feature: filters v2 server-side warning/hiding (#2793)

* Remove dead code

* Filter statuses when converting to frontend representation

* status.filtered is an array

* Make matching case-insensitive

* Remove TODOs that don't need to be done now

* Add missing filter check for notification

* lint: rename ErrHideStatus

* APIFilterActionToFilterAction not used yet

* swaggerino docseroni

* Address review comments

* Add apimodel.FilterActionNone

---------

Co-authored-by: tobi <31960611+tsmethurst@users.noreply.github.com>
Co-authored-by: tobi <tobi.smethurst@protonmail.com>

docs/api/swagger.yaml

@@ -1,5 +1,9 @@
 basePath: /
 definitions:
+    FilterAction:
+        title: FilterAction is the action to apply to statuses matching a filter.
+        type: string
+        x-go-package: github.com/superseriousbusiness/gotosocial/internal/api/model
     InstanceConfigurationEmojis:
         properties:
             emoji_size_limit:
@@ -1037,6 +1041,60 @@ definitions:
         type: string
         x-go-name: FilterContext
         x-go-package: github.com/superseriousbusiness/gotosocial/internal/api/model
+    filterKeyword:
+        properties:
+            id:
+                description: The ID of the filter keyword entry in the database.
+                type: string
+                x-go-name: ID
+            keyword:
+                description: The text to be filtered.
+                example: fnord
+                type: string
+                x-go-name: Keyword
+            whole_word:
+                description: Should the filter consider word boundaries?
+                example: true
+                type: boolean
+                x-go-name: WholeWord
+        title: FilterKeyword represents text to filter within a v2 filter.
+        type: object
+        x-go-name: FilterKeyword
+        x-go-package: github.com/superseriousbusiness/gotosocial/internal/api/model
+    filterResult:
+        properties:
+            filter:
+                $ref: '#/definitions/filterV2'
+            keyword_matches:
+                description: The keywords within the filter that were matched.
+                items:
+                    type: string
+                type: array
+                x-go-name: KeywordMatches
+            status_matches:
+                description: The status IDs within the filter that were matched.
+                items:
+                    type: string
+                type: array
+                x-go-name: StatusMatches
+        title: FilterResult is returned along with a filtered status to explain why it was filtered.
+        type: object
+        x-go-name: FilterResult
+        x-go-package: github.com/superseriousbusiness/gotosocial/internal/api/model
+    filterStatus:
+        properties:
+            id:
+                description: The ID of the filter status entry in the database.
+                type: string
+                x-go-name: ID
+            phrase:
+                description: The status ID to be filtered.
+                type: string
+                x-go-name: StatusID
+        title: FilterStatus represents a single status to filter within a v2 filter.
+        type: object
+        x-go-name: FilterStatus
+        x-go-package: github.com/superseriousbusiness/gotosocial/internal/api/model
     filterV1:
         description: |-
             Note that v1 filters are mapped to v2 filters and v2 filter keywords internally.
@@ -1086,6 +1144,52 @@ definitions:
         type: object
         x-go-name: FilterV1
         x-go-package: github.com/superseriousbusiness/gotosocial/internal/api/model
+    filterV2:
+        description: v2 filters have names and can include multiple phrases and status IDs to filter.
+        properties:
+            context:
+                description: The contexts in which the filter should be applied.
+                example:
+                    - home
+                    - public
+                items:
+                    $ref: '#/definitions/filterContext'
+                minItems: 1
+                type: array
+                uniqueItems: true
+                x-go-name: Context
+            expires_at:
+                description: When the filter should no longer be applied. Null if the filter does not expire.
+                example: "2024-02-01T02:57:49Z"
+                type: string
+                x-go-name: ExpiresAt
+            filter_action:
+                $ref: '#/definitions/FilterAction'
+            id:
+                description: The ID of the filter in the database.
+                type: string
+                x-go-name: ID
+            keywords:
+                description: The keywords grouped under this filter.
+                items:
+                    $ref: '#/definitions/filterKeyword'
+                type: array
+                x-go-name: Keywords
+            statuses:
+                description: The statuses grouped under this filter.
+                items:
+                    $ref: '#/definitions/filterStatus'
+                type: array
+                x-go-name: Statuses
+            title:
+                description: The name of the filter.
+                example: Linux Words
+                type: string
+                x-go-name: Title
+        title: FilterV2 represents a user-defined filter for determining which statuses should not be shown to the user.
+        type: object
+        x-go-name: FilterV2
+        x-go-package: github.com/superseriousbusiness/gotosocial/internal/api/model
     headerFilter:
         properties:
             created_at:
@@ -2118,6 +2222,12 @@ definitions:
                 format: int64
                 type: integer
                 x-go-name: FavouritesCount
+            filtered:
+                description: A list of filters that matched this status and why they matched, if there are any such filters.
+                items:
+                    $ref: '#/definitions/filterResult'
+                type: array
+                x-go-name: Filtered
             id:
                 description: ID of the status.
                 example: 01FBVD42CQ3ZEEVMW180SBX03B
@@ -2321,6 +2431,12 @@ definitions:
                 format: int64
                 type: integer
                 x-go-name: FavouritesCount
+            filtered:
+                description: A list of filters that matched this status and why they matched, if there are any such filters.
+                items:
+                    $ref: '#/definitions/filterResult'
+                type: array
+                x-go-name: Filtered
             id:
                 description: ID of the status.
                 example: 01FBVD42CQ3ZEEVMW180SBX03B

