Advanced Services - SMS Connectivity CPP on Linux Sample application using HTTP to send an EMS message

The following sample application written in CPP on Linux sends an EMS message to a single mobile telephone. The application uses HTTP to communicate with HSL's systems. To send to more than one mobile telephone at a time, separate each mobile number in the destaddr field by a comma (e.g. "447968000111,447720000111,3378100100").

#include <cstring>

#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <netdb.h>
#include <errno.h>

#include <openssl/evp.h>

int main(int argc, char* argv[]) {
    const char* host = "194.247.82.149";
    const int port = 80;
    const char* action = "submitsm";
    const char* client_id = "<your client_id>";
    const char* destaddr = "<some fully-qualified MSISDN>";
    const char* shortmessage = "7C0C7A00424547494E3A494D454C4F44590D0A564552" \
        "53494F4E3A312E320D0A464F524D41543A434C415353312E300D0A4D454C4F44593A" \
        "64332363336433236333643372326433236333643365332366336533236633673361" \
        "33236733613323673361337232613323673361330D0A454E443A494D454C4F44590D0A";
    const char* secret = "<your secret>";

    // Digest variables
    EVP_MD_CTX md_context;
    const EVP_MD* md = EVP_md5();
    unsigned int md_length;
    unsigned char md_value[EVP_MAX_MD_SIZE];

    // Initialise the digest
    EVP_DigestInit(&md_context, md);

    // Feed data into the digest
    EVP_DigestUpdate(&md_context, secret, strlen(secret));
    EVP_DigestUpdate(&md_context, shortmessage, strlen(shortmessage));
    EVP_DigestUpdate(&md_context, destaddr, strlen(destaddr));

    // Get the digest and it's length
    EVP_DigestFinal(&md_context, md_value, &md_length);

    // Convert the digest's raw bytes into a string
    char lut[] = { '0', '1', '2', '3', '4', '5', '6', '7',
                   '8', '9', 'a', 'b', 'c', 'd', 'e', 'f' };
    char* hash = new char[md_length * 2 + 1];
    for(int i = 0; i < md_length; i++) {
        hash[2 * i] = lut[(md_value[i] & 0xF0) >> 4];
        hash[2 * i + 1] = lut[md_value[i] & 0x0F];
    }
    hash[md_length * 2] = '\0';

    // Create the URL
    const char* pattern = "GET /%s/?client_id=%s&destaddr=%s&esm=64" \
        "&shortmessage=%s&key=%s HTTP/1.0\r\n\r\n";
    int buffer_size = strlen(action) + strlen(client_id) + strlen(destaddr)
                      + strlen(shortmessage) + strlen(hash) + 64;
    char* buffer = new char[buffer_size];
    sprintf(buffer,
            pattern,
            action,
            client_id,
            destaddr,
            shortmessage,
            hash);

    // Clean up
    delete[] hash;

    // Create the socket
    int the_socket = socket(AF_INET, SOCK_STREAM, 0);

    // Set up the address
    struct sockaddr_in address;
    address.sin_family = AF_INET;
    address.sin_port = htons(port);
    inet_pton(AF_INET, host, &address.sin_addr);

     // Connect
    connect(the_socket, (struct sockaddr *)&address, sizeof(address));

    // Variables used for IO
    int bytes_to_io = strlen(buffer);
    int total_bytes_iod = 0;
    int bytes_iod = 0;

    // Send the request
    while(total_bytes_iod < bytes_to_io
          && (bytes_iod = send(the_socket,
                               buffer + total_bytes_iod,
                               bytes_to_io - total_bytes_iod,
                               0)) != -1)
    {
        total_bytes_iod += bytes_iod;
    }

    // Read the response
    buffer_size = 4096;
    buffer = new char[buffer_size];
    bytes_to_io = buffer_size;
    total_bytes_iod = 0;
    while(total_bytes_iod < buffer_size
          && (bytes_iod = recv(the_socket,
                               buffer + total_bytes_iod,
                               buffer_size - total_bytes_iod,
                               0)))
    {
        total_bytes_iod += bytes_iod;
    }

    buffer[total_bytes_iod] = '\0';

    // Inform the user of the outcome
    fprintf(stdout, "HTTP response:\n%s\n", buffer);

    delete[] buffer;

    return EXIT_SUCCESS;
}

ems_http.cpp

Copyright © Hay Systems Ltd 2004

Owner: support@haysystems.com 20 September 2004

Sample code link | Developers section link