File: Netplex_internal.html

package info (click to toggle)
ocamlnet 4.1.9-7
links: PTS, VCS
area: main
in suites: forky, sid
size: 54,024 kB
sloc: ml: 151,939; ansic: 11,071; sh: 2,003; makefile: 1,310
file content (425 lines) | stat: -rw-r--r-- 24,910 bytes
parent folder | download | duplicates (4)
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<link rel="stylesheet" href="style.css" type="text/css">
<meta content="text/html; charset=iso-8859-1" http-equiv="Content-Type">
<meta name="viewport" content="width=device-width, initial-scale=1">
<link rel="Start" href="index.html">
<link rel="previous" href="Netplex_mbox.html">
<link rel="next" href="Netplex_intro.html">
<link rel="Up" href="index.html">
<link title="Index of types" rel=Appendix href="index_types.html">
<link title="Index of extensions" rel=Appendix href="index_extensions.html">
<link title="Index of exceptions" rel=Appendix href="index_exceptions.html">
<link title="Index of values" rel=Appendix href="index_values.html">
<link title="Index of class attributes" rel=Appendix href="index_attributes.html">
<link title="Index of class methods" rel=Appendix href="index_methods.html">
<link title="Index of classes" rel=Appendix href="index_classes.html">
<link title="Index of class types" rel=Appendix href="index_class_types.html">
<link title="Index of modules" rel=Appendix href="index_modules.html">
<link title="Index of module types" rel=Appendix href="index_module_types.html">
<link title="Uq_gtk" rel="Chapter" href="Uq_gtk.html">
<link title="Uq_tcl" rel="Chapter" href="Uq_tcl.html">
<link title="Equeue" rel="Chapter" href="Equeue.html">
<link title="Unixqueue" rel="Chapter" href="Unixqueue.html">
<link title="Unixqueue_pollset" rel="Chapter" href="Unixqueue_pollset.html">
<link title="Unixqueue_select" rel="Chapter" href="Unixqueue_select.html">
<link title="Uq_resolver" rel="Chapter" href="Uq_resolver.html">
<link title="Uq_engines" rel="Chapter" href="Uq_engines.html">
<link title="Uq_multiplex" rel="Chapter" href="Uq_multiplex.html">
<link title="Uq_transfer" rel="Chapter" href="Uq_transfer.html">
<link title="Uq_socks5" rel="Chapter" href="Uq_socks5.html">
<link title="Uq_io" rel="Chapter" href="Uq_io.html">
<link title="Uq_lwt" rel="Chapter" href="Uq_lwt.html">
<link title="Uq_libevent" rel="Chapter" href="Uq_libevent.html">
<link title="Uq_mt" rel="Chapter" href="Uq_mt.html">
<link title="Uq_client" rel="Chapter" href="Uq_client.html">
<link title="Uq_server" rel="Chapter" href="Uq_server.html">
<link title="Uq_datagram" rel="Chapter" href="Uq_datagram.html">
<link title="Uq_engines_compat" rel="Chapter" href="Uq_engines_compat.html">
<link title="Equeue_intro" rel="Chapter" href="Equeue_intro.html">
<link title="Equeue_howto" rel="Chapter" href="Equeue_howto.html">
<link title="Netcamlbox" rel="Chapter" href="Netcamlbox.html">
<link title="Netcgi_apache" rel="Chapter" href="Netcgi_apache.html">
<link title="Netcgi_modtpl" rel="Chapter" href="Netcgi_modtpl.html">
<link title="Netcgi_plex" rel="Chapter" href="Netcgi_plex.html">
<link title="Netcgi_common" rel="Chapter" href="Netcgi_common.html">
<link title="Netcgi" rel="Chapter" href="Netcgi.html">
<link title="Netcgi_ajp" rel="Chapter" href="Netcgi_ajp.html">
<link title="Netcgi_scgi" rel="Chapter" href="Netcgi_scgi.html">
<link title="Netcgi_cgi" rel="Chapter" href="Netcgi_cgi.html">
<link title="Netcgi_fcgi" rel="Chapter" href="Netcgi_fcgi.html">
<link title="Netcgi_dbi" rel="Chapter" href="Netcgi_dbi.html">
<link title="Netcgi1_compat" rel="Chapter" href="Netcgi1_compat.html">
