Distributed programming: Difference between revisions
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{{task|Networking and Web Interaction}}
Write two programs (or one program with two modes) which run on networked computers, and send some messages between them.
The protocol used may be language-specific or not, and should be '''suitable for general distributed programming'''; that is, the ''protocol'' should be generic (not designed just for the particular example application), readily capable of handling the independent communications of many different components of a single application, and the transferring of arbitrary data structures natural for the language.
This task is intended to demonstrate high-level communication facilities beyond just creating [[sockets]].
=={{header|Ada}}==
{{works with|GNAT GPL|2010}}
{{works with|PolyORB}}
Ada defines facilities for distributed systems in its standard (Annex E, also called DSA).
This example works with PolyORB and the GNAT GPL 2010 compiler from AdaCore.
server.ads:
<syntaxhighlight lang="ada">package Server is
pragma Remote_Call_Interface;
procedure Foo;
function Bar return Natural;
end Server;</syntaxhighlight>
server.adb:
<syntaxhighlight lang="ada">package body Server is
Count : Natural := 0;
procedure Foo is
begin
Count := Count + 1;
end Foo;
function Bar return Natural is
begin
return Count;
end Bar;
end Server;</syntaxhighlight>
client.adb:
<syntaxhighlight lang="ada">with Server;
with Ada.Text_IO;
procedure Client is
begin
Ada.Text_IO.Put_Line ("Calling Foo...");
Server.Foo;
Ada.Text_IO.Put_Line ("Calling Bar: " & Integer'Image (Server.Bar));
end Client;</syntaxhighlight>
required config (dsa.cfg):
<syntaxhighlight lang="ada">configuration DSA is
pragma Starter (None);
-- Server
Server_Partition : Partition := (Server);
procedure Run_Server is in Server_Partition;
-- Client
Client_Partition : Partition;
for Client_Partition'Termination use Local_Termination;
procedure Client;
for Client_Partition'Main use Client;
end DSA;</syntaxhighlight>
compilation:
<pre>$po_gnatdist dsa.cfg
[...]
------------------------------
---- Configuration report ----
------------------------------
Configuration :
Name : dsa
Main : run_server
Starter : none
Partition server_partition
Main : run_server
Units :
- server (rci)
- run_server (normal)
- polyorb.dsa_p.partitions (rci, from PCS)
Environment variables :
- "POLYORB_DSA_NAME_SERVICE"
Partition client_partition
Main : client
Termination : local
Units :
- client (normal)
Environment variables :
- "POLYORB_DSA_NAME_SERVICE"
-------------------------------
[...]</pre>
preparation (run PolyORB name service):
<pre>$ po_ioc_naming
POLYORB_CORBA_NAME_SERVICE=IOR:010000002b00000049444[...]
POLYORB_CORBA_NAME_SERVICE=corbaloc:iiop:1.2@10.200.[...]</pre>
You have to set the environment variable POLYORB_DSA_NAME_SERVICE to one of the two values given by po_ioc_naming for the server/client partitions.
running server:
<pre>$ ./server_partition</pre>
running client:
<pre>$ ./client_partition
Calling Foo...
Calling Bar: 1
$ ./client_partition
Calling Foo...
Calling Bar: 2</pre>
=={{header|AutoHotkey}}==
See [[Distributed program/AutoHotkey]].
=={{header|
Using PVM [http://www.csm.ornl.gov/pvm/pvm_home.html]
This program is in a sense both a server and a client, depending on if its task is spawned with a command-line argument: if yes, it spawns another task of the same executible on the parallel virtual machine and waits for it to transmit data; if no, it transmits data and is done.
<syntaxhighlight lang="c">#include <stdio.h>
#include <stdlib.h>
#include <pvm3.h>
{
int tids[10];
int parent, spawn;
int i_data, i2;
double f_data;
if (c > 1) {
spawn = pvm_spawn("/tmp/a.out", 0, PvmTaskDefault, 0, 1, tids);
if (spawn <= 0) {
printf("Can't spawn task\n");
return 1;
}
printf("Spawning successful\n");
/* pvm_recv(task_id, msgtag). msgtag identifies what kind of data it is,
* for here: 1 = (int, double), 2 = (int, int)
* The receiving order is intentionally swapped, just to show.
* task_id = -1 means "receive from any task"
*/
pvm_recv(-1, 2);
pvm_unpackf("%d %d", &i_data, &i2);
printf("got msg type 2: %d %d\n", i_data, i2);
pvm_recv(-1, 1);
pvm_unpackf("%d %lf", &i_data, &f_data);
printf("got msg type 1: %d %f\n", i_data, f_data);
} else {
parent = pvm_parent();
pvm_initsend(PvmDataDefault);
i_data = rand();
f_data = (double)rand() / RAND_MAX;
pvm_packf("%d %lf", i_data, f_data);
pvm_send(parent, 1); /* send msg type 1 */
pvm_initsend(PvmDataDefault);
i2 = rand();
pvm_packf("%d %d", i_data, i2);
pvm_send(parent, 2); /* send msg type 2 */
}
pvm_exit();
return 0;
}</syntaxhighlight>{{out}}(running it on PVM console, exe is /tmp/a.out)<syntaxhighlight lang="text">pvm> spawn -> /tmp/a.out 1
spawn -> /tmp/a.out 1
[2]
1 successful
t40028
pvm> [2:t40029] EOF
[2:t40028] Spawning successful
[2:t40028] got msg type 2: 1804289383 1681692777
[2:t40028] got msg type 1: 1804289383 0.394383
[2:t40028] EOF
[2] finished</syntaxhighlight>
=={{header|C sharp|C#}}==
Start the program with "server" parameter to start the server, and "client" to start the client. The client will send data to the server and receive a response. The server will wait for data, display the data received, and send a response.
<syntaxhighlight lang="csharp">
using System;
using System.IO;
using System.Net;
using System.Net.Sockets;
using System.Runtime.Serialization.Formatters.Binary;
using System.Threading.Tasks;
using static System.Console;
class DistributedProgramming
{
const int Port = 555;
async static Task RunClient()
{
WriteLine("Connecting");
var client = new TcpClient();
await client.ConnectAsync("localhost", Port);
using (var stream = client.GetStream())
{
WriteLine("Sending loot");
var data = Serialize(new SampleData());
await stream.WriteAsync(data, 0, data.Length);
WriteLine("Receiving thanks");
var buffer = new byte[80000];
var bytesRead = await stream.ReadAsync(buffer, 0, buffer.Length);
var thanks = (string)Deserialize(buffer, bytesRead);
WriteLine(thanks);
}
client.Close();
}
async static Task RunServer()
{
WriteLine("Listening");
var listener = new TcpListener(IPAddress.Any, Port);
listener.Start();
var client = await listener.AcceptTcpClientAsync();
using (var stream = client.GetStream())
{
WriteLine("Receiving loot");
var buffer = new byte[80000];
var bytesRead = await stream.ReadAsync(buffer, 0, buffer.Length);
var data = (SampleData)Deserialize(buffer, bytesRead);
WriteLine($"{data.Loot} at {data.Latitude}, {data.Longitude}");
WriteLine("Sending thanks");
var thanks = Serialize("Thanks!");
await stream.WriteAsync(thanks, 0, thanks.Length);
}
client.Close();
listener.Stop();
Write("Press a key");
ReadKey();
}
static byte[] Serialize(object data)
{
using (var mem = new MemoryStream())
{
new BinaryFormatter().Serialize(mem, data);
return mem.ToArray();
}
}
static object Deserialize(byte[] data, int length)
{
using (var mem = new MemoryStream(data, 0, length))
{
return new BinaryFormatter().Deserialize(mem);
}
}
static void Main(string[] args)
{
if (args.Length == 0) return;
switch (args[0])
{
case "client": RunClient().Wait(); break;
case "server": RunServer().Wait(); break;
}
}
}
[Serializable]
class SampleData
{
public decimal Latitude = 44.33190m;
public decimal Longitude = 114.84129m;
public string Loot = "140 tonnes of jade";
}
</syntaxhighlight>
=={{header|D}}==
Uses the <b>rpc</b> library:
https://github.com/adamdruppe/misc-stuff-including-D-programming-language-web-stuff/blob/master/rpc.d
This library is not standard, so this code (by Adam D. Ruppe) could and should be rewritten using more standard means.
