Add meid

3 files changed, 30 insertions, 12 deletions

diff --git a/.config/example.yml b/.config/example.yml
index 32ad165623..48b1a0fd1c 100644
--- a/.config/example.yml
+++ b/.config/example.yml
@@ -127,18 +127,10 @@ drive:
 # change it according to your preferences.
 
 # Available methods:
-# aid ... Use AID for ID generation
-# ulid ... Use ulid for ID generation
-# objectid ... This is left for backward compatibility.
-
-# AID is the original ID generation method.
-
-# ULID: Universally Unique Lexicographically Sortable Identifier.
-# for more details: https://github.com/ulid/spec
-# * Normally, AID should be sufficient.
-
-# ObjectID is the method used in previous versions of Misskey.
-# * Choose this if you are migrating from a previous Misskey.
+# aid ... Short, Millisecond accuracy
+# meid ... Similar to ObjectID, Millisecond accuracy
+# ulid ... Millisecond accuracy
+# objectid ... This is left for backward compatibility
 
 id: 'aid'
 
diff --git a/src/misc/gen-id.ts b/src/misc/gen-id.ts
index d16910d015..5ee65e8177 100644
--- a/src/misc/gen-id.ts
+++ b/src/misc/gen-id.ts
@@ -1,5 +1,6 @@
 import { ulid } from 'ulid';
 import { genAid } from './id/aid';
+import { genMeid } from './id/meid';
 import { genObjectId } from './id/object-id';
 import config from '../config';
 
@@ -10,6 +11,7 @@ export function genId(date?: Date): string {
 
 	switch (metohd) {
 		case 'aid': return genAid(date);
+		case 'meid': return genMeid(date);
 		case 'ulid': return ulid(date.getTime());
 		case 'objectid': return genObjectId(date);
 		default: throw 'unknown id generation method';
diff --git a/src/misc/id/meid.ts b/src/misc/id/meid.ts
new file mode 100644
index 0000000000..0a0935e536
--- /dev/null
+++ b/src/misc/id/meid.ts
@@ -0,0 +1,24 @@
+const CHARS = '0123456789abcdef';
+
+function getTime(time: number) {
+	if (time < 0) time = 0;
+	if (time === 0) {
+		return CHARS[0];
+	}
+
+	return time.toString(16).padStart(16, CHARS[0]);
+}
+
+function getRandom() {
+	let str = '';
+
+	for (let i = 0; i < 7; i++) {
+		str += CHARS[Math.floor(Math.random() * CHARS.length)];
+	}
+
+	return str;
+}
+
+export function genMeid(date: Date): string {
+	return 'f' + getTime(date.getTime()) + getRandom();
+}