Implement advanced parsing of envelope (article)

go.mod

@@ -11,4 +11,16 @@ require (
 	github.com/pressly/goose/v3 v3.5.0
 )
 
-require github.com/pkg/errors v0.9.1 // indirect
+require (
+	github.com/cention-sany/utf7 v0.0.0-20170124080048-26cad61bd60a // indirect
+	github.com/gogs/chardet v0.0.0-20191104214054-4b6791f73a28 // indirect
+	github.com/jaytaylor/html2text v0.0.0-20200412013138-3577fbdbcff7 // indirect
+	github.com/jhillyerd/enmime v0.9.3 // indirect
+	github.com/mattn/go-runewidth v0.0.12 // indirect
+	github.com/olekukonko/tablewriter v0.0.5 // indirect
+	github.com/pkg/errors v0.9.1 // indirect
+	github.com/rivo/uniseg v0.2.0 // indirect
+	github.com/ssor/bom v0.0.0-20170718123548-6386211fdfcf // indirect
+	golang.org/x/net v0.0.0-20211015210444-4f30a5c0130f // indirect
+	golang.org/x/text v0.3.6 // indirect
+)

go.sum

@@ -17,6 +17,8 @@ github.com/beorn7/perks v1.0.0/go.mod h1:KWe93zE9D1o94FZ5RNwFwVgaQK1VOXiVxmqh+Ce
 github.com/bits-and-blooms/bitset v1.2.0/go.mod h1:gIdJ4wp64HaoK2YrL1Q5/N7Y16edYb8uY+O0FJTyyDA=
 github.com/bkaradzic/go-lz4 v1.0.0/go.mod h1:0YdlkowM3VswSROI7qDxhRvJ3sLhlFrRRwjwegp5jy4=
 github.com/cenkalti/backoff/v4 v4.1.1/go.mod h1:scbssz8iZGpm3xbr14ovlUdkxfGXNInqkPWOWmG2CLw=
+github.com/cention-sany/utf7 v0.0.0-20170124080048-26cad61bd60a h1:MISbI8sU/PSK/ztvmWKFcI7UGb5/HQT7B+i3a2myKgI=
+github.com/cention-sany/utf7 v0.0.0-20170124080048-26cad61bd60a/go.mod h1:2GxOXOlEPAMFPfp014mK1SWq8G8BN8o7/dfYqJrVGn8=
 github.com/cespare/xxhash v1.1.0/go.mod h1:XrSqR1VqqWfGrhpAt58auRo0WTKS1nRRg3ghfAqPWnc=
 github.com/checkpoint-restore/go-criu/v5 v5.0.0/go.mod h1:cfwC0EG7HMUenopBsUf9d89JlCLQIfgVcNsNN0t6T2M=
 github.com/cilium/ebpf v0.6.2/go.mod h1:4tRaxcgiL706VnOzHOdBlY8IEAIdxINsQBcU4xJJXRs=
@@ -58,10 +60,13 @@ github.com/go-sql-driver/mysql v1.5.0/go.mod h1:DCzpHaOWr8IXmIStZouvnhqoel9Qv2LB
 github.com/go-sql-driver/mysql v1.6.0 h1:BCTh4TKNUYmOmMUcQ3IipzF5prigylS7XXjEkfCHuOE=
 github.com/go-sql-driver/mysql v1.6.0/go.mod h1:DCzpHaOWr8IXmIStZouvnhqoel9Qv2LBy8hT2VhHyBg=
 github.com/go-stack/stack v1.8.0/go.mod h1:v0f6uXyyMGvRgIKkXu+yp6POWl0qKG85gN/melR3HDY=
+github.com/go-test/deep v1.0.7/go.mod h1:QV8Hv/iy04NyLBxAdO9njL0iVPN1S4d/A3NVv1V36o8=
 github.com/godbus/dbus/v5 v5.0.4/go.mod h1:xhWf0FNVPg57R7Z0UbKHbJfkEywrmjJnf7w5xrFpKfA=
 github.com/gogo/protobuf v1.1.1/go.mod h1:r8qH/GZQm5c6nD/R0oafs1akxWv10x8SbQlK7atdtwQ=
 github.com/gogo/protobuf v1.2.1/go.mod h1:hp+jE20tsWTFYpLwKvXlhS1hjn+gTNwPg2I6zVXpSg4=
 github.com/gogo/protobuf v1.3.2/go.mod h1:P1XiOD3dCwIKUDQYPy72D8LYyHL2YPYrpS2s69NZV8Q=
+github.com/gogs/chardet v0.0.0-20191104214054-4b6791f73a28 h1:gBeyun7mySAKWg7Fb0GOcv0upX9bdaZScs8QcRo8mEY=
+github.com/gogs/chardet v0.0.0-20191104214054-4b6791f73a28/go.mod h1:Pcatq5tYkCW2Q6yrR2VRHlbHpZ/R4/7qyL1TCF7vl14=
 github.com/golang-sql/civil v0.0.0-20190719163853-cb61b32ac6fe/go.mod h1:8vg3r2VgvsThLBIFL93Qb5yWzgyZWhEmBwUJWevAkK0=
 github.com/golang/glog v0.0.0-20160126235308-23def4e6c14b/go.mod h1:SBH7ygxi8pfUlaOkMMuAQtPIUF8ecWP5IEl/CR7VP2Q=
 github.com/golang/groupcache v0.0.0-20190129154638-5b532d6fd5ef/go.mod h1:cIg4eruTrX1D+g88fzRXU5OdNfaM+9IcxsU14FzY7Hc=
@@ -94,6 +99,10 @@ github.com/grpc-ecosystem/grpc-gateway v1.9.0/go.mod h1:vNeuVxBJEsws4ogUvrchl83t
 github.com/hashicorp/hcl v1.0.0/go.mod h1:E5yfLk+7swimpb2L/Alb/PJmXilQ/rhwaUYs4T20WEQ=
 github.com/imdario/mergo v0.3.12/go.mod h1:jmQim1M+e3UYxmgPu/WyfjB3N3VflVyUjjjwH0dnCYA=
 github.com/inconshreveable/mousetrap v1.0.0/go.mod h1:PxqpIevigyE2G7u3NXJIT2ANytuPF1OarO4DADm73n8=
+github.com/jaytaylor/html2text v0.0.0-20200412013138-3577fbdbcff7 h1:g0fAGBisHaEQ0TRq1iBvemFRf+8AEWEmBESSiWB3Vsc=
+github.com/jaytaylor/html2text v0.0.0-20200412013138-3577fbdbcff7/go.mod h1:CVKlgaMiht+LXvHG173ujK6JUhZXKb2u/BQtjPDIvyk=
+github.com/jhillyerd/enmime v0.9.3 h1:XKqSbnX3AV+MbzM2NnhRlO6BBa123sPTdwtGl2pySik=
+github.com/jhillyerd/enmime v0.9.3/go.mod h1:S5ge4lnv/dDDBbAWwtoOFlj14NHiXdw/EqMB2lJz3b8=
 github.com/jmoiron/sqlx v1.2.0/go.mod h1:1FEQNm3xlJgrMD+FBdI9+xvCksHtbpVBBw5dYhBSsks=
 github.com/jmoiron/sqlx v1.3.4 h1:wv+0IJZfL5z0uZoUjlpKgHkgaFSYD+r9CfrXjEXsO7w=
 github.com/jmoiron/sqlx v1.3.4/go.mod h1:2BljVx/86SuTyjE+aPYlHCTNvZrnJXghYGpNiXLBMCQ=
@@ -120,6 +129,9 @@ github.com/matryer/is v1.4.0 h1:sosSmIWwkYITGrxZ25ULNDeKiMNzFSr4V/eqBQP0PeE=
 github.com/matryer/is v1.4.0/go.mod h1:8I/i5uYgLzgsgEloJE1U6xx5HkBQpAZvepWuujKwMRU=
 github.com/mattn/go-isatty v0.0.12 h1:wuysRhFDzyxgEmMf5xjvJ2M9dZoWAXNNr5LSBS7uHXY=
 github.com/mattn/go-isatty v0.0.12/go.mod h1:cbi8OIDigv2wuxKPP5vlRcQ1OAZbq2CE4Kysco4FUpU=
+github.com/mattn/go-runewidth v0.0.9/go.mod h1:H031xJmbD/WCDINGzjvQ9THkh0rPKHF+m2gUSrubnMI=
+github.com/mattn/go-runewidth v0.0.12 h1:Y41i/hVW3Pgwr8gV+J23B9YEY0zxjptBuCWEaxmAOow=
+github.com/mattn/go-runewidth v0.0.12/go.mod h1:RAqKPSqVFrSLVXbA8x7dzmKdmGzieGRCM46jaSJTDAk=
