Let's see how we can store python objects, this include strings, list, function, etc.., inside a DB likepysonDB

Consider I've functionfoo which takes an argumentx and returnx * (x + x). Which I want to store inside a DB.

deffoo(x:float)->float:returnx*(x+x)

First things first we nee to convert this object to byte string. To do that we can use thepickle. module.

importpicklebyte_string=pickle.dumps(foo)

This byte string cannot be directly added to a PysonDB database, as byte strings are not JSON serializable. So a simple workaround will be to add quotes around the byte string which can be easily done like this.

obj_string=f"{byte_string}"

This string can be now added to the DB

frompysondbimportdba=db.getDb("test.json")a.add({"name":"foo_function","obj":obj_string})

To get the object back we can do the following steps.

data=a.getBy({"name":"foo_function"})

Nowdata will look something like this.

[{'name':'foo_function','obj':"b'\\x80\\x04\\x95\\x14\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x8c\\x08__main__\\x94\\x8c\\x03foo\\x94\\x93\\x94.'",'id':316182400052721056}]

To convert the obj string back to a callable function. We can do the following.

str_obj=data[0]["obj"]

Remember thatstr_obj is still a string and not a byte string, which is what we need, since the required byte string is inside this string, we can simply evaluate the string.

importastbyte_obj=ast.literal_eval(str_obj)

To call the function we can do this.

call_obj=pickle.loads(byte_obj)print(call_obj(3))# output18

Entire Code

importastimportpicklefrompysondbimportdbdeffoo(x:float)->float:returnx*(x+x)byte_string=pickle.dumps(foo)obj_string=f"{byte_string}"a=db.getDb("test2.json")a.add({"name":"foo_function","obj":obj_string})data=a.getBy({"name":"foo_function"})str_obj=data[0]["obj"]byte_obj=ast.literal_eval(str_obj)call_obj=pickle.loads(byte_obj)print(call_obj(3))

So we have successfully stored a python object inside a DB. The steps are the same for all the objects like list or dict.