使用mongo与FLASK和python

Question

我正在尝试学习python,mongodb和flask,并且正在使用来自Miguel Grinberg的非常优秀的博客,他在blog.miguelgrinberg.com上提供了一系列精彩的教程.

我有一个小的RESTful服务器工作正常,但现在想从mongo而不是mysql中提取东西

我可以使用下面的代码拉出mongo记录,但我很难让它渲染.

我在下面的代码中使用了箭头来显示我在哪里挣扎,我认为缺乏经验.任何想法将不胜感激.

#!flask/bin/python
from flask import Flask, jsonify, abort, make_response, url_for
from pymongo import MongoClient

# connect to mongo database hosted on AWS
# the script expects the host name to be in  /etc/hosts file

'''
Set up global variables here
'''
mongo_server = "mongo_api"
mongo_port = "27017"
mongo_user = "admin"
mongo_passwd = ":mysecretpassword@"
connect_string = "mongodb://"+ mongo_user 
                             + mongo_passwd 
                             + mongo_server 
                             + ":" 
                             + mongo_port

app = Flask(__name__)

@app.errorhandler(404)
def not_found(error):
    return make_response(jsonify( { 'error': 'Notfound' } ), 404)


def make_public_page(page):
    new_page = {}
    for field in page:
        if field == 'id':
            new_page['uri'] = url_for('get_page', page_id = page['id'], _external = True)
        else:
            new_page[field] = page[field]
    return new_page



@app.route('/api/v1.0/pages/<int:page_id>',methods = ['GET'])
def get_page(page_id):
    '''
    Can connect otherwise exit with message
    '''
    try:
        connection = MongoClient(connect_string)    # equal to > show dbs
    except:
        exit("Error: Unable to connect to the database") # exit with an error
    '''
    connect to database and pull back collections
    '''
    db = connection.test_database # equal to > use test_database                
    pages = db.pages
    page = pages.find_one({"id": int(page_id)})   <------ this pulls back a document
    if page == None:  <---- if a null set comes back then this works great
        abort(404)
    return jsonify( { 'page' : make_public_page(page[0])} ) <- error says its not json

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

任何帮助表示赞赏,页面[0]是我无法使用的代码

TypeError:ObjectId('527e17c538320915e9893f17')不是JSON可序列化的

提前致谢

BTW不能推荐Miguel的大型教程作为开始构建内容的地方

Answer 1

首先,find_one如果集合中没有匹配的元素,则返回单个字典或None.所以我认为这page[0]相当于获取密钥的页面字典值0

如果返回的文档包含ObjectId因为_id您不能简单地使用jsonify因为,就像ObjectId不是JSON可序列化一样.你可以使用这样的东西:

jsonify({ 'page': make_public_page({k:v for k, v in page.items() if k != '_id'}))

或者你可以简单地_id通过电话删除page.pop('_id')

你也可以使用bson.json_util.它包含用于在BSON和JSON之间进行转换的工具.

from flask import Response 
from bson import json_util

然后jsonify用类似的东西替换:

return Response(
    json_util.dumps({'page' : make_public_page(page)}),
    mimetype='application/json'
)

编辑

如果你想要简短而肮脏的方式处理问题,你可以这样做:

from bson import json_util, ObjectId
import json

#Lets create some dummy document to prove it will work
page = {'foo': ObjectId(), 'bar': [ObjectId(), ObjectId()]}

#Dump loaded BSON to valid JSON string and reload it as dict
page_sanitized = json.loads(json_util.dumps(page))