diff options
Diffstat (limited to 'rpc/v2/doc.go')
-rw-r--r-- | rpc/v2/doc.go | 102 |
1 files changed, 102 insertions, 0 deletions
diff --git a/rpc/v2/doc.go b/rpc/v2/doc.go new file mode 100644 index 000000000..e51494adb --- /dev/null +++ b/rpc/v2/doc.go @@ -0,0 +1,102 @@ +// Copyright 2015 The go-ethereum Authors +// This file is part of the go-ethereum library. +// +// The go-ethereum library is free software: you can redistribute it and/or modify +// it under the terms of the GNU Lesser General Public License as published by +// the Free Software Foundation, either version 3 of the License, or +// (at your option) any later version. +// +// The go-ethereum library is distributed in the hope that it will be useful, +// but WITHOUT ANY WARRANTY; without even the implied warranty of +// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the +// GNU Lesser General Public License for more details. +// +// You should have received a copy of the GNU Lesser General Public License +// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>. + +/* +Package rpc provides access to the exported methods of an object across a network +or other I/O connection. After creating a server instance objects can be registered, +making it visible from the outside. Exported methods that follow specific +conventions can be called remotely. It also has support for the publish/subscribe +pattern. + +Methods that satisfy the following criteria are made available for remote access: + - object must be exported + - method must be exported + - method returns 0, 1 (response or error) or 2 (response and error) values + - method argument(s) must be exported or builtin types + - method returned value(s) must be exported or builtin types + +An example method: + func (s *CalcService) Div(a, b int) (int, error) + +When the returned error isn't nil the returned integer is ignored and the error is +send back to the client. Otherwise the returned integer is send back to the client. + +The server offers the ServeCodec method which accepts a ServerCodec instance. It will +read requests from the codec, process the request and sends the response back to the +client using the codec. The server can execute requests concurrently. Responses +can be send back to the client out of order. + +An example server which uses the JSON codec: + type CalculatorService struct {} + + func (s *CalculatorService) Add(a, b int) int { + return a + b + } + + func (s *CalculatorService Div(a, b int) (int, error) { + if b == 0 { + return 0, errors.New("divide by zero") + } + return a/b, nil + } + + calculator := new(CalculatorService) + server := NewServer() + server.RegisterName("calculator", calculator") + + l, _ := net.ListenUnix("unix", &net.UnixAddr{Net: "unix", Name: "/tmp/calculator.sock"}) + for { + c, _ := l.AcceptUnix() + codec := v2.NewJSONCodec(c) + go server.ServeCodec(codec) + } + +The package also supports the publish subscribe pattern through the use of subscriptions. +A method that is considered eligible for notifications must satisfy the following criteria: + - object must be exported + - method must be exported + - method argument(s) must be exported or builtin types + - method must return the tuple Subscription, error + + +An example method: + func (s *BlockChainService) Head() (Subscription, error) { + sub := s.bc.eventMux.Subscribe(ChainHeadEvent{}) + return v2.NewSubscription(sub), nil + } + +This method will push all raised ChainHeadEvents to subscribed clients. If the client is only +interested in every N'th block it is possible to add a criteria. + + func (s *BlockChainService) HeadFiltered(nth uint64) (Subscription, error) { + sub := s.bc.eventMux.Subscribe(ChainHeadEvent{}) + + criteria := func(event interface{}) bool { + chainHeadEvent := event.(ChainHeadEvent) + if chainHeadEvent.Block.NumberU64() % nth == 0 { + return true + } + return false + } + + return v2.NewSubscriptionFiltered(sub, criteria), nil + } + +Subscriptions are deleted when: + - the user sends an unsubscribe request + - the connection which was used to create the subscription is closed +*/ +package v2 |