Nelson Neves / GSL_03-Network_HttpClient_GetStream

Simple code to demonstrate how to make an HTTP GET request to fetch a stream from an RSS feed. Note: Demo program to be used on the GeekSessionLab Talk (November 2011). http://devrendezvous.com/?lang=en

Dependencies:   EthernetNetIf mbed

main.cpp@0:0946c896455e, 2011-10-27 (annotated)

Committer:
botdream
Date:
Thu Oct 27 22:37:47 2011 +0000
Revision:
0:0946c896455e
GeekSessionLab talk.

Who changed what in which revision?

UserRevisionLine numberNew contents of line
botdream 0:0946c896455e 1 //---------------------------------------------------------------------------------------------
botdream 0:0946c896455e 2 #include "mbed.h"
botdream 0:0946c896455e 3 #include "EthernetNetIf.h"
botdream 0:0946c896455e 4 #include "HTTPClient.h"
botdream 0:0946c896455e 5 //---------------------------------------------------------------------------------------------
botdream 0:0946c896455e 6 DigitalOut myled(LED1);
botdream 0:0946c896455e 7 Serial pc(USBTX, USBRX); // tx, rx
botdream 0:0946c896455e 8 //---------------------------------------------------------------------------------------------
botdream 0:0946c896455e 9 #define internaldebug // send debug messages to USB Serial port (9600,1,N)
botdream 0:0946c896455e 10 #define dhcpenable // auto-setup IP Address from DHCP router
botdream 0:0946c896455e 11 //---------------------------------------------------------------------------------------------
botdream 0:0946c896455e 12 // Ethernet Object Setup
botdream 0:0946c896455e 13 //---------------------------------------------------------------------------------------------
botdream 0:0946c896455e 14 #ifdef dhcpenable
botdream 0:0946c896455e 15 EthernetNetIf eth;
botdream 0:0946c896455e 16 #else
botdream 0:0946c896455e 17 EthernetNetIf eth(
botdream 0:0946c896455e 18 IpAddr(192,168,1,100), //IP Address
botdream 0:0946c896455e 19 IpAddr(255,255,255,0), //Network Mask
botdream 0:0946c896455e 20 IpAddr(192,168,1,254), //Gateway
botdream 0:0946c896455e 21 IpAddr(192,168,1,254) //DNS
botdream 0:0946c896455e 22 );
botdream 0:0946c896455e 23 #endif
botdream 0:0946c896455e 24 //---------------------------------------------------------------------------------------------
botdream 0:0946c896455e 25 // HttpClient
botdream 0:0946c896455e 26 HTTPClient http;
botdream 0:0946c896455e 27
botdream 0:0946c896455e 28 HTTPResult result;
botdream 0:0946c896455e 29 bool completed = false;
botdream 0:0946c896455e 30 void request_callback(HTTPResult r)
botdream 0:0946c896455e 31 {
botdream 0:0946c896455e 32 result = r;
botdream 0:0946c896455e 33 completed = true;
botdream 0:0946c896455e 34 }
botdream 0:0946c896455e 35 //---------------------------------------------------------------------------------------------
botdream 0:0946c896455e 36 // MAIN
botdream 0:0946c896455e 37 //---------------------------------------------------------------------------------------------
botdream 0:0946c896455e 38 int main()
botdream 0:0946c896455e 39 {
botdream 0:0946c896455e 40 // Set Serial Port Transfer Rate
botdream 0:0946c896455e 41 pc.baud(115200);
botdream 0:0946c896455e 42
botdream 0:0946c896455e 43 //--------------------------------------------------------
botdream 0:0946c896455e 44 // Setting Ethernet
botdream 0:0946c896455e 45 //--------------------------------------------------------
botdream 0:0946c896455e 46 #ifdef internaldebug
botdream 0:0946c896455e 47 printf("\r\nSetting up Ethernet interface!\r\n");
botdream 0:0946c896455e 48 #endif
botdream 0:0946c896455e 49 // Create return object for error check
botdream 0:0946c896455e 50 EthernetErr ethErr = eth.setup();
botdream 0:0946c896455e 51 if(ethErr)
botdream 0:0946c896455e 52 {
botdream 0:0946c896455e 53 #ifdef internaldebug
botdream 0:0946c896455e 54 printf("\r\nError %d in Ethernet setup.\r\n", ethErr);
botdream 0:0946c896455e 55 #endif
botdream 0:0946c896455e 56 return -1;
botdream 0:0946c896455e 57 }
botdream 0:0946c896455e 58 #ifdef internaldebug
botdream 0:0946c896455e 59 printf("\r\nEthernet setup completed with success!\r\n");
botdream 0:0946c896455e 60 #endif
botdream 0:0946c896455e 61 //--------------------------------------------------------
botdream 0:0946c896455e 62
botdream 0:0946c896455e 63 //--------------------------------------------------------
botdream 0:0946c896455e 64 // HTTP Get Stream Request
botdream 0:0946c896455e 65 //--------------------------------------------------------
botdream 0:0946c896455e 66 HTTPStream stream;
botdream 0:0946c896455e 67
botdream 0:0946c896455e 68 char BigBuf[512 + 1] = {0};
botdream 0:0946c896455e 69 stream.readNext((byte*)BigBuf, 512); //Point to buffer for the first read
botdream 0:0946c896455e 70
botdream 0:0946c896455e 71 printf("\r\nHttpClient Get Stream Request ...\r\n");
botdream 0:0946c896455e 72
botdream 0:0946c896455e 73 HTTPResult r = http.get("http://services.sapo.pt/RSS/Feed/tek", &stream, request_callback); //Load a very large page, such as the hackaday RSS feed
botdream 0:0946c896455e 74
botdream 0:0946c896455e 75 while(!completed)
botdream 0:0946c896455e 76 {
botdream 0:0946c896455e 77 Net::poll(); //Polls the Networking stack
botdream 0:0946c896455e 78 if(stream.readable())
botdream 0:0946c896455e 79 {
botdream 0:0946c896455e 80 BigBuf[stream.readLen()] = 0; //Transform this buffer in a zero-terminated char* string
botdream 0:0946c896455e 81 printf("%s\r\n",BigBuf); //Display it while loading
botdream 0:0946c896455e 82 //Note: some servers do not like if you throttle them too much, so printf'ing during a request is generally bad practice
botdream 0:0946c896455e 83 stream.readNext((byte*)BigBuf, 512); //Buffer has been read, now we can put more data in it
botdream 0:0946c896455e 84 }
botdream 0:0946c896455e 85 }
botdream 0:0946c896455e 86 printf("\n--------------\n");
botdream 0:0946c896455e 87 if(result == HTTP_OK)
botdream 0:0946c896455e 88 {
botdream 0:0946c896455e 89 printf("Read completely\n");
botdream 0:0946c896455e 90 }
botdream 0:0946c896455e 91 else
botdream 0:0946c896455e 92 {
botdream 0:0946c896455e 93 printf("Error %d\n", result);
botdream 0:0946c896455e 94 }
botdream 0:0946c896455e 95 //--------------------------------------------------------
botdream 0:0946c896455e 96
botdream 0:0946c896455e 97 // main loop
botdream 0:0946c896455e 98 while(1)
botdream 0:0946c896455e 99 {
botdream 0:0946c896455e 100 myled = 1;
botdream 0:0946c896455e 101 wait(0.5);
botdream 0:0946c896455e 102 myled = 0;
botdream 0:0946c896455e 103 wait(0.5);
botdream 0:0946c896455e 104 }
botdream 0:0946c896455e 105 }
botdream 0:0946c896455e 106 //---------------------------------------------------------------------------------------------