feat: add b64 raw encode and decode templating function (#535)

Signed-off-by: florian.cazals <[email protected]>

README.md

@@ -260,6 +260,8 @@ The following templating functions are available:
 | **`evalCache`**    | Evaluates the value of a template variable, and cache for future usage (to avoid further computation)                                                                                                                                                                                                                                                           | ``{{evalCache `var1`}}``                                 |
 | **`fromJson`**     | Decodes a JSON document into a structure. If the input cannot be decoded as JSON, the function will return an empty string                                                                                                                                                                                                                                      | ``{{fromJson `{"a":"b"}`}}``                             |
 | **`mustFromJson`** | Similar to **`fromJson`**, but will return an error in case the JSON is invalid. A common usecase consists of returning a JSON stringified data structure from a JavaScript expression (object, array), and use one of its members in the template. Example: ``{{(eval `myExpression` \| fromJson).myArr}}`` or ``{{(eval `myExpression` \| fromJson).myObj}}`` | ``{{mustFromJson `{"a":"b"}`}}``                         |
+| **`b64RawEnc`**    | Encode a string to a b64 raw encoded string as defined in [RFC 4648 section 3.2](https://www.rfc-editor.org/rfc/rfc4648.html#section-3.2). Example: ``{{eval `myString` \| b64RawEnc}}``                                                                                                                                                                                                                                      | ``{{b64RawEnc `a nice string`}}``                             |
+| **`b64RawDec`**    | Decode a b64 raw encoded string as defined in [RFC 4648 section 3.2](https://www.rfc-editor.org/rfc/rfc4648.html#section-3.2) to a decoded string. Example: ``{{eval `cmF3IG1lc3NhZ2U` \| b64RawDec}}``                                                                                                                                                                                                                                      | ``{{b64RawDec cmF3IG1lc3NhZ2U`}}``                             |
 
 ### Basic properties
 

engine/engine_test.go

@@ -1355,3 +1355,18 @@ func TestResolveCallback(t *testing.T) {
 	// callback has been created, waiting for its resolution
 	assert.Equal(t, resolution.StateWaiting, res.State)
 }
+
+func TestB64RawEncodeDecode(t *testing.T) {
+	res, err := createResolution("rawb64EncodingDecoding.yaml", nil, nil)
+	assert.NotNil(t, res)
+	assert.Nil(t, err)
+
+	res, err = runResolution(res)
+	assert.NotNil(t, res)
+	assert.Nil(t, err)
+	assert.Equal(t, resolution.StateDone, res.State)
+
+	output := res.Steps["stepOne"].Output.(map[string]interface{})
+	assert.Equal(t, "cmF3IG1lc3NhZ2U", output["a"])
+	assert.Equal(t, "raw message", output["b"])
+}

engine/templates_tests/rawb64EncodingDecoding.yaml

@@ -0,0 +1,24 @@
+name: rawb64EncodingDecoding
+description: Ensure that b64 encoding and decoding can be used in template
+title_format: "[test] correct b64 raw encoding and decoding"
+auto_runnable: true
+
+
+
+variables:
+  - name: rawDecoded
+    expression: |-
+      "raw message";
+  - name: rawEncoded
+    expression: |-
+      "cmF3IG1lc3NhZ2U";
+
+steps:
+  stepOne:
+    description: first step
+    action:
+      type: echo
+      configuration:
+        output:
+          a: '{{ eval `rawDecoded` | b64RawEnc }}'
+          b: '{{ eval `rawEncoded` | b64RawDec }}'

engine/values/values.go

@@ -2,6 +2,7 @@ package values
 
 import (
 	"bytes"
+	"encoding/base64"
 	"encoding/json"
 	"fmt"
 	"reflect"
@@ -77,6 +78,8 @@ func NewValues() *Values {
 	v.funcMap["fromJson"] = v.fromJSON
 	v.funcMap["mustFromJson"] = v.mustFromJSON
 	v.funcMap["uuid"] = uuid.NewV4
+	v.funcMap["b64RawEnc"] = v.b64RawEnc
+	v.funcMap["b64RawDec"] = v.b64RawDec
 
 	return v
 }
@@ -499,6 +502,18 @@ func (v *Values) mustFromJSON(s string) (reflect.Value, error) {
 	return reflect.ValueOf(output), err
 }
 
+func (v *Values) b64RawDec(s string) string {
+	data, err := base64.RawStdEncoding.DecodeString(s)
+	if err != nil {
+		return err.Error()
+	}
+	return string(data)
+}
+
+func (v *Values) b64RawEnc(s string) string {
+	return base64.RawStdEncoding.EncodeToString([]byte(s))
+}
+
 var errTimedOut = errors.New("Timed out variable evaluation")
 
 func evalUnsafe(exp []byte, delay time.Duration) (v otto.Value, err error) {