 github.com/mattn/go-sqlite3 v1.9.0/go.mod h1:FPy6KqzDD04eiIsT53CuJW3U88zkxoIYsOqkbpncsNc=
 github.com/mattn/go-sqlite3 v1.14.6/go.mod h1:NyWgC/yNuGj7Q9rpYnZvas74GogHl5/Z4A/KQRfk6bU=
 github.com/mattn/go-sqlite3 v1.14.9/go.mod h1:NyWgC/yNuGj7Q9rpYnZvas74GogHl5/Z4A/KQRfk6bU=
@@ -134,6 +146,8 @@ github.com/moby/term v0.0.0-20201216013528-df9cb8a40635/go.mod h1:FBS0z0QWA44HXy
 github.com/mrunalp/fileutils v0.5.0/go.mod h1:M1WthSahJixYnrXQl/DFQuteStB1weuxD2QJNHXfbSQ=
 github.com/mwitkow/go-conntrack v0.0.0-20161129095857-cc309e4a2223/go.mod h1:qRWi+5nqEBWmkhHvq77mSJWrCKwh8bxhgT7d/eI7P4U=
 github.com/oklog/ulid v1.3.1/go.mod h1:CirwcVhetQ6Lv90oh/F+FBtV6XMibvdAFo93nm5qn4U=
+github.com/olekukonko/tablewriter v0.0.5 h1:P2Ga83D34wi1o9J6Wh1mRuqd4mF/x/lgBS7N7AbDhec=
+github.com/olekukonko/tablewriter v0.0.5/go.mod h1:hPp6KlRPjbx+hW8ykQs1w3UBbZlj6HuIJcUGPhkA7kY=
 github.com/opencontainers/go-digest v1.0.0-rc1/go.mod h1:cMLVZDEM3+U2I4VmLI6N8jQYUd2OVphdqWwCJHrFt2s=
 github.com/opencontainers/go-digest v1.0.0/go.mod h1:0JzlMkj0TRzQZfJkVvzbP0HBR3IKzErnv2BNG4W4MAM=
 github.com/opencontainers/image-spec v1.0.1/go.mod h1:BtxoFyWECRxE4U/7sNtV5W15zMzWCbyJoFRP3s7yZA0=
@@ -161,6 +175,9 @@ github.com/prometheus/procfs v0.0.0-20190507164030-5867b95ac084/go.mod h1:TjEm7z
 github.com/prometheus/tsdb v0.7.1/go.mod h1:qhTCs0VvXwvX/y3TZrWD7rabWM+ijKTux40TwIPHuXU=
 github.com/remyoudompheng/bigfft v0.0.0-20200410134404-eec4a21b6bb0 h1:OdAsTTz6OkFY5QxjkYwrChwuRruF69c169dPK26NUlk=
 github.com/remyoudompheng/bigfft v0.0.0-20200410134404-eec4a21b6bb0/go.mod h1:qqbHyh8v60DhA7CoWK5oRCqLrMHRGoxYCSS9EjAz6Eo=
+github.com/rivo/uniseg v0.1.0/go.mod h1:J6wj4VEh+S6ZtnVlnTBMWIodfgj8LQOQFoIToxlJtxc=
+github.com/rivo/uniseg v0.2.0 h1:S1pD9weZBuJdFmowNwbpi7BJ8TNftyUImj/0WQi72jY=
+github.com/rivo/uniseg v0.2.0/go.mod h1:J6wj4VEh+S6ZtnVlnTBMWIodfgj8LQOQFoIToxlJtxc=
 github.com/rogpeppe/fastuuid v0.0.0-20150106093220-6724a57986af/go.mod h1:XWv6SoW27p1b0cqNHllgS5HIMJraePCO15w5zCzIWYg=
 github.com/russross/blackfriday/v2 v2.0.1/go.mod h1:+Rmxgy9KzJVeS9/2gXHxylqXiyQDYRxCVz55jmeOWTM=
 github.com/seccomp/libseccomp-golang v0.9.1/go.mod h1:GbW5+tmTXfcxTToHLXlScSlAvWlF4P2Ca7zGrPiEpWo=
@@ -176,6 +193,8 @@ github.com/spf13/cobra v1.0.0/go.mod h1:/6GTrnGXV9HjY+aR4k0oJ5tcvakLuG6EuKReYlHN
 github.com/spf13/jwalterweatherman v1.0.0/go.mod h1:cQK4TGJAtQXfYWX+Ddv3mKDzgVb68N+wFjFa4jdeBTo=
 github.com/spf13/pflag v1.0.3/go.mod h1:DYY7MBk1bdzusC3SYhjObp+wFpr4gzcvqqNjLnInEg4=
 github.com/spf13/viper v1.4.0/go.mod h1:PTJ7Z/lr49W6bUbkmS1V3by4uWynFiR9p7+dSq/yZzE=
+github.com/ssor/bom v0.0.0-20170718123548-6386211fdfcf h1:pvbZ0lM0XWPBqUKqFU8cmavspvIl9nulOYwdy6IFRRo=
+github.com/ssor/bom v0.0.0-20170718123548-6386211fdfcf/go.mod h1:RJID2RhlZKId02nZ62WenDCkgHFerpIOmW0iT7GKmXM=
 github.com/stretchr/objx v0.1.0/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=
 github.com/stretchr/objx v0.1.1/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=
 github.com/stretchr/testify v1.2.2/go.mod h1:a8OnRcib4nhh0OaRAV+Yts87kKdq0PP7pXfy6kDkUVs=
@@ -220,6 +239,8 @@ golang.org/x/net v0.0.0-20190620200207-3b0461eec859/go.mod h1:z5CRVTTTmAJ677TzLL
 golang.org/x/net v0.0.0-20200226121028-0de0cce0169b/go.mod h1:z5CRVTTTmAJ677TzLLGU+0bjPO0LkuOLi4/5GtJWs/s=
 golang.org/x/net v0.0.0-20201021035429-f5854403a974/go.mod h1:sp8m0HH+o8qH0wwXwYZr8TS3Oi6o0r6Gce1SSxlDquU=
 golang.org/x/net v0.0.0-20201224014010-6772e930b67b/go.mod h1:m0MpNAwzfU5UDzcl9v0D8zg8gWTRqZa9RBIspLL5mdg=
+golang.org/x/net v0.0.0-20210501142056-aec3718b3fa0/go.mod h1:OJAsFXCWl8Ukc7SiCT/9KSuxbyM7479/AVlXFRxuMCk=
+golang.org/x/net v0.0.0-20211015210444-4f30a5c0130f h1:OfiFi4JbukWwe3lzw+xunroH1mnC1e2Gy5cxNJApiSY=
 golang.org/x/net v0.0.0-20211015210444-4f30a5c0130f/go.mod h1:9nx3DQGgdP8bBQD5qxJ1jj9UTztislL4KSBs9R2vV5Y=
 golang.org/x/oauth2 v0.0.0-20180821212333-d2e6202438be/go.mod h1:N/0e6XlmueqKjAGxoOufVs8QHGRruUQn6yWY3a++T0U=
 golang.org/x/sync v0.0.0-20180314180146-1d60e4601c6f/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
@@ -255,6 +276,7 @@ golang.org/x/sys v0.0.0-20211007075335-d3039528d8ac/go.mod h1:oPkhp1MJrh7nUepCBc
 golang.org/x/term v0.0.0-20201126162022-7de9c90e9dd1/go.mod h1:bj7SfCRtBDWHUb9snDiAeCFNEtKQo2Wmx5Cou7ajbmo=
 golang.org/x/text v0.3.0/go.mod h1:NqM8EUOU14njkJ3fqMW+pc6Ldnwhi/IjpwHt7yyuwOQ=
 golang.org/x/text v0.3.3/go.mod h1:5Zoc/QRtKVWzQhOtBMvqHzDpF6irO9z98xDceosuGiQ=
+golang.org/x/text v0.3.6 h1:aRYxNxv6iGQlyVaZmk6ZgYEDa+Jg18DxebPSrd6bg1M=
 golang.org/x/text v0.3.6/go.mod h1:5Zoc/QRtKVWzQhOtBMvqHzDpF6irO9z98xDceosuGiQ=
 golang.org/x/time v0.0.0-20190308202827-9d24e82272b4/go.mod h1:tRJNPiyCQ0inRvYxbN9jk5I+vvW/OXSQhTDSoE431IQ=
 golang.org/x/tools v0.0.0-20180221164845-07fd8470d635/go.mod h1:n7NCudcB/nEzxVGmLbDWY5pfWTLqBcC2KZ6jyYvM4mQ=

