2 files changed, 74 insertions, 3 deletions
diff --git a/client/client.go b/client/client.go
index 551eff7..34fa8a2 100644
--- a/client/client.go
+++ b/client/client.go
@@ -49,7 +49,7 @@ func NewClientFromPath(logId, chainPath, keyPath, operatorsPath string, cli *htt
 	}
 
 	k, err := stfe.LoadEd25519SigningKey(keyPath)
-	if err != nil {
+	if err != nil && keyPath != "" {
 		return nil, err
 	}
 
@@ -119,8 +119,24 @@ func (c *Client) AddEntry(ctx context.Context, name, checksum []byte) (*stfe.StI
 }
 
 func (c *Client) GetSth(ctx context.Context) (*stfe.StItem, error) {
-	glog.V(2).Info("creating get-sth request")
-	return nil, fmt.Errorf("TODO")
+	req, err := http.NewRequest("GET", c.protocol()+c.Log.BaseUrl+"/get-sth", nil)
+	if err != nil {
+		return nil, fmt.Errorf("failed creating http request: %v", err)
+	}
+	glog.V(2).Infof("created request: %s %s", req.Method, req.URL)
+
+	item, err := c.doRequestWithStItemResponse(ctx, req)
+	if err != nil {
+		return nil, err
+	}
+	if item.Format != stfe.StFormatSignedTreeHeadV1 {
+		return nil, fmt.Errorf("bad StItem format: %v", item.Format)
+	}
+	if err := item.SignedTreeHeadV1.Verify(c.Log.Scheme, c.Log.PublicKey); err != nil {
+		return nil, fmt.Errorf("bad SignedDebugInfoV1 signature: %v", err)
+	}
+	glog.V(2).Infof("get-sth request succeeded")
+	return item, nil
 }
 
 func (c *Client) GetConsistencyProof(ctx context.Context, first, second uint64) (*stfe.StItem, error) {
@@ -171,6 +187,22 @@ func (c *Client) doRequest(ctx context.Context, req *http.Request, out interface
 	return nil
 }
 
+func (c *Client) doRequestWithStItemResponse(ctx context.Context, req *http.Request) (*stfe.StItem, error) {
+	var itemStr string
+	if err := c.doRequest(ctx, req, &itemStr); err != nil {
+		return nil, err
+	}
+	b, err := base64.StdEncoding.DecodeString(itemStr)
+	if err != nil {
+		return nil, fmt.Errorf("failed decoding base64 body: %v", err)
+	}
+	var item stfe.StItem
+	if err := item.Unmarshal(b); err != nil {
+		return nil, fmt.Errorf("failed decoding StItem: %v", err)
+	}
+	return &item, nil
+}
+
 // protocol returns a protocol string that preceeds the log's base url
 func (c *Client) protocol() string {
 	if c.useHttp {
diff --git a/client/get-sth/main.go b/client/get-sth/main.go
new file mode 100644
index 0000000..6f0075b
--- /dev/null
+++ b/client/get-sth/main.go
@@ -0,0 +1,39 @@
+package main
+
+import (
+	"context"
+	"flag"
+	"fmt"
+
+	"net/http"
+
+	"github.com/golang/glog"
+	"github.com/system-transparency/stfe/client"
+)
+
+var (
+	operators = flag.String("operators", "../../server/descriptor/stfe.json", "path to json-encoded list of log operators")
+	logId     = flag.String("log_id", "B9oCJk4XIOMXba8dBM5yUj+NLtqTE6xHwbvR9dYkHPM=", "base64-encoded log identifier")
+	chain     = flag.String("chain", "../../server/testdata/chain/ee.pem", "path to pem-encoded certificate chain that the log accepts")
+)
+
+func main() {
+	flag.Parse()
+
+	client, err := client.NewClientFromPath(*logId, *chain, "", *operators, &http.Client{}, true)
+	if err != nil {
+		glog.Fatal(err)
+	}
+	sth, err := client.GetSth(context.Background())
+	if err != nil {
+		glog.Fatalf("get-sth failed: %v", err)
+	}
+
+	str, err := sth.MarshalB64()
+	if err != nil {
+		glog.Fatalf("failed encoding valid signed tree head: %v", err)
+	}
+	fmt.Println(str)
+
+	glog.Flush()
+}