From mboxrd@z Thu Jan  1 00:00:00 1970
X-Spam-Checker-Version: SpamAssassin 3.4.4 (2020-01-24) on polar.synack.me
X-Spam-Level: 
X-Spam-Status: No, score=0.1 required=5.0 tests=BAYES_00,FREEMAIL_FROM,
	PDS_OTHER_BAD_TLD autolearn=no autolearn_force=no version=3.4.4
X-Google-Thread: a07f3367d7,8a39a73d0242ca42,start
X-Google-Attributes: gida07f3367d7,public,usenet
X-Google-NewGroupId: yes
X-Google-Language: ENGLISH,ASCII-7-bit
Path: 
 g2news2.google.com!postnews.google.com!25g2000yqb.googlegroups.com!not-for-mail
From: "Jacob M. H. Smith" <jacob.m.h.smith@googlemail.com>
Newsgroups: comp.lang.ada
Subject: GNAT.Sockets. Blocking?
Date: Tue, 23 Jun 2009 14:06:35 -0700 (PDT)
Organization: http://groups.google.com
Message-ID: <158756da-21b7-4e2d-b288-7ba030f1f35c@25g2000yqb.googlegroups.com>
NNTP-Posting-Host: 141.31.188.43
Mime-Version: 1.0
Content-Type: text/plain; charset=ISO-8859-1
Content-Transfer-Encoding: 7bit
X-Trace: posting.google.com 1245791197 9381 127.0.0.1 (23 Jun 2009 21:06:37
 GMT)
X-Complaints-To: groups-abuse@google.com
NNTP-Posting-Date: Tue, 23 Jun 2009 21:06:37 +0000 (UTC)
Complaints-To: groups-abuse@google.com
Injection-Info: 25g2000yqb.googlegroups.com; posting-host=141.31.188.43;
	posting-account=lGLE9AkAAABZOvwB3iPLYCKw3E6P3RUe
User-Agent: G2/1.0
X-HTTP-UserAgent: Mozilla/5.0 (Macintosh; U; Intel Mac OS X 10_5_7; en-us)
	AppleWebKit/530.18 (KHTML,
 like Gecko) Version/4.0.1 Safari/530.18,gzip(gfe),gzip(gfe)
Xref: g2news2.google.com comp.lang.ada:6580
Date: 2009-06-23T14:06:35-07:00
List-Id: <comp.lang.ada>

Hi,

I'm kind of new to socket programming and I need some help here. I
wrote a simple little program that just fetches Google's index page.
The posted code works, but only because I used a "Connection: close"
header in the HTTP request. How would set up my code responsible for
reading the data from the stream so that I can read the page while
keeping the connection open? If I remove the header the program seems
to stop when calling the Ada.Streams.Read function if there is less
than BUFFER_SIZE data in the streams buffer. Can't I just read as much
as is available?

Thanks in advance.

Here's the code:

-------------------

with Ada.Text_IO;
with Ada.Streams;
with GNAT.Sockets;

procedure Socket_Test is

  procedure Connect (
      Socket  : out GNAT.Sockets.Socket_Type;
      Channel : out GNAT.Sockets.Stream_Access;
      Host    : in  String;
      Port    : in  GNAT.Sockets.Port_Type) is
    HOST_ENTRY : constant GNAT.Sockets.Host_Entry_Type :=
        GNAT.Sockets.Get_Host_By_Name (Host);
    Address : GNAT.Sockets.Sock_Addr_Type;
  begin
    --  Prepare the address structure. TODO: make a loop
    Address.Addr := GNAT.Sockets.Addresses (HOST_ENTRY, 1);
    Address.Port := Port;
    --  Set up the connection.
    GNAT.Sockets.Create_Socket (Socket);
    GNAT.Sockets.Connect_Socket (Socket, Address);
    Channel := GNAT.Sockets.Stream (Socket);
    --  TODO: error handling.
  end Connect;

  use type Ada.Streams.Stream_Element_Count;

  BUFFER_SIZE : constant Ada.Streams.Stream_Element_Count := 256;
  HTTP_PORT   : constant GNAT.Sockets.Port_Type := 80;
  CRLF        : constant String := (ASCII.CR, ASCII.LF);
  HOST        : constant String := "www.google.com";

  Socket     : GNAT.Sockets.Socket_Type;
  Channel    : GNAT.Sockets.Stream_Access;
  Byte_Count : Ada.Streams.Stream_Element_Count;
  Buffer     : Ada.Streams.Stream_Element_Array (1 .. BUFFER_SIZE);

begin

  --  Initialize.
  GNAT.Sockets.Initialize;

  --  Connect.
  Connect (Socket, Channel, "www.google.com", HTTP_PORT);

  --  Send HTTP request.
  String'Write (Channel,
      "GET / HTTP/1.1" & CRLF &
      "Host: " & HOST & CRLF &
      "Connection: close" & CRLF &
      CRLF);

  --  Read incoming data.
  loop
    Ada.Streams.Read (Channel.all, Buffer, Byte_Count);
    exit when Byte_Count = 0;
    for I in 1 .. Byte_Count loop
      Ada.Text_IO.Put (Character'Val (Buffer (I)));
    end loop;
  end loop;

end Socket_Test;