Vfrdtyky

I'm trying to integrate jQuery datatables server side processing with cherrypy & sqlalchemy, and I'm getting an error about "unhashable type: 'dict'".

The code I've written looks like this:

@cherrypy.tools.json_out()

def GET(self, *args, **kwargs):

    with GetDb().ScopedSession("Fetching detail for main page") as session:

        # defining columns

        columns = [

            ColumnDT(dbModels.DatabaseModel.Field1),

            ColumnDT(dbModels.DatabaseModel.Field2),

            # ...

        ]



        query = session.query(dbModels.DatabaseModel)



        # GET parameters

        params = kwargs  # I think this is what's causing the issue.



        print("==========================")

        print(params)

        print("==========================")



        # instantiating a DataTable for the query and table needed

        rowTable = DataTables(params, query, columns)



        # returns what is needed by DataTable

        result = rowTable.output_result()

        print("==========================")

        print(result)

        print("==========================")

        return result

The result of the 'params' print looks like this (truncated somewhat):

{'draw': '1', 'columns[0][data]': '', 'columns[0][name]': '', 'columns[0][searchable]': 'true' } 

And the result output looks like this:

{'draw': '1', 'recordsTotal': '125', 'recordsFiltered': '125', 'error': "unhashable type: 'dict'"}

My suspicion is that the DataTables() call doesn't like the 'jsonpath'-like GET parameter (see the "# I think this is what's causing the issue" part above), so I'm curious if there's a way I can have cherrypy return the **kwargs as nested key/value pairs, or a function to convert kwargs into a nested dictionary -- or, if I'm completely wrong and this is a different error altogether. :)

Thanks!

More data if it helps:

The webpage rendering shows an alert saying:

DataTables warning: table id=active-jobs - unhashable type: 'dict'

Clicking OK yields a type error in the datatables code:

datatables.min.js:52 Uncaught TypeError: Cannot read property 'length' of undefined

    at vb (datatables.min.js:52)

    at datatables.min.js:49

    at i (datatables.min.js:47)

    at Object.success (datatables.min.js:48)

    at fire (jquery-3.3.1.js:3268)

    at Object.fireWith [as resolveWith] (jquery-3.3.1.js:3398)

    at done (jquery-3.3.1.js:9305)

    at XMLHttpRequest.<anonymous> (jquery-3.3.1.js:9548)

vb @ datatables.min.js:52

(anonymous) @ datatables.min.js:49

i @ datatables.min.js:47

success @ datatables.min.js:48

fire @ jquery-3.3.1.js:3268

fireWith @ jquery-3.3.1.js:3398

done @ jquery-3.3.1.js:9305

(anonymous) @ jquery-3.3.1.js:9548

load (async)

send @ jquery-3.3.1.js:9567

ajax @ jquery-3.3.1.js:9206

sa @ datatables.min.js:48

lb @ datatables.min.js:49

P @ datatables.min.js:41

T @ datatables.min.js:43

ha @ datatables.min.js:60

e @ datatables.min.js:105

(anonymous) @ datatables.min.js:105

each @ jquery-3.3.1.js:354

each @ jquery-3.3.1.js:189

n @ datatables.min.js:95

h.fn.DataTable @ datatables.min.js:177

RebuildTable @ (index):128

(anonymous) @ (index):266

mightThrow @ jquery-3.3.1.js:3534

process @ jquery-3.3.1.js:3602

setTimeout (async)

(anonymous) @ jquery-3.3.1.js:3640

fire @ jquery-3.3.1.js:3268

fireWith @ jquery-3.3.1.js:3398

fire @ jquery-3.3.1.js:3406

fire @ jquery-3.3.1.js:3268

fireWith @ jquery-3.3.1.js:3398

ready @ jquery-3.3.1.js:3878

completed @ jquery-3.3.1.js:3888

I finally figured this out. One of my columns was of type "JSONType" from sqlalchemy_utils, and the sqlalchemy-datatables class wasn't handling that it was getting a 'dict' back for the JSON data.

I solved this - for better or for worse - by not including that in my columns, and instead having a hand-crafted column that I filled an object out with the details that I needed.