Question

I have been writing a simple web server (http 1.0) for a class, but whenever I try to get a file (wget 127.0.0.1 /filename) is is short a few bytes. The confusing thing is when I sum the number of sent bytes it matches the file size, but not the amount wget receives.

Why is wget not getting all of the data I write to the socket?

some wget output

wget:

    --2012-10-27 19:02:00--  (try: 4)  http://127.0.0.1:5555/
    Connecting to 127.0.0.1:5555... connected.
    HTTP request sent, awaiting response... 200 Document follows
    Length: 5777 (5.6K) [text/html]
    Saving to: `index.html.6'

    99% [=====================================> ] 5,776       --.-K/s   in 0s      

    2012-10-27 19:02:00 (322 MB/s) - Read error at byte 5776/5777 (Connection reset by peer).  Retrying.


    --2012-10-27 19:03:52--  (try: 4)  http://127.0.0.1:5555/ZoEY8.jpg
    Connecting to 127.0.0.1:5555... connected.
    HTTP request sent, awaiting response... 200 Document follows
    Length: 163972 (160K) [image/jpeg]
    Saving to: `ZoEY8.jpg.4'

    91% [==================================>    ] 149,449     --.-K/s   in 0.001s  

    2012-10-27 19:03:52 (98.8 MB/s) - Read error at byte 163917/163972 (Connection reset by peer). Retrying.

Get method:

void *
processGetRequest(requestParser request)
{

  string resp= "HTTP/1.0 200 Document follows\r\nServer: lab5 \r\nContent-Length: ";
  string path="";
  path =request.path;

  //find file
  int page= open (path.c_str(),O_RDONLY);
  FILE * pageF= fdopen(page,"rb"); 


  //get size
  fseek(pageF, 0L, SEEK_END);
  int sz = ftell(pageF);
  fseek(pageF, 0L, SEEK_SET);

  //form content length
  stringstream ss;
  ss<<resp<<sz<<"\r\n";
  resp=ss.str(); 

  //make response
  if(page<0){
      cout<<"404 \n";
    resp = "HTTP/1.0 404 File Not Found\r\nServer: lab5 \r\nContent-type: text/html \r\n \r\n";

    write( request.fd, resp.c_str(), resp.length());

  return 0; 
  }
  if(path.find(".gif")!=string::npos)
   resp += "Content-type: image/gif\r\n \r\n";
  else if(path.find(".png")!=string::npos)
   resp += "Content-type: image/png\r\n \r\n";
  else if(path.find(".jpg")!=string::npos)
   resp += "Content-type: image/jpeg\r\n \r\n";
  else
   resp += "Content-type: text/html \r\n \r\n";

  //write response
  write( request.fd, resp.c_str(), resp.length());

  int total=0;      
  char buff[1024];
  int readBytes = 0;
  int er;

  //send file
  do{

  readBytes= read(page, buff, 1024);
  cout<<"read bytes "<<readBytes<<"\n";

  if(readBytes<0){
    perror("read");

    break;
  }
  total+=readBytes;
  er=  send( request.fd, buff, readBytes,0 );   
  cout<<"sent bytes "<<er<<"\n";
  if (er==-1){
    perror("send");
  }
  else if( er != readBytes){
    cout<<"Read write miss match\n";
  }

 }while(readBytes>0);

 close(page);
 return 0;
}

Edit:

I have been working at this while and I’m wondering if Im doing my sockets wrong

// Set the IP address and port for this server
struct sockaddr_in serverIPAddress; 
memset( &serverIPAddress, 0, sizeof(serverIPAddress) );
serverIPAddress.sin_family = AF_INET;
serverIPAddress.sin_addr.s_addr = INADDR_ANY;
serverIPAddress.sin_port = htons((u_short) port);

// Allocate a socket
int masterSocket =  socket(PF_INET, SOCK_STREAM, 0);
if ( masterSocket < 0) {
  perror("socket");
  exit( -1 );
}

while ( 1 ) {

// Accept incoming connections
struct sockaddr_in clientIPAddress;
int alen = sizeof( clientIPAddress );
int slaveSocket = accept( masterSocket,
              (struct sockaddr *)&clientIPAddress,
              (socklen_t*)&alen);
// send slaveSocket to get method 
}

Answer 1

My first answer is below, but i just noticed something..

"Content-type: text/html \r\n \r\n";

The headers must be separated from the content with two CR/LF. It looks like you have space in there

you can try this:

 "Content-type: text/html\r\n\r\n";

---

Is the output buffer being correctly flushed and closed after the last write? Try changing the size of your 1024 byte read buffer to something larger than your gif file. This isnt a fix, but you may get different results, and this may help track down the cause of the problem. Maybe also put some logging into the read write loop. See if the size of the last buffer write equals the number of bytes the response is missing.