<syntaxhighlight lang="d">import arsd.rpc;
struct S1 {
int number;
string name;
}
struct S2 {
string name;
int number;
}
interface ExampleNetworkFunctions {
string sayHello(string name);
int add(in int a, in int b) const pure nothrow;
S2 structTest(S1);
void die();
}
// The server must implement the interface.
class ExampleServer : ExampleNetworkFunctions {
override string sayHello(string name) {
return "Hello, " ~ name;
}
override int add(in int a, in int b) const pure nothrow {
return a + b;
}
override S2 structTest(S1 a) {
return S2(a.name, a.number);
}
override void die() {
throw new Exception("death requested");
}
mixin NetworkServer!ExampleNetworkFunctions;
}
class Client {
mixin NetworkClient!ExampleNetworkFunctions;
}
void main(in string[] args) {
import std.stdio;
if (args.length > 1) {
auto client = new Client("localhost", 5005);
// These work like the interface above, but instead of
// returning the value, they take callbacks for success (where
// the arg is the retval) and failure (the arg is the
// exception).
client.sayHello("whoa", (a) { writeln(a); }, null);
client.add(1,2, (a){ writeln(a); }, null);
client.add(10,20, (a){ writeln(a); }, null);
client.structTest(S1(20, "cool!"),
(a){ writeln(a.name, " -- ", a.number); },
null);
client.die(delegate(){ writeln("shouldn't happen"); },
delegate(a){ writeln(a); });
client.eventLoop;
} else {
auto server = new ExampleServer(5005);
server.eventLoop;
}
}</syntaxhighlight>
=={{header|E}}==
'''Protocol:''' Pluribus
Line 82 ⟶ 366:
(The protocol is symmetric; this program is the server only in that it is the one which is started first and exports an object.)
<syntaxhighlight lang
This will print the URL of the service and run it until aborted.
Line 108 ⟶ 392:
The URL provided by the server is given as the argument to this program.
<syntaxhighlight lang
}</syntaxhighlight>
=={{header|Erlang}}==
The protocol is erlang's own
=== Server ===
srv.erl
<syntaxhighlight lang
=== Client ===
client.erl
<syntaxhighlight lang
running it (*comes later)
Line 177 ⟶ 461:
|erlc client.erl
|erl -run client start -run init stop -noshell -server srv@agneyam
Received hi
=={{header|Factor}}==
The protocol is the one provided by Factor (concurrency.distributed, concurrency.messaging)
Example summary:
- A server node is listening for messages made of natural data types and structures, and simply prettyprint them.
- A client node is sending such data structure: an array of one string and one hashtable (with one key/value pair).
===Server===
<syntaxhighlight lang="factor">USING: concurrency.distributed concurrency.messaging threads io.sockets io.servers ;
QUALIFIED: concurrency.messaging
: prettyprint-message ( -- ) concurrency.messaging:receive . flush prettyprint-message ;
[ prettyprint-message ] "logger" spawn dup name>> register-remote-thread
"127.0.0.1" 9000 <inet4> <node-server> start-server</syntaxhighlight>
Note: we are using QUALIFIED: with the concurrency.messaging vocabulary because the "receive" word is defined in io.sockets vocabulary too. If someone have a cleaner way to handle this.
===Client===
<syntaxhighlight lang="factor">USING: concurrency.distributed io.sockets ;
QUALIFIED: concurrency.messaging
{ "Hello Remote Factor!" H{ { "key1" "value1" } } }
"127.0.0.1" 9000 <inet4> "logger" <remote-thread> concurrency.messaging:send</syntaxhighlight>
How to Run:
- Copy/Paste the server code in an instance of Factor Listener
- Copy/Paste the client code in another instance of Factor Listener.
The server node should prettyprint the data structure send by the client: { "Hello Remote Factor!" H{ { "key1" "value1" } } }
=={{header|Go}}==
===Standard library net/rpc===
Package net/rpc in the Go standard library serializes data with the Go-native "gob" type. The example here sends only a single floating point number, but the package will send any user-defined data type, including of course structs with multiple fields.
'''Server:'''
<syntaxhighlight lang="go">package main
import (
"errors"
"log"
"net"
"net/http"
"net/rpc"
)
type TaxComputer float64
func (taxRate TaxComputer) Tax(x float64, r *float64) error {
if x < 0 {
return errors.New("Negative values not allowed")
}
*r = x * float64(taxRate)
return nil
}
func main() {
c := TaxComputer(.05)
rpc.Register(c)
rpc.HandleHTTP()
listener, err := net.Listen("tcp", ":1234")
if err != nil {
log.Fatal(err)
}
http.Serve(listener, nil)
}</syntaxhighlight>
'''Client:'''
<syntaxhighlight lang="go">package main
import (
"fmt"
"log"
"net/rpc"
)
func main() {
client, err := rpc.DialHTTP("tcp", "localhost:1234")
if err != nil {
fmt.Println(err)
return
}
amount := 3.
var tax float64
err = client.Call("TaxComputer.Tax", amount, &tax)
if err != nil {
log.Fatal(err)
}
fmt.Printf("Tax on %.2f: %.2f\n", amount, tax)
}</syntaxhighlight>
{{out | Client output}}
<pre>
Tax on 3.00: 0.15
</pre>
===gRPC===
See http://www.grpc.io/
The default serialization for gRPC is "protocol buffers." gRPC uses a .proto file to define an interface for the client and server. The .proto has its own syntax, independent of client and server implementation languages. Server and client programs here are Go however.