<link title="Netcgi_test" rel="Chapter" href="Netcgi_test.html">
<link title="Netcgi_porting" rel="Chapter" href="Netcgi_porting.html">
<link title="Nethttp_client_conncache" rel="Chapter" href="Nethttp_client_conncache.html">
<link title="Nethttp_client" rel="Chapter" href="Nethttp_client.html">
<link title="Nettelnet_client" rel="Chapter" href="Nettelnet_client.html">
<link title="Netftp_data_endpoint" rel="Chapter" href="Netftp_data_endpoint.html">
<link title="Netftp_client" rel="Chapter" href="Netftp_client.html">
<link title="Nethttp_fs" rel="Chapter" href="Nethttp_fs.html">
<link title="Netftp_fs" rel="Chapter" href="Netftp_fs.html">
<link title="Netsmtp" rel="Chapter" href="Netsmtp.html">
<link title="Netpop" rel="Chapter" href="Netpop.html">
<link title="Netldap" rel="Chapter" href="Netldap.html">
<link title="Netclient_tut" rel="Chapter" href="Netclient_tut.html">
<link title="Netgss_bindings" rel="Chapter" href="Netgss_bindings.html">
<link title="Netgss" rel="Chapter" href="Netgss.html">
<link title="Nethttpd_types" rel="Chapter" href="Nethttpd_types.html">
<link title="Nethttpd_kernel" rel="Chapter" href="Nethttpd_kernel.html">
<link title="Nethttpd_reactor" rel="Chapter" href="Nethttpd_reactor.html">
<link title="Nethttpd_engine" rel="Chapter" href="Nethttpd_engine.html">
<link title="Nethttpd_services" rel="Chapter" href="Nethttpd_services.html">
<link title="Nethttpd_plex" rel="Chapter" href="Nethttpd_plex.html">
<link title="Nethttpd_util" rel="Chapter" href="Nethttpd_util.html">
<link title="Nethttpd_intro" rel="Chapter" href="Nethttpd_intro.html">
<link title="Netmcore" rel="Chapter" href="Netmcore.html">
<link title="Netmcore_camlbox" rel="Chapter" href="Netmcore_camlbox.html">
<link title="Netmcore_mempool" rel="Chapter" href="Netmcore_mempool.html">
<link title="Netmcore_heap" rel="Chapter" href="Netmcore_heap.html">
<link title="Netmcore_ref" rel="Chapter" href="Netmcore_ref.html">
<link title="Netmcore_array" rel="Chapter" href="Netmcore_array.html">
<link title="Netmcore_sem" rel="Chapter" href="Netmcore_sem.html">
<link title="Netmcore_mutex" rel="Chapter" href="Netmcore_mutex.html">
<link title="Netmcore_condition" rel="Chapter" href="Netmcore_condition.html">
<link title="Netmcore_queue" rel="Chapter" href="Netmcore_queue.html">
<link title="Netmcore_buffer" rel="Chapter" href="Netmcore_buffer.html">
<link title="Netmcore_matrix" rel="Chapter" href="Netmcore_matrix.html">
<link title="Netmcore_hashtbl" rel="Chapter" href="Netmcore_hashtbl.html">
<link title="Netmcore_process" rel="Chapter" href="Netmcore_process.html">
<link title="Netmcore_tut" rel="Chapter" href="Netmcore_tut.html">
<link title="Netmcore_basics" rel="Chapter" href="Netmcore_basics.html">
<link title="Netplex_types" rel="Chapter" href="Netplex_types.html">
<link title="Netplex_mp" rel="Chapter" href="Netplex_mp.html">
<link title="Netplex_mt" rel="Chapter" href="Netplex_mt.html">
<link title="Netplex_log" rel="Chapter" href="Netplex_log.html">
<link title="Netplex_controller" rel="Chapter" href="Netplex_controller.html">
<link title="Netplex_container" rel="Chapter" href="Netplex_container.html">
<link title="Netplex_sockserv" rel="Chapter" href="Netplex_sockserv.html">
<link title="Netplex_workload" rel="Chapter" href="Netplex_workload.html">
<link title="Netplex_main" rel="Chapter" href="Netplex_main.html">
<link title="Netplex_config" rel="Chapter" href="Netplex_config.html">
<link title="Netplex_kit" rel="Chapter" href="Netplex_kit.html">
<link title="Rpc_netplex" rel="Chapter" href="Rpc_netplex.html">
