[feature] Discover webfinger through host-meta (#1588)

* [feature] Discover webfinger through host-meta

This implements a fallback for discovering the webfinger endpoint in
case the /.well-known/webfinger endpoint wasn't properly redirected.
Some instances do this because the recommendation used to be to use
host-meta for the webfinger redirect in the before times.

Closes #1558.

* [bug] Ensure we only ever update cache on success

* [chore] Move finger tests to their own place

This adds a test suite for transport and moves the finger cache tests
into there instead of abusing the search test suite.

* [chore] cleanup the test a bit more

We don't really need a separate function for the oddly located webfinger
response as we check the full URL string anyway

* Address review comments

* [chore] update config example

* [chore] access DB only through state in controller

3 files changed, 83 insertions, 0 deletions

diff --git a/internal/config/config.go b/internal/config/config.go
index a7a36eebf..f7a59d760 100644
--- a/internal/config/config.go
+++ b/internal/config/config.go
@@ -207,6 +207,10 @@ type GTSCacheConfiguration struct {
 	UserMaxSize   int           `name:"user-max-size"`
 	UserTTL       time.Duration `name:"user-ttl"`
 	UserSweepFreq time.Duration `name:"user-sweep-freq"`
+
+	WebfingerMaxSize   int           `name:"webfinger-max-size"`
+	WebfingerTTL       time.Duration `name:"webfinger-ttl"`
+	WebfingerSweepFreq time.Duration `name:"webfinger-sweep-freq"`
 }
 
 // MarshalMap will marshal current Configuration into a map structure (useful for JSON/TOML/YAML).
diff --git a/internal/config/defaults.go b/internal/config/defaults.go
index 7d2427ee7..418858827 100644
--- a/internal/config/defaults.go
+++ b/internal/config/defaults.go
@@ -166,6 +166,10 @@ var Defaults = Configuration{
 			UserMaxSize:   100,
 			UserTTL:       time.Minute * 5,
 			UserSweepFreq: time.Second * 30,
+
+			WebfingerMaxSize:   250,
+			WebfingerTTL:       time.Hour * 24,
+			WebfingerSweepFreq: time.Minute * 15,
 		},
 	},
 
diff --git a/internal/config/helpers.gen.go b/internal/config/helpers.gen.go
index b021ed617..14fa72b24 100644
--- a/internal/config/helpers.gen.go
+++ b/internal/config/helpers.gen.go
@@ -3003,6 +3003,81 @@ func GetCacheGTSUserSweepFreq() time.Duration { return global.GetCacheGTSUserSwe
 // SetCacheGTSUserSweepFreq safely sets the value for global configuration 'Cache.GTS.UserSweepFreq' field
 func SetCacheGTSUserSweepFreq(v time.Duration) { global.SetCacheGTSUserSweepFreq(v) }
 