internal/models/article.go

@@ -2,6 +2,7 @@ package models
 
 import (
 	"database/sql"
+	"github.com/jhillyerd/enmime"
 	"net/textproto"
 	"time"
 )
@@ -14,5 +15,6 @@ type Article struct {
 	Thread    sql.NullString `db:"thread"`
 
 	Header        textproto.MIMEHeader `db:"-"`
+	Envelope      *enmime.Envelope     `db:"-"`
 	ArticleNumber int                  `db:"-"`
 }

internal/server/handler.go

@@ -11,7 +11,7 @@ import (
 	"github.com/ChronosX88/yans/internal/protocol"
 	"github.com/ChronosX88/yans/internal/utils"
 	"github.com/google/uuid"
-	"io"
+	"github.com/jhillyerd/enmime"
 	"net/mail"
 	"strconv"
 	"strings"
@@ -304,43 +304,42 @@ func (h *Handler) handlePost(s *Session, command string, arguments []string, id
 		return err
 	}
 
-	headers, err := s.tconn.ReadMIMEHeader()
+	dr := s.tconn.DotReader()
+
+	envelope, err := enmime.ReadEnvelope(dr)
 	if err != nil {
 		return err
 	}
 
 	// generate message id
 	messageID := fmt.Sprintf("<%s@%s>", uuid.New().String(), h.serverDomain)
-	headers.Set("Message-ID", messageID)
+	envelope.SetHeader("Message-ID", []string{messageID})
 
 	// set path header
-	headers.Set("Path", fmt.Sprintf("%s!not-for-mail", h.serverDomain))
+	envelope.SetHeader("Path", []string{fmt.Sprintf("%s!not-for-mail", h.serverDomain)})
 
 	// set date header
-	if headers.Get("Date") == "" {
+	envelope.AddHeader("Date", time.Now().UTC().Format(time.RFC1123Z))
-		headers.Set("Date", time.Now().UTC().Format(time.RFC1123Z))
-	}
 
-	headerJson, err := json.Marshal(headers)
+	headerJson, err := json.Marshal(envelope.Root.Header)
 	if err != nil {
 		return err
 	}
 
 	a := models.Article{}
 	a.HeaderRaw = string(headerJson)
-	a.Header = headers
+	a.Header = envelope.Root.Header
+	a.Envelope = envelope
 
-	dr := s.tconn.DotReader()
 	// TODO handle multipart message
-	body, err := io.ReadAll(dr)
 	if err != nil {
 		return err
 	}
-	a.Body = string(body)
+	a.Body = string(envelope.Text)
 