<link title="Netplex_cenv" rel="Chapter" href="Netplex_cenv.html">
<link title="Netplex_semaphore" rel="Chapter" href="Netplex_semaphore.html">
<link title="Netplex_sharedvar" rel="Chapter" href="Netplex_sharedvar.html">
<link title="Netplex_mutex" rel="Chapter" href="Netplex_mutex.html">
<link title="Netplex_encap" rel="Chapter" href="Netplex_encap.html">
<link title="Netplex_mbox" rel="Chapter" href="Netplex_mbox.html">
<link title="Netplex_internal" rel="Chapter" href="Netplex_internal.html">
<link title="Netplex_intro" rel="Chapter" href="Netplex_intro.html">
<link title="Netplex_advanced" rel="Chapter" href="Netplex_advanced.html">
<link title="Netplex_admin" rel="Chapter" href="Netplex_admin.html">
<link title="Netshm" rel="Chapter" href="Netshm.html">
<link title="Netshm_data" rel="Chapter" href="Netshm_data.html">
<link title="Netshm_hashtbl" rel="Chapter" href="Netshm_hashtbl.html">
<link title="Netshm_array" rel="Chapter" href="Netshm_array.html">
<link title="Netshm_intro" rel="Chapter" href="Netshm_intro.html">
<link title="Netstring_pcre" rel="Chapter" href="Netstring_pcre.html">
<link title="Netconversion" rel="Chapter" href="Netconversion.html">
<link title="Netchannels" rel="Chapter" href="Netchannels.html">
<link title="Netstream" rel="Chapter" href="Netstream.html">
<link title="Netmime_string" rel="Chapter" href="Netmime_string.html">
<link title="Netmime" rel="Chapter" href="Netmime.html">
<link title="Netsendmail" rel="Chapter" href="Netsendmail.html">
<link title="Neturl" rel="Chapter" href="Neturl.html">
<link title="Netaddress" rel="Chapter" href="Netaddress.html">
<link title="Netbuffer" rel="Chapter" href="Netbuffer.html">
<link title="Netmime_header" rel="Chapter" href="Netmime_header.html">
<link title="Netmime_channels" rel="Chapter" href="Netmime_channels.html">
<link title="Neturl_ldap" rel="Chapter" href="Neturl_ldap.html">
<link title="Netdate" rel="Chapter" href="Netdate.html">
<link title="Netencoding" rel="Chapter" href="Netencoding.html">
<link title="Netulex" rel="Chapter" href="Netulex.html">
<link title="Netaccel" rel="Chapter" href="Netaccel.html">
<link title="Netaccel_link" rel="Chapter" href="Netaccel_link.html">
<link title="Nethtml" rel="Chapter" href="Nethtml.html">
<link title="Netstring_str" rel="Chapter" href="Netstring_str.html">
<link title="Netmappings" rel="Chapter" href="Netmappings.html">
<link title="Netaux" rel="Chapter" href="Netaux.html">
<link title="Nethttp" rel="Chapter" href="Nethttp.html">
<link title="Netpagebuffer" rel="Chapter" href="Netpagebuffer.html">
<link title="Netfs" rel="Chapter" href="Netfs.html">
<link title="Netglob" rel="Chapter" href="Netglob.html">
<link title="Netauth" rel="Chapter" href="Netauth.html">
<link title="Netsockaddr" rel="Chapter" href="Netsockaddr.html">
<link title="Netnumber" rel="Chapter" href="Netnumber.html">
<link title="Netxdr_mstring" rel="Chapter" href="Netxdr_mstring.html">
<link title="Netxdr" rel="Chapter" href="Netxdr.html">
<link title="Netcompression" rel="Chapter" href="Netcompression.html">
<link title="Netunichar" rel="Chapter" href="Netunichar.html">
<link title="Netasn1" rel="Chapter" href="Netasn1.html">
<link title="Netasn1_encode" rel="Chapter" href="Netasn1_encode.html">
<link title="Netoid" rel="Chapter" href="Netoid.html">
<link title="Netstring_tstring" rel="Chapter" href="Netstring_tstring.html">
<link title="Netdn" rel="Chapter" href="Netdn.html">
<link title="Netx509" rel="Chapter" href="Netx509.html">
<link title="Netascii_armor" rel="Chapter" href="Netascii_armor.html">