internal/api/model/filterresult.go

@@ -0,0 +1,34 @@
+// GoToSocial
+// Copyright (C) GoToSocial Authors admin@gotosocial.org
+// SPDX-License-Identifier: AGPL-3.0-or-later
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Affero General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU Affero General Public License for more details.
+//
+// You should have received a copy of the GNU Affero General Public License
+// along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+package model
+
+// FilterResult is returned along with a filtered status to explain why it was filtered.
+//
+// swagger:model filterResult
+//
+// ---
+// tags:
+// - filters
+type FilterResult struct {
+	// The filter that was matched.
+	Filter FilterV2 `json:"filter"`
+	// The keywords within the filter that were matched.
+	KeywordMatches []string `json:"keyword_matches"`
+	// The status IDs within the filter that were matched.
+	StatusMatches []string `json:"status_matches"`
+}

internal/api/model/filterv2.go

@@ -0,0 +1,106 @@
+// GoToSocial
+// Copyright (C) GoToSocial Authors admin@gotosocial.org
+// SPDX-License-Identifier: AGPL-3.0-or-later
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Affero General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU Affero General Public License for more details.
+//
+// You should have received a copy of the GNU Affero General Public License
+// along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+package model
+
+// FilterV2 represents a user-defined filter for determining which statuses should not be shown to the user.
+// v2 filters have names and can include multiple phrases and status IDs to filter.
+//
+// swagger:model filterV2
+//
+// ---
+// tags:
+// - filters
+type FilterV2 struct {
+	// The ID of the filter in the database.
+	ID string `json:"id"`
+	// The name of the filter.
+	//
+	// Example: Linux Words
+	Title string `json:"title"`
+	// The contexts in which the filter should be applied.
+	//
+	// Minimum items: 1
+	// Unique: true
+	// Enum:
+	//	- home
+	//	- notifications
+	//	- public
+	//	- thread
+	//	- account
+	// Example: ["home", "public"]
+	Context []FilterContext `json:"context"`
+	// When the filter should no longer be applied. Null if the filter does not expire.
+	//
+	// Example: 2024-02-01T02:57:49Z
+	ExpiresAt *string `json:"expires_at"`
+	// The action to be taken when a status matches this filter.
+	// Enum:
+	//	- warn
+	//	- hide
+	FilterAction FilterAction `json:"filter_action"`
+	// The keywords grouped under this filter.
+	Keywords []FilterKeyword `json:"keywords"`
+	// The statuses grouped under this filter.
+	Statuses []FilterStatus `json:"statuses"`
+}
+
+// FilterAction is the action to apply to statuses matching a filter.
+type FilterAction string
+
+const (
+	// FilterActionNone filters should not exist, except internally, for partially constructed or invalid filters.
+	FilterActionNone FilterAction = ""
+	// FilterActionWarn filters will include this status in API results with a warning.
+	FilterActionWarn FilterAction = "warn"
+	// FilterActionHide filters will remove this status from API results.
+	FilterActionHide FilterAction = "hide"
+)
+
+// FilterKeyword represents text to filter within a v2 filter.
+//
+// swagger:model filterKeyword
+//
+// ---
+// tags:
+// - filters
+type FilterKeyword struct {
+	// The ID of the filter keyword entry in the database.
+	ID string `json:"id"`
+	// The text to be filtered.
+	//
+	// Example: fnord
+	Keyword string `json:"keyword"`
+	// Should the filter consider word boundaries?
+	//
+	// Example: true
+	WholeWord bool `json:"whole_word"`
+}
+
+// FilterStatus represents a single status to filter within a v2 filter.
+//
+// swagger:model filterStatus
+//
+// ---
+// tags:
+// - filters
+type FilterStatus struct {
+	// The ID of the filter status entry in the database.
+	ID string `json:"id"`
+	// The status ID to be filtered.
+	StatusID string `json:"phrase"`
+}

internal/api/model/status.go

@@ -100,6 +100,8 @@ type Status struct {
 	// so the user may redraft from the source text without the client having to reverse-engineer
 	// the original text from the HTML content.
 	Text string `json:"text,omitempty"`
+	// A list of filters that matched this status and why they matched, if there are any such filters.
+	Filtered []FilterResult `json:"filtered,omitempty"`
 
 	// Additional fields not exposed via JSON
 	// (used only internally for templating etc).

internal/filter/status/status.go

@@ -0,0 +1,45 @@
+// GoToSocial
+// Copyright (C) GoToSocial Authors admin@gotosocial.org
+// SPDX-License-Identifier: AGPL-3.0-or-later
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Affero General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU Affero General Public License for more details.
+//
+// You should have received a copy of the GNU Affero General Public License
+// along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+// Package status represents status filters managed by the user through the API.
+package status
+
+import (
+	"errors"
+)
+
+// ErrHideStatus indicates that a status has been filtered and should not be returned at all.
+var ErrHideStatus = errors.New("hide status")
+
+// FilterContext determines the filters that apply to a given status or list of statuses.
+type FilterContext string
+
+const (
+	// FilterContextNone means no filters should be applied.
+	// There are no filters with this context; it's for internal use only.
+	FilterContextNone FilterContext = ""
+	// FilterContextHome means this status is being filtered as part of a home or list timeline.
+	FilterContextHome FilterContext = "home"
+	// FilterContextNotifications means this status is being filtered as part of the notifications timeline.
+	FilterContextNotifications FilterContext = "notifications"
+	// FilterContextPublic means this status is being filtered as part of a public or tag timeline.
+	FilterContextPublic FilterContext = "public"
+	// FilterContextThread means this status is being filtered as part of a thread's context.
+	FilterContextThread FilterContext = "thread"
+	// FilterContextAccount means this status is being filtered as part of an account's statuses.
+	FilterContextAccount FilterContext = "account"
+)

