bsc/rpc/errors.go
zhiqiangxu 6f08c2f3f1
rpc: add method to test for subscription support (#25942)
This adds two ways to check for subscription support. First, one can now check
whether the transport method (HTTP/WS/etc.) is capable of subscriptions using
the new Client.SupportsSubscriptions method.

Second, the error returned by Subscribe can now reliably be tested using this
pattern:
    
    sub, err := client.Subscribe(...)
    if errors.Is(err, rpc.ErrNotificationsUnsupported) {
        // no subscription support
    }

---------

Co-authored-by: Felix Lange <fjl@twurst.com>
2023-06-14 14:04:41 +02:00

157 lines
4.7 KiB
Go

// 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
import "fmt"
// HTTPError is returned by client operations when the HTTP status code of the
// response is not a 2xx status.
type HTTPError struct {
StatusCode int
Status string
Body []byte
}
func (err HTTPError) Error() string {
if len(err.Body) == 0 {
return err.Status
}
return fmt.Sprintf("%v: %s", err.Status, err.Body)
}
// Error wraps RPC errors, which contain an error code in addition to the message.
type Error interface {
Error() string // returns the message
ErrorCode() int // returns the code
}
// A DataError contains some data in addition to the error message.
type DataError interface {
Error() string // returns the message
ErrorData() interface{} // returns the error data
}
// Error types defined below are the built-in JSON-RPC errors.
var (
_ Error = new(methodNotFoundError)
_ Error = new(subscriptionNotFoundError)
_ Error = new(parseError)
_ Error = new(invalidRequestError)
_ Error = new(invalidMessageError)
_ Error = new(invalidParamsError)
_ Error = new(internalServerError)
)
const (
errcodeDefault = -32000
errcodeTimeout = -32002
errcodeResponseTooLarge = -32003
errcodePanic = -32603
errcodeMarshalError = -32603
legacyErrcodeNotificationsUnsupported = -32001
)
const (
errMsgTimeout = "request timed out"
errMsgResponseTooLarge = "response too large"
errMsgBatchTooLarge = "batch too large"
)
type methodNotFoundError struct{ method string }
func (e *methodNotFoundError) ErrorCode() int { return -32601 }
func (e *methodNotFoundError) Error() string {
return fmt.Sprintf("the method %s does not exist/is not available", e.method)
}
type notificationsUnsupportedError struct{}
func (e notificationsUnsupportedError) Error() string {
return "notifications not supported"
}
func (e notificationsUnsupportedError) ErrorCode() int { return -32601 }
// Is checks for equivalence to another error. Here we define that all errors with code
// -32601 (method not found) are equivalent to notificationsUnsupportedError. This is
// done to enable the following pattern:
//
// sub, err := client.Subscribe(...)
// if errors.Is(err, rpc.ErrNotificationsUnsupported) {
// // server doesn't support subscriptions
// }
func (e notificationsUnsupportedError) Is(other error) bool {
if other == (notificationsUnsupportedError{}) {
return true
}
rpcErr, ok := other.(Error)
if ok {
code := rpcErr.ErrorCode()
return code == -32601 || code == legacyErrcodeNotificationsUnsupported
}
return false
}
type subscriptionNotFoundError struct{ namespace, subscription string }
func (e *subscriptionNotFoundError) ErrorCode() int { return -32601 }
func (e *subscriptionNotFoundError) Error() string {
return fmt.Sprintf("no %q subscription in %s namespace", e.subscription, e.namespace)
}
// Invalid JSON was received by the server.
type parseError struct{ message string }
func (e *parseError) ErrorCode() int { return -32700 }
func (e *parseError) Error() string { return e.message }
// received message isn't a valid request
type invalidRequestError struct{ message string }
func (e *invalidRequestError) ErrorCode() int { return -32600 }
func (e *invalidRequestError) Error() string { return e.message }
// received message is invalid
type invalidMessageError struct{ message string }
func (e *invalidMessageError) ErrorCode() int { return -32700 }
func (e *invalidMessageError) Error() string { return e.message }
// unable to decode supplied params, or an invalid number of parameters
type invalidParamsError struct{ message string }
func (e *invalidParamsError) ErrorCode() int { return -32602 }
func (e *invalidParamsError) Error() string { return e.message }
// internalServerError is used for server errors during request processing.
type internalServerError struct {
code int
message string
}
func (e *internalServerError) ErrorCode() int { return e.code }
func (e *internalServerError) Error() string { return e.message }