Initial QSfera import

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

@@ -0,0 +1,60 @@
+package opa
+
+import (
+	"bytes"
+	"fmt"
+	"net/http"
+
+	"github.com/open-policy-agent/opa/ast"
+	"github.com/open-policy-agent/opa/rego"
+	"github.com/open-policy-agent/opa/types"
+	"github.com/opencloud-eu/reva/v2/pkg/rhttp"
+)
+
+// RFResourceDownload extends the rego dictionary with the possibility to download qsfera resources.
+//
+// Rego: `qsfera.resource.download("qsfera/path/0034892347349827")`
+// Result: bytes
+var RFResourceDownload = rego.Function1(
+	&rego.Function{
+		Name:             "qsfera.resource.download",
+		Decl:             types.NewFunction(types.Args(types.S), types.A),
+		Memoize:          true,
+		Nondeterministic: true,
+	},
+	func(_ rego.BuiltinContext, a *ast.Term) (*ast.Term, error) {
+		var url string
+
+		if err := ast.As(a.Value, &url); err != nil {
+			return nil, err
+		}
+
+		req, err := http.NewRequest(http.MethodGet, url, nil)
+		if err != nil {
+			return nil, err
+		}
+
+		client := rhttp.GetHTTPClient(rhttp.Insecure(true))
+		res, err := client.Do(req)
+		if err != nil {
+			return nil, err
+		}
+		defer res.Body.Close()
+
+		if res.StatusCode != http.StatusOK {
+			return nil, fmt.Errorf("unexpected status code from Download %v", res.StatusCode)
+		}
+
+		buf := new(bytes.Buffer)
+		if _, err := buf.ReadFrom(res.Body); err != nil {
+			return nil, err
+		}
+
+		v, err := ast.InterfaceToValue(buf.Bytes())
+		if err != nil {
+			return nil, err
+		}
+
+		return ast.NewTerm(v), nil
+	},
+)