not dumping users with guest role

[jagarop]

Describe the bug
Guest users information is not being dumped to users.json.

To Reproduce
Steps to reproduce the behavior:

1. Join a workspace with guest/multi-channel guest users
2. Dump it
3. Check users.json
4. All their messages will show with only their ID in a full dump, and users.json doesn't have a record for those users.

Expected behavior
Populated guest users in users.json

Output
Not applicable

Desktop (please complete the following information):

• OS: [Windows 10 x64]

Additional context
I tested this in a workspace that have about 400 normal users and 2000 guests. Got data for all normal users and no data from guests. It shows fine in browser/slack desktop client.

[rusq]

Hey @jagarop, I'm trying to reproduce this, as my test workspace is on free account, I'm not able to invite guests, but I have one workspace where I have a guest account.

What I've done so far - I exported a workspace where I'm a "guest", and users.json indeed does not contain some of the users, which are present in the channel conversations, and are resolved correctly by slack client.

I'll see how this can be addressed.

[jagarop]

Hey @jagarop, I'm trying to reproduce this, as my test workspace is on free account, I'm not able to invite guests, but I have one workspace where I have a guest account.

What I've done so far - I exported a workspace where I'm a "guest", and users.json indeed does not contain some of the users, which are present in the channel conversations, and are resolved correctly by slack client.

I'll see how this can be addressed.

Hello @rusq, thanks for taking a look at this issue, really apreciate!

If you need anything else from me that would help on this matter, please let me know.

[rusq]

So I investigated quite a bit on this - the Slack Client calls a set of undocumented Slack edge APIs in order to retrieve the names of the users. I'm currently experimenting with this and made some progress, but it's far from completion. It is the same APIs that mentioned in #64. I'm parking it for now, as I think that implementing Mattermost export compatibility would take less time, and there's a high demand on that right now, as people are migrating from Slack to Mattermost (#107).

I can only guess, that the reason that Slack does not return a complete set of users using the standard API and client token is that it does not expect someone to call standard Slack APIs under the guest account.