internal/processing/account/bookmarks.go

@@ -23,6 +23,7 @@
 
 	apimodel "github.com/superseriousbusiness/gotosocial/internal/api/model"
 	"github.com/superseriousbusiness/gotosocial/internal/db"
+	statusfilter "github.com/superseriousbusiness/gotosocial/internal/filter/status"
 	"github.com/superseriousbusiness/gotosocial/internal/gtserror"
 	"github.com/superseriousbusiness/gotosocial/internal/gtsmodel"
 	"github.com/superseriousbusiness/gotosocial/internal/log"
@@ -74,7 +75,7 @@ func (p *Processor) BookmarksGet(ctx context.Context, requestingAccount *gtsmode
 		}
 
 		// Convert the status.
-		item, err := p.converter.StatusToAPIStatus(ctx, status, requestingAccount)
+		item, err := p.converter.StatusToAPIStatus(ctx, status, requestingAccount, statusfilter.FilterContextNone, nil)
 		if err != nil {
 			log.Errorf(ctx, "error converting bookmarked status to api: %s", err)
 			continue

internal/processing/account/statuses.go

@@ -24,6 +24,7 @@
 
 	apimodel "github.com/superseriousbusiness/gotosocial/internal/api/model"
 	"github.com/superseriousbusiness/gotosocial/internal/db"
+	statusfilter "github.com/superseriousbusiness/gotosocial/internal/filter/status"
 	"github.com/superseriousbusiness/gotosocial/internal/gtserror"
 	"github.com/superseriousbusiness/gotosocial/internal/gtsmodel"
 	"github.com/superseriousbusiness/gotosocial/internal/log"
@@ -96,9 +97,15 @@ func (p *Processor) StatusesGet(
 		return nil, gtserror.NewErrorInternalError(err)
 	}
 
+	filters, err := p.state.DB.GetFiltersForAccountID(ctx, requestingAccount.ID)
+	if err != nil {
+		err = gtserror.Newf("couldn't retrieve filters for account %s: %w", requestingAccount.ID, err)
+		return nil, gtserror.NewErrorInternalError(err)
+	}
+
 	for _, s := range filtered {
 		// Convert filtered statuses to API statuses.
-		item, err := p.converter.StatusToAPIStatus(ctx, s, requestingAccount)
+		item, err := p.converter.StatusToAPIStatus(ctx, s, requestingAccount, statusfilter.FilterContextAccount, filters)
 		if err != nil {
 			log.Errorf(ctx, "error convering to api status: %v", err)
 			continue

internal/processing/common/status.go

@@ -24,6 +24,7 @@
 	apimodel "github.com/superseriousbusiness/gotosocial/internal/api/model"
 	"github.com/superseriousbusiness/gotosocial/internal/db"
 	"github.com/superseriousbusiness/gotosocial/internal/federation/dereferencing"
+	statusfilter "github.com/superseriousbusiness/gotosocial/internal/filter/status"
 	"github.com/superseriousbusiness/gotosocial/internal/gtserror"
 	"github.com/superseriousbusiness/gotosocial/internal/gtsmodel"
 	"github.com/superseriousbusiness/gotosocial/internal/log"
@@ -184,7 +185,7 @@ func (p *Processor) GetAPIStatus(
 	apiStatus *apimodel.Status,
 	errWithCode gtserror.WithCode,
 ) {
-	apiStatus, err := p.converter.StatusToAPIStatus(ctx, target, requester)
+	apiStatus, err := p.converter.StatusToAPIStatus(ctx, target, requester, statusfilter.FilterContextNone, nil)
 	if err != nil {
 		err = gtserror.Newf("error converting status: %w", err)
 		return nil, gtserror.NewErrorInternalError(err)
@@ -192,87 +193,6 @@ func (p *Processor) GetAPIStatus(
 	return apiStatus, nil
 }
 
