http: expose node delete api; resolves #622

docs/HTTP.md

@@ -1,6 +1,7 @@
 # HTTP Methods
 
-This file cover deprecated v1 HTTP API. All the methods of v2 HTTP API is described in OpenAPI/Swagger [spec](./api/swagger.yml) and can be viewed by passing `https://raw.githubusercontent.com/cayleygraph/cayley/master/docs/api/swagger.yml` address to [Swagger UI demo](http://petstore.swagger.io/).
+This file covers deprecated v1 HTTP API. All the methods of v2 HTTP API is described in OpenAPI/Swagger [spec](./api/swagger.yml)
+and can be viewed by importing `https://raw.githubusercontent.com/cayleygraph/cayley/master/docs/api/swagger.yml` URL into [Swagger Editor](https://editor.swagger.io/) or [Swagger UI demo](http://petstore.swagger.io/).
 
 ## Gephi
 

docs/api/swagger.yml

@@ -1,7 +1,7 @@
 openapi: "3.0.0"
 info:
   description: ""
-  version: "2.0.0"
+  version: "2.1.0"
   title: "Cayley API"
   license:
     name: "Apache 2.0"
@@ -35,20 +35,29 @@ paths:
                 type: "object"
                 properties:
                   id:
+                    description: "unique name of the format"
                     type: "string"
                   read:
+                    description: "format is supported for loading quads"
                     type: "boolean"
                   write:
+                    description: "format is supported for exporting quads"
+                    type: "boolean"
+                  nodes:
+                    description: "format can be used to describe nodes"
                     type: "boolean"
                   ext:
+                    description: "typical file extensions for this format"
                     type: "array"
                     items:
                       type: "string"
                   mime:
+                    description: "typical content types for this format"
                     type: "array"
                     items:
                       type: "string"
                   binary:
+                    description: "format uses binary encoding"
                     type: "boolean"
         default:
           description: "Unexpected error"
@@ -158,6 +167,53 @@ paths:
             application/json:
               schema:
                 $ref: '#/components/schemas/Error'
+  /api/v2/node/delete:
+    post:
+      tags:
+      - "data"
+      summary: "Removes a node add all associated quads"
+      description: ""
+      operationId: "deleteNode"
+      requestBody:
+        description: "File in one of formats specified in Content-Type."
+        required: true
+        content:
+          'application/n-quads':
+            schema:
+              $ref: '#/components/schemas/NQuadsNode'
+          'application/json':
+            schema:
+              $ref: '#/components/schemas/JsonNode'
+          'application/x-protobuf':
+            schema:
+              $ref: '#/components/schemas/PNode'
+      parameters:
+      - name: "format"
+        in: "query"
+        description: "Data decoder to use for request. Overrides Content-Type."
+        required: false
+        schema:
+          type: "string"
+      responses:
+        200:
+          description: "delete successful"
+          content:
+            application/json:
+              schema:
+                type: "object"
+                properties:
+                  result:
+                    type: "string"
+                    description: "legacy success message"
+                  count:
+                    type: "integer"
+                    description: "number of nodes deleted"
+        default:
+          description: "Unexpected error"
+          content:
+            application/json:
+              schema:
+                $ref: '#/components/schemas/Error'
   /api/v2/delete:
     post:
       tags:
@@ -217,7 +273,7 @@ paths:
       - "queries"
       summary: "Query the graph"
       description: ""
-      operationId: "readQuads"
+      operationId: "query"
       parameters:
       - name: "lang"
         in: "query"
@@ -319,6 +375,10 @@ components:
         <predicates> <are> <status> .
         <emily> <status> "smart_person" <smart_graph> .
         <greg> <status> "smart_person" <smart_graph> .
+    NQuadsNode:
+      type: "string"
+      format: "binary"
+      example: "<alice>"
     JSONLD:
       type: "string"
       format: "binary"
@@ -356,6 +416,8 @@ components:
             type: "string"
           label:
             type: "string"
+    JsonNode:
+      type: "string"
     JsonQuadsStream:
       type: "string"
       format: "binary"
@@ -364,6 +426,10 @@ components:
       type: "string"
       format: "binary"
       description: "Cayley-specific binary encoding of quads based on protobuf"
+    PNode:
+      type: "string"
+      format: "binary"
+      description: "Cayley-specific binary encoding of node value based on protobuf"
     Error:
       type: "object"
       properties:

quad/formats.go

@@ -19,6 +19,10 @@ type Format struct {
 	Writer func(io.Writer) WriteCloser
 	// Binary is set to true if format is not human-readable.
 	Binary bool
+	// MarshalValue encodes one value in specific a format.
+	MarshalValue func(v Value) ([]byte, error)
+	// UnmarshalValue decodes a value from specific format.
+	UnmarshalValue func(b []byte) (Value, error)
 }
 
 var (

quad/json/json.go

@@ -16,6 +16,18 @@ func init() {
 		Mime:   []string{"application/json"},
 		Writer: func(w io.Writer) quad.WriteCloser { return NewWriter(w) },
 		Reader: func(r io.Reader) quad.ReadCloser { return NewReader(r) },
+		MarshalValue: func(v quad.Value) ([]byte, error) {
+			return json.Marshal(quad.ToString(v))
+		},
+		UnmarshalValue: func(b []byte) (quad.Value, error) {
+			var s *string
+			if err := json.Unmarshal(b, &s); err != nil {
+				return nil, err
+			} else if s == nil {
+				return nil, nil
+			}
+			return quad.StringToValue(*s), nil
+		},
 	})
 	quad.RegisterFormat(quad.Format{
 		Name:   "json-stream",

quad/json/json_test.go

@@ -22,6 +22,7 @@ import (
 	"testing"
 
