compress -> urlenc

And associated cleanup.

Blocked until oss.terrastruct.com/util-go is importable.

ci/sub

@@ -1 +1 @@
-Subproject commit 702b771228f41e5485b5f3f593ce79f6efcb555d
+Subproject commit e894a489abaead7314a3f126cdb32f18b272a23f

go.mod

@@ -25,6 +25,7 @@ require (
 	nhooyr.io/websocket v1.8.7
 	oss.terrastruct.com/cmdlog v0.0.0-20221201100934-012c01b3431c
 	oss.terrastruct.com/diff v1.0.2-0.20221116222035-8bf4dd3ab541
+	oss.terrastruct.com/util-go v0.0.0-20221201174206-77c68780d6f0
 	oss.terrastruct.com/xcontext v0.0.0-20221018000442-50fdafb12f4f
 	oss.terrastruct.com/xdefer v0.0.0-20221017222355-6f3b6e4d1557
 	oss.terrastruct.com/xjson v0.0.0-20221018000420-4986731c4c4a

go.sum

@@ -802,6 +802,8 @@ oss.terrastruct.com/cmdlog v0.0.0-20221201100934-012c01b3431c h1:C1DDLzj2NrVi1YJ
 oss.terrastruct.com/cmdlog v0.0.0-20221201100934-012c01b3431c/go.mod h1:C8u/lYTvQWc1xC7rHpgFfpScfQC4NMeGGMmlKVZZUXM=
 oss.terrastruct.com/diff v1.0.2-0.20221116222035-8bf4dd3ab541 h1:I9B1O1IJ6spivIQxbFRZmbhAwVeLwrcQRR1JbYUOvrI=
 oss.terrastruct.com/diff v1.0.2-0.20221116222035-8bf4dd3ab541/go.mod h1:ags2QDy/T6jr69hT6bpmAmhr2H98n9o8Atf3QlUJPiU=
+oss.terrastruct.com/util-go v0.0.0-20221201174206-77c68780d6f0 h1:zaSiaG+BkHysYOs7M/flh1FEOlJzqA+wwQvCplMBhxA=
+oss.terrastruct.com/util-go v0.0.0-20221201174206-77c68780d6f0/go.mod h1:AN5T0bJ89/Q6ZebXIdPGpwAqVhK9PkDpgygWJaT2JzQ=
 oss.terrastruct.com/xcontext v0.0.0-20221018000442-50fdafb12f4f h1:7voRCwKM7TZkTo9u7hj+uV/zXoVB8czWrTq6MVIh3dg=
 oss.terrastruct.com/xcontext v0.0.0-20221018000442-50fdafb12f4f/go.mod h1:Y0coTLsWwX0q3a+/Ndq797t+vWyxm42T49Ik3bzaDKY=
 oss.terrastruct.com/xdefer v0.0.0-20221017222355-6f3b6e4d1557 h1:rPbhJbN1q7B4tnppSPoAMwq0t6Pk5SrQDQ5S6uoNNHg=

lib/compress/compress_test.go

@@ -1,27 +0,0 @@
-package compress
-
-import (
-	"testing"
-
-	"oss.terrastruct.com/diff"
-)
-
-func TestCompression(t *testing.T) {
-	script := `x -> y
-I just forgot my whole philosophy of life!!!: {
-  s: TV is chewing gum for the eyes
-}
-`
-
-	encoded, err := Compress(script)
-	if err != nil {
-		t.Fatal(err)
-	}
-
-	decoded, err := Decompress(encoded)
-	if err != nil {
-		t.Fatal(err)
-	}
-
-	diff.AssertStringEq(t, script, decoded)
-}

lib/urlenc/urlenc.go

@@ -1,4 +1,4 @@
-package compress
+package urlenc
 
 import (
 	"bytes"
@@ -7,6 +7,8 @@ import (
 	"io"
 	"strings"
 
+	"oss.terrastruct.com/util-go/xdefer"
+
 	"oss.terrastruct.com/d2/d2graph"
 )
 
@@ -15,13 +17,25 @@ var compressionDict = "->" +
 	"--" +
 	"<->"
 
-var compressionDictBytes []byte
+func init() {
+	for k := range d2graph.StyleKeywords {
+		compressionDict += k
+	}
+	for k := range d2graph.ReservedKeywords {
+		compressionDict += k
+	}
+	for k := range d2graph.ReservedKeywordHolders {
+		compressionDict += k
+	}
+}
 
-// Compress takes a D2 script and compresses it to a URL-encoded string
+// Encode takes a D2 script and encodes it as a compressed base64 string for embedding in URLs.
-func Compress(raw string) (string, error) {
+func Encode(raw string) (_ string, err error) {
-	var b bytes.Buffer
+	defer xdefer.Errorf(&err, "failed to encode d2 script")
 
-	zw, err := flate.NewWriterDict(&b, flate.DefaultCompression, []byte(compressionDict))
+	b := &bytes.Buffer{}
+
+	zw, err := flate.NewWriterDict(b, flate.DefaultCompression, []byte(compressionDict))
 	if err != nil {
 		return "", err
 	}
@@ -36,8 +50,10 @@ func Compress(raw string) (string, error) {
 	return encoded, nil
 }
 
-// Decompress takes a compressed, URL-encoded string and returns the decompressed D2 script
+// Decode decodes a compressed base64 D2 string.
-func Decompress(encoded string) (string, error) {
+func Decode(encoded string) (_ string, err error) {
+	defer xdefer.Errorf(&err, "failed to decode d2 script")
+
 	b64Decoded, err := base64.URLEncoding.DecodeString(encoded)
 	if err != nil {
 		return "", err
@@ -53,15 +69,3 @@ func Decompress(encoded string) (string, error) {
 	}
 	return b.String(), nil
 }
-
-func init() {
-	for k := range d2graph.StyleKeywords {
-		compressionDict += k
-	}
-	for k := range d2graph.ReservedKeywords {
-		compressionDict += k
-	}
-	for k := range d2graph.ReservedKeywordHolders {
-		compressionDict += k
-	}
-}

lib/urlenc/urlenc_test.go

@@ -0,0 +1,23 @@
+package urlenc
+
+import (
+	"testing"
+
+	"oss.terrastruct.com/util-go/assert"
+)
+
+func TestBasic(t *testing.T) {
+	const script = `x -> y
+I just forgot my whole philosophy of life!!!: {
+  s: TV is chewing gum for the eyes
+}
+`
+
+	encoded, err := Encode(script)
+	assert.Success(t, err)
+
+	decoded, err := Decode(encoded)
+	assert.Success(t, err)
+
+	assert.String(t, script, decoded)
+}