 	// set thread property
-	if headers.Get("In-Reply-To") != "" {
+	if envelope.GetHeader("In-Reply-To") != "" {
-		parentMessage, err := h.backend.GetArticle(headers.Get("In-Reply-To"))
+		parentMessage, err := h.backend.GetArticle(envelope.GetHeader("In-Reply-To"))
 		if err != nil {
 			if err == sql.ErrNoRows {
 				return s.tconn.PrintfLine(protocol.NNTPResponse{Code: 441, Message: "no such message you are replying to"}.String())
@@ -487,18 +486,19 @@ func (h *Handler) handleArticle(s *Session, command string, arguments []string,
 	switch command {
 	case protocol.CommandArticle:
 		{
-			m := utils.NewMessage()
-			for k, v := range a.Header {
-				m.SetHeader(k, v...)
-			}
-
-			m.SetBody("text/plain", a.Body) // FIXME currently only plain text is supported
 			dw := s.tconn.DotWriter()
-			_, err = dw.Write([]byte(protocol.NNTPResponse{Code: 220, Message: fmt.Sprintf("%d %s", num, a.Header.Get("Message-ID"))}.String() + protocol.CRLF))
+			builder := utils.Builder()
+			for k, v := range a.Header {
+				for _, j := range v {
+					builder = builder.Header(k, j)
+				}
+			}
+			builder = builder.Text([]byte(a.Body)) // FIXME currently only plain text is supported
+			p, err := builder.Build()
 			if err != nil {
 				return err
 			}
-			_, err = m.WriteTo(dw)
+			err = p.Encode(dw)
 			if err != nil {
 				return err
 			}
@@ -507,9 +507,15 @@ func (h *Handler) handleArticle(s *Session, command string, arguments []string,
 		}
 	case protocol.CommandHead:
 		{
-			m := utils.NewMessage()
+			builder := utils.Builder()
 			for k, v := range a.Header {
-				m.SetHeader(k, v...)
+				for _, j := range v {
+					builder = builder.Header(k, j)
+				}
+			}
+			p, err := builder.Build()
+			if err != nil {
+				return err
 			}
 
 			dw := s.tconn.DotWriter()
@@ -517,7 +523,7 @@ func (h *Handler) handleArticle(s *Session, command string, arguments []string,
 			if err != nil {
 				return err
 			}
-			_, err = m.WriteTo(dw)
+			err = p.Encode(dw)
 			if err != nil {
 				return err
 			}
@@ -526,12 +532,6 @@ func (h *Handler) handleArticle(s *Session, command string, arguments []string,
 		}
 	case protocol.CommandBody:
 		{
-			m := utils.NewMessage()
-			for k, v := range a.Header {
-				m.SetHeader(k, v...)
-			}
-
-			m.SetBody("text/plain", a.Body) // FIXME currently only plain text is supported
 			dw := s.tconn.DotWriter()
 
 			_, err = dw.Write([]byte(protocol.NNTPResponse{Code: 222, Message: fmt.Sprintf("%d %s", num, a.Header.Get("Message-ID"))}.String() + protocol.CRLF))
@@ -812,13 +812,22 @@ func (h *Handler) handleOver(s *Session, command string, arguments []string, id
 		dw.Write([]byte(v.Header.Get("References") + "	"))
 
 		// count bytes for message
-		m := utils.NewMessage()
+		builder := utils.Builder()
 		for k, v := range v.Header {
-			m.SetHeader(k, v...)
+			for _, j := range v {
+				builder = builder.Header(k, j)
+			}
 		}
-		m.SetBody("text/plain", v.Body) // FIXME currently only plain text is supported
+		builder = builder.Text([]byte(v.Body)) // FIXME currently only plain text is supported
 		b := bytes.NewBuffer([]byte{})
-		m.WriteTo(b)
+		p, err := builder.Build()
+		if err != nil {
+			return err
+		}
+		err = p.Encode(b)
+		if err != nil {
+			return err
+		}
 
 		bytesMetadata := b.Len()
 		linesMetadata := strings.Count(v.Body, "\n")

