json.dumps vs flask.jsonify

PythonJsonFlask

Python Problem Overview

I am not sure I understand the purpose of the flask.jsonify method. I try to make a JSON string from this:

data = {"id": str(album.id), "title": album.title}

but what I get with json.dumps differs from what I get with flask.jsonify.

json.dumps(data): [{"id": "4ea856fd6506ae0db42702dd", "title": "Business"}]
flask.jsonify(data): {"id":…, "title":…}

Obviously I need to get a result that looks more like what json.dumps returns. What am I doing wrong?

Python Solutions

Solution 1 - Python

The jsonify() function in flask returns a flask.Response() object that already has the appropriate content-type header 'application/json' for use with json responses. Whereas, the json.dumps() method will just return an encoded string, which would require manually adding the MIME type header.

See more about the jsonify() function here for full reference.

Edit: Also, I've noticed that jsonify() handles kwargs or dictionaries, while json.dumps() additionally supports lists and others.

Solution 2 - Python

You can do:

flask.jsonify(**data)

or

flask.jsonify(id=str(album.id), title=album.title)

Solution 3 - Python

This is flask.jsonify()

def jsonify(*args, **kwargs):
    if __debug__:
        _assert_have_json()
    return current_app.response_class(json.dumps(dict(*args, **kwargs),
        indent=None if request.is_xhr else 2), mimetype='application/json')

The json module used is either simplejson or json in that order. current_app is a reference to the Flask() object i.e. your application. response_class() is a reference to the Response() class.

Solution 4 - Python

The choice of one or another depends on what you intend to do. From what I do understand:

  • jsonify would be useful when you are building an API someone would query and expect json in return. E.g: The REST github API could use this method to answer your request.

  • dumps, is more about formating data/python object into json and work on it inside your application. For instance, I need to pass an object to my representation layer where some javascript will display graph. You'll feed javascript with the Json generated by dumps.

Solution 5 - Python

consider

data={'fld':'hello'}

now

jsonify(data)

will yield {'fld':'hello'} and

json.dumps(data)

gives

"<html><body><p>{'fld':'hello'}</p></body></html>"
Categories
Recommended Python Solutions
Recommended Json Solutions
Recommended Flask Solutions

Previous Solution:

How to parse data in JSON format?

PythonJsonParsing

Next Solution:

Best practices for SQL varchar column length

MysqlSqlSql ServerPostgresql

Attributions

All content for this solution is sourced from the original question on Stackoverflow.

The content on this page is licensed under the Attribution-ShareAlike 4.0 International (CC BY-SA 4.0) license.

Content TypeOriginal AuthorOriginal Content on Stackoverflow
QuestionSergei BasharovView Question on Stackoverflow
Solution 1 - PythonKenneth WilkeView Answer on Stackoverflow
Solution 2 - PythonmikerobiView Answer on Stackoverflow
Solution 3 - PythonMichael EkokaView Answer on Stackoverflow
Solution 4 - PythonchaiyachaiyaView Answer on Stackoverflow
Solution 5 - PythonGovind KelkarView Answer on Stackoverflow