Refresh webfinger (#1323)

* Refresh local info for remote accounts when webfinger returns new values

It only refreshes account info if one of the URLs or the public-key changes,
in which cases it refreshes the full info, re-downloading the feeds from that
user.

Some special handling should probably be done when the public key changes,
but I have been unable to find any use for it in Mastodon yet.

* Re-fetch remote users we aren't subscribed to.

This might induce performance issues, we might want to only do that for users
we explicitly attempted to subscribe but failed to.

* Refactor changes

* Do not refresh existing remote account details more than once a day

* Avoid re-fetching webfinger info in tests unless otherwise specified

app/services/follow_remote_account_service.rb

@@ -16,7 +16,7 @@ class FollowRemoteAccountService < BaseService
     return Account.find_local(username) if TagManager.instance.local_domain?(domain)
 
     account = Account.find_remote(username, domain)
-    return account unless account.nil?
+    return account unless account&.last_webfingered_at.nil? || 1.day.from_now(account.last_webfingered_at) < Time.now.utc
 
     Rails.logger.debug "Looking up webfinger for #{uri}"
 
@@ -29,20 +29,24 @@ class FollowRemoteAccountService < BaseService
     return Account.find_local(confirmed_username) if TagManager.instance.local_domain?(confirmed_domain)
 
     confirmed_account = Account.find_remote(confirmed_username, confirmed_domain)
-    return confirmed_account unless confirmed_account.nil?
-
-    Rails.logger.debug "Creating new remote account for #{uri}"
+    if confirmed_account.nil?
+      Rails.logger.debug "Creating new remote account for #{uri}"
+
+      domain_block = DomainBlock.find_by(domain: domain)
+      account = Account.new(username: confirmed_username, domain: confirmed_domain)
+      account.suspended   = true if domain_block && domain_block.suspend?
+      account.silenced    = true if domain_block && domain_block.silence?
+      account.private_key = nil
+    else
+      account = confirmed_account
+    end
 
-    domain_block = DomainBlock.find_by(domain: domain)
+    account.last_webfingered_at = Time.now.utc
 
-    account = Account.new(username: confirmed_username, domain: confirmed_domain)
     account.remote_url  = data.link('http://schemas.google.com/g/2010#updates-from').href
     account.salmon_url  = data.link('salmon').href
     account.url         = data.link('http://webfinger.net/rel/profile-page').href
     account.public_key  = magic_key_to_pem(data.link('magic-public-key').href)
-    account.private_key = nil
-    account.suspended   = true if domain_block && domain_block.suspend?
-    account.silenced    = true if domain_block && domain_block.silence?
 
     body, xml = get_feed(account.remote_url)
     hubs      = get_hubs(xml)

db/migrate/20170409170753_add_last_webfingered_at_to_accounts.rb

+class AddLastWebfingeredAtToAccounts < ActiveRecord::Migration[5.0]
+  def change
+    add_column :accounts, :last_webfingered_at, :datetime
+  end
+end

db/schema.rb

@@ -40,6 +40,7 @@ ActiveRecord::Schema.define(version: 20170406215816) do
     t.datetime "header_updated_at"
     t.string   "avatar_remote_url"
     t.datetime "subscription_expires_at"
+    t.datetime "last_webfingered_at"
     t.boolean  "silenced",                default: false, null: false
     t.boolean  "suspended",               default: false, null: false
     t.boolean  "locked",                  default: false, null: false

spec/fabricators/account_fabricator.rb

 Fabricator(:account) do
   username { Faker::Internet.user_name(nil, %w(_)) }
+  last_webfingered_at { Time.now.utc }
 end