pkg/client: Search fix zero-value Describe queries.

Adds support for zero value blob.Ref {Unm,M}arshalJSON.

Fix for:
https://camlistore.org/issue/308

Change-Id: I910fc4f05015b0c3ddc57eba9d1d8fe1bfe992bf

pkg/blob/ref.go

@@ -464,23 +464,31 @@ func ValidRefString(s string) bool {
 	return ParseOrZero(s).Valid()
 }
 
+var null = []byte(`null`)
+
 func (r *Ref) UnmarshalJSON(d []byte) error {
 	if r.digest != nil {
 		return errors.New("Can't UnmarshalJSON into a non-zero Ref")
 	}
+	if len(d) == 0 || bytes.Equal(d, null) {
+		return nil
+	}
 	if len(d) < 2 || d[0] != '"' || d[len(d)-1] != '"' {
 		return fmt.Errorf("blob: expecting a JSON string to unmarshal, got %q", d)
 	}
-	refStr := string(d[1 : len(d)-1])
-	p, ok := Parse(refStr)
+	d = d[1 : len(d)-1]
+	p, ok := ParseBytes(d)
 	if !ok {
-		return fmt.Errorf("blobref: invalid blobref %q (%d)", refStr, len(refStr))
+		return fmt.Errorf("blobref: invalid blobref %q (%d)", d, len(d))
 	}
 	*r = p
 	return nil
 }
 
 func (r Ref) MarshalJSON() ([]byte, error) {
+	if !r.Valid() {
+		return null, nil
+	}
 	dname := r.digest.digestName()
 	bs := r.digest.bytes()
 	buf := make([]byte, 0, 3+len(dname)+len(bs)*2)

pkg/blob/ref_test.go

@@ -126,14 +126,39 @@ func TestJSONUnmarshal(t *testing.T) {
 	if g, e := f.B.String(), "abc-def123"; g != e {
 		t.Errorf("got %q, want %q", g, e)
 	}
+
+	f = Foo{}
+	if err := json.Unmarshal([]byte(`{}`), &f); err != nil {
+		t.Fatalf("Unmarshal: %v", err)
+	}
+	if f.B.Valid() {
+		t.Fatal("blobref is valid and shouldn't be")
+	}
+
+	f = Foo{}
+	if err := json.Unmarshal([]byte(`{"foo":null}`), &f); err != nil {
+		t.Fatalf("Unmarshal: %v", err)
+	}
+	if f.B.Valid() {
+		t.Fatal("blobref is valid and shouldn't be")
+	}
 }
 
 func TestJSONMarshal(t *testing.T) {
-	f := &Foo{B: MustParse("def-1234abcd")}
+	f := &Foo{}
 	bs, err := json.Marshal(f)
 	if err != nil {
 		t.Fatalf("Marshal: %v", err)
 	}
+	if g, e := string(bs), `{"foo":null}`; g != e {
+		t.Errorf("got %q, want %q", g, e)
+	}
+
+	f = &Foo{B: MustParse("def-1234abcd")}
+	bs, err = json.Marshal(f)
+	if err != nil {
+		t.Fatalf("Marshal: %v", err)
+	}
 	if g, e := string(bs), `{"foo":"def-1234abcd"}`; g != e {
 		t.Errorf("got %q, want %q", g, e)
 	}

pkg/search/handler.go

@@ -642,26 +642,28 @@ func (sh *Handler) serveClaims(rw http.ResponseWriter, req *http.Request) {
 type DescribeRequest struct {
 	// BlobRefs are the blobs to describe. If length zero, BlobRef
 	// is used.
-	BlobRefs []blob.Ref
+	BlobRefs []blob.Ref `json:"blobrefs,omitempty"`
 
 	// BlobRef is the blob to describe.
-	BlobRef blob.Ref
+	BlobRef blob.Ref `json:"blobref,omitempty"`
 
 	// Depth is the optional traversal depth to describe from the
 	// root BlobRef. If zero, a default is used.
-	Depth int
+	Depth int `json:"depth,omitempty"`
 	// MaxDirChildren is the requested optional limit to the number
 	// of children that should be fetched when describing a static
 	// directory. If zero, a default is used.
-	MaxDirChildren int
+	MaxDirChildren int `json:"maxDirChildren,omitempty"`
 
 	// At specifies the time which we wish to see the state of
 	// this blob.  If zero (unspecified), all claims will be
 	// considered, otherwise, any claims after this date will not
 	// be considered.
-	At types.Time3339
+	At types.Time3339 `json:"at"`
 
-	ThumbnailSize int // or zero for none
+	// ThumbnailSize sets the max dimension for the thumbnail ULR generated,
+	// or zero for none
+	ThumbnailSize int `json:"thumbnailSize,omitempty"`
 
 	// Internal details, used while loading.
 	// Initialized by sh.initDescribeRequest.

pkg/search/query_test.go

@@ -895,6 +895,60 @@ func TestPlannedQuery(t *testing.T) {
 	}
 }
 
+func TestDescribeMarshal(t *testing.T) {
+	// Empty Describe
+	q := &SearchQuery{
+		Describe: &DescribeRequest{},
+	}
+	enc, err := json.Marshal(q)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if got, want := string(enc), `{"describe":{"blobref":null,"at":null}}`; got != want {
+		t.Errorf("JSON: %s; want %s", got, want)
+	}
+	back := &SearchQuery{}
+	err = json.Unmarshal(enc, back)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if !reflect.DeepEqual(q, back) {
+		t.Errorf("Didn't round-trip. Got %#v; want %#v", back, q)
+	}
+
+	// DescribeRequest with multiple blobref
+	q = &SearchQuery{
+		Describe: &DescribeRequest{
+			BlobRefs: []blob.Ref{blob.MustParse("sha-1234"), blob.MustParse("sha-abcd")},
+		},
+	}
+	enc, err = json.Marshal(q)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if got, want := string(enc), `{"describe":{"blobrefs":["sha-1234","sha-abcd"],"blobref":null,"at":null}}`; got != want {
+		t.Errorf("JSON: %s; want %s", got, want)
+	}
+	back = &SearchQuery{}
+	err = json.Unmarshal(enc, back)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if !reflect.DeepEqual(q, back) {
+		t.Errorf("Didn't round-trip. Got %#v; want %#v", back, q)
+	}
+
+	// and the zero value
+	q = &SearchQuery{}
+	enc, err = json.Marshal(q)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if string(enc) != "{}" {
+		t.Errorf(`Zero value: %q; want null`, enc)
+	}
+}
+
 func TestSortMarshal(t *testing.T) {
 	q := &SearchQuery{
 		Sort: CreatedDesc,
@@ -904,7 +958,7 @@ func TestSortMarshal(t *testing.T) {
 		t.Fatal(err)
 	}
 	if got, want := string(enc), `{"sort":"-created"}`; got != want {
-		t.Logf("JSON: %s; want %s", got, want)
+		t.Errorf("JSON: %s; want %s", got, want)
 	}
 	back := &SearchQuery{}
 	err = json.Unmarshal(enc, back)