'''.proto:'''
<syntaxhighlight lang="proto">syntax = "proto3";
service TaxComputer {
rpc Tax(Amount) returns (Amount) {}
}
message Amount {
int32 cents = 1;
}</syntaxhighlight>
'''Server:'''
<syntaxhighlight lang="go">package main
import (
"errors"
"net"
"golang.org/x/net/context"
"google.golang.org/grpc"
"google.golang.org/grpc/grpclog"
"taxcomputer"
)
type taxServer struct {
rate float64
}
func (s *taxServer) Tax(ctx context.Context,
amt *taxcomputer.Amount) (*taxcomputer.Amount, error) {
if amt.Cents < 0 {
return nil, errors.New("Negative amounts not allowed")
}
return &taxcomputer.Amount{int32(float64(amt.Cents)*s.rate + .5)}, nil
}
func main() {
listener, err := net.Listen("tcp", ":1234")
if err != nil {
grpclog.Fatalf(err.Error())
}
grpcServer := grpc.NewServer()
taxcomputer.RegisterTaxComputerServer(grpcServer, &taxServer{.05})
grpcServer.Serve(listener)
}</syntaxhighlight>
'''Client:'''
<syntaxhighlight lang="go">package main
import (
"fmt"
"golang.org/x/net/context"
"google.golang.org/grpc"
"google.golang.org/grpc/grpclog"
"taxcomputer"
)
func main() {
conn, err := grpc.Dial("localhost:1234", grpc.WithInsecure())
if err != nil {
grpclog.Fatalf(err.Error())
}
defer conn.Close()
client := taxcomputer.NewTaxComputerClient(conn)
amt := &taxcomputer.Amount{300}
tax, err := client.Tax(context.Background(), amt)
if err != nil {
grpclog.Fatalf(err.Error())
}
fmt.Println("Tax on", amt.Cents, "cents is", tax.Cents, "cents")
}</syntaxhighlight>
{{out | Client output}}
<pre>
Tax on 300 cents is 15 cents
</pre>
===Apache Thrift===
See https://thrift.apache.org/
'''.thrift'''
Like gRPC, Thrift requires a language independent interface definition file:
<syntaxhighlight lang="thrift">service TaxService {
i32 tax(1: i32 amt)
}</syntaxhighlight>
'''Server:'''
<syntaxhighlight lang="go">package main
import (
"errors"
"log"
"git.apache.org/thrift.git/lib/go/thrift"
"gen-go/tax"
)
type taxHandler float64
func (r taxHandler) Tax(amt int32) (int32, error) {
if amt < 0 {
return 0, errors.New("Negative amounts not allowed")
}
return int32(float64(amt)*float64(r) + .5), nil
}
func main() {
transport, err := thrift.NewTServerSocket("localhost:3141")
if err != nil {
log.Fatal(err)
}
transFac := thrift.NewTTransportFactory()
protoFac := thrift.NewTCompactProtocolFactory()
proc := tax.NewTaxServiceProcessor(taxHandler(.05))
s := thrift.NewTSimpleServer4(proc, transport, transFac, protoFac)
if err := s.Serve(); err != nil {
log.Fatal(err)
}
}</syntaxhighlight>
'''Client:'''
<syntaxhighlight lang="go">package main
import (
"fmt"
"log"
"git.apache.org/thrift.git/lib/go/thrift"
"gen-go/tax"
)
func main() {
transport, err := thrift.NewTSocket("localhost:3141")
if err != nil {
log.Fatal(err)
}
if err := transport.Open(); err != nil {
log.Fatal(err)
}
protoFac := thrift.NewTCompactProtocolFactory()
client := tax.NewTaxServiceClientFactory(transport, protoFac)
amt := int32(300)
t, err := client.Tax(amt)
if err != nil {
log.Print(err)
} else {
fmt.Println("tax on", amt, "is", t)
}
transport.Close()
}</syntaxhighlight>
{{out | Client output}}
<pre>
tax on 300 is 15
</pre>
=={{header|Haskell}}==
See:
* http://www.haskell.org/haskellwiki/HaXR#Server
* http://www.haskell.org/haskellwiki/HaXR#Client
Check license:
http://www.haskell.org/haskellwiki/HaskellWiki:Copyrights
=={{header|JavaScript}}==
{{works with|node.js}}
===Server===
<syntaxhighlight lang="javascript">var net = require('net')
var server = net.createServer(function (c){
c.write('hello\r\n')
c.pipe(c) // echo messages back
})
server.listen(3000, 'localhost')
</syntaxhighlight>
===Client===
<syntaxhighlight lang="javascript">var net = require('net')
conn = net.createConnection(3000, '192.168.1.x')
conn.on('connect', function(){
console.log('connected')
conn.write('test')
})
conn.on('data', function(msg){
console.log(msg.toString())
})</syntaxhighlight>
=={{header|Julia}}==
Julia was designed with distributed conmputing. in particular cluster computing, as a primary use target.
If a group of CPUs, including multiple cores on a single machine or a cluster running with paswordless ssh login, is used,
the following can be set up as an example:
<syntaxhighlight lang="julia"># From Julia 1.0's online docs. File countheads.jl available to all machines:
function count_heads(n)
c::Int = 0
for i = 1:n
c += rand(Bool)
end
c
end</syntaxhighlight>
We then run the following on the primary client:
<syntaxhighlight lang="julia">
using Distributed
@everywhere include_string(Main, $(read("count_heads.jl", String)), "count_heads.jl")
a = @spawn count_heads(100000000) # runs on an available processor
b = @spawn count_heads(100000000) # runs on another available processor
println(fetch(a)+fetch(b)) # total heads of 200 million coin flips, half on each CPU
</syntaxhighlight> {{output}} <pre>
100001564
</pre>
=={{header|LFE}}==
The protocol used is the one native to Erlang (and thus native to LFE, Lisp Flavored Erlang).
These examples are done completely in the LFE REPL.
===Server===
In one terminal window, start up the REPL
<syntaxhighlight lang="bash">
$ ./bin/lfe
Erlang/OTP 17 [erts-6.2] [source] [64-bit] [smp:4:4] [async-threads:10] [hipe] [kernel-poll:false]
LFE Shell V6.2 (abort with ^G)
>
</syntaxhighlight>
And then enter the following code
<syntaxhighlight lang="lisp">
> (defun get-server-name ()
(list_to_atom (++ "exampleserver@" (element 2 (inet:gethostname)))))
> (defun start ()
(net_kernel:start `(,(get-server-name) shortnames))
(erlang:set_cookie (node) 'rosettaexample)
(let ((pid (spawn #'listen/0)))
(register 'serverref pid)
(io:format "~p ready~n" (list (node pid)))
'ok))
> (defun listen ()
(receive
(`#(echo ,pid ,data)
(io:format "Got ~p from ~p~n" (list data (node pid)))
(! pid `#(hello ,data))
(listen))
(x
(io:format "Unexpected pattern: ~p~n" `(,x)))))
</syntaxhighlight>
===Client===
In another terminal window, start up another LFE REPL and ender the following code:
<syntaxhighlight lang="lisp">
> (defun get-server-name ()
(list_to_atom (++ "exampleserver@" (element 2 (inet:gethostname)))))
> (defun send (data)
(net_kernel:start '(exampleclient shortnames))
(erlang:set_cookie (node) 'rosettaexample)
(io:format "connecting to ~p~n" `(,(get-server-name)))
(! `#(serverref ,(get-server-name)) `#(echo ,(self) ,data))
(receive
(`#(hello ,data)
(io:format "Received ~p~n" `(,data)))
(x
(io:format "Unexpected pattern: ~p~n" (list x))))
'ok)
</syntaxhighlight>
To use this code, simply start the server in the server terminal:
<syntaxhighlight lang="lisp">
> (start)
exampleserver@yourhostname ready
ok
(exampleserver@yourhostname)>
</syntaxhighlight>
Send some messages from the client terminal:
<syntaxhighlight lang="lisp">
> (send "hi there")
connecting to exampleserver@yourhostname
Received "hi there"
ok
(exampleclient@yourhostname)> (send 42)
connecting to exampleserver@yourhostname
Received 42
ok
(exampleclient@yourhostname)> (send #(key value))
connecting to exampleserver@yourhostname
Received {key,value}
ok
(exampleclient@yourhostname)>
</syntaxhighlight>
And check out the results back in the server terminal window:
<syntaxhighlight lang="lisp">
Got "hi there" from exampleclient@yourhostname
Got 42 from exampleclient@yourhostname
Got {key,value} from exampleclient@yourhostname
</syntaxhighlight>
=={{header|Mathematica}} / {{header|Wolfram Language}}==
The following sends a request for a random number to be generated on each of two nodes, these are then transmitted back to be assembled into an array with two elements. Omitting the first line, will cause the program to be run on all configured remote computers.
