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b628d72766
This changes the CI / release builds to use the latest Go version. It also upgrades golangci-lint to a newer version compatible with Go 1.19. In Go 1.19, godoc has gained official support for links and lists. The syntax for code blocks in doc comments has changed and now requires a leading tab character. gofmt adapts comments to the new syntax automatically, so there are a lot of comment re-formatting changes in this PR. We need to apply the new format in order to pass the CI lint stage with Go 1.19. With the linter upgrade, I have decided to disable 'gosec' - it produces too many false-positive warnings. The 'deadcode' and 'varcheck' linters have also been removed because golangci-lint warns about them being unmaintained. 'unused' provides similar coverage and we already have it enabled, so we don't lose much with this change.
110 lines
4.3 KiB
Go
110 lines
4.3 KiB
Go
// Copyright 2015 The go-ethereum Authors
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// This file is part of the go-ethereum library.
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//
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// The go-ethereum library is free software: you can redistribute it and/or modify
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// it under the terms of the GNU Lesser General Public License as published by
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// the Free Software Foundation, either version 3 of the License, or
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// (at your option) any later version.
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//
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// The go-ethereum library is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU Lesser General Public License for more details.
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//
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// You should have received a copy of the GNU Lesser General Public License
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// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
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/*
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Package rpc implements bi-directional JSON-RPC 2.0 on multiple transports.
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It provides access to the exported methods of an object across a network or other I/O
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connection. After creating a server or client instance, objects can be registered to make
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them visible as 'services'. Exported methods that follow specific conventions can be
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called remotely. It also has support for the publish/subscribe pattern.
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# RPC Methods
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Methods that satisfy the following criteria are made available for remote access:
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- method must be exported
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- method returns 0, 1 (response or error) or 2 (response and error) values
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An example method:
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func (s *CalcService) Add(a, b int) (int, error)
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When the returned error isn't nil the returned integer is ignored and the error is sent
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back to the client. Otherwise the returned integer is sent back to the client.
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Optional arguments are supported by accepting pointer values as arguments. E.g. if we want
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to do the addition in an optional finite field we can accept a mod argument as pointer
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value.
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func (s *CalcService) Add(a, b int, mod *int) (int, error)
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This RPC method can be called with 2 integers and a null value as third argument. In that
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case the mod argument will be nil. Or it can be called with 3 integers, in that case mod
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will be pointing to the given third argument. Since the optional argument is the last
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argument the RPC package will also accept 2 integers as arguments. It will pass the mod
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argument as nil to the RPC method.
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The server offers the ServeCodec method which accepts a ServerCodec instance. It will read
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requests from the codec, process the request and sends the response back to the client
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using the codec. The server can execute requests concurrently. Responses can be sent back
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to the client out of order.
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An example server which uses the JSON codec:
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type CalculatorService struct {}
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func (s *CalculatorService) Add(a, b int) int {
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return a + b
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}
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func (s *CalculatorService) Div(a, b int) (int, error) {
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if b == 0 {
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return 0, errors.New("divide by zero")
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}
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return a/b, nil
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}
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calculator := new(CalculatorService)
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server := NewServer()
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server.RegisterName("calculator", calculator)
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l, _ := net.ListenUnix("unix", &net.UnixAddr{Net: "unix", Name: "/tmp/calculator.sock"})
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server.ServeListener(l)
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# Subscriptions
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The package also supports the publish subscribe pattern through the use of subscriptions.
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A method that is considered eligible for notifications must satisfy the following
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criteria:
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- method must be exported
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- first method argument type must be context.Context
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- method must have return types (rpc.Subscription, error)
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An example method:
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func (s *BlockChainService) NewBlocks(ctx context.Context) (rpc.Subscription, error) {
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...
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}
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When the service containing the subscription method is registered to the server, for
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example under the "blockchain" namespace, a subscription is created by calling the
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"blockchain_subscribe" method.
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Subscriptions are deleted when the user sends an unsubscribe request or when the
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connection which was used to create the subscription is closed. This can be initiated by
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the client and server. The server will close the connection for any write error.
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For more information about subscriptions, see https://github.com/ethereum/go-ethereum/wiki/RPC-PUB-SUB.
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# Reverse Calls
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In any method handler, an instance of rpc.Client can be accessed through the
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ClientFromContext method. Using this client instance, server-to-client method calls can be
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performed on the RPC connection.
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*/
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package rpc
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