/api/v1/connected should be publicly accessible

[hanzei]

Summary

/api/v1/connected should be publicly accessible. Otherwise, the webapp can't figure out if a user is connected or not in the login screen.

QA Steps

1. Deploy PR
2. Open Mattermost in an incognito window
3. Confirm no js error message is shown

Ticket Link

Fixes #278

[larkox]

Nit: Not sure if necessary, but to make more clear this, I would only call getGitHubUserInfo if the userID is different to the empty string. This function will be clearer in its intent, and we will do one less call to the KVStore.

[hanzei]

Good point on the call to KV Store. I tried implementing it that way, but the code didn't got cleaner. By increasing the indenting, it's harder to read what the code does.

[larkox]

Not sure if clearer or not, but what about deferring the marshaling and writing of resp? Something like this:

resp := ...
defer func () {
    b, _ := json.Marshal(resp)
    w.Write(b)
}()

userID := r.Header.Get("Mattermost-User-ID")
if userID == "" {
    return
}

info, _ := p.getGitHubUserInfo(userID)
if info == nil || info.Token == nil {
   return
}
...

[larkox]

Another solution would be to declare such function inside the function and use it before the returns.

resp := ...
writeResp := func () {
    b, _ := json.Marshal(resp)
    w.Write(b)
}

userID := r.Header.Get("Mattermost-User-ID")
if userID == "" {
    writeResp()
    return
}

info, _ := p.getGitHubUserInfo(userID)
if info == nil || info.Token == nil {
   writeResp()
   return
}
...

[hanzei]

Let's use the helper methods added in #252 to make the code cleaner. I will alter the code when either PR get's merged.

[codecov-commenter]

Codecov Report

Merging #279 into master will decrease coverage by 0.04%.
The diff coverage is 2.63%.

@@            Coverage Diff             @@
##           master     #279      +/-   ##
==========================================
- Coverage   18.13%   18.09%   -0.05%     
==========================================
  Files          10       10              
  Lines        2371     2377       +6     
==========================================
  Hits          430      430              
- Misses       1916     1922       +6     
  Partials       25       25              

Impacted Files	Coverage Δ
server/api.go	5.67% <2.63%> (-0.05%)	⬇️

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[DHaussermann]

Tested and passed

• When logging in as a user not connected to GutHub in incognito session, the corresponding 401 error in js console no longer occurs
• Regression tested connecting and disconnecting a user a precaution - No change in behavior

LGTM!