Initial QSfera import

Server/services/policies/pkg/engine/engine.go

@@ -0,0 +1,74 @@
+package engine
+
+import (
+	"context"
+	"encoding/json"
+
+	user "github.com/cs3org/go-cs3apis/cs3/identity/user/v1beta1"
+	provider "github.com/cs3org/go-cs3apis/cs3/storage/provider/v1beta1"
+	v0 "github.com/qsfera/server/protogen/gen/qsfera/messages/policies/v0"
+	"google.golang.org/protobuf/encoding/protojson"
+)
+
+// Engine defines the granted handlers.
+type Engine interface {
+	Evaluate(ctx context.Context, query string, env Environment) (bool, error)
+}
+
+type (
+	// Stage defines the used auth stage
+	Stage string
+)
+
+var (
+	// StagePP defines the post-processing stage
+	StagePP Stage = "pp"
+
+	// StageHTTP defines the http stage
+	StageHTTP Stage = "http"
+)
+
+// Resource contains resource information and is used as part of the evaluated environment.
+type Resource struct {
+	ID   provider.ResourceId `json:"resource_id"`
+	Name string              `json:"name"`
+	URL  string              `json:"url"`
+	Size uint64              `json:"size"`
+}
+
+// Request contains request information and is used as part of the evaluated environment.
+type Request struct {
+	Method string `json:"method"`
+	Path   string `json:"path"`
+}
+
+// Environment contains every data that is needed to decide if the request should pass or not
+type Environment struct {
+	Stage    Stage     `json:"stage"`
+	User     user.User `json:"user"`
+	Request  Request   `json:"request"`
+	Resource Resource  `json:"resource"`
+}
+
+// NewEnvironmentFromPB converts a PBEnvironment to Environment.
+func NewEnvironmentFromPB(pEnv *v0.Environment) (Environment, error) {
+	env := Environment{}
+
+	rData, err := protojson.Marshal(pEnv)
+	if err != nil {
+		return env, err
+	}
+
+	if err := json.Unmarshal(rData, &env); err != nil {
+		return env, err
+	}
+
+	switch pEnv.Stage {
+	case v0.Stage_STAGE_HTTP:
+		env.Stage = StageHTTP
+	case v0.Stage_STAGE_PP:
+		env.Stage = StagePP
+	}
+
+	return env, nil
+}