Fix coreNode error when fetching public data with no user session

[markmhendrickson]

As first encountered with markmhendrickson/humans#12, I'm getting TypeError: Cannot read property 'coreNode' of undefined upon calling getFile and reaching: https://github.com/blockstack/blockstack.js/blob/950dc4fc838099835ce0592f245453c770663b84/src/storage/index.ts#L253

sessionData.userData is undefined and throws an error instead of getting to use caller.appConfig.coreNode

cc @zone117x since he appears to be the last person to touch this part of the code

[markmhendrickson]

@agraebe is this something the DevX team may want to take on soon?

[zone117x]

Hmm, @markmhx can you provide a repo/snippet of code to easily reproduce? Looks like this is an easy fix but not entirely sure what the intention behind this code

[markmhendrickson]

How about this as a snippet?

The intention is basically to query a user's public data using their ID without necessarily having a session oneself (e.g. for a public profile).

[hstove]

It seems like this could be fixed with a sessionData.userData?.coreNode ?

[friedger]

This breaks the todo-list tutorial to lookup public lists for new users. https://docs.blockstack.org/authentication/building-todo-app#sign-out-and-see-your-public-tasks

[markmhendrickson]

@agraebe It seems this was de-prioritized on the DevX side, correct? It seems like pretty core SDK functionality to me, so I'd suggest taking another look if we can.

[agraebe]

I think this was never prioritized and we got started on the monorepo work in the meantime. @yknl could you take a look, please? maybe we could include this in the monorepo release?

[agraebe]

@yknl what should be the next step for this issue?

[agraebe]

@zone117x how much effort would it be to fix this bug? is this a ~P3?

[markmhendrickson]

@aulneau mind adding your workaround here in the meantime for reference?

[aulneau]

@aulneau mind adding your workaround here in the meantime for reference?

The code snippet I provided is not actually a workaround for this specific issue.

[markmhendrickson]

If an app needs to retrieve data for a particular username without an active user session, might it cobble together a GET query for the data they want, constructing the file's path manually and initiate the request outside of the Stacks.js library somehow?

export async function fetchAppGaiaHubUrl(username: string): Promise<string | null> {
  const response = await fetch(`https://core.blockstack.org/v1/users/${username}`);
  const zonefile = await response.json(); // the users zonefile
 
  const app = APP_URL; // the app you're looking for, eg 'http://localhost:3000'
  const zone_file = Object.values(zonefile)?.[0] as any;
 
  // account for both legacy use and the new format from the extension
  if (zone_file?.profile.apps || zone_file?.profile.appsMeta) {
    if (zone_file.profile?.appsMeta?.[app]) {
      return zone_file.profile?.appsMeta?.[app].storage;
    }
    if (zone_file.profile?.apps?.[app]) {
      return zone_file.profile?.apps?.[app];
   }
  }
  throw Error('Cannot find zonefile');
} 

[zone117x]

It looks like changing this line https://github.com/blockstack/stacks.js/blob/7915c953d4b7c6a2d8e7a2f3125c449687ff8aac/packages/storage/src/storage.ts#L867
To

 const configuredCoreNode = sessionData.userData?.coreNode || userSession.appConfig.coreNode;

should at least fix the error being thrown that Mark first mentioned.

@marcosc90 is this something you could take on?

[markmhendrickson]

@reedrosenbluth was this resolved in a particular PR?

[reedrosenbluth]

@markmhx my bad, didn't mean to close this