2 files changed, 120 insertions, 0 deletions
diff --git a/common/docserver/docserver.go b/common/docserver/docserver.go
new file mode 100644
index 000000000..5e076aa7e
--- /dev/null
+++ b/common/docserver/docserver.go
@@ -0,0 +1,82 @@
+package docserver
+
+import (
+	"fmt"
+	"io/ioutil"
+	"net/http"
+
+	"github.com/ethereum/go-ethereum/common"
+	"github.com/ethereum/go-ethereum/crypto"
+)
+
+// http://golang.org/pkg/net/http/#RoundTripper
+var (
+	schemes = map[string]func(*DocServer) http.RoundTripper{
+		// Simple File server from local disk file:///etc/passwd :)
+		"file": fileServerOnDocRoot,
+	}
+)
+
+func fileServerOnDocRoot(ds *DocServer) http.RoundTripper {
+	return http.NewFileTransport(http.Dir(ds.DocRoot))
+}
+
+type DocServer struct {
+	*http.Transport
+	DocRoot string
+}
+
+func New(docRoot string) (self *DocServer, err error) {
+	self = &DocServer{
+		Transport: &http.Transport{},
+		DocRoot:   docRoot,
+	}
+	err = self.RegisterProtocols(schemes)
+	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 *DocServer) Client() *http.Client {
+	return &http.Client{
+		Transport: self,
+	}
+}
+
+func (self *DocServer) RegisterProtocols(schemes map[string]func(*DocServer) http.RoundTripper) (err error) {
+	for scheme, rtf := range schemes {
+		self.RegisterProtocol(scheme, rtf(self))
+	}
+	return
+}
+
+func (self *DocServer) GetAuthContent(uri string, hash common.Hash) (content []byte, err error) {
+	// retrieve content
+	resp, err := self.Client().Get(uri)
+	defer func() {
+		if resp != nil {
+			resp.Body.Close()
+		}
+	}()
+	if err != nil {
+		return
+	}
+	content, err = ioutil.ReadAll(resp.Body)
+	if err != nil {
+		return
+	}
+
+	// check hash to authenticate content
+	hashbytes := crypto.Sha3(content)
+	var chash common.Hash
+	copy(chash[:], hashbytes)
+	if chash != hash {
+		content = nil
+		err = fmt.Errorf("content hash mismatch")
+	}
+
+	return
+
+}
diff --git a/common/docserver/docserver_test.go b/common/docserver/docserver_test.go
new file mode 100644
index 000000000..400d7447a
--- /dev/null
+++ b/common/docserver/docserver_test.go
@@ -0,0 +1,38 @@
+package docserver
+
+import (
+	"io/ioutil"
+	"os"
+	"testing"
+
+	"github.com/ethereum/go-ethereum/common"
+	"github.com/ethereum/go-ethereum/crypto"
+)
+
+func TestGetAuthContent(t *testing.T) {
+	text := "test"
+	hash := common.Hash{}
+	copy(hash[:], crypto.Sha3([]byte(text)))
+	ioutil.WriteFile("/tmp/test.content", []byte(text), os.ModePerm)
+
+	ds, err := New("/tmp/")
+	content, err := ds.GetAuthContent("file:///test.content", hash)
+	if err != nil {
+		t.Errorf("no error expected, got %v", err)
+	}
+	if string(content) != text {
+		t.Errorf("incorrect content. expected %v, got %v", text, string(content))
+	}
+
+	hash = common.Hash{}
+	content, err = ds.GetAuthContent("file:///test.content", hash)
+	expected := "content hash mismatch"
+	if err == nil {
+		t.Errorf("expected error, got nothing")
+	} else {
+		if err.Error() != expected {
+			t.Errorf("expected error '%s' got '%v'", expected, err)
+		}
+	}
+
+}