Cause of mongoengine.errors.InvalidQueryError

问题

The journey with Flask, MongoDB and MongoEngine continues.

I've (hopefully) synced up the database with my model in a normal fashion, yet when I attempt to query the database for something as simple as an address name, I get this message:

mongoengine.errors.InvalidQueryError
InvalidQueryError: Not a query object: {'wsgi.multiprocess': False, 'SERVER_SOFTWARE': 
'Werkzeug/0.9.6', 'SCRIPT_NAME': '', 'REQUEST_METHOD': 'GET', 'PATH_INFO': '/result', 
'SERVER_PROTOCOL': 'HTTP/1.1', 'QUERY_STRING': 'query=28+Paritai+Drive+Orakei', 
'werkzeug.server.shutdown': <function shutdown_server at 0x10f8cd1b8>, 'CONTENT_LENGTH': '', 
'HTTP_USER_AGENT': 'Mozilla/5.0 (Macintosh; Intel Mac OS X 10_9_4) AppleWebKit/537.36 (KHTML, like 
Gecko) Chrome/36.0.1985.143 Safari/537.36', 'HTTP_CONNECTION': 'keep-alive', 'SERVER_NAME': 
'127.0.0.1', 'REMOTE_PORT': 60329, 'wsgi.url_scheme': 'http', 'SERVER_PORT': '5000', 
'werkzeug.request': <Request 'http://localhost:5000/result?query=28+Paritai+Drive+Orakei' [GET]>, 
'wsgi.input': <socket._fileobject object at 0x10f8932d0>, 'HTTP_HOST': 'localhost:5000', 
'wsgi.multithread': False, 'HTTP_CACHE_CONTROL': 'max-age=0', 'HTTP_ACCEPT': 
'text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,*/*;q=0.8', 'wsgi.version': (1, 
0), 'wsgi.run_once': False, 'wsgi.errors': <open file '<stderr>', mode 'w' at 0x10e8581e0>, 
'REMOTE_ADDR': '127.0.0.1', 'HTTP_ACCEPT_LANGUAGE': 'en-US,en;q=0.8', 'CONTENT_TYPE': '', 
'HTTP_ACCEPT_ENCODING': 'gzip,deflate,sdch'}.
Did you intend to use key=value?

Traceback (most recent call last)

I've also gotten this error (that may be related) from poking around in the Python shell:

>>> db.properties.objects()
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
File "/Library/Python/2.7/site-packages/pymongo/collection.py", line 1705, in __call__
self.__name)
TypeError: 'Collection' object is not callable. If you meant to call the 'objects' method on a     
'Database' object it is failing because no such method exists.

Here's my code for models.py, linked up properly to Flask:

from app import db

# ----------------------------------------
# Taking steps towards a working backend.
# ----------------------------------------

class Person(db.Document):

    # Meta variables.
    meta = {
        'collection': 'properties'
    }

    # Document variables.
    name = db.StringField(max_length=255, required=True)
    address =  db.StringField(max_length=255, required=True)
    email = db.StringField(max_length=255, required=True)

    def __repr__(self):
        return address

    def get_person_from_db(self, query_string):
        if not query_string:
            raise ValueError()
        # Ultra-simple search for the moment.
        person_class_object = Property
        bingo = person_class_object.objects(__raw__={'name': query_string})
        return bingo

And here's where I call get_person_from_db(...), the function in question:

@app.route('/result')
def result():
search_string = request.args['query']
if search_string == '':
    return render_template('index.html')
else:

    person_class_object = models.Person()
    specific_person = person_class_object.get_person_from_db(search_string)

    return specific_person

Any ideas as to what the cause of this error may be? Thanks in advance for the input!

回答1:

The cause of this error was actually surprisingly simple – the object was being retrieved correctly, but the Flask web application is not amenable to receiving pure JSON on the front end.

For some reason I expected it would print the JSON as a string, but that was not the case.

In order to get the desired outcome, one could call field names specifically (specific_person.name) or using Flask's render_template functionality to format the output nicely on a webpage.

回答2:

I know it's VERY late but might help someone else. you can do something like:

return jsonify(bingo=bingo)

Don't forget to import jsonify though.

来源：https://stackoverflow.com/questions/25467559/cause-of-mongoengine-errors-invalidqueryerror

标签

python

mongoengine

flask-mongoengine