I'm using the json library to serialize objects out for web use.

Whenever I serialize a datetime or other included python library object (uuid as another example), it fails with 

TypeError: datetime.datetime(2014, 5, 20, 9, 37, 56, 133627) is not JSON serializable

While this behaviour is well and good, what I am suggesting is that I would like a way for this library to attempt to serialize an object when it encounters an exception. 

For instance, if it attempts to serialize a datetime and fails, I would like the option of submitting a method as a parameter to the json.dumps() method that the object is put into in an attempt to serialize it.

As a code example:

    import datetime, json
    json.dumps(dict(mydate=datetime.datetime.now()),
        serialize=str)

That way, when it encounters a TypeError, it will set mydate to a string and will be serialized out.

Right now, I have to use str() on a few different fields because they are not standard types (str, int, bool, float, None, etc)

This isn't a priority and I'm open to criticisms. Would you accept a patch for this if you are too busy to work on this feature?

Thank you for your time.
Dann

json module already allows you to customize the serialization: see *default* parameter for json.dumps [1]

[1] https://docs.python.org/3/library/json.html#json.dump

I was reading the older 2.7 docs and it didn't click that default() was
what I wanted. Thank you for clarifying.

On Tue, May 20, 2014 at 10:09 AM, akira <report@bugs.python.org> wrote:

>
> akira added the comment:
>
> json module already allows you to customize the serialization: see
> *default* parameter for json.dumps [1]
>
> [1] https://docs.python.org/3/library/json.html#json.dump
>
> ----------
> nosy: +akira
>
> _______________________________________
> Python tracker <report@bugs.python.org>
> <http://bugs.python.org/issue21543>
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