<syntaxhighlight lang="mathematica">LaunchKernels[2];
ParallelEvaluate[RandomReal[]]
</syntaxhighlight>
=={{header|Nim}}==
{{libheader|nanomsg}}
<syntaxhighlight lang="nim">import os, nanomsg
proc sendMsg(s: cint, msg: string) =
echo "SENDING \"",msg,"\""
let bytes = s.send(msg.cstring, msg.len + 1, 0)
assert bytes == msg.len + 1
proc recvMsg(s: cint) =
var buf: cstring
let bytes = s.recv(addr buf, MSG, 0)
if bytes > 0:
echo "RECEIVED \"",buf,"\""
discard freemsg buf
proc sendRecv(s: cint, msg: string) =
var to: cint = 100
discard s.setSockOpt(SOL_SOCKET, RCVTIMEO, addr to, sizeof to)
while true:
s.recvMsg
sleep 1000
s.sendMsg msg
proc node0(url: string) =
var s = socket(AF_SP, nanomsg.PAIR)
assert s >= 0
let res = s.bindd url
assert res >= 0
s.sendRecv "node0"
discard s.shutdown 0
proc node1(url: string) =
var s = socket(AF_SP, nanomsg.PAIR)
assert s >= 0
let res = s.connect url
assert res >= 0
s.sendRecv "node1"
discard s.shutdown 0
if paramStr(1) == "node0":
node0 paramStr(2)
elif paramStr(1) == "node1":
node1 paramStr(2)</syntaxhighlight>
Usage:
<pre>./pair node0 tcp://127.0.0.1:25000
./pair node1 tcp://127.0.0.1:25000</pre>
=={{header|Objective-C}}==
Distributed Objects are ''natural'' to Objective-C, and OpenStep and derivated framework offers an easy way of ''using'' remote objects as if it were local. The client must only know the protocol the remote object support. For the rest, calling a remote object's method or local object's method is transparent.
Line 189 ⟶ 945:
<tt>ActionObjectProtocol.h</tt>
<
// our protocol allows "sending" "strings", but we can implement
// everything we could for a "local" object
@protocol ActionObjectProtocol
- (NSString *)sendMessage: (NSString *)msg;
@end</
<tt>ActionObject.h</tt>
<
#import "ActionObjectProtocol.h"
@interface ActionObject : NSObject <ActionObjectProtocol>
// we do not have much for this example!
@end</
<tt>ActionObject.m</tt>
<
#import "ActionObject.h"
Line 214 ⟶ 970:
return @"server answers ...";
}
@end</
<tt>server.m</tt>
<
#import "ActionObject.h"
int main (void)
{
@autoreleasepool {
NSSocketPort *port = (NSSocketPort *)[NSSocketPort port];
// initWithTCPPort: 1234 and other methods are not supported yet
// by GNUstep
NSConnection *connect = [NSConnection
connectionWithReceivePort: port
sendPort: port]; // or sendPort: nil
[connect setRootObject: action];
/* "vend" the object ActionObject as DistributedAction; on GNUstep
the Name Server that allows the resolution of the registered name
is bound to port 538 */
if (![connect registerName:@"DistributedAction"
withNameServer: [NSSocketPortNameServer sharedInstance] ]
{
NSLog(@"can't register the server DistributedAction");
exit(EXIT_FAILURE);
}
NSLog(@"waiting for messages...");
[[NSRunLoop currentRunLoop] run];
}
return 0;
}</
===Client===
<tt>client.m</tt>
<
#import "ActionObjectProtocol.h"
int main(void)
{
@autoreleasepool {
id <ActionObjectProtocol> action = (id <ActionObjectProtocol>)
[NSConnection
rootProxyForConnectionWithRegisteredName: @"DistributedAction"
host: @"localhost"
usingNameServer: [NSSocketPortNameServer sharedInstance] ];
if (action == nil)
NSLog(@"can't connect to the server");
}
NSArray *args = [[NSProcessInfo processInfo] arguments];
if ([args count] == 1)
{
NSLog(@"specify a message");
exit(EXIT_FAILURE);
}
NSString *msg =
// "send" (call the selector "sendMessage:" of the (remote) object
// action) the first argument's text as msg, store the message "sent
// back" and then show it in the log
NSString *backmsg = [action sendMessage: msg];
NSLog("%@", backmsg);
}
return 0;
}</
=={{header|OCaml}}==
{{works with|JoCaml}}
Line 310 ⟶ 1,056:
=== Server ===
<syntaxhighlight lang
=== Client ===
<syntaxhighlight lang
=={{header|
We show a program that starts a server on a remote machine, exchanges two messages with that server and finally shuts it down.
<syntaxhighlight lang="oz">declare
functor ServerCode
export
port:Prt
define
Stream
Prt = {NewPort ?Stream}
thread
for Request#Reply in Stream do
case Request
of echo(Data) then Reply = Data
[] compute(Function) then Reply = {Function}
end
end
end
end
%% create the server on some machine
%% (just change "localhost" to some machine
%% that you can use with a passwordless rsh login
%% and that has the same Mozart version installed)
RM = {New Remote.manager init(host:localhost)}
%% execute the code encapsulated in the ServerCode functor
Server = {RM apply(ServerCode $)}
%% Shortcut: send a message to Server and receive a reply
fun {Send X}
{Port.sendRecv Server.port X}
end
in
%% echo
{System.showInfo "Echo reply: "#{Send echo(hello)}}
%% compute
{System.showInfo "Result of computation: "#
{Send compute(fun {$} 8 div 4 end)}}
%% shut down server
{RM close}</syntaxhighlight>
=={{header|Perl}}==
Using Data::Dumper and Safe to transmit arbitrary data structures as serialized text between hosts. Same code works as both sender and receiver.
<syntaxhighlight lang="perl">use strict;
use warnings;
use Data::Dumper;
use IO::Socket::INET;
use Safe;
sub get_data {
my $sock = IO::Socket::INET->new(
LocalHost => "localhost",
LocalPort => "10000",
Proto => "tcp",
Listen => 1,
Reuse => 1);
unless ($sock) { die "Socket creation failure" }
my $cli = $sock->accept();
# of course someone may be tempted to send you 'system("rm -rf /")',
# to be safe(r), use Safe::
my $safe = Safe->new;
my $x = $safe->reval(join("", <$cli>));
close $cli;
close $sock;
return $x;
}
sub send_data {
my $host = shift;
my $data = shift;
my $sock = IO::Socket::INET->new(
PeerAddr => "$host:10000",
Proto => "tcp",
Reuse => 1);
unless ($sock) { die "Socket creation failure" }
print $sock Data::Dumper->Dump([$data]);
close $sock;
}
if (@ARGV) {
my $x = get_data();
print "Got data\n", Data::Dumper->Dump([$x]);
} else {
send_data('some_host', { a=>100, b=>[1 .. 10] });
}</syntaxhighlight>
=={{header|Phix}}==
From/using [http://phix.x10.mx/pmwiki/pmwiki.php?n=Main.Libzmq the ZeroMQ wrapper from PCAN], a suitable simple publish/subscriber pair.
There is also a server/client/broker example.
Obviously you can trivially serialize() and deserialize() any Phix data to and from a string.
