Create new HTTP resource for namespace rules (cayleygraph#925)

The resource supports getting all registered rules and registering a rule

docs/api/swagger.yml

@@ -381,6 +381,50 @@ paths:
             application/json:
               schema:
                 $ref: "#/components/schemas/Error"
+  /api/v2/namespace-rules:
+    get:
+      tags:
+        - "data"
+      summary: "Reads all namespace rules from the database"
+      description: ""
+      operationId: "getNamespaceRules"
+      responses:
+        200:
+          description: "Success"
+          content:
+            "application/json":
+              schema:
+                type: "array"
+                items:
+                  type: "object"
+                  properties:
+                    prefix:
+                      description: "Prefix of the namespace"
+                      type: "string"
+                    namespace:
+                      description: "The namespace prefixed"
+                      type: "string"
+        default:
+          description: "Unexpected error"
+          content:
+            application/json:
+              schema:
+                $ref: "#/components/schemas/Error"
+    post:
+      tags:
+        - "data"
+      summary: "Registers new namespace rule to the database"
+      description: ""
+      operationId: "registerNamespaceRule"
+      responses:
+        201:
+          description: "Success"
+        default:
+          description: "Unexpected error"
+          content:
+            application/json:
+              schema:
+                $ref: "#/components/schemas/Error"
   /gephi/gs:
     get:
       tags:

server/http/api_v2.go

@@ -36,6 +36,7 @@ import (
 	// Writer is imported for writers to be registered
 	_ "github.com/cayleygraph/cayley/writer"
 	"github.com/cayleygraph/quad"
+	"github.com/cayleygraph/quad/voc"
 )
 
 const (
@@ -584,3 +585,56 @@ func (api *APIv2) ServeQuery(w http.ResponseWriter, r *http.Request) {
 	}
 	writeResults(w, out)
 }
+
+// NamespaceRule defines a prefix for a namespace when prepended to the suffix of a compact IRI, results in an IRI.
+// For example rdfs is a prefix for the namespace http://www.w3.org/2000/01/rdf-schema#.
+type NamespaceRule struct {
+	Prefix    string `json:"prefix"`
+	Namespace string `json:"namespace"`
+}
+
+// getNamespaceRules returns all the registered rules
+func getNamespaceRules() []NamespaceRule {
+	var rules []NamespaceRule
+	for _, n := range voc.List() {
+		rules = append(rules, NamespaceRule{
+			Prefix:    strings.TrimSuffix(n.Prefix, ":"),
+			Namespace: n.Full,
+		})
+	}
+	return rules
+}
+
+// serveGetNamespaceRules responds with all the registered rules encoded to JSON
+func serveGetNamespaceRules(w http.ResponseWriter) {
+	rules := getNamespaceRules()
+	encoder := json.NewEncoder(w)
+	w.Header().Set(hdrContentType, contentTypeJSON)
+	w.WriteHeader(http.StatusOK)
+	encoder.Encode(rules)
+}
+
+// serveGetNamespaceRules registers received rule encoded in JSON
+func servePostNamespaceRules(w http.ResponseWriter, r *http.Request) {
+	var rule NamespaceRule
+	decoder := json.NewDecoder(r.Body)
+	decoder.Decode(&rule)
+	voc.RegisterPrefix(rule.Prefix, rule.Namespace)
+	w.WriteHeader(http.StatusCreated)
+}
+
+// ServeNamespaceRules serves requests for the namespace rules resource.
+// The resource supports getting all registered rules and registering a rule.
+// The resource wraps the quad/voc module.
+func (api *APIv2) ServeNamespaceRules(w http.ResponseWriter, r *http.Request) {
+	switch r.Method {
+	case http.MethodGet:
+		serveGetNamespaceRules(w)
+		return
+	case http.MethodPost:
+		servePostNamespaceRules(w, r)
+		return
+	default:
+		jsonResponse(w, http.StatusMethodNotAllowed, nil)
+	}
+}

server/http/api_v2_test.go

@@ -65,7 +65,7 @@ func TestV2Write(t *testing.T) {
 	handler := http.HandlerFunc(api.ServeWrite)
 	handler.ServeHTTP(rr, req)
 
-	require.Equal(t, rr.Code, http.StatusOK, rr.Body.String())
+	require.Equal(t, http.StatusOK, rr.Code, rr.Body.String())
 
 	expectedResponse := newWriteResponse(len(quads))
 
@@ -87,7 +87,7 @@ func TestV2Read(t *testing.T) {
 	handler := http.HandlerFunc(api.ServeRead)
 	handler.ServeHTTP(rr, req)
 
-	require.Equal(t, rr.Code, http.StatusOK, rr.Body.String())
+	require.Equal(t, http.StatusOK, rr.Code, rr.Body.String())
 
 	reader := jsonld.NewReader(rr.Body)
 	receivedQuads, err := quad.ReadAll(reader)
@@ -111,5 +111,53 @@ func TestV2Delete(t *testing.T) {
 	handler := http.HandlerFunc(api.ServeDelete)
 	handler.ServeHTTP(rr, req)
 
-	require.Equal(t, rr.Code, http.StatusOK, rr.Body.String())
+	require.Equal(t, http.StatusOK, rr.Code, rr.Body.String())
+}
+
+func TestV2GetNamespaceRules(t *testing.T) {
+	api := makeServerV2(t)
+	buf := bytes.NewBuffer(nil)
+	req, err := http.NewRequest(http.MethodGet, prefix+"/namespace-rules", buf)
+	require.NoError(t, err)
+	rr := httptest.NewRecorder()
+	handler := http.HandlerFunc(api.ServeNamespaceRules)
+	handler.ServeHTTP(rr, req)
+	var rules []NamespaceRule
+	err = json.Unmarshal(rr.Body.Bytes(), &rules)
+	require.NoError(t, err)
+	require.Equal(t, http.StatusOK, rr.Code)
+	require.Equal(t, contentTypeJSON, rr.Header().Get(hdrContentType))
+	require.NotEmpty(t, rules)
+}
+
+func TestV2PostNamespaceRules(t *testing.T) {
+	api := makeServerV2(t)
+	rule := NamespaceRule{
+		Prefix:    "foaf",
+		Namespace: "http://xmlns.com/foaf/0.1/",
+	}
+	buf := bytes.NewBuffer(nil)
+	encoder := json.NewEncoder(buf)
+	encoder.Encode(rule)
+	req, err := http.NewRequest(http.MethodPost, prefix+"/namespace-rules", buf)
+	require.NoError(t, err)
+	rr := httptest.NewRecorder()
+	handler := http.HandlerFunc(api.ServeNamespaceRules)
+	handler.ServeHTTP(rr, req)
+	require.NoError(t, err)
+	require.Equal(t, http.StatusCreated, rr.Code)
+	require.Empty(t, rr.Body.Bytes())
+
+	// Check effect
+	req, err = http.NewRequest(http.MethodGet, prefix+"/namespace-rules", buf)
+	require.NoError(t, err)
+	rr = httptest.NewRecorder()
+	handler = http.HandlerFunc(api.ServeNamespaceRules)
+	handler.ServeHTTP(rr, req)
+	var rules []NamespaceRule
+	err = json.Unmarshal(rr.Body.Bytes(), &rules)
+	require.NoError(t, err)
+	require.Equal(t, http.StatusOK, rr.Code)
+	require.Equal(t, contentTypeJSON, rr.Header().Get(hdrContentType))
+	require.Contains(t, rules, rule)
 }