✨ add test/jsonrpc.nas and fix bug

bug: in nasocket.cpp, recv and recvfrom do not place 0 after reciving
data into the buffer.

module/nasocket.cpp

@@ -34,7 +34,7 @@ var nas_socket(var* args,usize size,gc* ngc) {
 
 var nas_closesocket(var* args,usize size,gc* ngc) {
     if (args[0].type!=vm_num)
-        return nas_err("closesocket","\"\" should be number");
+        return nas_err("closesocket","\"sd\" should be number");
 #ifdef _WIN32
     return var::num((double)closesocket(args[0].num()));
 #else
@@ -149,7 +149,9 @@ var nas_recv(var* args,usize size,gc* ngc) {
     var res=ngc->temp=ngc->alloc(vm_hash);
     auto& hash=res.hash().elems;
     char* buf=new char[(int)args[1].num()];
-    hash["size"]=var::num((double)recv(args[0].num(),buf,args[1].num(),args[2].num()));
+    auto recvsize=recv(args[0].num(),buf,args[1].num(),args[2].num());
+    hash["size"]=var::num((double)recvsize);
+    buf[recvsize>=0?recvsize:0]=0;
     hash["str"]=ngc->newstr(buf);
     delete[] buf;
     ngc->temp=nil;
@@ -171,11 +173,12 @@ var nas_recvfrom(var* args,usize size,gc* ngc) {
     auto& hash=res.hash().elems;
     char* buf=new char[(int)args[1].num()+1];
 #ifdef _WIN32
-    hash["size"]=var::num((double)recvfrom(args[0].num(),buf,args[1].num(),args[2].num(),(sockaddr*)&addr,&socklen));
+    auto recvsize=recvfrom(args[0].num(),buf,args[1].num(),args[2].num(),(sockaddr*)&addr,&socklen);
 #else
-    hash["size"]=var::num((double)recvfrom(args[0].num(),buf,args[1].num(),args[2].num(),(sockaddr*)&addr,(socklen_t*)&socklen));
+    auto recvsize=recvfrom(args[0].num(),buf,args[1].num(),args[2].num(),(sockaddr*)&addr,(socklen_t*)&socklen);
 #endif
-    buf[(int)hash["size"].num()]=0;
+    hash["size"]=var::num((double)recvsize);
+    buf[recvsize>=0?recvsize:0]=0;
     hash["str"]=ngc->newstr(buf);
     delete[] buf;
     hash["fromip"]=ngc->newstr(inet_ntoa(addr.sin_addr));

test/jsonrpc.nas

@@ -0,0 +1,80 @@
+import.module.libsock;
+import.stl.json;
+
+var jsonrpc=func(){
+    var sd=nil;
+    return {
+        establish:func(ip,port) {
+            sd=socket.socket(socket.AF_INET,socket.SOCK_STREAM,socket.IPPROTO_IP);
+            if(socket.bind(sd,ip,port)<0) {
+                println("failed to bind socket "~sd~" at "~ip~":"~port~".");
+                return 0;
+            }
+            socket.listen(sd,1);
+            println("[",os.time(),"] start connection at [",ip,":",port,"]");
+            return 1;
+        },
+        connect:func(ip,port) {
+            sd=socket.socket(socket.AF_INET,socket.SOCK_STREAM,socket.IPPROTO_IP);
+            while(socket.connect(sd,ip,port)<0) {
+                println("[",os.time(),"] failed to connect socket "~sd~" to "~ip~":"~port~", retrying.");
+                unix.sleep(1);
+            }
+            println("[",os.time(),"] start connection at [",ip,":",port,"]");
+            return {ip:ip,sd:sd}; # get server ip and sd
+        },
+        shutdown:func() {
+            println("[",os.time(),"] shutdown");
+            socket.closesocket(sd);
+        },
+        accept:func() {
+            return socket.accept(sd);
+        },
+        disconnect:func(client) {
+            println("[",os.time(),"] [",client.ip,"] disconnected");
+            return socket.closesocket(client.sd);
+        },
+        recv:func(client){
+            var data=socket.recv(client.sd,2048);
+            if(data.size<=0){
+                println("[",os.time(),"] [",client.ip,"] closed connection");
+                return nil;
+            }
+            println("[",os.time(),"] [",client.ip,"] receive ",data.str);
+            return data.str;
+        },
+        send:func(client,content){
+            println("[",os.time(),"] [",client.ip,"] sending ",content);
+            return socket.send(client.sd,content);
+        }
+    };
+}();
+
+var id=1;
+var args=runtime.argv();
+if (size(args)!=0) {
+    if (args[0]=="--server") {
+        jsonrpc.establish("127.0.0.1",8080);
+        var client=jsonrpc.accept();
+        jsonrpc.send(client, JSON.stringify({jsonrpc:2.0, id:1, result:{info:"from server: first info"}}));
+        while(1) {
+            var data=jsonrpc.recv(client);
+            if (data!=nil) {
+                data=JSON.parse(data);
+            } else {
+                break;
+            }
+            jsonrpc.send(client, JSON.stringify({jsonrpc:2.0, id:data.id+1, result:{info:"from server"}}));
+        }
+        jsonrpc.disconnect(client);
+    } elsif (args[0]=="--client") {
+        var server=jsonrpc.connect("127.0.0.1",8080);
+        while(1) {
+            unix.sleep(1);
+            var respond=JSON.parse(jsonrpc.recv(server));
+            var data=JSON.stringify({jsonrpc:2.0, id:respond.id+1, result:{info:"from client"}});
+            jsonrpc.send(server, data);
+        }
+        jsonrpc.disconnect(server);
+    }
+}