-// GetVisibleAPIStatuses converts an array of gtsmodel.Status (inputted by next function) into
-// API model statuses, checking first for visibility. Please note that all errors will be
-// logged at ERROR level, but will not be returned. Callers are likely to run into show-stopping
-// errors in the lead-up to this function, whereas calling this should not be a show-stopper.
-func (p *Processor) GetVisibleAPIStatuses(
-	ctx context.Context,
-	requester *gtsmodel.Account,
-	next func(int) *gtsmodel.Status,
-	length int,
-) []*apimodel.Status {
-	return p.getVisibleAPIStatuses(ctx, 3, requester, next, length)
-}
-
-// GetVisibleAPIStatusesPaged is functionally equivalent to GetVisibleAPIStatuses(),
-// except the statuses are returned as a converted slice of statuses as interface{}.
-func (p *Processor) GetVisibleAPIStatusesPaged(
-	ctx context.Context,
-	requester *gtsmodel.Account,
-	next func(int) *gtsmodel.Status,
-	length int,
-) []interface{} {
-	statuses := p.getVisibleAPIStatuses(ctx, 3, requester, next, length)
-	if len(statuses) == 0 {
-		return nil
-	}
-	items := make([]interface{}, len(statuses))
-	for i, status := range statuses {
-		items[i] = status
-	}
-	return items
-}
-
-func (p *Processor) getVisibleAPIStatuses(
-	ctx context.Context,
-	calldepth int, // used to skip wrapping func above these's names
-	requester *gtsmodel.Account,
-	next func(int) *gtsmodel.Status,
-	length int,
-) []*apimodel.Status {
-	// Start new log entry with
-	// the above calling func's name.
-	l := log.
-		WithContext(ctx).
-		WithField("caller", log.Caller(calldepth+1))
-
-	// Preallocate slice according to expected length.
-	statuses := make([]*apimodel.Status, 0, length)
-
-	for i := 0; i < length; i++ {
-		// Get next status.
-		status := next(i)
-		if status == nil {
-			continue
-		}
-
-		// Check whether this status is visible to requesting account.
-		visible, err := p.filter.StatusVisible(ctx, requester, status)
-		if err != nil {
-			l.Errorf("error checking status visibility: %v", err)
-			continue
-		}
-
-		if !visible {
-			// Not visible to requester.
-			continue
-		}
-
-		// Convert the status to an API model representation.
-		apiStatus, err := p.converter.StatusToAPIStatus(ctx, status, requester)
-		if err != nil {
-			l.Errorf("error converting status: %v", err)
-			continue
-		}
-
-		// Append API model to return slice.
-		statuses = append(statuses, apiStatus)
-	}
-
-	return statuses
-}
-
 // InvalidateTimelinedStatus is a shortcut function for invalidating the cached
 // representation one status in the home timeline and all list timelines of the
 // given accountID. It should only be called in cases where a status update

internal/processing/search/util.go

@@ -21,6 +21,7 @@
 	"context"
 
 	apimodel "github.com/superseriousbusiness/gotosocial/internal/api/model"
+	statusfilter "github.com/superseriousbusiness/gotosocial/internal/filter/status"
 	"github.com/superseriousbusiness/gotosocial/internal/gtserror"
 	"github.com/superseriousbusiness/gotosocial/internal/gtsmodel"
 	"github.com/superseriousbusiness/gotosocial/internal/log"
@@ -113,7 +114,7 @@ func (p *Processor) packageStatuses(
 			continue
 		}
 
-		apiStatus, err := p.converter.StatusToAPIStatus(ctx, status, requestingAccount)
+		apiStatus, err := p.converter.StatusToAPIStatus(ctx, status, requestingAccount, statusfilter.FilterContextNone, nil)
 		if err != nil {
 			log.Debugf(ctx, "skipping status %s because it couldn't be converted to its api representation: %s", status.ID, err)
 			continue

internal/processing/status/get.go

@@ -23,6 +23,7 @@
 	"strings"
 
 	apimodel "github.com/superseriousbusiness/gotosocial/internal/api/model"
+	statusfilter "github.com/superseriousbusiness/gotosocial/internal/filter/status"
 	"github.com/superseriousbusiness/gotosocial/internal/gtserror"
 	"github.com/superseriousbusiness/gotosocial/internal/gtsmodel"
 	"github.com/superseriousbusiness/gotosocial/internal/util"
@@ -280,7 +281,15 @@ func TopoSort(apiStatuses []*apimodel.Status, targetAccountID string) {
 
 // ContextGet returns the context (previous and following posts) from the given status ID.
 func (p *Processor) ContextGet(ctx context.Context, requestingAccount *gtsmodel.Account, targetStatusID string) (*apimodel.Context, gtserror.WithCode) {
-	return p.contextGet(ctx, requestingAccount, targetStatusID, p.converter.StatusToAPIStatus)
+	filters, err := p.state.DB.GetFiltersForAccountID(ctx, requestingAccount.ID)
+	if err != nil {
+		err = gtserror.Newf("couldn't retrieve filters for account %s: %w", requestingAccount.ID, err)
+		return nil, gtserror.NewErrorInternalError(err)
+	}
+	convert := func(ctx context.Context, status *gtsmodel.Status, requestingAccount *gtsmodel.Account) (*apimodel.Status, error) {
+		return p.converter.StatusToAPIStatus(ctx, status, requestingAccount, statusfilter.FilterContextThread, filters)
+	}
+	return p.contextGet(ctx, requestingAccount, targetStatusID, convert)
 }
 
 // WebContextGet is like ContextGet, but is explicitly

internal/processing/stream/statusupdate_test.go

@@ -24,6 +24,7 @@
 	"testing"
 
