Added methods to get and put data into context (#1938)

changelog/unreleased/context-methods.md

@@ -0,0 +1,5 @@
+Enhancement: Add methods to get and put context values
+
+Added `GetKeyValues` and `PutKeyValues` methods to fetch/put values from/to context.
+
+https://github.com/cs3org/reva/pull/1938

pkg/appctx/ctxmap.go

@@ -0,0 +1,69 @@
+// Copyright 2018-2021 CERN
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+//
+// In applying this license, CERN does not waive the privileges and immunities
+// granted to it by virtue of its status as an Intergovernmental Organization
+// or submit itself to any jurisdiction.
+
+package appctx
+
+import (
+	"context"
+	"reflect"
+	"unsafe"
+)
+
+// PutKeyValuesToCtx puts all the key-value pairs from the provided map to a background context.
+func PutKeyValuesToCtx(m map[interface{}]interface{}) context.Context {
+	ctx := context.Background()
+	for key, value := range m {
+		ctx = context.WithValue(ctx, key, value)
+	}
+	return ctx
+}
+
+// GetKeyValuesFromCtx retrieves all the key-value pairs from the provided context.
+func GetKeyValuesFromCtx(ctx context.Context) map[interface{}]interface{} {
+	m := make(map[interface{}]interface{})
+	getKeyValue(ctx, m)
+	return m
+}
+
+func getKeyValue(ctx interface{}, m map[interface{}]interface{}) {
+	ctxVals := reflect.ValueOf(ctx).Elem()
+	ctxType := reflect.TypeOf(ctx).Elem()
+
+	if ctxType.Kind() == reflect.Struct {
+		for i := 0; i < ctxVals.NumField(); i++ {
+			currField, currIf := extractField(ctxVals, ctxType, i)
+			switch currField {
+			case "Context":
+				getKeyValue(currIf, m)
+			case "key":
+				nextField, nextIf := extractField(ctxVals, ctxType, i+1)
+				if nextField == "val" {
+					m[currIf] = nextIf
+					i++
+				}
+			}
+		}
+	}
+}
+
+func extractField(vals reflect.Value, fieldType reflect.Type, pos int) (string, interface{}) {
+	currVal := vals.Field(pos)
+	currVal = reflect.NewAt(currVal.Type(), unsafe.Pointer(currVal.UnsafeAddr())).Elem()
+	currField := fieldType.Field(pos)
+	return currField.Name, currVal.Interface()
+}

pkg/appctx/ctxmap_test.go

@@ -0,0 +1,102 @@
+// Copyright 2018-2021 CERN
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+//
+// In applying this license, CERN does not waive the privileges and immunities
+// granted to it by virtue of its status as an Intergovernmental Organization
+// or submit itself to any jurisdiction.
+
+package appctx
+
+import (
+	"context"
+	"testing"
+
+	userpb "github.com/cs3org/go-cs3apis/cs3/identity/user/v1beta1"
+	"github.com/stretchr/testify/assert"
+)
+
+type ctxStringKey string
+type ctxIntKey int
+
+func TestGetKeyValues(t *testing.T) {
+	tests := []struct {
+		name string
+		ctx  context.Context
+		m    map[interface{}]interface{}
+	}{
+		{
+			"Background context",
+			context.Background(),
+			map[interface{}]interface{}{},
+		},
+		{
+			"Context with Values",
+			context.WithValue(context.Background(), ctxStringKey("key"), "value"),
+			map[interface{}]interface{}{
+				ctxStringKey("key"): "value",
+			},
+		},
+		{
+			"Context with user object",
+			context.WithValue(context.WithValue(context.Background(), ctxStringKey("key"), "value"), ctxStringKey("user"), &userpb.User{Username: "einstein"}),
+			map[interface{}]interface{}{
+				ctxStringKey("key"):  "value",
+				ctxStringKey("user"): &userpb.User{Username: "einstein"},
+			},
+		},
+		{
+			"Nested Context with Values of different types",
+			context.WithValue(context.WithValue(context.Background(), ctxStringKey("key"), "value"), ctxIntKey(123), "value2"),
+			map[interface{}]interface{}{
+				ctxStringKey("key"): "value",
+				ctxIntKey(123):      "value2",
+			},
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			kvMap := GetKeyValuesFromCtx(tt.ctx)
+			assert.Equal(t, tt.m, kvMap)
+		})
+	}
+}
+
+func TestPutKeyValues(t *testing.T) {
+	tests := []struct {
+		name string
+		m    map[interface{}]interface{}
+		ctx  context.Context
+	}{
+		{
+			"empty context",
+			map[interface{}]interface{}{},
+			context.Background(),
+		},
+		{
+			"single kv pair",
+			map[interface{}]interface{}{
+				ctxStringKey("key"): "value",
+			},
+			context.WithValue(context.Background(), ctxStringKey("key"), "value"),
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			ctx := PutKeyValuesToCtx(tt.m)
+			assert.Equal(t, tt.ctx, ctx)
+		})
+	}
+}