<link title="Nettls_support" rel="Chapter" href="Nettls_support.html">
<link title="Netmech_scram" rel="Chapter" href="Netmech_scram.html">
<link title="Netmech_scram_gssapi" rel="Chapter" href="Netmech_scram_gssapi.html">
<link title="Netmech_scram_sasl" rel="Chapter" href="Netmech_scram_sasl.html">
<link title="Netmech_scram_http" rel="Chapter" href="Netmech_scram_http.html">
<link title="Netgssapi_support" rel="Chapter" href="Netgssapi_support.html">
<link title="Netgssapi_auth" rel="Chapter" href="Netgssapi_auth.html">
<link title="Netchannels_crypto" rel="Chapter" href="Netchannels_crypto.html">
<link title="Netx509_pubkey" rel="Chapter" href="Netx509_pubkey.html">
<link title="Netx509_pubkey_crypto" rel="Chapter" href="Netx509_pubkey_crypto.html">
<link title="Netsaslprep" rel="Chapter" href="Netsaslprep.html">
<link title="Netmech_plain_sasl" rel="Chapter" href="Netmech_plain_sasl.html">
<link title="Netmech_crammd5_sasl" rel="Chapter" href="Netmech_crammd5_sasl.html">
<link title="Netmech_digest_sasl" rel="Chapter" href="Netmech_digest_sasl.html">
<link title="Netmech_digest_http" rel="Chapter" href="Netmech_digest_http.html">
<link title="Netmech_krb5_sasl" rel="Chapter" href="Netmech_krb5_sasl.html">
<link title="Netmech_gs2_sasl" rel="Chapter" href="Netmech_gs2_sasl.html">
<link title="Netmech_spnego_http" rel="Chapter" href="Netmech_spnego_http.html">
<link title="Netchannels_tut" rel="Chapter" href="Netchannels_tut.html">
<link title="Netmime_tut" rel="Chapter" href="Netmime_tut.html">
<link title="Netsendmail_tut" rel="Chapter" href="Netsendmail_tut.html">
<link title="Netulex_tut" rel="Chapter" href="Netulex_tut.html">
<link title="Neturl_tut" rel="Chapter" href="Neturl_tut.html">
<link title="Netsys" rel="Chapter" href="Netsys.html">
<link title="Netsys_posix" rel="Chapter" href="Netsys_posix.html">
<link title="Netsys_pollset" rel="Chapter" href="Netsys_pollset.html">
<link title="Netlog" rel="Chapter" href="Netlog.html">
<link title="Netexn" rel="Chapter" href="Netexn.html">
<link title="Netsys_win32" rel="Chapter" href="Netsys_win32.html">
<link title="Netsys_pollset_posix" rel="Chapter" href="Netsys_pollset_posix.html">
<link title="Netsys_pollset_win32" rel="Chapter" href="Netsys_pollset_win32.html">
<link title="Netsys_pollset_generic" rel="Chapter" href="Netsys_pollset_generic.html">
<link title="Netsys_signal" rel="Chapter" href="Netsys_signal.html">
<link title="Netsys_oothr" rel="Chapter" href="Netsys_oothr.html">
<link title="Netsys_xdr" rel="Chapter" href="Netsys_xdr.html">
<link title="Netsys_rng" rel="Chapter" href="Netsys_rng.html">
<link title="Netsys_crypto_types" rel="Chapter" href="Netsys_crypto_types.html">
<link title="Netsys_types" rel="Chapter" href="Netsys_types.html">
<link title="Netsys_mem" rel="Chapter" href="Netsys_mem.html">
<link title="Netsys_tmp" rel="Chapter" href="Netsys_tmp.html">
<link title="Netsys_sem" rel="Chapter" href="Netsys_sem.html">
<link title="Netsys_pmanage" rel="Chapter" href="Netsys_pmanage.html">
<link title="Netsys_crypto" rel="Chapter" href="Netsys_crypto.html">
<link title="Netsys_tls" rel="Chapter" href="Netsys_tls.html">
<link title="Netsys_ciphers" rel="Chapter" href="Netsys_ciphers.html">
<link title="Netsys_digests" rel="Chapter" href="Netsys_digests.html">
<link title="Netsys_crypto_modes" rel="Chapter" href="Netsys_crypto_modes.html">
<link title="Netsys_gssapi" rel="Chapter" href="Netsys_gssapi.html">
<link title="Netsys_sasl_types" rel="Chapter" href="Netsys_sasl_types.html">
