如何在 Dart 中从 Cloud Firestore 获取随机文档（适用于 Flutter）？ [关闭]

Lets say I have the following documents inside a Firestore collection:
How can I randomly get one or more documents without having to download them all?

By the way, I've already seen Dan McGrath's Answer, but he didn't specifically explain how to generate the auto-id for Flutter, also, I would love to see a complete example in Dart since his explanation was very generic.

Thanks in advance!

根据丹的回答，这是我当前的实现。

static const AUTO_ID_ALPHABET = 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789';
static const AUTO_ID_LENGTH = 20;
  String _getAutoId() {
    final buffer = StringBuffer();
    final random = Random.secure();

    final maxRandom = AUTO_ID_ALPHABET.length;

    for (int i = 0; i < AUTO_ID_LENGTH; i++) {
      buffer.write(AUTO_ID_ALPHABET[random.nextInt(maxRandom)]);
    }
    return buffer.toString();
  }

查询代码：

final autoId = _getAutoId();

final query = ref
    .where("qId", isGreaterThanOrEqualTo: autoId)
    .orderBy("qId")
    .limit(count);
QuerySnapshot response = await query.getDocuments();
if (response.documents == null || response.documents.length == 0) {
  final anotherQuery = ref
      .where('qId', isLessThan: autoId)
      .orderBy('qId')
      .limit(count);
  response = await anotherQuery.getDocuments();
}

一些解释：

1. qId 是我文档的一个字段。它与 documentId 相同。
2. 根据 Dan 的说法，此实现基于双向 回答。我们的结果仍然不公平，但我对此表示同意。如果有人有更好的算法，请分享。
3. _getAutoId()是基于firebase库的Java代码重写的。

如果您有任何疑问，请询问。我会尽力提供帮助。

祝你今天过得愉快！