<!--<syntaxhighlight lang="phix">(notonline)-->
<span style="color: #008080;">without</span> <span style="color: #008080;">js</span> <span style="color: #000080;font-style:italic;">-- (zmq dll/so)</span>
<span style="color: #7060A8;">puts</span><span style="color: #0000FF;">(</span><span style="color: #000000;">1</span><span style="color: #0000FF;">,</span> <span style="color: #008000;">"durapub:\n"</span><span style="color: #0000FF;">)</span>
<span style="color: #008080;">include</span> <span style="color: #000000;">zmq</span><span style="color: #0000FF;">/</span><span style="color: #000000;">zmq</span><span style="color: #0000FF;">.</span><span style="color: #000000;">e</span>
<span style="color: #004080;">atom</span> <span style="color: #000000;">context</span> <span style="color: #0000FF;">=</span> <span style="color: #000000;">zmq_init</span><span style="color: #0000FF;">(</span><span style="color: #000000;">1</span><span style="color: #0000FF;">)</span>
<span style="color: #000000;">zmq_assert</span><span style="color: #0000FF;">(</span><span style="color: #000000;">context</span><span style="color: #0000FF;">,</span> <span style="color: #008000;">"zmq_init"</span><span style="color: #0000FF;">)</span>
<span style="color: #000080;font-style:italic;">--// subscriber tells us when it's ready here</span>
<span style="color: #004080;">atom</span> <span style="color: #000000;">sync</span> <span style="color: #0000FF;">=</span> <span style="color: #000000;">zmq_socket</span><span style="color: #0000FF;">(</span><span style="color: #000000;">context</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">ZMQ_PULL</span><span style="color: #0000FF;">)</span>
<span style="color: #000000;">zmq_bind</span><span style="color: #0000FF;">(</span><span style="color: #000000;">sync</span><span style="color: #0000FF;">,</span> <span style="color: #008000;">"tcp://*:5564"</span><span style="color: #0000FF;">)</span>
<span style="color: #000080;font-style:italic;">--// send update via this socket</span>
<span style="color: #004080;">atom</span> <span style="color: #000000;">publisher</span> <span style="color: #0000FF;">=</span> <span style="color: #000000;">zmq_socket</span><span style="color: #0000FF;">(</span><span style="color: #000000;">context</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">ZMQ_PUB</span><span style="color: #0000FF;">)</span>
<span style="color: #000000;">zmq_bind</span><span style="color: #0000FF;">(</span><span style="color: #000000;">publisher</span><span style="color: #0000FF;">,</span> <span style="color: #008000;">"tcp://*:5565"</span><span style="color: #0000FF;">)</span>
<span style="color: #000080;font-style:italic;">--// broadcast 10 updates, with pause</span>
<span style="color: #008080;">for</span> <span style="color: #000000;">update_nbr</span> <span style="color: #0000FF;">=</span> <span style="color: #000000;">1</span> <span style="color: #008080;">to</span> <span style="color: #000000;">10</span> <span style="color: #008080;">do</span>
<span style="color: #004080;">string</span> <span style="color: #000000;">s</span> <span style="color: #0000FF;">=</span> <span style="color: #7060A8;">sprintf</span><span style="color: #0000FF;">(</span><span style="color: #008000;">"Update %d"</span><span style="color: #0000FF;">,</span> <span style="color: #0000FF;">{</span> <span style="color: #000000;">update_nbr</span> <span style="color: #0000FF;">})</span>
<span style="color: #000000;">zmq_s_send</span><span style="color: #0000FF;">(</span><span style="color: #000000;">publisher</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">s</span><span style="color: #0000FF;">)</span>
<span style="color: #7060A8;">sleep</span><span style="color: #0000FF;">(</span><span style="color: #000000;">1</span><span style="color: #0000FF;">)</span>
<span style="color: #008080;">end</span> <span style="color: #008080;">for</span>
<span style="color: #000000;">zmq_s_send</span><span style="color: #0000FF;">(</span><span style="color: #000000;">publisher</span><span style="color: #0000FF;">,</span> <span style="color: #008000;">"END"</span><span style="color: #0000FF;">)</span>
<span style="color: #7060A8;">sleep</span><span style="color: #0000FF;">(</span><span style="color: #000000;">1</span><span style="color: #0000FF;">)</span>
<span style="color: #000000;">zmq_close</span><span style="color: #0000FF;">(</span><span style="color: #000000;">sync</span><span style="color: #0000FF;">)</span>
<span style="color: #000000;">zmq_close</span><span style="color: #0000FF;">(</span><span style="color: #000000;">publisher</span><span style="color: #0000FF;">)</span>
<span style="color: #000000;">zmq_term</span><span style="color: #0000FF;">(</span><span style="color: #000000;">context</span><span style="color: #0000FF;">)</span>
<!--</syntaxhighlight>-->
<!--<syntaxhighlight lang="phix">(notonline)-->
<span style="color: #008080;">without</span> <span style="color: #008080;">js</span> <span style="color: #000080;font-style:italic;">-- (zmq dll/so)</span>
<span style="color: #7060A8;">puts</span><span style="color: #0000FF;">(</span><span style="color: #000000;">1</span><span style="color: #0000FF;">,</span> <span style="color: #008000;">"durasub:\n"</span><span style="color: #0000FF;">)</span>
<span style="color: #008080;">include</span> <span style="color: #000000;">zmq</span><span style="color: #0000FF;">/</span><span style="color: #000000;">zmq</span><span style="color: #0000FF;">.</span><span style="color: #000000;">e</span>
<span style="color: #004080;">atom</span> <span style="color: #000000;">context</span> <span style="color: #0000FF;">=</span> <span style="color: #000000;">zmq_init</span><span style="color: #0000FF;">(</span><span style="color: #000000;">1</span><span style="color: #0000FF;">)</span>
<span style="color: #000000;">zmq_assert</span><span style="color: #0000FF;">(</span><span style="color: #000000;">context</span><span style="color: #0000FF;">,</span> <span style="color: #008000;">"zmq_init"</span><span style="color: #0000FF;">)</span>
<span style="color: #000080;font-style:italic;">--// connect our subscriber socket</span>
<span style="color: #004080;">atom</span> <span style="color: #000000;">subscriber</span> <span style="color: #0000FF;">=</span> <span style="color: #000000;">zmq_socket</span><span style="color: #0000FF;">(</span><span style="color: #000000;">context</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">ZMQ_SUB</span><span style="color: #0000FF;">)</span>
<span style="color: #004080;">atom</span> <span style="color: #000000;">id</span> <span style="color: #0000FF;">=</span> <span style="color: #7060A8;">allocate_string</span><span style="color: #0000FF;">(</span><span style="color: #008000;">"Hello"</span><span style="color: #0000FF;">)</span>
<span style="color: #000000;">zmq_setsockopt</span><span style="color: #0000FF;">(</span><span style="color: #000000;">subscriber</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">ZMQ_IDENTITY</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">id</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">5</span><span style="color: #0000FF;">)</span>
<span style="color: #000000;">zmq_setsockopt</span><span style="color: #0000FF;">(</span><span style="color: #000000;">subscriber</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">ZMQ_SUBSCRIBE</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">0</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">0</span><span style="color: #0000FF;">)</span>
<span style="color: #000000;">zmq_connect</span><span style="color: #0000FF;">(</span><span style="color: #000000;">subscriber</span><span style="color: #0000FF;">,</span> <span style="color: #008000;">"tcp://localhost:5565"</span><span style="color: #0000FF;">)</span>
<span style="color: #7060A8;">free</span><span style="color: #0000FF;">(</span><span style="color: #000000;">id</span><span style="color: #0000FF;">)</span>
<span style="color: #000080;font-style:italic;">--// synchronise with publisher</span>
