python - 为什么我的 Firebase Firestore 查询不在 order_by 中？

Question

我已经阅读了其他几个问题，但它们似乎都是将日期存储为字符串而不是时间戳的地方。这是我的领域:



我试图按照我的 upload_timestamp 字段的顺序返回文档，但它们似乎是随机顺序......这是我的 Python Flask 代码:

@app.route('/uploads/<string:last_doc>', methods=['GET'])

def uploads(last_doc=False):

    rentalAgreements = db.collection('rentals')
    query = rentalAgreements.where('username', '==', 'johnny5isalive').order_by('upload_timestamp', direction=firestore.Query.ASCENDING).limit(5)
    results = query.get()

    response = {}
    for doc in results:
        response[doc.id] = doc.to_dict()
        last_doc = doc.id
        print(doc.id)
    response['last_doc'] = last_doc

    return jsonify({"response" : response})

结果是这样的:

{
  "response": {
    "4cbacd525c9842bbae29f2f9ef15109f": {
      "filename": "RL 20 DECEMBER 2019v2.csv", 
      "rental_list": "4cbacd525c9842bbae29f2f9ef15109f", 
      "status": "imported", 
      "upload_timestamp": "Wed, 01 Jan 2020 19:53:42 GMT", 
      "username": "johnny5isalive"
    }, 
    "82e8f254607a49699d7986bf7cd7cbae": {
      "filename": "RL 20 DECEMBER 2019v2.csv", 
      "rental_list": "82e8f254607a49699d7986bf7cd7cbae", 
      "status": "imported", 
      "upload_timestamp": "Sat, 28 Dec 2019 08:44:08 GMT", 
      "username": "johnny5isalive"
    }, 
    "874d39a8cfb246bbbc5a722498dff651": {
      "filename": "RL 20 DECEMBER 2019.csv", 
      "rental_list": "874d39a8cfb246bbbc5a722498dff651", 
      "status": "imported", 
      "upload_timestamp": "Fri, 27 Dec 2019 19:52:52 GMT", 
      "username": "johnny5isalive"
    }, 
    "adf6b21511774656a5ed0391618e5ad9": {
      "filename": "RL 20 DECEMBER 2019.csv", 
      "rental_list": "adf6b21511774656a5ed0391618e5ad9", 
      "status": "imported", 
      "upload_timestamp": "Wed, 01 Jan 2020 19:53:36 GMT", 
      "username": "johnny5isalive"
    }, 
    "c738e86053704fd6b3ce70395696b950": {
      "filename": "RL 20 DECEMBER 2019vparent-child.csv", 
      "rental_list": "c738e86053704fd6b3ce70395696b950", 
      "status": "imported", 
      "upload_timestamp": "Wed, 01 Jan 2020 16:57:35 GMT", 
      "username": "johnny5isalive"
    },
    "last_doc": "4cbacd525c9842bbae29f2f9ef15109f"
  }
}

Answer 1

这是因为我们使用的 dict ( response = {} ) 并不意味着要订购。因此，您按顺序从 Firestore 获取值，但是在插入到 dict 后，该顺序丢失了。

您可以使用 OrderedDict。我找到了很好的引用和示例 here

我希望它会有所帮助:)