Improve API4 initialization (#18680)

* Improve API4 initialization

- Refactored openGraphDataCache to be inside app layer.
- Moved the cache instance from global variable to be inside server.
- Moved out the app instantiation from the global commands package
to be instantiated on every call. Only the server instance is passed.
- Moved InitLocal to be called from inside Init.

```release-note
NONE
```

* Remove commented line

```release-note
NONE
```

app/app_iface.go

@@ -18,7 +18,6 @@ import (
 	"reflect"
 	"time"
 
-	"github.com/dyatlov/go-opengraph/opengraph"
 	"github.com/mattermost/mattermost-server/v6/app/request"
 	"github.com/mattermost/mattermost-server/v6/audit"
 	"github.com/mattermost/mattermost-server/v6/einterfaces"
@@ -654,7 +653,7 @@ type AppIface interface {
 	GetOAuthLoginEndpoint(w http.ResponseWriter, r *http.Request, service, teamID, action, redirectTo, loginHint string, isMobile bool) (string, *model.AppError)
 	GetOAuthSignupEndpoint(w http.ResponseWriter, r *http.Request, service, teamID string) (string, *model.AppError)
 	GetOAuthStateToken(token string) (*model.Token, *model.AppError)
-	GetOpenGraphMetadata(requestURL string) *opengraph.OpenGraph
+	GetOpenGraphMetadata(requestURL string) ([]byte, error)
 	GetOrCreateDirectChannel(c *request.Context, userID, otherUserID string, channelOptions ...model.ChannelOption) (*model.Channel, *model.AppError)
 	GetOutgoingWebhook(hookID string) (*model.OutgoingWebhook, *model.AppError)
 	GetOutgoingWebhooksForChannelPageByUser(channelID string, userID string, page, perPage int) ([]*model.OutgoingWebhook, *model.AppError)

app/opengraph.go

@@ -7,6 +7,7 @@ import (
 	"html"
 	"io"
 	"net/url"
+	"time"
 
 	"github.com/dyatlov/go-opengraph/opengraph"
 	"golang.org/x/net/html/charset"
@@ -14,16 +15,36 @@ import (
 	"github.com/mattermost/mattermost-server/v6/shared/mlog"
 )
 
-const MaxOpenGraphResponseSize = 1024 * 1024 * 50
+const (
+	MaxOpenGraphResponseSize   = 1024 * 1024 * 50
+	openGraphMetadataCacheSize = 10000
+)
+
+func (a *App) GetOpenGraphMetadata(requestURL string) ([]byte, error) {
+	var ogJSONGeneric []byte
+	err := a.Srv().openGraphDataCache.Get(requestURL, &ogJSONGeneric)
+	if err == nil {
+		return ogJSONGeneric, nil
+	}
 
-func (a *App) GetOpenGraphMetadata(requestURL string) *opengraph.OpenGraph {
 	res, err := a.HTTPService().MakeClient(false).Get(requestURL)
 	if err != nil {
-		mlog.Debug("GetOpenGraphMetadata request failed", mlog.String("requestURL", requestURL), mlog.Err(err))
-		return nil
+		return nil, err
 	}
 	defer res.Body.Close()
-	return a.parseOpenGraphMetadata(requestURL, res.Body, res.Header.Get("Content-Type"))
+
+	graph := a.parseOpenGraphMetadata(requestURL, res.Body, res.Header.Get("Content-Type"))
+
+	ogJSON, err := graph.ToJSON()
+	if err != nil {
+		return nil, err
+	}
+	err = a.Srv().openGraphDataCache.SetWithExpiry(requestURL, ogJSON, 1*time.Hour)
+	if err != nil {
+		return nil, err
+	}
+
+	return ogJSON, nil
 }
 
 func (a *App) parseOpenGraphMetadata(requestURL string, body io.Reader, contentType string) *opengraph.OpenGraph {

app/opentracing/opentracing_layer.go

@@ -18,7 +18,6 @@ import (
 	"reflect"
 	"time"
 
-	"github.com/dyatlov/go-opengraph/opengraph"
 	"github.com/mattermost/mattermost-server/v6/app"
 	"github.com/mattermost/mattermost-server/v6/app/request"
 	"github.com/mattermost/mattermost-server/v6/audit"
@@ -6899,7 +6898,7 @@ func (a *OpenTracingAppLayer) GetOAuthStateToken(token string) (*model.Token, *m
 	return resultVar0, resultVar1
 }
 
-func (a *OpenTracingAppLayer) GetOpenGraphMetadata(requestURL string) *opengraph.OpenGraph {
+func (a *OpenTracingAppLayer) GetOpenGraphMetadata(requestURL string) ([]byte, error) {
 	origCtx := a.ctx
 	span, newCtx := tracing.StartSpanWithParentByContext(a.ctx, "app.GetOpenGraphMetadata")
 
@@ -6911,9 +6910,14 @@ func (a *OpenTracingAppLayer) GetOpenGraphMetadata(requestURL string) *opengraph
 	}()
 
 	defer span.Finish()
-	resultVar0 := a.app.GetOpenGraphMetadata(requestURL)
+	resultVar0, resultVar1 := a.app.GetOpenGraphMetadata(requestURL)
 
-	return resultVar0
+	if resultVar1 != nil {
+		span.LogFields(spanlog.Error(resultVar1))
+		ext.Error.Set(span, true)
+	}
+
+	return resultVar0, resultVar1
 }
 
 func (a *OpenTracingAppLayer) GetOrCreateDirectChannel(c *request.Context, userID string, otherUserID string, channelOptions ...model.ChannelOption) (*model.Channel, *model.AppError) {

app/server.go

@@ -137,6 +137,7 @@ type Server struct {
 	htmlTemplateWatcher     *templates.Container
 	seenPendingPostIdsCache cache.Cache
 	statusCache             cache.Cache
+	openGraphDataCache      cache.Cache
 	configListenerId        string
 	licenseListenerId       string
 	clusterLeaderListenerId string
@@ -349,6 +350,11 @@ func NewServer(options ...Option) (*Server, error) {
 	}); err != nil {
 		return nil, errors.Wrap(err, "Unable to create status cache")
 	}
+	if s.openGraphDataCache, err = s.CacheProvider.NewCache(&cache.CacheOptions{
+		Size: openGraphMetadataCacheSize,
+	}); err != nil {
+		return nil, errors.Wrap(err, "Unable to create opengraphdata cache")
+	}
 
 	s.createPushNotificationsHub()
 
@@ -708,6 +714,16 @@ func NewServer(options ...Option) (*Server, error) {
 		}
 	})
 
+	// Dump the image cache if the proxy settings have changed. (need switch URLs to the correct proxy)
+	s.AddConfigListener(func(oldCfg, newCfg *model.Config) {
+		if (oldCfg.ImageProxySettings.Enable != newCfg.ImageProxySettings.Enable) ||
+			(oldCfg.ImageProxySettings.ImageProxyType != newCfg.ImageProxySettings.ImageProxyType) ||
+			(oldCfg.ImageProxySettings.RemoteImageProxyURL != newCfg.ImageProxySettings.RemoteImageProxyURL) ||
+			(oldCfg.ImageProxySettings.RemoteImageProxyOptions != newCfg.ImageProxySettings.RemoteImageProxyOptions) {
+			s.openGraphDataCache.Purge()
+		}
+	})
+
 	return s, nil
 }