Implemented safe update.

client.go

@@ -77,7 +77,7 @@ type Meta struct {
 	Plain        map[string]string `json:"plain"`
 	Created      time.Time         `json:"created"`
 	LastModified time.Time         `json:"last_modified"`
-	Version string         `json:"version"`
+	Version string         `json:"version,omitempty"`
 }
 
 // Record contains a plaintext 'Meta' object containing record metadata,
@@ -294,12 +294,19 @@ func (c *Client) Read(ctx context.Context, recordID string) (*Record, error) {
 // Write writes a new encrypted record to the database. Returns the new record (with
 // the original, unencrypted data)
 func (c *Client) Write(ctx context.Context, recordType string, data *map[string]string, plain *map[string]string) (*Record, error) {
+	var plainMap map[string]string
+	if plain == nil {
+		plainMap = nil
+	}	else {
+		plainMap = *plain
+	}
+
 	record := &Record{
 		Meta: Meta{
 			Type:     recordType,
 			WriterID: c.Options.ClientID,
 			UserID:   c.Options.ClientID, // for now
-			Plain: *plain,
+			Plain: plainMap,
 		},
 		Data: *data,
 	}
@@ -319,7 +326,7 @@ func (c *Client) Write(ctx context.Context, recordType string, data *map[string]
 	resp, err := c.rawCall(ctx, req, encryptedRecord)
 	if err != nil {
 		return nil, err
-	}
+ 	}
 
 	defer closeResp(resp)
 
@@ -330,6 +337,35 @@ func (c *Client) Write(ctx context.Context, recordType string, data *map[string]
 	return record, nil
 }
 
+// Updates a record, if the version field matches the
+// version stored by E3DB. 
+// 
+// Returns HTTP 409 (Conflict) in error if the record cannot be updated.
+func (c *Client) Update(ctx context.Context, record *Record) error {
+	encryptedRecord, err := c.encryptRecord(ctx, record)
+	if err != nil {
+		return err
+	}
+
+	buf := new(bytes.Buffer)
+	json.NewEncoder(buf).Encode(encryptedRecord)
+	u := fmt.Sprintf("%s/v1/storage/records/safe/%s/%s", c.apiURL(), url.QueryEscape(record.Meta.RecordID), url.QueryEscape(record.Meta.Version))
+	req, err := http.NewRequest("PUT", u, buf)
+	if err != nil {
+		return err
+	}
+
+	resp, err := c.rawCall(ctx, req, encryptedRecord)
+	if err != nil {
+		return err
+	}
+
+	defer closeResp(resp)
+
+	record.Meta = encryptedRecord.Meta
+	return nil
+}
+
 // Delete deletes a record given a record ID.
 func (c *Client) Delete(ctx context.Context, recordID string) error {
 	u := fmt.Sprintf("%s/v1/storage/records/%s", c.apiURL(), url.QueryEscape(recordID))

client_integration_test.go

@@ -15,6 +15,7 @@ import (
 	"fmt"
 	"os"
 	"testing"
+	"net/http"
 
 	cli "github.com/jawher/mow.cli"
 )
@@ -75,12 +76,13 @@ func TestGetClientInfo(t *testing.T) {
 }
 
 func TestWriteRead(t *testing.T) {
-	rec1 := client.NewRecord("test-data")
-	rec1.Data["message"] = "Hello, world!"
-	recordID, err := client.Write(context.Background(), rec1)
+	data := make(map[string]string)
+	data["message"] = "Hello, world!"
+	rec1, err := client.Write(context.Background(), "test-data", &data, nil)
 	if err != nil {
 		t.Fatal(err)
 	}
+	recordID := rec1.Meta.RecordID
 
 	rec2, err := client.Read(context.Background(), recordID)
 	if err != nil {
@@ -106,12 +108,13 @@ func TestWriteRead(t *testing.T) {
 
 // TestWriteThenDelete should delete a record
 func TestWriteThenDelete(t *testing.T) {
-	rec1 := client.NewRecord("test-data")
-	rec1.Data["message"] = "Hello, world!"
-	recordID, err := client.Write(context.Background(), rec1)
+	data := make(map[string]string)
+	data["message"] = "Hello, world!"
+	record, err := client.Write(context.Background(), "test-data", &data, nil)
 	if err != nil {
 		t.Fatal(err)
 	}
+	recordID := record.Meta.RecordID
 
 	err = client.Delete(context.Background(), recordID)
 	if err != nil {
@@ -120,9 +123,9 @@ func TestWriteThenDelete(t *testing.T) {
 }
 
 func TestShare(t *testing.T) {
-	rec1 := client.NewRecord("test-data")
-	rec1.Data["message"] = "Hello, world!"
-	_, err := client.Write(context.Background(), rec1)
+	data := make(map[string]string)
+	data["message"] = "Hello, world!"
+	_, err := client.Write(context.Background(), "test-data", &data, nil)
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -135,9 +138,9 @@ func TestShare(t *testing.T) {
 
 // TestShareThenUnshare should share then revoke sharing
 func TestShareThenUnshare(t *testing.T) {
-	rec1 := client.NewRecord("test-share-data")
-	rec1.Data["message"] = "Hello, world!"
-	_, err := client.Write(context.Background(), rec1)
+	data := make(map[string]string)
+	data["message"] = "Hello, world!"
+	_, err := client.Write(context.Background(), "test-share-data", &data, nil)
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -186,3 +189,57 @@ func TestEvents(t *testing.T) {
 	for range done {
 	}
 }
+
+func TestCounter(t *testing.T) {
+	data := make(map[string]string)
+	data["counter"] = "1"
+	rec1, err := client.Write(context.Background(), "test-data", &data, nil)
+	if err != nil {
+		t.Fatal(err)
+	}
+	recordID := rec1.Meta.RecordID
+
+	// Update w/ correct version
+	err = client.Update(context.Background(), rec1)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	rec1.Data["counter"] = "X"
+	rec1.Meta.Version = "6bc381c7-a41d-45ae-89aa-0890ad654673"
+	// should not update
+	err = client.Update(context.Background(), rec1)
+	if err == nil {
+		t.Fatal("Should not be able to update record with wrong version.")
+	}
+
+	if httpErr, ok := err.(*httpError); ok {
+		if httpErr.StatusCode != http.StatusConflict {
+			t.Fatal("Version conflict not reported.")
+		}
+	}
+
+	rec2, err := client.Read(context.Background(), recordID)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	if rec2.Data["counter"] != "1" {
+		t.Fatal("Counter had wrong value.")
+	}
+
+	rec2.Data["counter"] = "2"
+	err = client.Update(context.Background(), rec2)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	rec3, err := client.Read(context.Background(), recordID)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	if rec3.Data["counter"] != "2" {
+		t.Fatal("Counter had wrong value")
+	}
+}