LWIP HTTP Client
Provide code to use the Ethernet MAC Layer as a HTTP Client. It uses the lwIP lib direct without any C++ wrapper.
Library
Import Library:
http://mbed.org/projects/cookbook/svn/EMAC/lwip/trunk
or import precompiled Library:
http://mbed.org/projects/cookbook/svn/EMAC/lwip/precomp
Import Example program:
http://mbed.org/projects/cookbook/svn/EMAC/lwip/examples/purehttpc
- For details on how to use this in the compiler, see Importing Projects and Libraries in to the Compiler
Pure HTTPd
#include "lwip/opt.h"
#include "lwip/stats.h"
#include "lwip/sys.h"
#include "lwip/pbuf.h"
#include "lwip/udp.h"
#include "lwip/tcp.h"
#include "lwip/dns.h"
#include "lwip/dhcp.h"
#include "lwip/init.h"
#include "lwip/netif.h"
#include "netif/etharp.h"
#include "netif/loopif.h"
#include "device.h"
#include "mbed.h"
DigitalOut led(LED1);
/* Struct with hold the Ethernet Data */
struct netif netif_data;
/* Every time called if a packet is received for a */
/* TCPConnection which registerd this Callback. */
err_t recv_callback(void *arg, struct tcp_pcb *pcb, struct pbuf *p, err_t err) {
printf("recv_callback\n");
if (p==NULL) {
printf("Connection closed by server!\n");
return ERR_OK;
}
while (p) {
char * ch = (char*)p->payload;
printf("\n>>>>>>>>>>>>\n");
for (int i=0; i < p->len; i++) {
printf("%c", ch[i]);
}
printf("\n<<<<<<<<<<<<\n");
p = p->next;
}
tcp_recved(pcb, p->tot_len);
pbuf_free(p);
return ERR_OK;
}
/* Connection etablished, lets try to get a http page */
err_t connected_callback(void *arg, struct tcp_pcb *pcb, err_t err) {
tcp_recv(pcb, &recv_callback);
printf("Connected Callback!\n");
char msg[] = "GET / HTTP/1.1\r\nHost: www.google.co.uk\r\n\r\n";
if (tcp_write(pcb, msg, strlen(msg), 1) != ERR_OK) {
error("Could not write", 0);
}
return ERR_OK;
}
int main(void) {
/* Create and initialise variables */
struct netif *netif = &netif_data;
struct ip_addr ipaddr;
struct ip_addr target;
struct ip_addr netmask;
struct ip_addr gateway;
Ticker tickFast, tickSlow, tickARP, eth_tick, dns_tick, dhcp_coarse, dhcp_fine;
char *hostname = "mbed-c3p0";
/* Start Network with DHCP */
IP4_ADDR(&netmask, 255,255,255,255);
IP4_ADDR(&gateway, 0,0,0,0);
IP4_ADDR(&ipaddr, 0,0,0,0);
IP4_ADDR(&target, 209,85,229,147); // www.google.co.uk
/* Initialise after configuration */
lwip_init();
netif->hwaddr_len = ETHARP_HWADDR_LEN;
device_address((char *)netif->hwaddr);
netif = netif_add(netif, &ipaddr, &netmask, &gateway, NULL, device_init, ip_input);
netif->hostname = hostname;
netif_set_default(netif);
dhcp_start(netif); // <-- Use DHCP
/* Initialise all needed timers */
tickARP.attach_us( ðarp_tmr, ARP_TMR_INTERVAL * 1000);
tickFast.attach_us(&tcp_fasttmr, TCP_FAST_INTERVAL * 1000);
tickSlow.attach_us(&tcp_slowtmr, TCP_SLOW_INTERVAL * 1000);
dns_tick.attach_us(&dns_tmr, DNS_TMR_INTERVAL * 1000);
dhcp_coarse.attach_us(&dhcp_coarse_tmr, DHCP_COARSE_TIMER_MSECS * 1000);
dhcp_fine.attach_us(&dhcp_fine_tmr, DHCP_FINE_TIMER_MSECS * 1000);
// Wait for an IP Address
while (!netif_is_up(netif)) {
device_poll();
}
/* Connect do google */
struct tcp_pcb *pcb = tcp_new();
tcp_connect(pcb, &target, 80, &connected_callback);
/* Give the signal that we are ready */
printf("entering while loop\n");
while (1) {
led = !led;
wait(0.1);
device_poll();
}
}
|
| Source Code of purehttpc.bin (LPC1768 LPC2368) |