<span style="color: #004080;">atom</span> <span style="color: #000000;">sync</span> <span style="color: #0000FF;">=</span> <span style="color: #000000;">zmq_socket</span><span style="color: #0000FF;">(</span><span style="color: #000000;">context</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">ZMQ_PUSH</span><span style="color: #0000FF;">)</span>
<span style="color: #000000;">zmq_connect</span><span style="color: #0000FF;">(</span><span style="color: #000000;">sync</span><span style="color: #0000FF;">,</span> <span style="color: #008000;">"tcp://localhost:5564"</span><span style="color: #0000FF;">)</span>
<span style="color: #000000;">zmq_s_send</span><span style="color: #0000FF;">(</span><span style="color: #000000;">sync</span><span style="color: #0000FF;">,</span> <span style="color: #008000;">""</span><span style="color: #0000FF;">)</span>
<span style="color: #000080;font-style:italic;">--// get updates, Ctrl-C break</span>
<span style="color: #008080;">while</span> <span style="color: #004600;">true</span> <span style="color: #008080;">do</span>
<span style="color: #004080;">string</span> <span style="color: #000000;">s</span> <span style="color: #0000FF;">=</span> <span style="color: #000000;">zmq_s_recv</span><span style="color: #0000FF;">(</span><span style="color: #000000;">subscriber</span><span style="color: #0000FF;">)</span>
<span style="color: #7060A8;">printf</span><span style="color: #0000FF;">(</span><span style="color: #000000;">1</span><span style="color: #0000FF;">,</span> <span style="color: #008000;">"%s\n"</span><span style="color: #0000FF;">,</span> <span style="color: #0000FF;">{</span><span style="color: #000000;">s</span><span style="color: #0000FF;">})</span>
<span style="color: #008080;">if</span> <span style="color: #000000;">s</span><span style="color: #0000FF;">==</span><span style="color: #008000;">"END"</span> <span style="color: #008080;">then</span> <span style="color: #008080;">exit</span> <span style="color: #008080;">end</span> <span style="color: #008080;">if</span>
<span style="color: #008080;">end</span> <span style="color: #008080;">while</span>
<span style="color: #000000;">zmq_close</span><span style="color: #0000FF;">(</span><span style="color: #000000;">sync</span><span style="color: #0000FF;">)</span>
<span style="color: #000000;">zmq_close</span><span style="color: #0000FF;">(</span><span style="color: #000000;">subscriber</span><span style="color: #0000FF;">)</span>
<span style="color: #000000;">zmq_term</span><span style="color: #0000FF;">(</span><span style="color: #000000;">context</span><span style="color: #0000FF;">)</span>
<!--</syntaxhighlight>-->
=={{header|PicoLisp}}==
===Server===
<syntaxhighlight lang="picolisp">(task (port 12321) # Background server task
(let? Sock (accept @)
(unless (fork) # Handle request in child process
(in Sock
(while (rd) # Handle requests
(out Sock
(pr (eval @)) ) ) ) # Evaluate and send reply
(bye) ) # Exit child process
(close Sock) ) ) # Close socket in parent process</syntaxhighlight>
===Client===
<syntaxhighlight lang="picolisp">(let? Sock (connect "localhost" 12321)
(out Sock (pr '*Pid)) # Query PID from server
(println 'PID (in Sock (rd))) # Receive and print reply
(out Sock (pr '(* 3 4))) # Request some calculation
(println 'Result (in Sock (rd))) # Print result
(close Sock) ) # Close connection to server</syntaxhighlight>
Output:
<pre>PID 18372
Result 12</pre>
=={{header|Python}}==
{{works with|Python|2.4 and 2.6}}
=== XML-RPC ===
'''Protocol:''' XML-RPC
==== Server ====
<syntaxhighlight lang="python">#!/usr/bin/env python
# -*- coding: utf-8 -*-
Line 402 ⟶ 1,330:
except KeyboardInterrupt:
print 'Exiting...'
server.server_close()</syntaxhighlight>
==== Client ====
<syntaxhighlight lang="python">#!/usr/bin/env python
# -*- coding: utf-8 -*-
Line 429 ⟶ 1,355:
# control if foo_function returns True
if rpc.foo_function():
print 'Server says: foo_function returned True'</syntaxhighlight>
===HTTP===
'''Protocol:''' HTTP
==== Server ====
<syntaxhighlight lang="python">#!/usr/bin/python
# -*- coding: utf-8 -*-
Line 467 ⟶ 1,390:
except KeyboardInterrupt:
print 'Exiting...'
server.server_close()</syntaxhighlight>
==== Client ====
<syntaxhighlight lang="python">#!/usr/bin/python
# -*- coding: utf-8 -*-
Line 486 ⟶ 1,407:
print 'Server Status: %d' % response.status
print 'Server Message: %s' % response.read()</syntaxhighlight>
===Socket,
'''Protocol:''' raw socket / pickle format
This example builds a very basic RPC mechanism on top of sockets and the [http://docs.python.org/library/pickle.html#module-pickle pickle module]. Please note that the pickle module is not secure - a malicious client can build malformed data to execute arbitrary code on the server. If untrusted clients can access the server, the [http://docs.python.org/library/json.html json module] could be used as a substitute, but we lose the ability to transfer arbitrary Python objects that way.
==== Server ====
<syntaxhighlight lang="python">#!/usr/bin/python
# -*- coding: utf-8 -*-
import SocketServer
import pickle
HOST = "localhost"
PORT = 8000
class RPCServer(SocketServer.ThreadingMixIn, SocketServer.TCPServer):
# The object_to_proxy member should be set to the object we want
# methods called on. Unfortunately, we can't do this in the constructor
# because the constructor should not be overridden in TCPServer...
daemon_threads = True
class RPCHandler(SocketServer.StreamRequestHandler):
def handle(self):
in_channel = pickle.Unpickler(self.rfile)
out_channel = pickle.Pickler(self.wfile, protocol=2)
name, args, kwargs = in_channel.load()
print 'got %s %s %s' % (name, args, kwargs)
except EOFError:
# EOF means we're done with this request.
# Catching this exception to detect EOF is a bit hackish,
# but will work for a quick demo like this
break
try:
method = getattr(self.server.object_to_proxy, name)
result = method(*args, **kwargs)
except Exception, e:
out_channel.dump(('Error',e))
else:
out_channel.dump(('OK',result))
class MyHandlerInstance(object):
def echo(self, data):
'''Method for returning data got from client'''
return 'Server responded: %s' % data
def div(self, dividend, divisor):
'''Method to divide 2 numbers'''
return dividend/divisor
def is_computer_on(self):
return True
if __name__ == '__main__':
rpcserver.object_to_proxy = MyHandlerInstance()
try:
except KeyboardInterrupt:
print 'Exiting...'
</syntaxhighlight>
==== Client ====
<syntaxhighlight lang="python">#!/usr/bin/python
# -*- coding: utf-8 -*-
import socket
import pickle
HOST = "localhost"
PORT = 8000
class RPCClient(object):
def __init__(self, host, port):
self.socket = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
self.socket.connect((host, port))
self.rfile = self.socket.makefile('rb')
self.wfile = self.socket.makefile('wb')
self.in_channel = pickle.Unpickler(self.rfile)
self.out_channel = pickle.Pickler(self.wfile, protocol=2)
def _close(self):
self.socket.close()
self.rfile.close()
self.wfile.close()
# Make calling remote methods easy by overriding attribute access.
# Accessing any attribute on our instances will give a proxy method that
# calls the method with the same name on the remote machine.
def __getattr__(self, name):
def proxy(*args, **kwargs):
self.out_channel.dump((name, args, kwargs))
self.wfile.flush() # to make sure the server won't wait forever
status, result = self.in_channel.load()
if status == 'OK':
return result
else:
raise result
return proxy
if __name__ == '__main__':
# connect to server and send data
rpcclient = RPCClient(HOST, PORT)
print 'Testing the echo() method:'
print rpcclient.echo('Hello world!')
print
print 'Calculating 42/2 on the remote machine:'
print rpcclient.div(42, 2)
print
print 'is_computer_on on the remote machine returns:'
print rpcclient.is_computer_on()
print
print 'Testing keyword args:'
print '42/2 is:', rpcclient.div(divisor=2, dividend=42)
rpcclient._close()
del rpcclient</syntaxhighlight>
===Pyro===
'''Note:''' You should install Pyro (http://pyro.sourceforge.net) first and run '''pyro-ns''' binary to run code below.