<link title="Netsys_sasl" rel="Chapter" href="Netsys_sasl.html">
<link title="Netsys_polypipe" rel="Chapter" href="Netsys_polypipe.html">
<link title="Netsys_polysocket" rel="Chapter" href="Netsys_polysocket.html">
<link title="Netsys_global" rel="Chapter" href="Netsys_global.html">
<link title="Nettls_gnutls_bindings" rel="Chapter" href="Nettls_gnutls_bindings.html">
<link title="Nettls_nettle_bindings" rel="Chapter" href="Nettls_nettle_bindings.html">
<link title="Nettls_gnutls" rel="Chapter" href="Nettls_gnutls.html">
<link title="Netunidata" rel="Chapter" href="Netunidata.html">
<link title="Netgzip" rel="Chapter" href="Netgzip.html">
<link title="Rpc_auth_local" rel="Chapter" href="Rpc_auth_local.html">
<link title="Rpc_xti_client" rel="Chapter" href="Rpc_xti_client.html">
<link title="Rpc" rel="Chapter" href="Rpc.html">
<link title="Rpc_program" rel="Chapter" href="Rpc_program.html">
<link title="Rpc_util" rel="Chapter" href="Rpc_util.html">
<link title="Rpc_portmapper_aux" rel="Chapter" href="Rpc_portmapper_aux.html">
<link title="Rpc_packer" rel="Chapter" href="Rpc_packer.html">
<link title="Rpc_transport" rel="Chapter" href="Rpc_transport.html">
<link title="Rpc_client" rel="Chapter" href="Rpc_client.html">
<link title="Rpc_simple_client" rel="Chapter" href="Rpc_simple_client.html">
<link title="Rpc_portmapper_clnt" rel="Chapter" href="Rpc_portmapper_clnt.html">
<link title="Rpc_portmapper" rel="Chapter" href="Rpc_portmapper.html">
<link title="Rpc_server" rel="Chapter" href="Rpc_server.html">
<link title="Rpc_auth_sys" rel="Chapter" href="Rpc_auth_sys.html">
<link title="Rpc_auth_gssapi" rel="Chapter" href="Rpc_auth_gssapi.html">
<link title="Rpc_proxy" rel="Chapter" href="Rpc_proxy.html">
<link title="Rpc_intro" rel="Chapter" href="Rpc_intro.html">
<link title="Rpc_mapping_ref" rel="Chapter" href="Rpc_mapping_ref.html">
<link title="Rpc_intro_gss" rel="Chapter" href="Rpc_intro_gss.html">
<link title="Shell_sys" rel="Chapter" href="Shell_sys.html">
<link title="Shell" rel="Chapter" href="Shell.html">
<link title="Shell_uq" rel="Chapter" href="Shell_uq.html">
<link title="Shell_fs" rel="Chapter" href="Shell_fs.html">
<link title="Shell_intro" rel="Chapter" href="Shell_intro.html">
<link title="Intro" rel="Chapter" href="Intro.html">
<link title="Platform" rel="Chapter" href="Platform.html">
<link title="Foreword" rel="Chapter" href="Foreword.html">
<link title="Ipv6" rel="Chapter" href="Ipv6.html">
<link title="Regexp" rel="Chapter" href="Regexp.html">
<link title="Tls" rel="Chapter" href="Tls.html">
<link title="Crypto" rel="Chapter" href="Crypto.html">
<link title="Authentication" rel="Chapter" href="Authentication.html">
<link title="Credentials" rel="Chapter" href="Credentials.html">
<link title="Gssapi" rel="Chapter" href="Gssapi.html">
<link title="Ocamlnet4" rel="Chapter" href="Ocamlnet4.html">
<link title="Get" rel="Chapter" href="Get.html"><link title="How to configure and use internal services" rel="Section" href="#intro">
<link title="Using internal services via RPC" rel="Section" href="#2_UsinginternalservicesviaRPC">
<link title="Complete example" rel="Subsection" href="#3_Completeexample">
<title>Ocamlnet 4 Reference Manual : Netplex_internal</title>
</head>
<body>
<div class="navbar"><a class="pre" href="Netplex_mbox.html" title="Netplex_mbox">Previous</a>
&nbsp;<a class="up" href="index.html" title="Index">Up</a>
&nbsp;<a class="post" href="Netplex_intro.html" title="Netplex_intro">Next</a>
</div>
<h1>Module <a href="type_Netplex_internal.html">Netplex_internal</a></h1>

