syntax: path parsing helper

atproto/syntax/path.go

···
+package syntax
+
+import (
+	"errors"
+	"fmt"
+	"strings"
+)
+
+// Parses an atproto repo path string in to "collection" (NSID) and record key parts.
+//
+// Does not return partial success: either both collection and record key are complete (and error is nil), or both are empty string (and error is not nil)
+func ParseRepoPath(raw string) (NSID, RecordKey, error) {
+	parts := strings.SplitN(raw, "/", 3)
+	if len(parts) != 2 {
+		return "", "", errors.New("expected path to have two parts, separated by single slash")
+	}
+	nsid, err := ParseNSID(parts[0])
+	if err != nil {
+		return "", "", fmt.Errorf("collection part of path not a valid NSID: %w", err)
+	}
+	rkey, err := ParseRecordKey(parts[1])
+	if err != nil {
+		return "", "", fmt.Errorf("record key part of path not valid: %w", err)
+	}
+	return nsid, rkey, nil
+}

atproto/syntax/path_test.go

···
+package syntax
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestRepoPath(t *testing.T) {
+	assert := assert.New(t)
+
+	testValid := [][]string{
+		{"app.bsky.feed.post/asdf", "app.bsky.feed.post", "asdf"},
+	}
+
+	testErr := []string{
+		"",
+		"/",
+		"/app.bsky.feed.post/asdf",
+		"/asdf",
+		"./app.bsky.feed.post",
+		"blob/asdf",
+		"app.bsky.feed.post/",
+		"app.bsky.feed.post/.",
+		"app.bsky.feed.post/!",
+	}
+
+	for _, parts := range testValid {
+		nsid, rkey, err := ParseRepoPath(parts[0])
+		assert.NoError(err)
+		assert.Equal(parts[1], nsid.String())
+		assert.Equal(parts[2], rkey.String())
+	}
+
+	for _, raw := range testErr {
+		nsid, rkey, err := ParseRepoPath(raw)
+		assert.Error(err)
+		assert.Equal("", nsid.String())
+		assert.Equal("", rkey.String())
+	}
+}