96 lines
2.8 KiB
Go
96 lines
2.8 KiB
Go
package validation
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import (
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"errors"
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"net/mail"
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"strings"
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"git.pcux.cn/xuans/Smail/dto/parsemail"
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)
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var (
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ErrInvalidEmail = errors.New("invalid email")
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ErrTooManyRecipients = errors.New("too many recipients")
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ErrTooManyAttachments = errors.New("too many attachments")
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ErrAttachmentTooLarge = errors.New("attachment too large")
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ErrEmailTooLarge = errors.New("email too large")
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)
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type EmailLimits struct {
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MaxRecipients int
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MaxAttachments int
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MaxAttachmentBytes int64
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MaxTotalAttachmentBytes int64
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MaxBodyBytes int64
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MaxEstimatedBytes int64
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}
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func ValidateEmail(email *parsemail.Email, limits EmailLimits) error {
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if email == nil || email.From == nil || email.Sender == nil {
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return ErrInvalidEmail
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}
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recipients := len(email.To) + len(email.Cc) + len(email.Bcc) + len(email.ReplyTo)
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if recipients == 0 {
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return ErrInvalidEmail
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}
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if limits.MaxRecipients > 0 && recipients > limits.MaxRecipients {
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return ErrTooManyRecipients
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}
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for _, list := range [][]*parsemail.User{email.To, email.Cc, email.Bcc, email.ReplyTo} {
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for _, user := range list {
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if user == nil || !IsMailboxAddress(user.EmailAddress) {
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return ErrInvalidEmail
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}
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}
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}
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bodyBytes := int64(len(email.Text)) + int64(len(email.HTML))
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if limits.MaxBodyBytes > 0 && bodyBytes > limits.MaxBodyBytes {
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return ErrEmailTooLarge
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}
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if limits.MaxAttachments > 0 && len(email.Attachments) > limits.MaxAttachments {
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return ErrTooManyAttachments
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}
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totalAttachmentBytes := int64(0)
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estimatedBytes := base64Size(int64(len(email.Text))) + base64Size(int64(len(email.HTML))) + 64<<10
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for _, attachment := range email.Attachments {
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if attachment == nil || strings.ContainsAny(attachment.ContentType, "\r\n") {
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return ErrInvalidEmail
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}
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size := int64(len(attachment.Content))
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if limits.MaxAttachmentBytes > 0 && size > limits.MaxAttachmentBytes {
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return ErrAttachmentTooLarge
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}
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if size > 0 && totalAttachmentBytes > int64(^uint64(0)>>1)-size {
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return ErrEmailTooLarge
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}
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totalAttachmentBytes += size
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if limits.MaxTotalAttachmentBytes > 0 && totalAttachmentBytes > limits.MaxTotalAttachmentBytes {
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return ErrEmailTooLarge
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}
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estimatedBytes += base64Size(size) + int64(len(attachment.Filename)) + int64(len(attachment.ContentType)) + 1024
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if limits.MaxEstimatedBytes > 0 && estimatedBytes > limits.MaxEstimatedBytes {
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return ErrEmailTooLarge
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}
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}
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if limits.MaxEstimatedBytes > 0 && estimatedBytes > limits.MaxEstimatedBytes {
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return ErrEmailTooLarge
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}
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return nil
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}
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func IsMailboxAddress(address string) bool {
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address = strings.TrimSpace(address)
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parsed, err := mail.ParseAddress(address)
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return err == nil && parsed.Address == address
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}
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func base64Size(size int64) int64 {
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if size <= 0 {
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return 0
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}
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return ((size + 2) / 3) * 4
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}
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