feat(protocol): add FTP, FTPS and FTPES downloads (#1569)

pkg/protocol/ftp/model.go

@@ -0,0 +1,54 @@
+package ftp
+
+// TLS modes for the "tls" field of an ftp:// request. ftps:// URLs always use
+// implicit TLS and ftpes:// URLs always use explicit TLS.
+const (
+	TLSNone     = "none"
+	TLSExplicit = "explicit"
+	TLSImplicit = "implicit"
+)
+
+// ReqExtra is the extra of an FTP request. The TLS mode is part of the request,
+// because resolving the link already needs a connection.
+type ReqExtra struct {
+	// TLS upgrades a plain ftp:// URL: "none" (default), "explicit" (AUTH TLS)
+	// or "implicit". It is ignored for ftps:// and ftpes:// URLs.
+	TLS string `json:"tls"`
+}
+
+type OptsExtra struct {
+	// Connections is the maximum number of parallel logins. Servers often cap
+	// logins per user, so the fetcher lowers it when the server refuses one.
+	Connections int `json:"connections"`
+	// AutoTorrent when task download complete, and it is a .torrent file, it will be auto create a new task for the torrent file
+	// nil means use global config, true/false means explicit setting
+	AutoTorrent *bool `json:"autoTorrent"`
+	// DeleteTorrentAfterDownload when true, deletes the .torrent file after creating BT task
+	// nil means use global config, true/false means explicit setting
+	DeleteTorrentAfterDownload *bool `json:"deleteTorrentAfterDownload"`
+	// AutoExtract when task download complete, and it is an archive file, it will be auto extracted
+	// nil means use global config, true/false means explicit setting
+	AutoExtract *bool `json:"autoExtract"`
+	// ArchivePassword is the password for extracting password-protected archives
+	ArchivePassword string `json:"archivePassword"`
+	// DeleteAfterExtract when true, deletes the archive file after successful extraction
+	DeleteAfterExtract bool `json:"deleteAfterExtract"`
+}
+
+// Stats for download. It has the same shape as the HTTP protocol's stats, so
+// clients can show FTP connections the way they show HTTP connections.
+type Stats struct {
+	Connections []*StatsConnection `json:"connections"`
+}
+
+// StatsConnection describes one login that took part in the download.
+type StatsConnection struct {
+	Downloaded int64 `json:"downloaded"`
+	// Total is the resource size divided by the number of connections,
+	// rounded up to a whole byte, as in the HTTP protocol's stats. It is zero
+	// when the resource size is unknown.
+	Total      int64 `json:"total"`
+	Completed  bool  `json:"completed"`
+	Failed     bool  `json:"failed"`
+	RetryTimes int   `json:"retryTimes"`
+}