Enable download of datapackage as zip

[Bachibouzouk]

This enable the download of a datapackage of a scenario.

One can use the URL:
http://127.0.0.1:8000/en/scenario/export/datapackage/

Or click on "Export as datapackage" on the scenario step 2 footer

TODO:

• Generate the datapackage.json automatically as well
• Get the foreign keys of datapackage.json correctly
• Figure out a parameter matching between open_plan parameters and the placades parameters --> this is done in Add components from openPlan tool placades#5

[Bachibouzouk]

The idea is to enable download of datapackage and then iterate to make changes to the to_datapackage method

[paulapreuss]

Using the current pinned version of tabular in the requirements (pointing to the dev branch), I get the error infer_metadata_from_data() got an unexpected keyword argument 'fk_targets'. I looked around the oemof-tabular repo and saw your PR which introduces this keyword in fix/datapackage. However, pointing to this branch instead causes the following dependency conflict in the requirements:

ERROR: Cannot install datapackage==1.5.1 and jsonschema==4.4.0 because these package versions have conflicting dependencies.

The conflict is caused by:
    The user requested jsonschema==4.4.0
    datapackage 1.5.1 depends on jsonschema<3.0 and >=2.5

I was able to bypass this error by unpinning the jsonschema version, but now I am not sure if the version installed might cause issues within the functions that use the package. Would have to double check this.

After this, the datapackage export seems to work and contain all the necessary files. Very cool feature!

[Bachibouzouk]

I was able to bypass this error by unpinning the jsonschema version, but now I am not sure if the version installed might cause issues within the functions that use the package. Would have to double check this.

I think we should now soon be able to upgrade the datapackage package in oemof-tabular. Moreover we decided with @uvchik it would be more convenient to create https://github.com/oemof/oemof-datapackage instead of making breaking changes in oemof-tabular. I will focus now on making the datapackages downloaded from OpenPlan app run using placade

[Bachibouzouk]

Note @paulapreuss : the structure of the Storage Assets is outdated, as soon as we simulate using placades we can simplify the storages and bring their structure one to one with the fields of the corresponding placades

[Bachibouzouk]

@paulapreuss - everything is ready to be reviewed. Currently there is still the error you mentionned and I plan to fix it by following the changes made in oemof/oemof-tabular#188 in order to free ourselves from the datapackage dependency problem

[Bachibouzouk]

@paulapreuss, @uvchik - I fixed the installation problem in a branch based on oemof/oemof-datapackage#1. However I don't have the rights to push it to oemof-datapackage repo. Once this is merged, we should have a pypi installable version of oemof-datapackage (@paulapreuss this is why we currently still need 9d53876). Locally you need to install pip install git+https://github.com/oemof/oemof-datapackage.git@fix/infer_datapackage (once fix/infer_datapackage is pushed as I get the rights)

[paulapreuss]

This is really, really nice 😀 I tested around a bit and found that it works really nicely, I also had no issues with the depency install. Imo, this is ready to be merged to main and tested on the staging server.