<pre><span id="MODULENetplex_internal"><span class="keyword">module</span> Netplex_internal</span>: <code class="code">sig</code> <a href="Netplex_internal.html">..</a> <code class="code">end</code></pre><div class="info module top">
<div class="info-desc">
<p>Internal services</p>
</div>
</div>
<hr width="100%">
<p>Internal services are available to multi-threaded programs only, and
    implemented via <a href="Netsys_polysocket.html"><code class="code">Netsys_polysocket</code></a>.</p>

<p>See below for an introduction.</p>

<pre><span id="VALregister_server"><span class="keyword">val</span> register_server</span> : <code class="type">string -> <a href="Netplex_types.html#TYPEpolyserver_box">Netplex_types.polyserver_box</a> -> unit</code></pre><div class="info ">
<div class="info-desc">
<p><code class="code">register_server name server</code>: registers a server under the given
      <code class="code">name</code>. It is an error if a server is already registered for the
      same name.</p>

<p>The registration is thread-safe.</p>
</div>
</div>

<pre><span id="VALconnect_client"><span class="keyword">val</span> connect_client</span> : <code class="type">'a <a href="Netplex_types.html#TYPEkind_check">Netplex_types.kind_check</a> -><br>       int -> string -> 'a <a href="Netsys_polysocket.html#TYPEpolyclient">Netsys_polysocket.polyclient</a></code></pre><div class="info ">
<div class="info-desc">
<p><code class="code">connect_client is_kind n name</code>: Creates a new polyclient that is
      connected to the registered service <code class="code">name</code>. The arg <code class="code">is_kind</code> determines 
      the type of the messages that can be exchanged. The number <code class="code">n</code> is the
      size of the pipe buffer, in number of messages.</p>

<p>The function fails if the service is not registered, or assumes the wrong
      message kind.</p>

<p>The client lookup is thread-safe.</p>

<p>Example how to invoke a service exchanging strings (kind <code class="code">Tstring</code>):</p>
<pre class="codepre"><code class="code">let same : type s t . s polysocket_kind * t polysocket_kind -&gt; (s,t) eq =
  function
  | Tstring, Tstring -&gt; Equal
  | _ -&gt; Not_equal

let client =
  Netplex_internal.connect_client
    { Netplex_types.kind_check = fun k -&gt; same(Tstring,k) }
    n
    "name"
      </code></pre>
<p>(You should strictly stick to this pattern. Any abbreviation will probably
      not type-check.)</p>
</div>
</div>
<h3 id="intro">How to configure and use internal services</h3>
<p>Internal services are a fast mechanism to invoke containers from other
containers. So far, internal services are only available for multi-threaded
programs. The messages can have any type.</p>

<p>You add an internal service by configuring an address "internal" in the
protocol section of the configuration file, e.g.</p>

<pre class="codepre"><code class="code">protocol {
  name = "my-protocol";
  address {
    type = "internal";
    name = "my-identifier";
  }
  address {                    (* other addresses ok *)
    ...
  }
}
</code></pre>
<p>The internal service is only activated when multi-threading is selected.
In programs using multi-processing the internal service is simply ignored.</p>