internal/utils/builder.go

@@ -0,0 +1,226 @@
+package utils
+
+import (
+	"github.com/jhillyerd/enmime"
+	"io/ioutil"
+	"mime"
+	"net/textproto"
+	"os"
+	"path/filepath"
+	"reflect"
+)
+
+const (
+	cdAttachment = "attachment"
+	cdInline     = "inline"
+
+	ctMultipartAltern  = "multipart/alternative"
+	ctMultipartMixed   = "multipart/mixed"
+	ctMultipartRelated = "multipart/related"
+	ctTextPlain        = "text/plain"
+	ctTextHTML         = "text/html"
+
+	hnMIMEVersion = "MIME-Version"
+
+	utf8 = "utf-8"
+)
+
+// MailBuilder facilitates the easy construction of a MIME message.  Each manipulation method
+// returns a copy of the receiver struct.  It can be considered immutable if the caller does not
+// modify the string and byte slices passed in.  Immutability allows the headers or entire message
+// to be reused across multiple threads.
+type MailBuilder struct {
+	header               textproto.MIMEHeader
+	text, html           []byte
+	inlines, attachments []*enmime.Part
+	err                  error
+}
+
+// Builder returns an empty MailBuilder struct.
+func Builder() MailBuilder {
+	return MailBuilder{}
+}
+
+// Error returns the stored error from a file attachment/inline read or nil.
+func (p MailBuilder) Error() error {
+	return p.err
+}
+
+// Header returns a copy of MailBuilder with the specified value added to the named header.
+func (p MailBuilder) Header(name, value string) MailBuilder {
+	// Copy existing header map
+	h := textproto.MIMEHeader{}
+	for k, v := range p.header {
+		h[k] = v
+	}
+	h.Add(name, value)
+	p.header = h
+	return p
+}
+
+// Text returns a copy of MailBuilder that will use the provided bytes for its text/plain Part.
+func (p MailBuilder) Text(body []byte) MailBuilder {
+	p.text = body
+	return p
+}
+
+// HTML returns a copy of MailBuilder that will use the provided bytes for its text/html Part.
+func (p MailBuilder) HTML(body []byte) MailBuilder {
+	p.html = body
+	return p
+}
+
+// AddAttachment returns a copy of MailBuilder that includes the specified attachment.
+func (p MailBuilder) AddAttachment(b []byte, contentType string, fileName string) MailBuilder {
+	part := enmime.NewPart(contentType)
+	part.Content = b
+	part.FileName = fileName
+	part.Disposition = cdAttachment
+	p.attachments = append(p.attachments, part)
+	return p
+}
+
+// AddFileAttachment returns a copy of MailBuilder that includes the specified attachment.
+// fileName, will be populated from the base name of path.  Content type will be detected from the
+// path extension.
+func (p MailBuilder) AddFileAttachment(path string) MailBuilder {
+	// Only allow first p.err value
+	if p.err != nil {
+		return p
+	}
+	f, err := os.Open(path)
+	if err != nil {
+		p.err = err
+		return p
+	}
+	b, err := ioutil.ReadAll(f)
+	if err != nil {
+		p.err = err
+		return p
+	}
+	name := filepath.Base(path)
+	ctype := mime.TypeByExtension(filepath.Ext(name))
+	return p.AddAttachment(b, ctype, name)
+}
+
+// AddInline returns a copy of MailBuilder that includes the specified inline.  fileName and
+// contentID may be left empty.
+func (p MailBuilder) AddInline(
+	b []byte,
+	contentType string,
+	fileName string,
+	contentID string,
+) MailBuilder {
+	part := enmime.NewPart(contentType)
+	part.Content = b
+	part.FileName = fileName
+	part.Disposition = cdInline
+	part.ContentID = contentID
+	p.inlines = append(p.inlines, part)
+	return p
+}
+
+// AddFileInline returns a copy of MailBuilder that includes the specified inline.  fileName and
+// contentID will be populated from the base name of path.  Content type will be detected from the
+// path extension.
+func (p MailBuilder) AddFileInline(path string) MailBuilder {
+	// Only allow first p.err value
+	if p.err != nil {
+		return p
+	}
+	f, err := os.Open(path)
+	if err != nil {
+		p.err = err
+		return p
+	}
+	b, err := ioutil.ReadAll(f)
+	if err != nil {
+		p.err = err
+		return p
+	}
+	name := filepath.Base(path)
+	ctype := mime.TypeByExtension(filepath.Ext(name))
+	return p.AddInline(b, ctype, name, name)
+}
+
+// Build performs some basic validations, then constructs a tree of Part structs from the configured
+// MailBuilder.  It will set the Date header to now if it was not explicitly set.
+func (p MailBuilder) Build() (*enmime.Part, error) {
+	if p.err != nil {
+		return nil, p.err
+	}
+	// Validations
+	// Fully loaded structure; the presence of text, html, inlines, and attachments will determine
+	// how much is necessary:
+	//
+	//  multipart/mixed
+	//  |- multipart/related
+	//  |  |- multipart/alternative
+	//  |  |  |- text/plain
+	//  |  |  `- text/html
+	//  |  `- inlines..
+	//  `- attachments..
+	//
+	// We build this tree starting at the leaves, re-rooting as needed.
+	var root, part *enmime.Part
+	if p.text != nil || p.html == nil {
+		root = enmime.NewPart(ctTextPlain)
+		root.Content = p.text
+		root.Charset = utf8
+	}
+	if p.html != nil {
+		part = enmime.NewPart(ctTextHTML)
+		part.Content = p.html
+		part.Charset = utf8
+		if root == nil {
+			root = part
+		} else {
+			root.NextSibling = part
+		}
+	}
+	if p.text != nil && p.html != nil {
+		// Wrap Text & HTML bodies
+		part = root
+		root = enmime.NewPart(ctMultipartAltern)
+		root.AddChild(part)
+	}
+	if len(p.inlines) > 0 {
+		part = root
+		root = enmime.NewPart(ctMultipartRelated)
+		root.AddChild(part)
+		for _, ip := range p.inlines {
+			// Copy inline Part to isolate mutations
+			part = &enmime.Part{}
+			*part = *ip
+			part.Header = make(textproto.MIMEHeader)
+			root.AddChild(part)
+		}
+	}
+	if len(p.attachments) > 0 {
+		part = root
+		root = enmime.NewPart(ctMultipartMixed)
+		root.AddChild(part)
+		for _, ap := range p.attachments {
+			// Copy attachment Part to isolate mutations
+			part = &enmime.Part{}
+			*part = *ap
+			part.Header = make(textproto.MIMEHeader)
+			root.AddChild(part)
+		}
+	}
+	// Headers
+	h := root.Header
+	h.Set(hnMIMEVersion, "1.0")
+	for k, v := range p.header {
+		for _, s := range v {
+			h.Set(k, s)
+		}
+	}
+	return root, nil
+}
+
+// Equals uses the reflect package to test two MailBuilder structs for equality, primarily for unit
+// tests.
+func (p MailBuilder) Equals(o MailBuilder) bool {
+	return reflect.DeepEqual(p, o)
+}