 	"github.com/stretchr/testify/suite"
+	statusfilter "github.com/superseriousbusiness/gotosocial/internal/filter/status"
 	"github.com/superseriousbusiness/gotosocial/internal/stream"
 	"github.com/superseriousbusiness/gotosocial/internal/typeutils"
 )
@@ -39,7 +40,7 @@ func (suite *StatusUpdateTestSuite) TestStreamNotification() {
 	suite.NoError(errWithCode)
 
 	editedStatus := suite.testStatuses["remote_account_1_status_1"]
-	apiStatus, err := typeutils.NewConverter(&suite.state).StatusToAPIStatus(context.Background(), editedStatus, account)
+	apiStatus, err := typeutils.NewConverter(&suite.state).StatusToAPIStatus(context.Background(), editedStatus, account, statusfilter.FilterContextNotifications, nil)
 	suite.NoError(err)
 
 	suite.streamProcessor.StatusUpdate(context.Background(), account, apiStatus, stream.TimelineHome)

internal/processing/timeline/faved.go

@@ -24,6 +24,7 @@
 
 	apimodel "github.com/superseriousbusiness/gotosocial/internal/api/model"
 	"github.com/superseriousbusiness/gotosocial/internal/db"
+	statusfilter "github.com/superseriousbusiness/gotosocial/internal/filter/status"
 	"github.com/superseriousbusiness/gotosocial/internal/gtserror"
 	"github.com/superseriousbusiness/gotosocial/internal/log"
 	"github.com/superseriousbusiness/gotosocial/internal/oauth"
@@ -54,7 +55,7 @@ func (p *Processor) FavedTimelineGet(ctx context.Context, authed *oauth.Auth, ma
 			continue
 		}
 
-		apiStatus, err := p.converter.StatusToAPIStatus(ctx, s, authed.Account)
+		apiStatus, err := p.converter.StatusToAPIStatus(ctx, s, authed.Account, statusfilter.FilterContextNone, nil)
 		if err != nil {
 			log.Errorf(ctx, "error convering to api status: %v", err)
 			continue

internal/processing/timeline/home.go

@@ -23,6 +23,7 @@
 
 	apimodel "github.com/superseriousbusiness/gotosocial/internal/api/model"
 	"github.com/superseriousbusiness/gotosocial/internal/db"
+	statusfilter "github.com/superseriousbusiness/gotosocial/internal/filter/status"
 	"github.com/superseriousbusiness/gotosocial/internal/filter/visibility"
 	"github.com/superseriousbusiness/gotosocial/internal/gtserror"
 	"github.com/superseriousbusiness/gotosocial/internal/gtsmodel"
@@ -98,7 +99,13 @@ func HomeTimelineStatusPrepare(state *state.State, converter *typeutils.Converte
 			return nil, err
 		}
 
-		return converter.StatusToAPIStatus(ctx, status, requestingAccount)
+		filters, err := state.DB.GetFiltersForAccountID(ctx, requestingAccount.ID)
+		if err != nil {
+			err = gtserror.Newf("couldn't retrieve filters for account %s: %w", requestingAccount.ID, err)
+			return nil, err
+		}
+
+		return converter.StatusToAPIStatus(ctx, status, requestingAccount, statusfilter.FilterContextHome, filters)
 	}
 }
 

internal/processing/timeline/list.go

@@ -23,6 +23,7 @@
 
 	apimodel "github.com/superseriousbusiness/gotosocial/internal/api/model"
 	"github.com/superseriousbusiness/gotosocial/internal/db"
+	statusfilter "github.com/superseriousbusiness/gotosocial/internal/filter/status"
 	"github.com/superseriousbusiness/gotosocial/internal/filter/visibility"
 	"github.com/superseriousbusiness/gotosocial/internal/gtserror"
 	"github.com/superseriousbusiness/gotosocial/internal/gtsmodel"
@@ -110,7 +111,13 @@ func ListTimelineStatusPrepare(state *state.State, converter *typeutils.Converte
 			return nil, err
 		}
 
-		return converter.StatusToAPIStatus(ctx, status, requestingAccount)
+		filters, err := state.DB.GetFiltersForAccountID(ctx, requestingAccount.ID)
+		if err != nil {
+			err = gtserror.Newf("couldn't retrieve filters for account %s: %w", requestingAccount.ID, err)
+			return nil, err
+		}
+
+		return converter.StatusToAPIStatus(ctx, status, requestingAccount, statusfilter.FilterContextHome, filters)
 	}
 }
 

internal/processing/timeline/notification.go

@@ -43,6 +43,12 @@ func (p *Processor) NotificationsGet(ctx context.Context, authed *oauth.Auth, ma
 		return util.EmptyPageableResponse(), nil
 	}
 
+	filters, err := p.state.DB.GetFiltersForAccountID(ctx, authed.Account.ID)
+	if err != nil {
+		err = gtserror.Newf("couldn't retrieve filters for account %s: %w", authed.Account.ID, err)
+		return nil, gtserror.NewErrorInternalError(err)
+	}
+
 	var (
 		items          = make([]interface{}, 0, count)
 		nextMaxIDValue string
@@ -70,7 +76,7 @@ func (p *Processor) NotificationsGet(ctx context.Context, authed *oauth.Auth, ma
 			continue
 		}
 
-		item, err := p.converter.NotificationToAPINotification(ctx, n)
+		item, err := p.converter.NotificationToAPINotification(ctx, n, filters)
 		if err != nil {
 			log.Debugf(ctx, "skipping notification %s because it couldn't be converted to its api representation: %s", n.ID, err)
 			continue
@@ -104,7 +110,13 @@ func (p *Processor) NotificationGet(ctx context.Context, account *gtsmodel.Accou
 		return nil, gtserror.NewErrorNotFound(err)
 	}
 
