I have spring-boot server that I am running in AWS. The server works fine. I can access it using chrome, postman, and curl with no issues. However, I have an embedded device that is running C and I am using sockets to try to connect to my server. The embedded device is running Linux so I can use curl to talk to the server with no issues. However, my C sockets code cannot seem to find the resource on the server. I keep getting 404's.
Here is my embedded client code,
#include <stdarg.h>
#include <stdio.h>
#include <errno.h>
#include <string.h>
#include <sys/socket.h>
#include <resolv.h>
#include <errno.h>
int main() {
// Define some parameters
int sockfd, bytes_read;
struct sockaddr_in dest;
char buffer[4000];
char hdr[1000];
// Create Server Client Strings
bzero(hdr, sizeof(hdr));
strcpy(hdr, "GET /hello HTTP/1.1\r\n");
strcat(hdr, "Host: 52.200.39.81\r\n\r\n");
// Clean things up a bit before sarting
printf("\n\n");
// Create Socket
if ( (sockfd = socket(AF_INET, SOCK_STREAM, 0)) < 0 ) {
printf("Socket not created\n");
return 0;
}
// Initialize server address/port struct
bzero(&dest, sizeof(dest));
// *** Added this line to fix the code ***
dest.sin_addr.s_addr = inet_addr("52.200.39.81", &dest.sin_addr.s_addr);
dest.sin_family = AF_INET;
dest.sin_port = htons(8080);
if ( inet_addr("52.200.39.81", &dest.sin_addr.s_addr) == 0 ) {
printf("Incorrect Address Expression\n");
return 0;
}
// Connect Socket
if ( connect(sockfd, (struct sockaddr*)&dest, sizeof(dest)) != 0 ) {
printf("Socket Connection Failed\n");
close(sockfd);
return 0;
}
// Send data
if (send(sockfd, hdr, strlen(hdr), 0) < 0) {
printf("Send Data Failed\n");
return 0;
}
printf("Socket successfully sent\n");
printf("\nSend Message - TxBufferSize = %d\n\n",strlen(hdr));
printf("%s", hdr);
bzero(buffer, sizeof(buffer));
bytes_read = recv(sockfd, buffer, sizeof(buffer), 0);
if (bytes_read < 0) {
printf("Read Data Failed\n");
}
if (bytes_read > 0) {
// Print out receive buffer
printf("\n\nReceived Message -- RxSize = %d \n\n", strlen(buffer));
printf("%s", buffer);
}
if (bytes_read == 0) {
printf("No Read Bytes Received\n");
}
/*---Clean up---*/
close(sockfd);
return 0;
}
Here is what I get back,
debian@beaglebone:~$ ./helloworld
Socket successfully sent
***** Send Message -- TxBufferSize = 80 *****
GET http://52.200.39.81:8080/hello HTTP/1.1
Host: 52.200.39.81
accept: */*
***** Received Message -- RxBufferSize = 467 *****
HTTP/1.1 404 Not Found
Date: Sat, 02 Apr 2016 17:36:37 GMT
Server: Apache/2.2.22 (Debian)
Vary: Accept-Encoding
Content-Length: 283
Content-Type: text/html; charset=iso-8859-1
<!DOCTYPE HTML PUBLIC "-//IETF//DTD HTML 2.0//EN">
<html><head>
<title>404 Not Found</title>
</head><body>
<h1>Not Found</h1>
<p>The requested URL /hello was not found on this server.</p>
<hr>
<address>Apache/2.2.22 (Debian) Server at 52.200.39.81 Port 8080</address>
</body></html>
debian@beaglebone:~$
If I use the curl command on the embedded device,
debian@beaglebone:~$ curl 52.200.39.81:8080/hello
Greetings WebServiceTest1 -- ServiceCount = 11
debian@beaglebone:~$
I get the correct response from the server. So I am confident that the embedded device is talking to my server. Just can't seem to get the sockets code to work. Any help would be appreciated.
Ok, I found out what the problem was. I did not set the socket address. A very simple omission but that what the problem was. I have updated the code and it is now working. I added gethostbyname to make the code more standardized. The new lines of code are in the comment section "// Initialize server address/port struct". I would like to thank Lilas for providing me the reference code that led me to the omission of the dest.sin_addr.s_addr line. Below is the corrected code.
#include <stdarg.h>
#include <stdio.h>
#include <string.h>
#include <sys/socket.h>
#include <resolv.h>
#include <netdb.h>
int main() {
// Define some parameters
int sockfd, bytes_read;
struct sockaddr_in dest;
char *hostname = "skmdev1.net";
struct hostent *hostent;
char buffer[4000];
char hdr[1000];
// Create Server Client Strings
bzero(hdr, sizeof(hdr));
strcpy(hdr, "GET /hello HTTP/1.1\r\n");
strcat(hdr, "Host: skmdev1.net\r\n\r\n");
// Clean things up a bit before sarting
printf("\n\n");
// Build the address
hostent = gethostbyname(hostname);
if (hostent == NULL) {
printf("error: gethostbyname(\"%s\")\n", hostname);
return 0;
}
// Create Socket
if ( (sockfd = socket(AF_INET, SOCK_STREAM, 0)) < 0 ) {
printf("Socket not created\n");
return 0;
}
// Initialize server address/port struct
bzero(&dest, sizeof(dest));
dest.sin_family = AF_INET;
dest.sin_port = htons(8080);
dest.sin_addr.s_addr = inet_addr(inet_ntoa(*(struct in_addr*)hostent->h_addr));
if ( dest.sin_addr.s_addr == INADDR_NONE ) {
printf("Incorrect Address Expression\n");
return 0;
}
// Connect Socket
if ( connect(sockfd, (struct sockaddr*)&dest, sizeof(dest)) != 0 ) {
printf("Socket Connection Failed\n");
close(sockfd);
return 0;
}
// Send data
if (send(sockfd, hdr, strlen(hdr), 0) < 0) {
printf("Send Data Failed\n");
return 0;
}
printf("Socket successfully sent\n");
printf("\nSend Message - TxBufferSize = %d\n\n",strlen(hdr));
printf("%s", hdr);
bzero(buffer, sizeof(buffer));
bytes_read = recv(sockfd, buffer, sizeof(buffer), 0);
if (bytes_read < 0) {
printf("Read Data Failed\n");
}
if (bytes_read > 0) {
// Print out receive buffer
printf("\n\nReceived Message -- RxSize = %d \n\n", strlen(buffer));
printf("%s\n\n", buffer);
}
if (bytes_read == 0) {
printf("No Read Bytes Received\n");
}
/*---Clean up---*/
close(sockfd);
return 0;
}