cosmos-sdk/client/common.go

package client

import (
	"errors"

	"github.com/tendermint/light-client/certifiers"
	certclient "github.com/tendermint/light-client/certifiers/client"
	certerr "github.com/tendermint/light-client/certifiers/errors"
	"github.com/tendermint/light-client/certifiers/files"

	"github.com/tendermint/light-client/proofs"

	rpcclient "github.com/tendermint/tendermint/rpc/client"
)

// GetNode prepares a simple rpc.Client for the given endpoint
func GetNode(url string) rpcclient.Client {
	return rpcclient.NewHTTP(url, "/websocket")
}

// GetRPCProvider retuns a certifier compatible data source using
// tendermint RPC
func GetRPCProvider(url string) certifiers.Provider {
	return certclient.NewHTTPProvider(url)
}

// GetLocalProvider returns a reference to a file store of headers
// wrapped with an in-memory cache
func GetLocalProvider(dir string) certifiers.Provider {
	return certifiers.NewCacheProvider(
		certifiers.NewMemStoreProvider(),
		files.NewProvider(dir),
	)
}

// GetCertifier initializes an inquiring certifier given a fixed chainID
// and a local source of trusted data with at least one seed
func GetCertifier(chainID string, trust certifiers.Provider,
	source certifiers.Provider) (*certifiers.Inquiring, error) {

	// this gets the most recent verified commit
	fc, err := trust.LatestCommit()
	if certerr.IsCommitNotFoundErr(err) {
		return nil, errors.New("Please run init first to establish a root of trust")
	}
	if err != nil {
		return nil, err
	}
	cert := certifiers.NewInquiring(chainID, fc, trust, source)
	return cert, nil
}

// SecureClient uses a given certifier to wrap an connection to an untrusted
// host and return a cryptographically secure rpc client.
func SecureClient(c rpcclient.Client, cert *certifiers.Inquiring) rpcclient.Client {
	return proofs.Wrap(c, cert)
}