-	apiNotif, err := p.converter.NotificationToAPINotification(ctx, notif)
+	filters, err := p.state.DB.GetFiltersForAccountID(ctx, account.ID)
+	if err != nil {
+		err = gtserror.Newf("couldn't retrieve filters for account %s: %w", account.ID, err)
+		return nil, gtserror.NewErrorInternalError(err)
+	}
+
+	apiNotif, err := p.converter.NotificationToAPINotification(ctx, notif, filters)
 	if err != nil {
 		if errors.Is(err, db.ErrNoEntries) {
 			return nil, gtserror.NewErrorNotFound(err)

internal/processing/timeline/public.go

@@ -24,6 +24,7 @@
 
 	apimodel "github.com/superseriousbusiness/gotosocial/internal/api/model"
 	"github.com/superseriousbusiness/gotosocial/internal/db"
+	statusfilter "github.com/superseriousbusiness/gotosocial/internal/filter/status"
 	"github.com/superseriousbusiness/gotosocial/internal/gtserror"
 	"github.com/superseriousbusiness/gotosocial/internal/gtsmodel"
 	"github.com/superseriousbusiness/gotosocial/internal/log"
@@ -46,6 +47,16 @@ func (p *Processor) PublicTimelineGet(
 		items          = make([]any, 0, limit)
 	)
 
+	var filters []*gtsmodel.Filter
+	if requester != nil {
+		var err error
+		filters, err = p.state.DB.GetFiltersForAccountID(ctx, requester.ID)
+		if err != nil {
+			err = gtserror.Newf("couldn't retrieve filters for account %s: %w", requester.ID, err)
+			return nil, gtserror.NewErrorInternalError(err)
+		}
+	}
+
 	// Try a few times to select appropriate public
 	// statuses from the db, paging up or down to
 	// reattempt if nothing suitable is found.
@@ -87,7 +98,10 @@ func (p *Processor) PublicTimelineGet(
 				continue inner
 			}
 
-			apiStatus, err := p.converter.StatusToAPIStatus(ctx, s, requester)
+			apiStatus, err := p.converter.StatusToAPIStatus(ctx, s, requester, statusfilter.FilterContextPublic, filters)
+			if errors.Is(err, statusfilter.ErrHideStatus) {
+				continue
+			}
 			if err != nil {
 				log.Errorf(ctx, "error converting to api status: %v", err)
 				continue inner

internal/processing/timeline/tag.go

@@ -24,6 +24,7 @@
 
 	apimodel "github.com/superseriousbusiness/gotosocial/internal/api/model"
 	"github.com/superseriousbusiness/gotosocial/internal/db"
+	statusfilter "github.com/superseriousbusiness/gotosocial/internal/filter/status"
 	"github.com/superseriousbusiness/gotosocial/internal/gtserror"
 	"github.com/superseriousbusiness/gotosocial/internal/gtsmodel"
 	"github.com/superseriousbusiness/gotosocial/internal/log"
@@ -111,6 +112,12 @@ func (p *Processor) packageTagResponse(
 		prevMinIDValue = statuses[0].ID
 	)
 
+	filters, err := p.state.DB.GetFiltersForAccountID(ctx, requestingAcct.ID)
+	if err != nil {
+		err = gtserror.Newf("couldn't retrieve filters for account %s: %w", requestingAcct.ID, err)
+		return nil, gtserror.NewErrorInternalError(err)
+	}
+
 	for _, s := range statuses {
 		timelineable, err := p.filter.StatusTagTimelineable(ctx, requestingAcct, s)
 		if err != nil {
@@ -122,7 +129,10 @@ func (p *Processor) packageTagResponse(
 			continue
 		}
 
-		apiStatus, err := p.converter.StatusToAPIStatus(ctx, s, requestingAcct)
+		apiStatus, err := p.converter.StatusToAPIStatus(ctx, s, requestingAcct, statusfilter.FilterContextPublic, filters)
+		if errors.Is(err, statusfilter.ErrHideStatus) {
+			continue
+		}
 		if err != nil {
 			log.Errorf(ctx, "error converting to api status: %v", err)
 			continue

internal/processing/workers/fromclientapi_test.go

@@ -28,6 +28,7 @@
 	"github.com/superseriousbusiness/gotosocial/internal/ap"
 	"github.com/superseriousbusiness/gotosocial/internal/config"
 	"github.com/superseriousbusiness/gotosocial/internal/db"
+	statusfilter "github.com/superseriousbusiness/gotosocial/internal/filter/status"
 	"github.com/superseriousbusiness/gotosocial/internal/gtsmodel"
 	"github.com/superseriousbusiness/gotosocial/internal/id"
 	"github.com/superseriousbusiness/gotosocial/internal/messages"
@@ -154,6 +155,8 @@ func (suite *FromClientAPITestSuite) statusJSON(
 		ctx,
 		status,
 		requestingAccount,
+		statusfilter.FilterContextNone,
+		nil,
 	)
 	if err != nil {
 		suite.FailNow(err.Error())
@@ -258,7 +261,7 @@ func (suite *FromClientAPITestSuite) TestProcessCreateStatusWithNotification() {
 		suite.FailNow("timed out waiting for new status notification")
 	}
 