 	"github.com/cayleygraph/cayley/quad"
+	"github.com/stretchr/testify/require"
 )
 
 var readTests = []struct {
@@ -147,3 +148,29 @@ func TestWriteJSON(t *testing.T) {
 		}
 	}
 }
+
+func TestValueEncoding(t *testing.T) {
+	vals := []quad.Value{
+		quad.String("some val"),
+		quad.IRI("iri"),
+		quad.BNode("bnode"),
+		quad.TypedString{Value: "10", Type: "int"},
+		quad.LangString{Value: "val", Lang: "en"},
+	}
+	enc := []string{
+		`"some val"`,
+		`"\u003ciri\u003e"`,
+		`"_:bnode"`,
+		`"\"10\"^^\u003cint\u003e"`,
+		`"\"val\"@en"`,
+	}
+	f := quad.FormatByName("json")
+	for i, v := range vals {
+		data, err := f.MarshalValue(v)
+		require.NoError(t, err)
+		require.Equal(t, enc[i], string(data), string(data))
+		v2, err := f.UnmarshalValue(data)
+		require.NoError(t, err)
+		require.Equal(t, v, v2)
+	}
+}

quad/nquads/nquads.go

@@ -55,6 +55,27 @@ func init() {
 			return NewReader(r, DecodeRaw)
 		},
 		Writer: func(w io.Writer) quad.WriteCloser { return NewWriter(w) },
+		MarshalValue: func(v quad.Value) ([]byte, error) {
+			if v == nil {
+				return nil, nil
+			}
+			return []byte(v.String()), nil
+		},
+		UnmarshalValue: func(b []byte) (quad.Value, error) {
+			// TODO: proper parser for a single value
+			r := NewReader(bytes.NewReader(bytes.Join([][]byte{
+				[]byte("<s> <p> "),
+				b,
+				[]byte(" <l> .\n"),
+			}, nil)), false)
+			q, err := r.ReadQuad()
+			if err == io.EOF {
+				return nil, quad.ErrInvalid
+			} else if err != nil {
+				return nil, err
+			}
+			return q.Object, nil
+		},
 	})
 }
 

quad/nquads/typed_test.go

@@ -27,6 +27,7 @@ import (
 	"time"
 
 	"github.com/cayleygraph/cayley/quad"
+	"github.com/stretchr/testify/require"
 )
 
 var testNQuads = []struct {
@@ -841,3 +842,29 @@ func BenchmarkParser(b *testing.B) {
 		result, _ = Parse("<http://example/s> <http://example/p> \"object of some real\\tlength\"@en . # comment")
 	}
 }
+
+func TestValueEncoding(t *testing.T) {
+	vals := []quad.Value{
+		quad.String("some val"),
+		quad.IRI("iri"),
+		quad.BNode("bnode"),
+		quad.TypedString{Value: "10", Type: "int"},
+		quad.LangString{Value: "val", Lang: "en"},
+	}
+	enc := []string{
+		`"some val"`,
+		`<iri>`,
+		`_:bnode`,
+		`"10"^^<int>`,
+		`"val"@en`,
+	}
+	f := quad.FormatByName("nquads")
+	for i, v := range vals {
+		data, err := f.MarshalValue(v)
+		require.NoError(t, err)
+		require.Equal(t, enc[i], string(data), string(data))
+		v2, err := f.UnmarshalValue(data)
+		require.NoError(t, err)
+		require.Equal(t, v, v2)
+	}
+}

quad/pquads/pquads.go

@@ -24,10 +24,12 @@ const ContentType = "application/x-protobuf"
 func init() {
 	quad.RegisterFormat(quad.Format{
 		Name: "pquads", Binary: true,
-		Ext:    []string{".pq"},
-		Mime:   []string{ContentType, "application/octet-stream"},
-		Writer: func(w io.Writer) quad.WriteCloser { return NewWriter(w, nil) },
-		Reader: func(r io.Reader) quad.ReadCloser { return NewReader(r, DefaultMaxSize) },
+		Ext:            []string{".pq"},
+		Mime:           []string{ContentType, "application/octet-stream"},
+		Writer:         func(w io.Writer) quad.WriteCloser { return NewWriter(w, nil) },
+		Reader:         func(r io.Reader) quad.ReadCloser { return NewReader(r, DefaultMaxSize) },
+		MarshalValue:   MarshalValue,
+		UnmarshalValue: UnmarshalValue,
 	})
 }
 

