From dd70b34dcbbb263baa39752a60feb163abebdd7f Mon Sep 17 00:00:00 2001
From: Maxim Lebedev <git@toby3d.me>
Date: Fri, 3 Dec 2021 06:58:37 +0500
Subject: [PATCH] :label: Created me domain

---
 internal/domain/me.go      | 114 +++++++++++++++++++++++++++++++++++++
 internal/domain/me_test.go |  70 +++++++++++++++++++++++
 2 files changed, 184 insertions(+)
 create mode 100644 internal/domain/me.go
 create mode 100644 internal/domain/me_test.go

diff --git a/internal/domain/me.go b/internal/domain/me.go
new file mode 100644
index 0000000..9dc0c5d
--- /dev/null
+++ b/internal/domain/me.go
@@ -0,0 +1,114 @@
+package domain
+
+import (
+	"fmt"
+	"net"
+	"strings"
+	"testing"
+
+	"github.com/stretchr/testify/require"
+	http "github.com/valyala/fasthttp"
+)
+
+// Me is a user URL identifier.
+type Me struct {
+	uri     *http.URI
+	isValid bool
+}
+
+// UnmarshalForm implements a custom form.Unmarshaler.
+func (me *Me) UnmarshalForm(v []byte) error {
+	if err := me.Parse(v); err != nil {
+		return fmt.Errorf("cannot unmarshal form: %w", err)
+	}
+
+	return nil
+}
+
+// Parse parse and validate me identifier.
+func (me *Me) Parse(v []byte) error {
+	if me.uri != nil {
+		http.ReleaseURI(me.uri)
+	}
+
+	me.uri = http.AcquireURI()
+	if err := me.uri.Parse(nil, v); err != nil {
+		return fmt.Errorf("cannot parse me: %w", err)
+	}
+
+	// NOTE(toby3d): MUST have either an https or http scheme
+	scheme := string(me.uri.Scheme())
+	if scheme != "http" && scheme != "https" {
+		return nil
+	}
+
+	// NOTE(toby3d): MUST contain a path component (/ is a valid path)
+	// NOTE(toby3d): MUST NOT contain single-dot or double-dot path segments
+	path := string(me.uri.PathOriginal())
+	if path == "" || strings.Contains(path, "/.") || strings.Contains(path, "/..") {
+		return nil
+	}
+
+	// NOTE(toby3d): MUST NOT contain a fragment component
+	if me.uri.Hash() != nil {
+		return nil
+	}
+
+	// NOTE(toby3d): MUST NOT contain a username or password component
+	if me.uri.Username() != nil || me.uri.Password() != nil {
+		return nil
+	}
+
+	// NOTE(toby3d): host names MUST be domain names
+	host := string(me.uri.Host())
+	if host == "" {
+		return nil
+	}
+
+	// NOTE(toby3d): MUST NOT contain a port
+	if _, _, err := net.SplitHostPort(host); err == nil {
+		return nil
+	}
+
+	// NOTE(toby3d): MUST NOT be ipv4 or ipv6 addresses
+	if net.ParseIP(host) != nil {
+		return nil
+	}
+
+	me.isValid = true
+
+	return nil
+}
+
+// String returns string representation of Me.
+func (me *Me) String() string {
+	if me.uri == nil {
+		return ""
+	}
+
+	return me.uri.String()
+}
+
+// URI returns copy of parsed *fasthttp.URI.
+// This copy MUST be released via fasthttp.ReleaseURI.
+func (me *Me) URI() *http.URI {
+	u := http.AcquireURI()
+	me.uri.CopyTo(u)
+
+	return u
+}
+
+// IsValid returns true if Me is a valid identifier.
+func (me *Me) IsValid() bool {
+	return me.isValid
+}
+
+// TestMe returns a valid testing Me.
+func TestMe(tb testing.TB) *Me {
+	tb.Helper()
+
+	me := new(Me)
+	require.NoError(tb, me.Parse([]byte("https://user.example.net/")))
+
+	return me
+}
diff --git a/internal/domain/me_test.go b/internal/domain/me_test.go
new file mode 100644
index 0000000..18b3cf8
--- /dev/null
+++ b/internal/domain/me_test.go
@@ -0,0 +1,70 @@
+package domain_test
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+
+	"source.toby3d.me/website/oauth/internal/domain"
+)
+
+func TestMeIsValid(t *testing.T) {
+	t.Parallel()
+
+	for _, testCase := range []struct {
+		name    string
+		input   string
+		isValid bool
+	}{{
+		name:    "valid",
+		input:   "https://example.com/",
+		isValid: true,
+	}, {
+		name:    "valid with path",
+		input:   "https://example.com/username",
+		isValid: true,
+	}, {
+		name:    "valid with query",
+		input:   "https://example.com/users?id=100",
+		isValid: true,
+	}, {
+		name:    "missing scheme",
+		input:   "example.com",
+		isValid: false,
+	}, {
+		name:    "invalid scheme",
+		input:   "mailto:user@example.com",
+		isValid: false,
+	}, {
+		name:    "contains a double-dot path segment",
+		input:   "https://example.com/foo/../bar",
+		isValid: false,
+	}, {
+		name:    "contains a fragment",
+		input:   "https://example.com/#me",
+		isValid: false,
+	}, {
+		name:    "contains a username and password",
+		input:   "https://user:pass@example.com/",
+		isValid: false,
+	}, {
+		name:    "contains a port",
+		input:   "https://example.com:8443/",
+		isValid: false,
+	}, {
+		name:    "host is an IP address",
+		input:   "https://172.28.92.51/",
+		isValid: false,
+	}} {
+		testCase := testCase
+
+		t.Run(testCase.name, func(t *testing.T) {
+			t.Parallel()
+
+			me := new(domain.Me)
+			require.NoError(t, me.Parse([]byte(testCase.input)))
+			assert.Equal(t, testCase.isValid, me.IsValid())
+		})
+	}
+}