==== Server ====
<syntaxhighlight lang="python">#!/usr/bin/python
# -*- coding: utf-8 -*-
Line 576 ⟶ 1,561:
except KeyboardInterrupt:
print 'Exiting...'
server.shutdown()</syntaxhighlight>
==== Client ====
<syntaxhighlight lang="python">#!/usr/bin/python
# -*- coding: utf-8 -*-
Line 597 ⟶ 1,580:
print 'We sent two numbers to divide: %d and %d' % (NUM1, NUM2)
print 'Server responded the result: %s' % math.div(NUM1, NUM2)</syntaxhighlight>
=== Spread ===
'''Note:''' You should install Spread (http://www.spread.org) and its python bindings (http://www.python.org/other/spread/)
==== Server ====
You don't need any code for server. You should start "spread" daemon by typing "spread -c /etc/spread.conf -n localhost". If you want more configuration, look at /etc/spread.conf.
After starting daemon, if you want to make sure that it is running, enter '''spuser -s 4803''' command where 4803 is your port set in spread.conf, you will see prompt, type '''j user''', you should see something like this message: ''Received REGULAR membership for group test with 3 members, where I am member 2''
==== Client (Listener) ====
<syntaxhighlight lang="python">#!/usr/bin/python
# -*- coding: utf-8 -*-
Line 627 ⟶ 1,608:
if hasattr(recv, 'sender') and hasattr(recv, 'message'):
print 'Sender: %s' % recv.sender
print 'Message: %s' % recv.message</syntaxhighlight>
==== Client (Sender) ====
<syntaxhighlight lang="python">#!/usr/bin/python
# -*- coding: utf-8 -*-
Line 643 ⟶ 1,622:
conn.multicast(spread.RELIABLE_MESS, 'test', 'hello, this is message sent from python')
conn.disconnect()</syntaxhighlight>
=={{header|
Server and client in the same piece of code, running a useless (fib 42) computation, four times, on four hosts (which all happen to be "localhost", but that can change, of course).
<syntaxhighlight lang="racket">
#lang racket/base
(require racket/place/distributed racket/place)
(define (fib n)
(if (<= n 1) n (+ (fib (- n 1)) (fib (- n 2)))))
(provide work)
(define (work)
(place ch
(place-channel-put ch (fib (place-channel-get ch)))))
(module+ main
(define places
(for/list ([host '("localhost" "localhost" "localhost" "localhost")]
[port (in-naturals 12345)])
(define-values [node place]
(spawn-node-supervise-place-at host #:listen-port port #:thunk #t
(quote-module-path "..") 'work))
place))
(message-router
(after-seconds 1
(for ([p places]) (*channel-put p 42))
(printf "Results: ~s\n" (map *channel-get places))
(exit))))
</syntaxhighlight>
=={{header|Raku}}==
(formerly Perl 6)
Server listens for JSON encoded messages. It processes requests for set|get|dump. 'set' stores a message, 'get' returns message, 'dump' returns all stored messages. Optional parameters for ip address and port.
Server.raku:
<pre>./server.raku --usage
Usage:
server.p6 [--server=<Any>] [--port=<Any>]</pre>
<syntaxhighlight lang="raku" line>#!/usr/bin/env raku
use JSON::Fast ;
sub MAIN( :$server='0.0.0.0' , :$port=3333 ) {
my %db ;
react {
whenever IO::Socket::Async.listen( $server , $port ) -> $conn {
whenever $conn.Supply.lines -> $line {
my %response = 'status' => '' ;
my $msg = from-json $line ;
say $msg.raku;
given $msg{"function"} {
when 'set' {
%db{ $msg<topic> } = $msg<message> ;
%response<status> = 'ok' ;
}
when 'get' {
%response<topic> = $msg<topic> ;
%response<message> = %db{ $msg<topic> } ;
%response<status> = 'ok' ;
}
when 'dump' {
%response = %db ;
}
when 'delete' {
%db{ $msg<topic> }:delete;
%response<status> = 'ok' ;
}
}
$conn.print( to-json(%response, :!pretty) ~ "\n" ) ;
LAST { $conn.close ; }
QUIT { default { $conn.close ; say "oh no, $_";}}
CATCH { default { say .^name, ': ', .Str , " handled in $?LINE";}}
}
}
}
}</syntaxhighlight>
client.raku:
<pre>Usage:
client.raku [--server=<Any>] [--port=<Any>] [--json=<Any>] set <topic> [<message>]
client.raku [--server=<Any>] [--port=<Any>] get <topic>
client.raku [--server=<Any>] [--port=<Any>] dump</pre>
<syntaxhighlight lang="raku" line>#!/usr/bin/env raku
use JSON::Fast ;
multi MAIN('set', $topic, $message='', :$server='localhost', :$port='3333', :$json='') {
my %msg = function => 'set' , topic=> $topic , message=> $message ;
%msg{"message"} = from-json( $json ) if $json ;
sendmsg( %msg , $server, $port) ;
}
multi MAIN('get', $topic, :$server='localhost', :$port='3333') {
my %msg = function => 'get' , topic=> $topic ;
sendmsg( %msg , $server, $port) ;
}
multi MAIN('delete', $topic, :$server='localhost', :$port='3333') {
my %msg = function => 'delete' , topic=> $topic ;
sendmsg( %msg , $server, $port) ;
}
multi MAIN('dump', :$server='localhost', :$port='3333') {
my %msg = function => 'dump' ;
sendmsg( %msg , $server, $port) ;
}
sub sendmsg( %msg , $server, $port){
my $conn = await IO::Socket::Async.connect( $server , $port );
$conn.print: to-json( %msg,:!pretty)~"\n";
react {
whenever $conn.Supply -> $data {
print $data;
$conn.close;
}
}
}</syntaxhighlight>
examples:
<pre>echo '{"function":"set","topic":"push","message":["perl5","raku","rakudo"]}' | nc localhost 3333
./client.raku set version raku
{"status": "ok"}
./client.raku get version
{"status": "ok","topic": "version","message": "raku"}
./client.raku --json='["one","two","three"]' set mylist
{"status": "ok"}
./client.raku dump
{"push": ["perl5","raku","rakudo"],"version": "raku","mylist": ["one","two","three"]}
./client.raku delete version
{"status": "ok"}
server output:
${:function("set"), :message($["perl5", "raku", "rakudo"]), :topic("push")}
${:function("set"), :message("raku"), :topic("version")}
${:function("get"), :topic("version")}
${:function("set"), :message($["one", "two", "three"]), :topic("mylist")}
${:function("dump")}
${:function("delete"), :topic("version")}</pre>
=={{header|Ruby}}==
Uses the distributed Ruby (dRuby) from the standard library. The "druby:" protocol uses TCP/IP sockets for communication.
