feat: tengo http support

plugins/internal/tengoutil/secure_script.go

@@ -1,7 +1,11 @@
 package tengoutil
 
 import (
+	"context"
 	"fmt"
+	"io"
+	"net/http"
+	"time"
 
 	"github.com/d5/tengo/v2"
 	"github.com/d5/tengo/v2/stdlib"
@@ -15,10 +19,12 @@
 func NewSecureScript(input []byte, globals map[string]interface{}) (*tengo.Script, error) {
 	s := tengo.NewScript(input)
 
-	s.SetImports(stdlib.GetModuleMap(
+	modules := stdlib.GetModuleMap(
 		// `os` is excluded, should *not* be importable from script.
 		"math", "text", "times", "rand", "fmt", "json", "base64", "hex", "enum",
-	))
+	)
+	modules.AddBuiltinModule("http", createHTTPModule())
+	s.SetImports(modules)
 	s.SetMaxAllocs(maxAllocs)
 	s.SetMaxConstObjects(maxConsts)
 
@@ -30,3 +36,66 @@
 
 	return s, nil
 }
+
+func createHTTPModule() map[string]tengo.Object {
+	return map[string]tengo.Object{
+		"get": &tengo.UserFunction{
+			Name: "get",
+			Value: func(args ...tengo.Object) (tengo.Object, error) {
+				if len(args) < 1 || len(args) > 2 {
+					return nil, fmt.Errorf("expected 1 or 2 arguments, got %d", len(args))
+				}
+
+				url, ok := tengo.ToString(args[0])
+				if !ok {
+					return nil, fmt.Errorf("expected argument 1 (URL) to be a string")
+				}
+
+				headers := make(map[string]string)
+				if len(args) == 2 {
+					headerMap, ok := args[1].(*tengo.Map)
+					if !ok {
+						return nil, fmt.Errorf("expected argument 2 (headers) to be a map")
+					}
+					for key, value := range headerMap.Value {
+						strValue, valueOk := tengo.ToString(value)
+						if !valueOk {
+							return nil, fmt.Errorf("header values must be strings")
+						}
+						headers[key] = strValue
+					}
+				}
+
+				ctx, cancel := context.WithTimeout(context.Background(), 5*time.Second)
+				defer cancel()
+
+				req, err := http.NewRequestWithContext(ctx, http.MethodGet, url, nil)
+				if err != nil {
+					return nil, err
+				}
+
+				for key, value := range headers {
+					req.Header.Add(key, value)
+				}
+
+				resp, err := http.DefaultClient.Do(req)
+				if err != nil {
+					return nil, err
+				}
+				defer resp.Body.Close()
+
+				body, err := io.ReadAll(resp.Body)
+				if err != nil {
+					return nil, err
+				}
+
+				return &tengo.Map{
+					Value: map[string]tengo.Object{
+						"body": &tengo.String{Value: string(body)},
+						"code": &tengo.Int{Value: int64(resp.StatusCode)},
+					},
+				}, nil
+			},
+		},
+	}
+}

plugins/internal/tengoutil/secure_script_test.go

@@ -55,4 +55,15 @@ func TestNewSecureScript(t *testing.T) {
 		_, err = s.Compile()
 		assert.NoError(t, err)
 	})
+
+	t.Run("Allows import of custom http module", func(t *testing.T) {
+		s, err := NewSecureScript(([]byte)(heredoc.Doc(`
+			http := import("http")
+			response := http.get("http://example.com")
+			response.body
+		`)), nil)
+		assert.NoError(t, err)
+		_, err = s.Compile()
+		assert.NoError(t, err)
+	})
 }