contextual vocabularies

[mamico]

Fixes #3216

When there is a contextualized vocabulary url in the schema, Volto must call it with the full path and not return it to the site root.

There is a risk, however, that this change may bring out problems hidden by the anomaly it solves.

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[davisagli]

I've run into this problem on one project, but I decided it was too risky to load all vocabularies with a context-sensitive path. For one thing, this means the results can't be HTTP-cached in cases when they are not context-dependent.

For that project, I customized this action to check a setting with a list of vocabularies that are context-dependent. That way it's possible to opt in where it's needed.

  const vocabulary = getVocabName(vocabNameOrURL);
  let vocabPath;
  if (config.settings.contextualVocabularies.includes(vocabulary)) {
    vocabPath = flattenToAppURL(vocabNameOrURL);
  } else {
    vocabPath = `/@vocabularies/${vocabulary}`;
  }

  let queryString = `b_start=${start}${size ? '&b_size=' + size : ''}`;
  if (query) {
    queryString = `${queryString}&title=${query}`;
  }
  return {
    type: GET_VOCABULARY,
    vocabulary: vocabNameOrURL,
    start,
    request: {
      op: 'get',
      path: `${vocabPath}?${queryString}`,
    },
    subrequest,
  };

[mamico]

I've run into this problem on one project, but I decided it was too risky to load all vocabularies with a context-sensitive path. For one thing, this means the results can't be HTTP-cached in cases when they are not context-dependent.

@davisagli, Good point! Do you think your solution might be in Volto?

With config.settings.contextualVocabularies defaulting to []

[davisagli]

@mamico I think that would be okay, and fully backward-compatible.

On the other hand, it might be nice if there were a way to mark a vocabulary as context-dependent when it is defined, and have plone.restapi & volto use that information. There would be a lot more details and moving parts to figure out for this, though.

[sneridagh]

@mamico @davisagli

Maintaining the list might suck, and not obvious for front-end/integrators that do not know about which vocabularies are contextual and which not.

Can we provide a default list of vocabularies at least? or defaulting to [] is for backwards compatibilities concerns? Maybe suggest a good known list of them for new projects? or the other way around, suggest the list by default, warn about it in the upgrade guide and suggest people to use [] if they want to be conservative.

Aside of this, LGTM.

[mamico]

@mamico @davisagli

Maintaining the list might suck, and not obvious for front-end/integrators that do not know about which vocabularies are contextual and which not.

Agree

Can we provide a default list of vocabularies at least? or defaulting to [] is for backwards compatibilities concerns? Maybe suggest a good known list of them for new projects? o

We can look into the default vocabularies of plone.restapi, but if we set a default other than [], this change will be breaking. Is this acceptable for version 18.* ?

or the other way around, suggest the list by default, warn about it in the upgrade guide and suggest people to use [] if they want to be conservative.

I had set the needs: docs label from the beginning for that purpose, just needed time to do it. :)

[davisagli]

@mamico @sneridagh So a different and maybe easier to use approach here would be:

1. If a vocab name is passed, get it from the root (same as now)
2. If a vocab URL is passed, get it from the URL as written, instead of extracting the name and fetching it from the root. This is a breaking change, it makes these vocabularies contextual.
3. Make sure that when plone.restapi generates a vocabulary URL, it uses an appropriate context. This might require inventing a way to mark on the vocabulary factory whether it is context-dependent or not.

We need to keep in mind that there might be a core vocabulary which never varies based on the context, but an integrator needs to replace it with a custom version that is context-dependent.

[mamico]

@davisagli @sneridagh

We need to keep in mind that there might be a core vocabulary which never varies based on the context, but an integrator needs to replace it with a custom version that is context-dependent.

IMHO we are talking about acting in the serializer of schemes, like here:

https://github.com/plone/plone.restapi/blob/f68fab7ea3209a096423d8567fa7f70a93786c7a/src/plone/restapi/types/adapters.py#L110

in other cases the developer has complete control of the vocabulary url.

My plan:

1. We change the serializer to return the full vocabulary url for contextual vocabularies, and only the vocabulary_name (or the vocabulary url pointing to the portal root?) for non-contextual vocabularies.

2. change (like my original proposal) to use the vocabulary url as is, if it is a url, or a vocabulary url, based on the portal root, if it is a vocabulary name.

I think both changes could be independent, without major breaking, and there are no needs for a new configuration.

thoughts?

[pnicolli]

@davisagli @mamico this is an interesting PR, how can we keep this going?

[davisagli]

@pnicolli @mamico Sorry, I'll come back to this, but I've been busy getting ready for the conference.