55 lines
1.2 KiB
Go
55 lines
1.2 KiB
Go
// Copyright (c) 2020 Shivaram Lingamneni
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// released under the MIT license
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package email
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import (
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"errors"
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dkim "github.com/toorop/go-dkim"
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"io/ioutil"
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)
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var (
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ErrMissingFields = errors.New("DKIM config is missing fields")
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)
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type DKIMConfig struct {
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Domain string
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Selector string
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KeyFile string `yaml:"key-file"`
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keyBytes []byte
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}
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func (dkim *DKIMConfig) Postprocess() (err error) {
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if dkim.Domain != "" {
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if dkim.Selector == "" || dkim.KeyFile == "" {
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return ErrMissingFields
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}
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dkim.keyBytes, err = ioutil.ReadFile(dkim.KeyFile)
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if err != nil {
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return err
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}
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}
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return nil
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}
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var defaultOptions = dkim.SigOptions{
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Version: 1,
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Canonicalization: "relaxed/relaxed",
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Algo: "rsa-sha256",
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Headers: []string{"from", "to", "subject", "message-id", "date"},
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BodyLength: 0,
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QueryMethods: []string{"dns/txt"},
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AddSignatureTimestamp: true,
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SignatureExpireIn: 0,
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}
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func DKIMSign(message []byte, dkimConfig DKIMConfig) (result []byte, err error) {
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options := defaultOptions
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options.PrivateKey = dkimConfig.keyBytes
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options.Domain = dkimConfig.Domain
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options.Selector = dkimConfig.Selector
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err = dkim.Sign(&message, options)
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return message, err
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}
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