feat: add namesys publish options (#94)

* feat: add namesys publish options
* feat: export DefaultIPNSRecordEOL
* feat: export DefaultIPNSRecordTTL

options/namesys/opts.go

@@ -13,6 +13,15 @@ const (
 	// trust resolution to eventually complete and can't put an upper
 	// limit on how many steps it will take.
 	UnlimitedDepth = 0
+
+	// DefaultIPNSRecordTTL specifies the time that the record can be cached
+	// before checking if its validity again.
+	DefaultIPNSRecordTTL = time.Minute
+
+	// DefaultIPNSRecordEOL specifies the time that the network will cache IPNS
+	// records after being published. Records should be re-published before this
+	// interval expires. We use the same default expiration as the DHT.
+	DefaultIPNSRecordEOL = 48 * time.Hour
 )
 
 // ResolveOpts specifies options for resolving an IPNS path
@@ -72,3 +81,43 @@ func ProcessOpts(opts []ResolveOpt) ResolveOpts {
 	}
 	return rsopts
 }
+
+// PublishOptions specifies options for publishing an IPNS record.
+type PublishOptions struct {
+	EOL time.Time
+	TTL time.Duration
+}
+
+// DefaultPublishOptions returns the default options for publishing an IPNS record.
+func DefaultPublishOptions() PublishOptions {
+	return PublishOptions{
+		EOL: time.Now().Add(DefaultIPNSRecordEOL),
+		TTL: DefaultIPNSRecordTTL,
+	}
+}
+
+// PublishOption is used to set an option for PublishOpts.
+type PublishOption func(*PublishOptions)
+
+// PublishWithEOL sets an EOL.
+func PublishWithEOL(eol time.Time) PublishOption {
+	return func(o *PublishOptions) {
+		o.EOL = eol
+	}
+}
+
+// PublishWithEOL sets a TTL.
+func PublishWithTTL(ttl time.Duration) PublishOption {
+	return func(o *PublishOptions) {
+		o.TTL = ttl
+	}
+}
+
+// ProcessPublishOptions converts an array of PublishOpt into a PublishOpts object.
+func ProcessPublishOptions(opts []PublishOption) PublishOptions {
+	rsopts := DefaultPublishOptions()
+	for _, option := range opts {
+		option(&rsopts)
+	}
+	return rsopts
+}