internal/utils/message.go

@@ -1,635 +0,0 @@
-package utils
-
-// this package has been kindly taken from https://github.com/go-gomail/gomail
-// licensed under MIT license
-
-// Copyright (c) 2014 Alexandre Cesaro
-
-import (
-	"bytes"
-	"encoding/base64"
-	"io"
-	"mime"
-	"mime/multipart"
-	"mime/quotedprintable"
-	"os"
-	"path/filepath"
-	"strings"
-	"time"
-)
-
-var newQPWriter = quotedprintable.NewWriter
-
-type mimeEncoder struct {
-	mime.WordEncoder
-}
-
-var (
-	bEncoding     = mimeEncoder{mime.BEncoding}
-	qEncoding     = mimeEncoder{mime.QEncoding}
-	lastIndexByte = strings.LastIndexByte
-)
-
-// Message represents an email.
-type Message struct {
-	header      header
-	parts       []*part
-	attachments []*file
-	embedded    []*file
-	charset     string
-	encoding    Encoding
-	hEncoder    mimeEncoder
-	buf         bytes.Buffer
-}
-
-type header map[string][]string
-
-type part struct {
-	contentType string
-	copier      func(io.Writer) error
-	encoding    Encoding
-}
-
-// NewMessage creates a new message. It uses UTF-8 and quoted-printable encoding
-// by default.
-func NewMessage(settings ...MessageSetting) *Message {
-	m := &Message{
-		header:   make(header),
-		charset:  "UTF-8",
-		encoding: QuotedPrintable,
-	}
-
-	m.applySettings(settings)
-
-	if m.encoding == Base64 {
-		m.hEncoder = bEncoding
-	} else {
-		m.hEncoder = qEncoding
-	}
-
-	return m
-}
-
-// Reset resets the message so it can be reused. The message keeps its previous
-// settings so it is in the same state that after a call to NewMessage.
-func (m *Message) Reset() {
-	for k := range m.header {
-		delete(m.header, k)
-	}
-	m.parts = nil
-	m.attachments = nil
-	m.embedded = nil
-}
-
-func (m *Message) applySettings(settings []MessageSetting) {
-	for _, s := range settings {
-		s(m)
-	}
-}
-
-// A MessageSetting can be used as an argument in NewMessage to configure an
-// email.
-type MessageSetting func(m *Message)
-
-// SetCharset is a message setting to set the charset of the email.
-func SetCharset(charset string) MessageSetting {
-	return func(m *Message) {
-		m.charset = charset
-	}
-}
-
-// SetEncoding is a message setting to set the encoding of the email.
-func SetEncoding(enc Encoding) MessageSetting {
-	return func(m *Message) {
-		m.encoding = enc
-	}
-}
-
-// Encoding represents a MIME encoding scheme like quoted-printable or base64.
-type Encoding string
-
-const (
-	// QuotedPrintable represents the quoted-printable encoding as defined in
-	// RFC 2045.
-	QuotedPrintable Encoding = "quoted-printable"
-	// Base64 represents the base64 encoding as defined in RFC 2045.
-	Base64 Encoding = "base64"
-	// Unencoded can be used to avoid encoding the body of an email. The headers
-	// will still be encoded using quoted-printable encoding.
-	Unencoded Encoding = "8bit"
-)
-
-// SetHeader sets a value to the given header field.
-func (m *Message) SetHeader(field string, value ...string) {
-	m.encodeHeader(value)
-	m.header[field] = value
-}
-
-func (m *Message) encodeHeader(values []string) {
-	for i := range values {
-		values[i] = m.encodeString(values[i])
-	}
-}
-
-func (m *Message) encodeString(value string) string {
-	return m.hEncoder.Encode(m.charset, value)
-}
-
-// SetHeaders sets the message headers.
-func (m *Message) SetHeaders(h map[string][]string) {
-	for k, v := range h {
-		m.SetHeader(k, v...)
-	}
-}
-
-// SetAddressHeader sets an address to the given header field.
-func (m *Message) SetAddressHeader(field, address, name string) {
-	m.header[field] = []string{m.FormatAddress(address, name)}
-}
-
-// FormatAddress formats an address and a name as a valid RFC 5322 address.
-func (m *Message) FormatAddress(address, name string) string {
-	if name == "" {
-		return address
-	}
-
-	enc := m.encodeString(name)
-	if enc == name {
-		m.buf.WriteByte('"')
-		for i := 0; i < len(name); i++ {
-			b := name[i]
-			if b == '\\' || b == '"' {
-				m.buf.WriteByte('\\')
-			}
-			m.buf.WriteByte(b)
-		}
-		m.buf.WriteByte('"')
-	} else if hasSpecials(name) {
-		m.buf.WriteString(bEncoding.Encode(m.charset, name))
-	} else {
-		m.buf.WriteString(enc)
-	}
-	m.buf.WriteString(" <")
-	m.buf.WriteString(address)
-	m.buf.WriteByte('>')
-
-	addr := m.buf.String()
-	m.buf.Reset()
-	return addr
-}
-
-func hasSpecials(text string) bool {
-	for i := 0; i < len(text); i++ {
-		switch c := text[i]; c {
-		case '(', ')', '<', '>', '[', ']', ':', ';', '@', '\\', ',', '.', '"':
-			return true
-		}
-	}
-
-	return false
-}
-
-// SetDateHeader sets a date to the given header field.
-func (m *Message) SetDateHeader(field string, date time.Time) {
-	m.header[field] = []string{m.FormatDate(date)}
-}
-
-// FormatDate formats a date as a valid RFC 5322 date.
-func (m *Message) FormatDate(date time.Time) string {
-	return date.Format(time.RFC1123Z)
-}
-
-// GetHeader gets a header field.
-func (m *Message) GetHeader(field string) []string {
-	return m.header[field]
-}
-
-// SetBody sets the body of the message. It replaces any content previously set
-// by SetBody, AddAlternative or AddAlternativeWriter.
-func (m *Message) SetBody(contentType, body string, settings ...PartSetting) {
-	m.parts = []*part{m.newPart(contentType, newCopier(body), settings)}
-}
-
-// AddAlternative adds an alternative part to the message.
-//
-// It is commonly used to send HTML emails that default to the plain text
-// version for backward compatibility. AddAlternative appends the new part to
-// the end of the message. So the plain text part should be added before the
-// HTML part. See http://en.wikipedia.org/wiki/MIME#Alternative
-func (m *Message) AddAlternative(contentType, body string, settings ...PartSetting) {
-	m.AddAlternativeWriter(contentType, newCopier(body), settings...)
-}
-
-func newCopier(s string) func(io.Writer) error {
-	return func(w io.Writer) error {
-		_, err := io.WriteString(w, s)
-		return err
-	}
-}
-
-// AddAlternativeWriter adds an alternative part to the message. It can be
-// useful with the text/template or html/template packages.
-func (m *Message) AddAlternativeWriter(contentType string, f func(io.Writer) error, settings ...PartSetting) {
-	m.parts = append(m.parts, m.newPart(contentType, f, settings))
-}
-
-func (m *Message) newPart(contentType string, f func(io.Writer) error, settings []PartSetting) *part {
-	p := &part{
-		contentType: contentType,
-		copier:      f,
-		encoding:    m.encoding,
-	}
-
-	for _, s := range settings {
-		s(p)
-	}
-
-	return p
-}
-
-// A PartSetting can be used as an argument in Message.SetBody,
-// Message.AddAlternative or Message.AddAlternativeWriter to configure the part
-// added to a message.
-type PartSetting func(*part)
-
-// SetPartEncoding sets the encoding of the part added to the message. By
-// default, parts use the same encoding than the message.
-func SetPartEncoding(e Encoding) PartSetting {
-	return PartSetting(func(p *part) {
-		p.encoding = e
-	})
-}
-
-type file struct {
-	Name     string
-	Header   map[string][]string
-	CopyFunc func(w io.Writer) error
-}
-
-func (f *file) setHeader(field, value string) {
-	f.Header[field] = []string{value}
-}
-
-// A FileSetting can be used as an argument in Message.Attach or Message.Embed.
-type FileSetting func(*file)
-
-// SetHeader is a file setting to set the MIME header of the message part that
-// contains the file content.
-//
-// Mandatory headers are automatically added if they are not set when sending
-// the email.
-func SetHeader(h map[string][]string) FileSetting {
-	return func(f *file) {
-		for k, v := range h {
-			f.Header[k] = v
-		}
-	}
-}
-
-// Rename is a file setting to set the name of the attachment if the name is
-// different than the filename on disk.
-func Rename(name string) FileSetting {
-	return func(f *file) {
-		f.Name = name
-	}
-}
-
-// SetCopyFunc is a file setting to replace the function that runs when the
-// message is sent. It should copy the content of the file to the io.Writer.
