CODEWITHSUNDEEP
csocketshttp
Mike L
Mike L

Reputation: 2035

building simple http client in c

sprintf(send_data,"GET / HTTP/1.1\r\nHost: %s\r\n\r\n",hoststr);
printf("%s",send_data);
send(sock,send_data,strlen(send_data), 0);
while(bytes_recieved)
  {
    bytes_recieved=recv(sock,recv_data,1024,0);
    printf("%d\n",bytes_recieved);
    if(bytes_recieved==0){ break; }
    recv_data[bytes_recieved] = '\0';
    printf("%s" , recv_data);
  }

When I request for example "www.example.com", I get the whole page and then at the end after two or three seconds I get bytes_received printed ('0') and then the loop breaks.

Why it takes 2-3 seconds to break the loop?

Is there a better way to implement simple http client then this?

Thanks.

Upvotes: 2

Views: 5150

Answers (2)

Elliott Frisch
Elliott Frisch

Reputation: 201527

As an optimization for the HTTP protocol, version 1.1 adds default persistent connections (aka Connection: Keep-Alive). The keep-alive holds the connection open so that you can send additional requests over the "reliable" channel; you can find additional information about that portion of the HTTP protocol in RFC2616 Section 8.1 - Persistent Connections.

Upvotes: 1

Some programmer dude
Some programmer dude

Reputation: 409442

When recv returns 0 it means that the other end of the connection has nicely closed the connection.

HTTP is, from the beginning, a pure request-response protocol, where each request got a response followed by a closed connection.

What you're seeing here is that first you receive the requested page, then after a timeout (due to the newer versions of the HTTP protocol (that you say you support) keeps the connection open) a closed connection from the server.

Upvotes: 1

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