How to JSON Serialize a Python Class Object?

Question

My goal is to write the response I get from a call to Amazon's Product Advertising API to a file in JSON format.

I call the API using

response = default_api.search_items(search_items_request)

I attempt to write the results to a file using:

with open('data.json', 'w') as f:
            json.dump(response, f)

I get the error message:

TypeError : Object of type 'SearchItemsResponse' is not JSON serializable

How can I fix this? I need to write the response in JSON. A solution is greatly appreciated.

score 0 · Answer 1 · answered Sep 10 '20 at 20:42

0

json only knows about standard data types -- int, float, list, string, dictionary, etc.

If you want to save an arbitrary class object with json, you'll have to write a custom dump routine that decomposes the object into those basic types, and a custom load routine that reads those basic types and reconstructs the object.

If you're able, it might be a lot easier to use pickle instead, which does support saving arbitrary class objects.

answered Sep 10 '20 at 20:42

John Gordon

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Can I use pickle to save into JSON? From what I see, Pickle only serializes and de-serializes into its own format. – B. Latif Sep 10 '20 at 21:43
I don't believe pickle and json are interchangeable. – John Gordon Sep 10 '20 at 22:25

How to JSON Serialize a Python Class Object?

1 Answers1