-//
-// The default copy function opens the file with the given filename, and copy
-// its content to the io.Writer.
-func SetCopyFunc(f func(io.Writer) error) FileSetting {
-	return func(fi *file) {
-		fi.CopyFunc = f
-	}
-}
-
-func (m *Message) appendFile(list []*file, name string, settings []FileSetting) []*file {
-	f := &file{
-		Name:   filepath.Base(name),
-		Header: make(map[string][]string),
-		CopyFunc: func(w io.Writer) error {
-			h, err := os.Open(name)
-			if err != nil {
-				return err
-			}
-			if _, err := io.Copy(w, h); err != nil {
-				h.Close()
-				return err
-			}
-			return h.Close()
-		},
-	}
-
-	for _, s := range settings {
-		s(f)
-	}
-
-	if list == nil {
-		return []*file{f}
-	}
-
-	return append(list, f)
-}
-
-// Attach attaches the files to the email.
-func (m *Message) Attach(filename string, settings ...FileSetting) {
-	m.attachments = m.appendFile(m.attachments, filename, settings)
-}
-
-// Embed embeds the images to the email.
-func (m *Message) Embed(filename string, settings ...FileSetting) {
-	m.embedded = m.appendFile(m.embedded, filename, settings)
-}
-
-// WriteTo implements io.WriterTo. It dumps the whole message into w.
-func (m *Message) WriteTo(w io.Writer) (int64, error) {
-	mw := &messageWriter{w: w}
-	mw.writeMessage(m)
-	return mw.n, mw.err
-}
-
-func (w *messageWriter) writeMessage(m *Message) {
-	if _, ok := m.header["Mime-Version"]; !ok {
-		w.writeString("Mime-Version: 1.0\r\n")
-	}
-	if _, ok := m.header["Date"]; !ok {
-		w.writeHeader("Date", m.FormatDate(time.Now()))
-	}
-	w.writeHeaders(m.header)
-
-	if m.hasMixedPart() {
-		w.openMultipart("mixed")
-	}
-
-	if m.hasRelatedPart() {
-		w.openMultipart("related")
-	}
-
-	if m.hasAlternativePart() {
-		w.openMultipart("alternative")
-	}
-	for _, part := range m.parts {
-		w.writePart(part, m.charset)
-	}
-	if m.hasAlternativePart() {
-		w.closeMultipart()
-	}
-
-	w.addFiles(m.embedded, false)
-	if m.hasRelatedPart() {
-		w.closeMultipart()
-	}
-
-	w.addFiles(m.attachments, true)
-	if m.hasMixedPart() {
-		w.closeMultipart()
-	}
-}
-
-func (m *Message) hasMixedPart() bool {
-	return (len(m.parts) > 0 && len(m.attachments) > 0) || len(m.attachments) > 1
-}
-
-func (m *Message) hasRelatedPart() bool {
-	return (len(m.parts) > 0 && len(m.embedded) > 0) || len(m.embedded) > 1
-}
-
-func (m *Message) hasAlternativePart() bool {
-	return len(m.parts) > 1
-}
-
-type messageWriter struct {
-	w          io.Writer
-	n          int64
-	writers    [3]*multipart.Writer
-	partWriter io.Writer
-	depth      uint8
-	err        error
-}
-
-func (w *messageWriter) openMultipart(mimeType string) {
-	mw := multipart.NewWriter(w)
-	contentType := "multipart/" + mimeType + ";\r\n boundary=" + mw.Boundary()
-	w.writers[w.depth] = mw
-
-	if w.depth == 0 {
-		w.writeHeader("Content-Type", contentType)
-		w.writeString("\r\n")
-	} else {
-		w.createPart(map[string][]string{
-			"Content-Type": {contentType},
-		})
-	}
-	w.depth++
-}
-
-func (w *messageWriter) createPart(h map[string][]string) {
-	w.partWriter, w.err = w.writers[w.depth-1].CreatePart(h)
-}
-
-func (w *messageWriter) closeMultipart() {
-	if w.depth > 0 {
-		w.writers[w.depth-1].Close()
-		w.depth--
-	}
-}
-
-func (w *messageWriter) writePart(p *part, charset string) {
-	w.writeHeaders(map[string][]string{
-		"Content-Type":              {p.contentType + "; charset=" + charset},
-		"Content-Transfer-Encoding": {string(p.encoding)},
-	})
-	w.writeBody(p.copier, p.encoding)
-}
-
-func (w *messageWriter) addFiles(files []*file, isAttachment bool) {
-	for _, f := range files {
-		if _, ok := f.Header["Content-Type"]; !ok {
-			mediaType := mime.TypeByExtension(filepath.Ext(f.Name))
-			if mediaType == "" {
-				mediaType = "application/octet-stream"
-			}
-			f.setHeader("Content-Type", mediaType+`; name="`+f.Name+`"`)
-		}
-
-		if _, ok := f.Header["Content-Transfer-Encoding"]; !ok {
-			f.setHeader("Content-Transfer-Encoding", string(Base64))
-		}
-
-		if _, ok := f.Header["Content-Disposition"]; !ok {
-			var disp string
-			if isAttachment {
-				disp = "attachment"
-			} else {
-				disp = "inline"
-			}
-			f.setHeader("Content-Disposition", disp+`; filename="`+f.Name+`"`)
-		}
-
-		if !isAttachment {
-			if _, ok := f.Header["Content-ID"]; !ok {
-				f.setHeader("Content-ID", "<"+f.Name+">")
-			}
-		}
-		w.writeHeaders(f.Header)
-		w.writeBody(f.CopyFunc, Base64)
-	}
-}
-
-func (w *messageWriter) Write(p []byte) (int, error) {
-	if w.err != nil {
-		return 0, w.err
-	}
-
-	var n int
-	n, w.err = w.w.Write(p)
-	w.n += int64(n)
-	return n, w.err
-}
-
-func (w *messageWriter) writeString(s string) {
-	n, _ := io.WriteString(w.w, s)
-	w.n += int64(n)
-}
-
-func (w *messageWriter) writeHeader(k string, v ...string) {
-	w.writeString(k)
-	if len(v) == 0 {
-		w.writeString(":\r\n")
-		return
-	}
-	w.writeString(": ")
-
-	// Max header line length is 78 characters in RFC 5322 and 76 characters
-	// in RFC 2047. So for the sake of simplicity we use the 76 characters
-	// limit.
-	charsLeft := 76 - len(k) - len(": ")
-
-	for i, s := range v {
-		// If the line is already too long, insert a newline right away.
-		if charsLeft < 1 {
-			if i == 0 {
-				w.writeString("\r\n ")
-			} else {
-				w.writeString(",\r\n ")
-			}
-			charsLeft = 75
-		} else if i != 0 {
-			w.writeString(", ")
-			charsLeft -= 2
-		}
-
-		// While the header content is too long, fold it by inserting a newline.
-		for len(s) > charsLeft {
-			s = w.writeLine(s, charsLeft)
-			charsLeft = 75
-		}
-		w.writeString(s)
-		if i := lastIndexByte(s, '\n'); i != -1 {
-			charsLeft = 75 - (len(s) - i - 1)
-		} else {
-			charsLeft -= len(s)
-		}
-	}
-	w.writeString("\r\n")
-}
-
-func (w *messageWriter) writeLine(s string, charsLeft int) string {
-	// If there is already a newline before the limit. Write the line.
-	if i := strings.IndexByte(s, '\n'); i != -1 && i < charsLeft {
-		w.writeString(s[:i+1])
-		return s[i+1:]
-	}
-
-	for i := charsLeft - 1; i >= 0; i-- {
-		if s[i] == ' ' {
-			w.writeString(s[:i])
-			w.writeString("\r\n ")
-			return s[i+1:]
-		}
-	}
-
-	// We could not insert a newline cleanly so look for a space or a newline
-	// even if it is after the limit.
-	for i := 75; i < len(s); i++ {
-		if s[i] == ' ' {
-			w.writeString(s[:i])
-			w.writeString("\r\n ")
-			return s[i+1:]
-		}
-		if s[i] == '\n' {
-			w.writeString(s[:i+1])
-			return s[i+1:]
-		}
-	}
-
-	// Too bad, no space or newline in the whole string. Just write everything.
-	w.writeString(s)
-	return ""
-}
-
-func (w *messageWriter) writeHeaders(h map[string][]string) {
-	if w.depth == 0 {
-		for k, v := range h {
-			if k != "Bcc" {
-				w.writeHeader(k, v...)
-			}
-		}
-	} else {
-		w.createPart(h)
-	}
-}
-
-func (w *messageWriter) writeBody(f func(io.Writer) error, enc Encoding) {
-	var subWriter io.Writer
-	if w.depth == 0 {
-		w.writeString("\r\n")
-		subWriter = w.w
-	} else {
-		subWriter = w.partWriter
-	}
-
-	if enc == Base64 {
-		wc := base64.NewEncoder(base64.StdEncoding, newBase64LineWriter(subWriter))
-		w.err = f(wc)
-		wc.Close()
-	} else if enc == Unencoded {
-		w.err = f(subWriter)
-	} else {
-		wc := newQPWriter(subWriter)
-		w.err = f(wc)
-		wc.Close()
-	}
-}
-
-// As required by RFC 2045, 6.7. (page 21) for quoted-printable, and
-// RFC 2045, 6.8. (page 25) for base64.
-const maxLineLen = 76
-
-// base64LineWriter limits text encoded in base64 to 76 characters per line
-type base64LineWriter struct {
-	w       io.Writer
-	lineLen int
-}
-
-func newBase64LineWriter(w io.Writer) *base64LineWriter {
-	return &base64LineWriter{w: w}
-}
-
-func (w *base64LineWriter) Write(p []byte) (int, error) {
-	n := 0
-	for len(p)+w.lineLen > maxLineLen {
-		w.w.Write(p[:maxLineLen-w.lineLen])
-		w.w.Write([]byte("\r\n"))
-		p = p[maxLineLen-w.lineLen:]
-		n += maxLineLen - w.lineLen
-		w.lineLen = 0
-	}
-
-	w.w.Write(p)
-	w.lineLen += len(p)
-
-	return n + len(p), nil
-}

