Apply json patch to a Mongoengine document

Question

I'm trying to apply a json-patch to a Mongoengine Document.

I'm using these json-patch library: https://github.com/stefankoegl/python-json-patch and mongoengine 0.14.3 with python 3.6.3

This is my actual code:

json_patch = JsonPatch.from_string(jp_string)
document = Document.objects(id=document_id)
json_documents = json.loads(document.as_pymongo().to_json())
json_patched_document = json_patch.apply(json_documents[0])
Document.objects(id=document_id).first().delete()
Document
    .from_json(json.dumps(json_patched_document))
    .save(force_insert=True)

Is there a better way to save an edited json document?

I've enhanced a little bit the code:

json_patch = JsonPatch.from_string(jp_string)
document = Document.objects(id=document_id)
json_document = json.loads(document.as_pymongo().to_json())
json_patched_document = json_patch.apply(json_documents[0])
Document
    .from_json(json.dumps(json_patched_document), created=True)
    .save()

but, is there a way to not convert the document to json?

Answer 1

I had slightly similar problem, the part that I dont wanted the complete Document for saving, I just wanted to update fields which are modified/added.

heres the code I tests on below inputs:

def tryjsonpatch():
    doc_in_db = {'foo': 'bar', "name": "aj", 'numbers': [1, 3, 7, 8]}
    input = {'foo': 'bar', "name": "dj", 'numbers': [1, 3, 4, 8]}
    input2 = {'foo': 'bar', "name": "aj", 'numbers': [1, 3, 7, 8], "extera": "12"}
    input3 = {'foo': 'bar', "name": "dj", 'numbers': [1, 3, 4, 8], "extera": "12"}

    patch = jsonpatch.JsonPatch.from_diff(doc_in_db, input3)
    print("\n***patch***\n", patch)
    doc = get_minimal_doc(doc_in_db, patch)

    result = patch.apply(doc, in_place=True)
    print("\n###result###\n", result,
           "\n###present###\n", doc_in_db)


def get_minimal_doc(present, patch):
    cur_dc = {}
    for change in patch.patch:
        if change['op'] not in ("add"):
            keys = change['path'].split("/")[1:]
            present_move = {}

            old_key = 1
            first = True
            for key in keys:
                if key.isdigit():  # old_key represented a array
                    cur_dc[old_key] = present_move
                else:
                    if first:
                        cur_dc[key] = {}
                        first = False
                    else:
                        cur_dc[old_key][key] = {}

                    old_key = key
                    present_move = present[old_key]
    return cur_dc
tryjsonpatch()