Monorepo for Tangled
tangled.org
appview/email: replace regex check with mail.ParseAddress
Signed-off-by: Evan Jarrett <evan@evanjarrett.com>
author
Evan Jarrett
committer
Tangled
date
(Dec 4, 2025, 10:51 AM UTC)
commit
59f43eb1
59f43eb13d25f5c66618a43baf236bd7dfb72513
parent
a4ee430c
a4ee430c3132c2275c1d700b5de87e66b2ff7bf8
+60
-12
+7
-12
appview/email/email.go
+7
-12
appview/email/email.go
···
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import (
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"fmt"
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"net"
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-
"regexp"
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+
"net/mail"
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"strings"
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"github.com/resend/resend-go/v2"
···
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}
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func IsValidEmail(email string) bool {
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// Basic length check
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if len(email) < 3 || len(email) > 254 {
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// Reject whitespace (ParseAddress normalizes it away)
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if strings.ContainsAny(email, " \t\n\r") {
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return false
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}
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// Regular expression for email validation (RFC 5322 compliant)
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pattern := `^[a-zA-Z0-9.!#$%&'*+/=?^_\x60{|}~-]+@[a-zA-Z0-9](?:[a-zA-Z0-9-]{0,61}[a-zA-Z0-9])?(?:\.[a-zA-Z0-9](?:[a-zA-Z0-9-]{0,61}[a-zA-Z0-9])?)*$`
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// Compile regex
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regex := regexp.MustCompile(pattern)
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// Check if email matches regex pattern
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if !regex.MatchString(email) {
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// Use stdlib RFC 5322 parser
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addr, err := mail.ParseAddress(email)
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if err != nil {
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return false
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}
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// Split email into local and domain parts
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parts := strings.Split(email, "@")
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parts := strings.Split(addr.Address, "@")
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domain := parts[1]
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mx, err := net.LookupMX(domain)
+53
appview/email/email_test.go
+53
appview/email/email_test.go
···
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package email
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import (
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"testing"
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)
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func TestIsValidEmail(t *testing.T) {
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tests := []struct {
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name string
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email string
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want bool
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}{
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// Valid emails using RFC 2606 reserved domains
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{"standard email", "user@example.com", true},
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{"single char local", "a@example.com", true},
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{"dot in middle", "first.last@example.com", true},
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{"multiple dots", "a.b.c@example.com", true},
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{"plus tag", "user+tag@example.com", true},
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{"numbers", "user123@example.com", true},
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{"example.org", "user@example.org", true},
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{"example.net", "user@example.net", true},
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// Invalid format - rejected by mail.ParseAddress
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{"empty string", "", false},
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{"no at sign", "userexample.com", false},
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{"no domain", "user@", false},
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{"no local part", "@example.com", false},
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{"double at", "user@@example.com", false},
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{"just at sign", "@", false},
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{"leading dot", ".user@example.com", false},
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{"trailing dot", "user.@example.com", false},
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{"consecutive dots", "user..name@example.com", false},
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+
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// Whitespace - rejected before parsing
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{"space in local", "user @example.com", false},
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{"space in domain", "user@ example.com", false},
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{"tab", "user\t@example.com", false},
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{"newline", "user\n@example.com", false},
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// MX lookup - using RFC 2606 reserved TLDs (guaranteed no MX)
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{"invalid TLD", "user@example.invalid", false},
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{"test TLD", "user@mail.test", false},
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}
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for _, tt := range tests {
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t.Run(tt.name, func(t *testing.T) {
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got := IsValidEmail(tt.email)
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if got != tt.want {
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t.Errorf("IsValidEmail(%q) = %v, want %v", tt.email, got, tt.want)
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}
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})
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}
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}