quad/value.go

@@ -128,6 +128,10 @@ func StringToValue(v string) Value {
 			return String(v[1 : len(v)-1])
 		} else if v[:2] == "_:" {
 			return BNode(v[2:])
+		} else if i := strings.Index(v, `"^^<`); i > 0 && v[0] == '"' && v[len(v)-1] == '>' {
+			return TypedString{Value: String(v[1:i]), Type: IRI(v[i+4 : len(v)-1])}
+		} else if i := strings.Index(v, `"@`); i > 0 && v[0] == '"' && v[len(v)-1] != '"' {
+			return LangString{Value: String(v[1:i]), Lang: v[i+2:]}
 		}
 	}
 	return String(v)

server/http/api_v2.go

@@ -91,6 +91,7 @@ func (api *APIv2) RegisterDataOn(r *httprouter.Router, wrappers ...HandlerWrappe
 	if !api.ro {
 		r.POST("/api/v2/write", wrap(api.ServeWrite, wrappers))
 		r.POST("/api/v2/delete", wrap(api.ServeDelete, wrappers))
+		r.POST("/api/v2/node/delete", wrap(api.ServeNodeDelete, wrappers))
 	}
 	r.POST("/api/v2/read", wrap(api.ServeRead, wrappers))
 	r.GET("/api/v2/read", wrap(api.ServeRead, wrappers))
@@ -216,7 +217,7 @@ func (api *APIv2) ServeDelete(w http.ResponseWriter, r *http.Request) {
 	}
 	format := getFormat(r, "", hdrContentType)
 	if format == nil || format.Reader == nil {
-		jsonResponse(w, http.StatusBadRequest, fmt.Errorf("format is not supported for reading data"))
+		jsonResponse(w, http.StatusBadRequest, fmt.Errorf("format is not supported for reading quads"))
 		return
 	}
 	rd, err := readerFrom(r, hdrContentEncoding)
@@ -243,6 +244,50 @@ func (api *APIv2) ServeDelete(w http.ResponseWriter, r *http.Request) {
 	fmt.Fprintf(w, `{"result": "Successfully deleted %d quads.", "count": %d}`+"\n", n, n)
 }
 
+func (api *APIv2) ServeNodeDelete(w http.ResponseWriter, r *http.Request) {
+	defer r.Body.Close()
+	if api.ro {
+		jsonResponse(w, http.StatusForbidden, errors.New("database is read-only"))
+		return
+	}
+	format := getFormat(r, "", hdrContentType)
+	if format == nil || format.UnmarshalValue == nil {
+		jsonResponse(w, http.StatusBadRequest, fmt.Errorf("format is not supported for reading nodes"))
+		return
+	}
+	const limit = 128*1024 + 1
+	rd := io.LimitReader(r.Body, limit)
+	data, err := ioutil.ReadAll(rd)
+	if err != nil {
+		jsonResponse(w, http.StatusBadRequest, err)
+		return
+	} else if len(data) == limit {
+		jsonResponse(w, http.StatusBadRequest, fmt.Errorf("request data is too large"))
+		return
+	}
+	v, err := format.UnmarshalValue(data)
+	if err != nil {
+		jsonResponse(w, http.StatusBadRequest, err)
+		return
+	} else if v == nil {
+		jsonResponse(w, http.StatusBadRequest, fmt.Errorf("cannot remove nil value"))
+		return
+	}
+	h, err := api.handleForRequest(r)
+	if err != nil {
+		jsonResponse(w, http.StatusBadRequest, err)
+		return
+	}
+	err = h.RemoveNode(v)
+	if err != nil {
+		jsonResponse(w, http.StatusInternalServerError, err)
+		return
+	}
+	w.Header().Set(hdrContentType, contentTypeJSON)
+	const n = 1
+	fmt.Fprintf(w, `{"result": "Successfully deleted %d nodes.", "count": %d}`+"\n", n, n)
+}
+
 type checkWriter struct {
 	w       io.Writer
 	written bool
@@ -296,6 +341,7 @@ func (api *APIv2) ServeFormats(w http.ResponseWriter, r *http.Request) {
 		Id     string   `json:"id"`
 		Read   bool     `json:"read,omitempty"`
 		Write  bool     `json:"write,omitempty"`
+		Nodes  bool     `json:"nodes,omitempty"`
 		Ext    []string `json:"ext,omitempty"`
 		Mime   []string `json:"mime,omitempty"`
 		Binary bool     `json:"binary,omitempty"`
@@ -307,6 +353,7 @@ func (api *APIv2) ServeFormats(w http.ResponseWriter, r *http.Request) {
 			Id:  f.Name,
 			Ext: f.Ext, Mime: f.Mime,
 			Read: f.Reader != nil, Write: f.Writer != nil,
+			Nodes:  f.UnmarshalValue != nil,
 			Binary: f.Binary,
 		})
 	}