-	apiNotif, err := testStructs.TypeConverter.NotificationToAPINotification(ctx, notif)
+	apiNotif, err := testStructs.TypeConverter.NotificationToAPINotification(ctx, notif, nil)
 	if err != nil {
 		suite.FailNow(err.Error())
 	}

internal/processing/workers/surfacenotify.go

@@ -467,7 +467,12 @@ func (s *Surface) Notify(
 	unlock()
 
 	// Stream notification to the user.
-	apiNotif, err := s.Converter.NotificationToAPINotification(ctx, notif)
+	filters, err := s.State.DB.GetFiltersForAccountID(ctx, targetAccount.ID)
+	if err != nil {
+		return gtserror.Newf("couldn't retrieve filters for account %s: %w", targetAccount.ID, err)
+	}
+
+	apiNotif, err := s.Converter.NotificationToAPINotification(ctx, notif, filters)
 	if err != nil {
 		return gtserror.Newf("error converting notification to api representation: %w", err)
 	}

internal/processing/workers/surfacetimeline.go

@@ -22,6 +22,7 @@
 	"errors"
 
 	"github.com/superseriousbusiness/gotosocial/internal/db"
+	statusfilter "github.com/superseriousbusiness/gotosocial/internal/filter/status"
 	"github.com/superseriousbusiness/gotosocial/internal/gtscontext"
 	"github.com/superseriousbusiness/gotosocial/internal/gtserror"
 	"github.com/superseriousbusiness/gotosocial/internal/gtsmodel"
@@ -111,6 +112,11 @@ func (s *Surface) timelineAndNotifyStatusForFollowers(
 			continue
 		}
 
+		filters, err := s.State.DB.GetFiltersForAccountID(ctx, follow.AccountID)
+		if err != nil {
+			return gtserror.Newf("couldn't retrieve filters for account %s: %w", follow.AccountID, err)
+		}
+
 		// Add status to any relevant lists
 		// for this follow, if applicable.
 		s.listTimelineStatusForFollow(
@@ -118,6 +124,7 @@ func (s *Surface) timelineAndNotifyStatusForFollowers(
 			status,
 			follow,
 			&errs,
+			filters,
 		)
 
 		// Add status to home timeline for owner
@@ -129,6 +136,7 @@ func (s *Surface) timelineAndNotifyStatusForFollowers(
 			follow.Account,
 			status,
 			stream.TimelineHome,
+			filters,
 		)
 		if err != nil {
 			errs.Appendf("error home timelining status: %w", err)
@@ -180,6 +188,7 @@ func (s *Surface) listTimelineStatusForFollow(
 	status *gtsmodel.Status,
 	follow *gtsmodel.Follow,
 	errs *gtserror.MultiError,
+	filters []*gtsmodel.Filter,
 ) {
 	// To put this status in appropriate list timelines,
 	// we need to get each listEntry that pertains to
@@ -222,6 +231,7 @@ func (s *Surface) listTimelineStatusForFollow(
 			follow.Account,
 			status,
 			stream.TimelineList+":"+listEntry.ListID, // key streamType to this specific list
+			filters,
 		); err != nil {
 			errs.Appendf("error adding status to timeline for list %s: %w", listEntry.ListID, err)
 			// implicit continue
@@ -332,6 +342,7 @@ func (s *Surface) timelineStatus(
 	account *gtsmodel.Account,
 	status *gtsmodel.Status,
 	streamType string,
+	filters []*gtsmodel.Filter,
 ) (bool, error) {
 	// Ingest status into given timeline using provided function.
 	if inserted, err := ingest(ctx, timelineID, status); err != nil {
@@ -343,7 +354,12 @@ func (s *Surface) timelineStatus(
 	}
 
 	// The status was inserted so stream it to the user.
-	apiStatus, err := s.Converter.StatusToAPIStatus(ctx, status, account)
+	apiStatus, err := s.Converter.StatusToAPIStatus(ctx,
+		status,
+		account,
+		statusfilter.FilterContextHome,
+		filters,
+	)
 	if err != nil {
 		err = gtserror.Newf("error converting status %s to frontend representation: %w", status.ID, err)
 		return true, err
@@ -457,6 +473,11 @@ func (s *Surface) timelineStatusUpdateForFollowers(
 			continue
 		}
 
+		filters, err := s.State.DB.GetFiltersForAccountID(ctx, follow.AccountID)
+		if err != nil {
+			return gtserror.Newf("couldn't retrieve filters for account %s: %w", follow.AccountID, err)
+		}
+
 		// Add status to any relevant lists
 		// for this follow, if applicable.
 		s.listTimelineStatusUpdateForFollow(
@@ -464,6 +485,7 @@ func (s *Surface) timelineStatusUpdateForFollowers(
 			status,
 			follow,
 			&errs,
+			filters,
 		)
 
