Use REST service via a proxy server with socket(C)

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Contents 1 Summary 2 Description 3 Sample program 4 Link

Summary

Use REST service via a proxy server with socket (C)

Description

To use proxy with socket, specify REST service's URL after making socket connection to proxy server.

struct sockaddr_in server;

// set proxy server
char proxy_host[BUF_LEN] = "<proxy_server>";
unsigned short proxy_port = <proxy_port>;
char url[BUF_LEN] = "http://xml.nig.ac.jp/rest/Invoke";

// make socket and connection
servhost = gethostbyname(proxy_host);
bzero(&server, sizeof(server);
server.sin_family = AF_INET;
bcopy(servhost->h_addr, &server.sin_addr, servhost->h_length);
server.sin_port = htons(proxy_port);
s = socket(AF_INET, SOCK_STREAM, 0);
connect(s, (struct sockaddr *)&server, sizeof(server));

//send data
sprintf(send_buf, "POST %s HTTP/1.0\n", url);
write(s, send_buf, strlen(send_buf));

Sample program

This program executes getDDBJEntryof GetEntry via a proxy server with socket of C.

Download this program

#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netdb.h>
#include <netinet/in.h>
#include <sys/param.h>
#include <sys/uio.h>
#include <unistd.h>

#define BUF_LEN 256

int main(){
	int s;
	struct hostent *servhost;
	struct sockaddr_in server;
	struct servent *service;
	
	char send_buf[BUF_LEN];

	//set proxy server
	char proxy_host[BUF_LEN] = "<proxy_server>";
	unsigned short proxy_port = <proxy_port>;
	
	//set API server
	char url[BUF_LEN] = "http://xml.nig.ac.jp/rest/Invoke";
	char query[BUF_LEN] = "service=GetEntry&method=getDDBJEntry&accession=AB000200";
        
	//make socket
	servhost = gethostbyname(proxy_host);
	bzero(&server, sizeof(server)); 
	server.sin_family = AF_INET;
	bcopy(servhost->h_addr, &server.sin_addr, servhost->h_length);
	server.sin_port = htons(proxy_port);
	s = socket(AF_INET, SOCK_STREAM, 0);

	//make connection
	connect(s, (struct sockaddr *)&server, sizeof(server));

	//send data
	sprintf(send_buf, "POST %s HTTP/1.0\n", url);
	write(s, send_buf, strlen(send_buf));

	sprintf(send_buf, "Host: %s:%d\n", proxy_host, proxy_port);
	write(s, send_buf, strlen(send_buf));

	sprintf(send_buf, "Content-Type: application/x-www-form-urlencoded\n");
	write(s, send_buf, strlen(send_buf));

	sprintf(send_buf, "User-Agent: c/socket\n");
	write(s, send_buf,strlen(send_buf));

	sprintf(send_buf, "Content-Length: %d \n\n", strlen(query));
	write(s, send_buf, strlen(send_buf));

	sprintf(send_buf, "%s", query);
	write(s, send_buf, strlen(send_buf));

	//get your result
	while (1){
	    char buf[BUF_LEN];
	    int read_size;
	    read_size = read(s, buf, BUF_LEN);
	    if ( read_size > 0 ){
	        write(1, buf, read_size);
	    } else {
	        break;
	    }
	}
	close(s);
	return 0;
}

Link

Japanese page