GeoPoint 类型的对象不可 JSON 序列化

Question

我想创建一个必须从 firestore 恢复数据并将其公开为 json 的 API，但我面临以下错误：

Object of type GeoPoint is not JSON serializable

怎么了？这是我的代码：

#!/usr/bin/env python
import firebase_admin
import json
from pprint import pprint as pp
from flask import Flask, flash, request, url_for, jsonify, Response
from firebase_admin import credentials
from firebase_admin import firestore

app = Flask(__name__)

cred = credentials.Certificate('xxxx.json')
firebase_admin.initialize_app(cred)
db = firestore.client()

@app.route('/')
def index():

    markers_ref = db.collection(u'Test')
    docs = markers_ref.get()

    data = []
    for doc in docs:
        data.append(doc.to_dict())

    json_data = json.dumps(data)
    resp = Response(json_data, status=200, mimetype='application/json')

    return resp

if __name__=='__main__':
app.run(debug=True)

Answer 1

以下应该可以解决问题 -

from flask import (Flask, request, session, g, redirect, url_for, abort, render_template, flash, Response, jsonify)
import firebase_admin
from firebase_admin import firestore

@app.route('/foods/<id>')
def read_food(id):

    result=FOODS.document(id).get().to_dict()
    record = {}
    # Populate the new dict with JSON serializiable values
    for key in result:
        if isinstance(result[key], firebase_admin.firestore.GeoPoint):
            record[key] =str(result[key].latitude)+','+str(result[key].longitude)
            continue
        record[key] = result[key]

    # Add the key so that we have a reference to the record
    record['key'] = result[key]

    return jsonify(record)

Answer 2

您还可以向 Python Json 模块提供 JSON 编码器的自定义实现，这将有助于在您传递自定义编码器时自动执行此操作。

import json
import google.cloud.firestore as firestore

class CustomEncoder(json.JSONEncoder):
    def default(self, obj):
        if isinstance(obj, map):
            return list(obj)
        elif isinstance(obj, firestore.GeoPoint):
            return {"latitude": obj.latitude, "longitude": obj.longitude}

        return json.JSONEncoder.default(self, obj)

json.dumps(
    obj, cls=CustomEncoder, ensure_ascii=True, sort_keys=True
)

现在，每当您使用

json.dumps

或

cls=CustomEncoder

时，它都会自动处理

GeoCode

。您可以在 DI 中进行配置，以便自动完成此设置