+// GetCacheGTSWebfingerMaxSize safely fetches the Configuration value for state's 'Cache.GTS.WebfingerMaxSize' field
+func (st *ConfigState) GetCacheGTSWebfingerMaxSize() (v int) {
+	st.mutex.Lock()
+	v = st.config.Cache.GTS.WebfingerMaxSize
+	st.mutex.Unlock()
+	return
+}
+
+// SetCacheGTSWebfingerMaxSize safely sets the Configuration value for state's 'Cache.GTS.WebfingerMaxSize' field
+func (st *ConfigState) SetCacheGTSWebfingerMaxSize(v int) {
+	st.mutex.Lock()
+	defer st.mutex.Unlock()
+	st.config.Cache.GTS.WebfingerMaxSize = v
+	st.reloadToViper()
+}
+
+// CacheGTSWebfingerMaxSizeFlag returns the flag name for the 'Cache.GTS.WebfingerMaxSize' field
+func CacheGTSWebfingerMaxSizeFlag() string { return "cache-gts-webfinger-max-size" }
+
+// GetCacheGTSWebfingerMaxSize safely fetches the value for global configuration 'Cache.GTS.WebfingerMaxSize' field
+func GetCacheGTSWebfingerMaxSize() int { return global.GetCacheGTSWebfingerMaxSize() }
+
+// SetCacheGTSWebfingerMaxSize safely sets the value for global configuration 'Cache.GTS.WebfingerMaxSize' field
+func SetCacheGTSWebfingerMaxSize(v int) { global.SetCacheGTSWebfingerMaxSize(v) }
+
+// GetCacheGTSWebfingerTTL safely fetches the Configuration value for state's 'Cache.GTS.WebfingerTTL' field
+func (st *ConfigState) GetCacheGTSWebfingerTTL() (v time.Duration) {
+	st.mutex.Lock()
+	v = st.config.Cache.GTS.WebfingerTTL
+	st.mutex.Unlock()
+	return
+}
+
+// SetCacheGTSWebfingerTTL safely sets the Configuration value for state's 'Cache.GTS.WebfingerTTL' field
+func (st *ConfigState) SetCacheGTSWebfingerTTL(v time.Duration) {
+	st.mutex.Lock()
+	defer st.mutex.Unlock()
+	st.config.Cache.GTS.WebfingerTTL = v
+	st.reloadToViper()
+}
+
+// CacheGTSWebfingerTTLFlag returns the flag name for the 'Cache.GTS.WebfingerTTL' field
+func CacheGTSWebfingerTTLFlag() string { return "cache-gts-webfinger-ttl" }
+
+// GetCacheGTSWebfingerTTL safely fetches the value for global configuration 'Cache.GTS.WebfingerTTL' field
+func GetCacheGTSWebfingerTTL() time.Duration { return global.GetCacheGTSWebfingerTTL() }
+
+// SetCacheGTSWebfingerTTL safely sets the value for global configuration 'Cache.GTS.WebfingerTTL' field
+func SetCacheGTSWebfingerTTL(v time.Duration) { global.SetCacheGTSWebfingerTTL(v) }
+
+// GetCacheGTSWebfingerSweepFreq safely fetches the Configuration value for state's 'Cache.GTS.WebfingerSweepFreq' field
+func (st *ConfigState) GetCacheGTSWebfingerSweepFreq() (v time.Duration) {
+	st.mutex.Lock()
+	v = st.config.Cache.GTS.WebfingerSweepFreq
+	st.mutex.Unlock()
+	return
+}
+
+// SetCacheGTSWebfingerSweepFreq safely sets the Configuration value for state's 'Cache.GTS.WebfingerSweepFreq' field
+func (st *ConfigState) SetCacheGTSWebfingerSweepFreq(v time.Duration) {
+	st.mutex.Lock()
+	defer st.mutex.Unlock()
+	st.config.Cache.GTS.WebfingerSweepFreq = v
+	st.reloadToViper()
+}
+
+// CacheGTSWebfingerSweepFreqFlag returns the flag name for the 'Cache.GTS.WebfingerSweepFreq' field
+func CacheGTSWebfingerSweepFreqFlag() string { return "cache-gts-webfinger-sweep-freq" }
+
+// GetCacheGTSWebfingerSweepFreq safely fetches the value for global configuration 'Cache.GTS.WebfingerSweepFreq' field
+func GetCacheGTSWebfingerSweepFreq() time.Duration { return global.GetCacheGTSWebfingerSweepFreq() }
+
+// SetCacheGTSWebfingerSweepFreq safely sets the value for global configuration 'Cache.GTS.WebfingerSweepFreq' field
+func SetCacheGTSWebfingerSweepFreq(v time.Duration) { global.SetCacheGTSWebfingerSweepFreq(v) }
+
 // GetAdminAccountUsername safely fetches the Configuration value for state's 'AdminAccountUsername' field
 func (st *ConfigState) GetAdminAccountUsername() (v string) {
 	st.mutex.Lock()