feat(template) add json escaping functions. (#70)

* feat(template) add json escaping functions. * doc(template): add json escape functions.
elastic · Oct 21, 2021 · 0d668fb · 0d668fb
1 parent 5b784e8
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diff --git a/CHANGELOG.md b/CHANGELOG.md
@@ -11,6 +11,8 @@ FEATURES:
 * to/vault: Support Vault >1.9 custom metadata for bundle metadata publication. [#68](https://github.com/elastic/harp/pull/68)
 * from/vault: Support Vault >1.9 custom metadata for bundle metadata retrieval. [#68](https://github.com/elastic/harp/pull/68)
 * from/vault: Support legacy bundle metadata format. [#69](https://github.com/elastic/harp/pull/69)
+* template/engine: `jsonEscape` / `jsonUnescape` is added to handle string escaping using JSON character escaping strategy [#70](https://github.com/elastic/harp/pull/70)
+* template/engine: `unquote` is added to unquote a `quote` escaped string [#70](https://github.com/elastic/harp/pull/70)
 
 ## 0.1.24
 

diff --git a/pkg/template/engine/funcs.go b/pkg/template/engine/funcs.go
@@ -19,7 +19,10 @@ package engine
 
 import (
 	"encoding/base64"
+	"encoding/json"
 	"net/url"
+	"strconv"
+	"strings"
 	"text/template"
 
 	"github.com/Masterminds/sprig/v3"
@@ -74,13 +77,6 @@ func FuncMap(secretReaders []SecretReaderFunc) template.FuncMap {
 		// Bech32
 		"bech32enc": bech32.Encode,
 		"bech32dec": crypto.Bech32Decode,
-		// URL
-		"urlPathEscape":    url.PathEscape,
-		"urlPathUnescape":  url.PathUnescape,
-		"urlQueryEscape":   url.QueryEscape,
-		"urlQueryUnescape": url.QueryUnescape,
-		// Escape
-		"shellEscape": shellescape.Quote,
 		// Base64
 		"b64urlenc": func(in string) string {
 			return base64.URLEncoding.EncodeToString([]byte(in))
@@ -89,6 +85,25 @@ func FuncMap(secretReaders []SecretReaderFunc) template.FuncMap {
 			out, err := base64.URLEncoding.DecodeString(in)
 			return string(out), err
 		},
+		// Escaping
+		"urlPathEscape":    url.PathEscape,
+		"urlPathUnescape":  url.PathUnescape,
+		"urlQueryEscape":   url.QueryEscape,
+		"urlQueryUnescape": url.QueryUnescape,
+		"shellEscape":      shellescape.Quote,
+		"jsonEscape": func(in string) (string, error) {
+			b, err := json.Marshal(in)
+			// Trim the beginning and trailing " character
+			return strings.Trim(string(b), `"`), err
+		},
+		"jsonUnescape": func(in string) (string, error) {
+			var out string
+			if err := json.Unmarshal([]byte(in), &out); err != nil {
+				return "", err
+			}
+			return out, nil
+		},
+		"unquote": strconv.Unquote,
 	}
 
 	for k, v := range extra {

diff --git a/pkg/template/engine/funcs_test.go b/pkg/template/engine/funcs_test.go
@@ -94,6 +94,18 @@ func TestFuncs(t *testing.T) {
 		tpl:    `{{ fromYamlArray . }}`,
 		expect: `[error unmarshaling JSON: while decoding JSON: json: cannot unmarshal object into Go value of type []interface {}]`,
 		vars:   `hello: world`,
+	}, {
+		tpl:    `{{ jsonEscape . }}`,
+		expect: `backslash: \\, A: \u0026 \u003c`,
+		vars:   `backslash: \, A: & <`,
+	}, {
+		tpl:    `{{ jsonUnescape . }}`,
+		expect: `backslash: \, A: & <`,
+		vars:   `"backslash: \\, A: \u0026 \u003c"`,
+	}, {
+		tpl:    `{{ unquote . }}`,
+		expect: `{"channel":"buu","name":"john", "msg":"doe"}`,
+		vars:   `"{\"channel\":\"buu\",\"name\":\"john\", \"msg\":\"doe\"}"`,
 	}}
 
 	for _, tt := range tests {

diff --git a/samples/onboarding/1-template-engine/2-functions.md b/samples/onboarding/1-template-engine/2-functions.md
@@ -73,6 +73,15 @@ https://logstash:{{ paranoidPassword | urlQueryEscape }}@ingester.es.cloud:1234
 https://logstash:K3iDayow9%5Cav67HawD6%210k~8lhcm8oLVUBt2wE%3E%5DLBJQJVj%3AfIx%2Fuo%40%7B%3D6kvgXHK@ingester.es.cloud:1234%
 ```
 
+#### jsonEscape / jsonUnescape
+
+Apply JSON ecaping strategy to a string
+
+```ruby
+{{ "backslash: \, A: & <" | jsonEscape }}
+backslash: \\, A: \u0026 \u003c
+```
+
 ### Secret loader
 
 #### secret