Print the name of the city
00030     lcd.locate(0,2);
00031     lcd.printf("%s:", loc);
00032     //Print the weather conditions
00033     lcd.locate(0,3);
00034     lcd.printf("%s",condition->getAttrValue("text"));
00035     //Print the termperature (in degrees Celcius)
00036     lcd.locate(0,4);
00037     lcd.printf("%sC",condition->getAttrValue("temp"));
00038     //Print the date and time
00039     lcd.locate(0,5);
00040     lcd.printf("%s",condition->getAttrValue("date"));
00041 }
00042 
00043 int main() {
00044     // the eth and HTTP code has be taken directly from the HTTPStream documentation page
00045     // see http://mbed.org/cookbook/HTTP-Client-Data-Containers
00046     lcd.cls();
00047     
00048     // string arrays associating cities with their codes for the yahoo! API
00049     string cities[5] = { "Atlanta", "Houston", "New York", "Seattle", "Sunnyvale" };
00050     string codes[5] = { "2357024", "2424766", "2459115", "2490383", "2442047" };
00051     
00052     string head = "http://weather.yahooapis.com/forecastrss?w=";
00053     //Display the cities to choose from
00054     for(int i = 0; i < 5; i++){
00055         lcd.locate(1, i);
00056         lcd.printf("%i: %s", i+1, cities[i]);
00057     }
00058     
00059     int curr = 0;
00060     int accept = but1, select = but2, pushed = 0;
00061     //This while loop handles selection of cities for display.
00062     while(accept == 0){
00063         lcd.locate(0, curr);
00064         lcd.printf(" ");
00065         //The next two if statements check to see if the button has been pushed, and then cycles through the selection choices as appropriate.
00066         if(select == 1){
00067             pushed = 1;
00068         }
00069         if((select == 0)&&(pushed == 1)){
00070             pushed = 0;
00071             curr = (curr + 1)%5;
00072         }
00073         lcd.locate(0, curr);
00074         lcd.printf(">");
00075         accept = but1; select = but2;
00076     }
00077     //Concatenate the city code for use by the Yahoo! API
00078     head += codes[curr];
00079     head += "&u=c";
00080     
00081     lcd.cls();
00082     
00083     lcd.locate(0,2);
00084     lcd.printf("net setup");
00085     lcd.locate(0,3);
00086     EthernetErr ethErr = eth.setup();
00087     if (ethErr) {
00088         lcd.printf("Error in setup");
00089         return -1;
00090     }
00091     lcd.printf("net ok");
00092 
00093     SP_XmlDomParser parser;
00094     HTTPStream stream;
00095 
00096     char BigBuf[512 + 1] = {0};
00097     stream.readNext((byte*)BigBuf, 512); //Point to buffer for the first read
00098     //Yahoo! weather API for selected city - get XML document for parsing
00099     HTTPResult r = http.get(head.c_str(), &stream, request_callback);
00100     while (!completed) {
00101         Net::poll(); //Polls the Networking stack
00102         if (stream.readable()) {
00103             BigBuf[stream.readLen()] = 0; //Transform this buffer in a zero-terminated char* string
00104             parser.append( BigBuf, strlen(BigBuf)); // stream current buffer data to the XML parser
00105             stream.readNext((byte*)BigBuf, 512); //Buffer has been read, now we can put more data in it
00106         }
00107     }
00108     lcd.cls();
00109     lcd.locate(0,2);
00110     if (result == HTTP_OK) {
00111         lcd.printf(" Read complete");
00112     } else {
00113         lcd. printf(" Error %d", result);
00114         return -1;
00115     }
00116 
00117     SP_XmlHandle rootHandle( parser.getDocument()->getRootElement() );
00118     SP_XmlElementNode * child2 = rootHandle.getChild( "channel" )
00119                                  .toElement();
00120     if ( child2 ) {
00121         parseWeather(child2, cities[curr]); //parses XML "current-conditions" info
00122     }
00123 
00124     if ( NULL != parser.getError() ) {
00125         lcd.printf( "\n error: %s\n", parser.getError() );
00126     }
00127 }