'''Server'''
<syntaxhighlight lang="ruby">require 'drb/drb'
# The URI for the server to connect to
URI="druby://localhost:8787"
class TimeServer
def get_current_time
return Time.now
end
end
# The object that handles requests on the server
FRONT_OBJECT = TimeServer.new
'''Client'''
<syntaxhighlight lang
=={{header|Tcl}}==
A rudimentary IRC Server
<
global connections
set connections [dict create]
Line 753 ⟶ 1,861:
}
main</
Client
<
global argv argc
if {$argc != 2} {
Line 790 ⟶ 1,898:
}
main</
=={{header|UnixPipes}}==
{{libheader|nc}}
Uses netcat and a buffer to cycle the server shell's stdout back to netcat's stdin.
===Server===
{{alertbox|yellow|'''Security risk!''' Anything, able to reach 127.0.0.1 port 1234, can run shell commands as the user who runs the server. This allows other users to gain privileges.}}
<syntaxhighlight lang="bash">: >/tmp/buffer
tail -f /tmp/buffer | nc -l 127.0.0.1 1234 | sh >/tmp/buffer 2>&1</syntaxhighlight>
Limitations:
* The server can accept only one connection (but continues to run, not exit, after this connection dies).
* With some systems, <code>tail -f</code> might be slow to notice changes to /tmp/buffer.
===Client===
<syntaxhighlight lang="bash">nc 127.0.0.1 1234</syntaxhighlight>
Now you can enter commands in the client terminal and get the output back through the same connection.
=={{header|Wren}}==
{{trans|Go}}
{{libheader|WrenGo}}
{{libheader|Wren-fmt}}
As Wren has no networking support at present, we use embedded programs for both the server and client with a Go host using the net/rpc package in its standard library.
Moreover, as Wren's VM is not re-entrant, we need to run two VMs from the server side, one to call Go from Wren and the other to call Wren from Go.
'''Server:'''
<br>
We need two Wren scripts one for each VM:
<syntaxhighlight lang="wren">/* Distributed_programming_server.wren */
class Rpc {
foreign static register()
foreign static handleHTTP()
}
foreign class Listener {
construct listen(network, address) {}
}
class HTTP {
foreign static serve(listener)
}
Rpc.register()
Rpc.handleHTTP()
var listener = Listener.listen("tcp", ":1234")
HTTP.serve(listener)</syntaxhighlight>
<br>
<syntaxhighlight lang="wren">/* Distributed_programming_server_2.wren */
class TaxComputer {
static tax(amount, rate) {
if (amount < 0) Fiber.abort("Negative values not allowed.")
return amount * rate
}
}</syntaxhighlight>
<br>
We now embed these scripts in the following Go program and run it on one terminal.
<syntaxhighlight lang="go">/* go run Distributed_programming_server.go */
package main
import(
wren "github.com/crazyinfin8/WrenGo"
"log"
"net"
"net/http"
"net/rpc"
)
type any = interface{}
type TaxComputer float64
var vm2 *wren.VM
var fileName = "Distributed_programming_server.wren"
var fileName2 = "Distributed_programming_server_2.wren"
func (taxRate TaxComputer) Tax(x float64, r *float64) error {
wrenVar, _ := vm2.GetVariable(fileName2, "TaxComputer")
wrenClass, _ := wrenVar.(*wren.Handle)
defer wrenClass.Free()
wrenMethod, _ := wrenClass.Func("tax(_,_)")
defer wrenMethod.Free()
ret, _ := wrenMethod.Call(x, float64(taxRate))
*r = ret.(float64)
return nil
}
func register(vm *wren.VM, parameters []any) (any, error) {
c := TaxComputer(0.05) // 5% tax rate
rpc.Register(c)
return nil, nil
}
func handleHTTP(vm *wren.VM, parameters []any) (any, error) {
rpc.HandleHTTP()
return nil, nil
}
func serve(vm *wren.VM, parameters []any) (any, error) {
handle := parameters[1].(*wren.ForeignHandle)
ifc, _ := handle.Get()
listener := ifc.(*net.Listener)
http.Serve(*listener, nil)
return nil, nil
}
func listen(vm *wren.VM, parameters []any) (any, error) {
network := parameters[1].(string)
address := parameters[2].(string)
listener, err := net.Listen(network, address)
if err != nil {
log.Fatal(err)
}
return &listener, nil
}
func main() {
vm := wren.NewVM()
vm2 = wren.NewVM()
vm2.InterpretFile(fileName2)
rpcMethodMap := wren.MethodMap {
"static register()": register,
"static handleHTTP()": handleHTTP,
}
httpMethodMap := wren.MethodMap { "static serve(_)":serve }
classMap := wren.ClassMap {
"Listener": wren.NewClass(listen, nil, nil),
"Rpc" : wren.NewClass(nil, nil, rpcMethodMap),
"HTTP" : wren.NewClass(nil, nil, httpMethodMap),
}
module := wren.NewModule(classMap)
vm.SetModule(fileName, module)
vm.InterpretFile(fileName)
vm.Free()
vm2.Free()
}</syntaxhighlight>
<br>
'''Client:'''
<br>
Just one Wren script needed here:
<syntaxhighlight lang="wren">/* Distributed_programming_client.wren */
import "./fmt" for Fmt
foreign class Client {
construct dialHTTP(network, address) {}
foreign call(serviceMethod, arg)
}
var client = Client.dialHTTP("tcp", "localhost:1234")
var amounts = [3, 5.6]
for (amount in amounts) {
var tax = client.call("TaxComputer.Tax", amount)
Fmt.print("Tax on $0.2f = $0.2f", amount, tax)
}</syntaxhighlight>
<br>
which we embed in the following Go program and run it on a different terminal.
<syntaxhighlight lang="go">/* go run Distributed_programming_client.go */
package main
import(
wren "github.com/crazyinfin8/WrenGo"
"log"
"net/rpc"
"strings"
)
type any = interface{}
func dialHTTP(vm *wren.VM, parameters []any) (any, error) {
network := parameters[1].(string)
address := parameters[2].(string)
client, err := rpc.DialHTTP(network, address)
if err != nil {
log.Fatal(err)
}
return &client, nil
}
func call(vm *wren.VM, parameters []any) (any, error) {
handle := parameters[0].(*wren.ForeignHandle)
ifc, _ := handle.Get()
client := ifc.(**rpc.Client)
serviceMethod := parameters[1].(string)
amount := parameters[2].(float64)
var tax float64
err := (*client).Call(serviceMethod, amount, &tax)
if err != nil {
log.Fatal(err)
}
return tax, nil
}
func moduleFn(vm *wren.VM, name string) (string, bool) {
if name != "meta" && name != "random" && !strings.HasSuffix(name, ".wren") {
name += ".wren"
}
return wren.DefaultModuleLoader(vm, name)
}
func main() {
cfg := wren.NewConfig()
cfg.LoadModuleFn = moduleFn
vm := cfg.NewVM()
fileName := "Distributed_programming_client.wren"
clientMethodMap := wren.MethodMap { "call(_,_)": call }
classMap := wren.ClassMap { "Client": wren.NewClass(dialHTTP, nil, clientMethodMap) }
module := wren.NewModule(classMap)
vm.SetModule(fileName, module)
vm.InterpretFile(fileName)
vm.Free()
}</syntaxhighlight>
{{out}}
Output on the client terminal:
<pre>
Tax on 3.00 = 0.15
Tax on 5.60 = 0.28
</pre>
{{omit from|Lotus 123 Macro Scripting}}
{{omit from|Maxima}}
{{omit from|PARI/GP}}
{{omit from|Retro}}
| |||