internal/utils/stringutil/addr.go

@@ -0,0 +1,21 @@
+package stringutil
+
+import (
+	"bytes"
+	"net/mail"
+)
+
+// JoinAddress formats a slice of Address structs such that they can be used in a To or Cc header.
+func JoinAddress(addrs []mail.Address) string {
+	if len(addrs) == 0 {
+		return ""
+	}
+	buf := &bytes.Buffer{}
+	for i, a := range addrs {
+		if i > 0 {
+			_, _ = buf.WriteString(", ")
+		}
+		_, _ = buf.WriteString(a.String())
+	}
+	return buf.String()
+}

internal/utils/stringutil/split.go

@@ -0,0 +1,37 @@
+package stringutil
+
+const escape = '\\'
+
+// SplitQuoted splits a string, ignoring separators present inside of quoted runs.  Separators
+// cannot be escaped outside of quoted runs, the escaping will be ignored.
+//
+// Quotes are preserved in result, but the separators are removed.
+func SplitQuoted(s string, sep rune, quote rune) []string {
+	a := make([]string, 0, 8)
+	quoted := false
+	escaped := false
+	p := 0
+	for i, c := range s {
+		if c == escape {
+			// Escape can escape itself.
+			escaped = !escaped
+			continue
+		}
+		if c == quote {
+			quoted = !quoted
+			continue
+		}
+		escaped = false
+		if !quoted && c == sep {
+			a = append(a, s[p:i])
+			p = i + 1
+		}
+	}
+
+	if quoted && quote != 0 {
+		// s contained an unterminated quoted-run, re-split without quoting.
+		return SplitQuoted(s, sep, rune(0))
+	}
+
+	return append(a, s[p:])
+}

internal/utils/stringutil/uuid.go

@@ -0,0 +1,24 @@
+package stringutil
+
+import (
+	"fmt"
+	"math/rand"
+	"sync"
+	"time"
+)
+
+var uuidRand = rand.New(rand.NewSource(time.Now().UnixNano()))
+var uuidMutex = &sync.Mutex{}
+
+// UUID generates a random UUID according to RFC 4122.
+func UUID() string {
+	uuid := make([]byte, 16)
+	uuidMutex.Lock()
+	_, _ = uuidRand.Read(uuid)
+	uuidMutex.Unlock()
+	// variant bits; see section 4.1.1
+	uuid[8] = uuid[8]&^0xc0 | 0x80
+	// version 4 (pseudo-random); see section 4.1.3
+	uuid[6] = uuid[6]&^0xf0 | 0x40
+	return fmt.Sprintf("%x-%x-%x-%x-%x", uuid[0:4], uuid[4:6], uuid[6:8], uuid[8:10], uuid[10:])
+}

internal/utils/stringutil/wrap.go

@@ -0,0 +1,36 @@
+package stringutil
+
+// Wrap builds a byte slice from strs, wrapping on word boundaries before max chars
+func Wrap(max int, strs ...string) []byte {
+	input := make([]byte, 0)
+	output := make([]byte, 0)
+	for _, s := range strs {
+		input = append(input, []byte(s)...)
+	}
+	if len(input) < max {
+		// Doesn't need to be wrapped
+		return input
+	}
+	ls := -1 // Last seen space index
+	lw := -1 // Last written byte index
+	ll := 0  // Length of current line
+	for i := 0; i < len(input); i++ {
+		ll++
+		switch input[i] {
+		case ' ', '\t':
+			ls = i
+		}
+		if ll >= max {
+			if ls >= 0 {
+				output = append(output, input[lw+1:ls]...)
+				output = append(output, '\r', '\n', ' ')
+				lw = ls // Jump over the space we broke on
+				ll = 1  // Count leading space above
+				// Rewind
+				i = lw + 1
+				ls = -1
+			}
+		}
+	}
+	return append(output, input[lw+1:]...)
+}