<p>You need to choose the types of your messages. There is the GADT
<a href="Netplex_types.html#TYPEpolysocket_kind"><code class="code">Netplex_types.polysocket_kind</code></a> listing possible types. It comes with
the variants <code class="code">Txdr</code> (for RPC messaging) and <code class="code">Tstring</code> (for any custom strings):</p>

<pre class="codepre"><code class="code">type _ polysocket_kind = ..
type _ polysocket_kind +=
   | Txdr : Netxdr.xdr_value polysocket_kind
   | Tstring : string polysocket_kind
</code></pre>
<p>This is an extensible GADT, i.e. you can add more variants with the "+="
notation. (Note that extensible variants are first available since
OCaml-4.02. With older OCaml versions, you cannot extend more variants.)</p>

<p>Let's add integers:</p>

<pre class="codepre"><code class="code">type _ polysocket_kind +=
  | Tint : int polysocket_kind
</code></pre>
<p>The connections to the internal services do not arrive via the normal
<code class="code">process</code> mechanism. There is a second path using the new processor
hooks <code class="code">config_internal</code> and <code class="code">process_internal</code>. The hook <code class="code">config_internal</code>
defines which message type you are really using. The hook <code class="code">process_internal</code>
is invoked when a new connection to the internal service is established.
It works very much like <code class="code">process</code>, only that it doesn't use file descriptors
but so-called polysockets (see <a href="Netsys_polysocket.html"><code class="code">Netsys_polysocket</code></a>).</p>

<pre class="codepre"><code class="code">class hello_world_processor hooks : processor =
object(self)
  inherit Netplex_kit.processor_base hooks

  method config_internal =
     [ "my-protocol", Polysocket_kind_box Tint ]

  method process_internal ~when_done container srvbox proto_name =
    let Polyserver_box(kind, srv) = srvbox in
    match kind with
      | Tint -&gt;
         let endpoint = Netsys_polysocket.accept ~nonblock:false srv in
         (* Now send and receive messages over endpoint *)
         ...;
         when_done()
      | _ -&gt;
         failwith "wrong kind"

  method process ~when_done container fd proto_name =
    (* this is still invoked when non-internal connections arrive *)
    ...
  method supported_ptypes = 
    ...
end
</code></pre>
<p>The <code class="code">endpoint</code> is actually a pair of polypipes (<a href="Netsys_polypipe.html"><code class="code">Netsys_polypipe</code></a>):</p>

<pre class="codepre"><code class="code">let (rd, wr) = endpoint
</code></pre>
<p>Over <code class="code">rd</code> you receive messages of type <code class="code">int</code> from the client, and via
<code class="code">wr</code> you can send messages to it.</p>

<p>Use <a href="Netplex_internal.html#VALconnect_client"><code class="code">Netplex_internal.connect_client</code></a> to get a client (usually in a
different container, or in an arbitrary other thread):</p>

<pre class="codepre"><code class="code">let same : type s t . s polysocket_kind * t polysocket_kind -&gt; (s,t) eq =
  function
  | Tint, Tint -&gt; Equal
  | _ -&gt; Not_equal

let client =
  Netplex_internal.connect_client
    { Netplex_types.kind_check = fun k -&gt; same(Tint,k) }
    5
    "my-identifier" in
let client_endpoint =
   Netsys_polysocket.endpoint ~synchronous:true ~nonblock:false client
</code></pre>
<p>Again, the endpoint is a pair of polypipes in reality:</p>

<pre class="codepre"><code class="code">let (client_rd, client_wr) = client_endpoint
</code></pre>
<h4 id="3_Completeexample">Complete example</h4>
<p>You find a complete example in the distribution tarball at
<code class="code">code/examples/netplex/internal_service.ml</code>.</p>

<h3 id="2_UsinginternalservicesviaRPC">Using internal services via RPC</h3>
<p>RPC clients and servers have now support for polysockets. Note that
you need to select <code class="code">Txdr</code> as message kind. The messages are not serialized
into strings, but instead the structured XDR format is used as transport
encoding.</p>

<p>XXX TODO</p>
</body></html>