Official Go implementation of the Ethereum protocol
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go-ethereum/common/httpclient/httpclient.go

124 lines
3.1 KiB

// 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 httpclient
import (
"fmt"
"io/ioutil"
"net/http"
"path/filepath"
"github.com/ethereum/go-ethereum/common"
"github.com/ethereum/go-ethereum/crypto"
)
type HTTPClient struct {
*http.Transport
DocRoot string
schemes []string
}
func New(docRoot string) (self *HTTPClient) {
self = &HTTPClient{
Transport: &http.Transport{},
DocRoot: docRoot,
schemes: []string{"file"},
}
self.RegisterProtocol("file", http.NewFileTransport(http.Dir(self.DocRoot)))
return
}
// Clients should be reused instead of created as needed. Clients are safe for concurrent use by multiple goroutines.
// A Client is higher-level than a RoundTripper (such as Transport) and additionally handles HTTP details such as cookies and redirects.
func (self *HTTPClient) Client() *http.Client {
return &http.Client{
Transport: self,
}
}
func (self *HTTPClient) RegisterScheme(scheme string, rt http.RoundTripper) {
self.schemes = append(self.schemes, scheme)
self.RegisterProtocol(scheme, rt)
}
func (self *HTTPClient) HasScheme(scheme string) bool {
for _, s := range self.schemes {
if s == scheme {
return true
}
}
return false
}
func (self *HTTPClient) GetAuthContent(uri string, hash common.Hash) ([]byte, error) {
// retrieve content
content, err := self.Get(uri, "")
if err != nil {
return nil, err
}
// check hash to authenticate content
chash := crypto.Keccak256Hash(content)
if chash != hash {
return nil, fmt.Errorf("content hash mismatch %x != %x (exp)", hash[:], chash[:])
}
return content, nil
}
// Get(uri, path) downloads the document at uri, if path is non-empty it
// is interpreted as a filepath to which the contents are saved
func (self *HTTPClient) Get(uri, path string) ([]byte, error) {
// retrieve content
resp, err := self.Client().Get(uri)
if err != nil {
return nil, err
}
defer func() {
if resp != nil {
resp.Body.Close()
}
}()
var content []byte
content, err = ioutil.ReadAll(resp.Body)
if err != nil {
return nil, err
}
if resp.StatusCode/100 != 2 {
return content, fmt.Errorf("HTTP error: %s", resp.Status)
}
if path != "" {
var abspath string
abspath, err = filepath.Abs(path)
if err != nil {
return nil, err
}
err = ioutil.WriteFile(abspath, content, 0600)
if err != nil {
return nil, err
}
}
return content, nil
}