 		// Add status to home timeline for owner
@@ -473,6 +495,7 @@ func (s *Surface) timelineStatusUpdateForFollowers(
 			follow.Account,
 			status,
 			stream.TimelineHome,
+			filters,
 		)
 		if err != nil {
 			errs.Appendf("error home timelining status: %w", err)
@@ -490,6 +513,7 @@ func (s *Surface) listTimelineStatusUpdateForFollow(
 	status *gtsmodel.Status,
 	follow *gtsmodel.Follow,
 	errs *gtserror.MultiError,
+	filters []*gtsmodel.Filter,
 ) {
 	// To put this status in appropriate list timelines,
 	// we need to get each listEntry that pertains to
@@ -530,6 +554,7 @@ func (s *Surface) listTimelineStatusUpdateForFollow(
 			follow.Account,
 			status,
 			stream.TimelineList+":"+listEntry.ListID, // key streamType to this specific list
+			filters,
 		); err != nil {
 			errs.Appendf("error adding status to timeline for list %s: %w", listEntry.ListID, err)
 			// implicit continue
@@ -544,8 +569,13 @@ func (s *Surface) timelineStreamStatusUpdate(
 	account *gtsmodel.Account,
 	status *gtsmodel.Status,
 	streamType string,
+	filters []*gtsmodel.Filter,
 ) error {
-	apiStatus, err := s.Converter.StatusToAPIStatus(ctx, status, account)
+	apiStatus, err := s.Converter.StatusToAPIStatus(ctx, status, account, statusfilter.FilterContextHome, filters)
+	if errors.Is(err, statusfilter.ErrHideStatus) {
+		// Don't put this status in the stream.
+		return nil
+	}
 	if err != nil {
 		err = gtserror.Newf("error converting status %s to frontend representation: %w", status.ID, err)
 		return err

internal/timeline/prepare.go

@@ -24,6 +24,7 @@
 
 	"codeberg.org/gruf/go-kv"
 	"github.com/superseriousbusiness/gotosocial/internal/db"
+	statusfilter "github.com/superseriousbusiness/gotosocial/internal/filter/status"
 	"github.com/superseriousbusiness/gotosocial/internal/gtserror"
 	"github.com/superseriousbusiness/gotosocial/internal/log"
 )
@@ -121,6 +122,12 @@ func (t *timeline) prepareXBetweenIDs(ctx context.Context, amount int, behindID
 	for e, entry := range toPrepare {
 		prepared, err := t.prepareFunction(ctx, t.timelineID, entry.itemID)
 		if err != nil {
+			if errors.Is(err, statusfilter.ErrHideStatus) {
+				// This item has been filtered out by the requesting user's filters.
+				// Remove it and skip past it.
+				t.items.data.Remove(e)
+				continue
+			}
 			if errors.Is(err, db.ErrNoEntries) {
 				// ErrNoEntries means something has been deleted,
 				// so we'll likely not be able to ever prepare this.

internal/typeutils/converter_test.go

@@ -473,16 +473,19 @@
 
 type TypeUtilsTestSuite struct {
 	suite.Suite
-	db              db.DB
-	state           state.State
-	testAccounts    map[string]*gtsmodel.Account
-	testStatuses    map[string]*gtsmodel.Status
-	testAttachments map[string]*gtsmodel.MediaAttachment
-	testPeople      map[string]vocab.ActivityStreamsPerson
-	testEmojis      map[string]*gtsmodel.Emoji
-	testReports     map[string]*gtsmodel.Report
-	testMentions    map[string]*gtsmodel.Mention
-	testPollVotes   map[string]*gtsmodel.PollVote
+	db                 db.DB
+	state              state.State
+	testAccounts       map[string]*gtsmodel.Account
+	testStatuses       map[string]*gtsmodel.Status
+	testAttachments    map[string]*gtsmodel.MediaAttachment
+	testPeople         map[string]vocab.ActivityStreamsPerson
+	testEmojis         map[string]*gtsmodel.Emoji
+	testReports        map[string]*gtsmodel.Report
+	testMentions       map[string]*gtsmodel.Mention
+	testPollVotes      map[string]*gtsmodel.PollVote
+	testFilters        map[string]*gtsmodel.Filter
+	testFilterKeywords map[string]*gtsmodel.FilterKeyword
+	testFilterStatues  map[string]*gtsmodel.FilterStatus
 
 	typeconverter *typeutils.Converter
 }
@@ -506,6 +509,9 @@ func (suite *TypeUtilsTestSuite) SetupTest() {
 	suite.testReports = testrig.NewTestReports()
 	suite.testMentions = testrig.NewTestMentions()
 	suite.testPollVotes = testrig.NewTestPollVotes()
+	suite.testFilters = testrig.NewTestFilters()
+	suite.testFilterKeywords = testrig.NewTestFilterKeywords()
+	suite.testFilterStatues = testrig.NewTestFilterStatuses()
 	suite.typeconverter = typeutils.NewConverter(&suite.state)
 
 	testrig.StandardDBSetup(suite.db, nil)

internal/typeutils/internaltofrontend.go

@@ -22,17 +22,21 @@
 	"errors"
 	"fmt"
 	"math"
+	"regexp"
 	"strconv"
 	"strings"
+	"time"
 
 	apimodel "github.com/superseriousbusiness/gotosocial/internal/api/model"
 	"github.com/superseriousbusiness/gotosocial/internal/config"
 	"github.com/superseriousbusiness/gotosocial/internal/db"
+	statusfilter "github.com/superseriousbusiness/gotosocial/internal/filter/status"
 	"github.com/superseriousbusiness/gotosocial/internal/gtserror"
 	"github.com/superseriousbusiness/gotosocial/internal/gtsmodel"
 	"github.com/superseriousbusiness/gotosocial/internal/language"
 	"github.com/superseriousbusiness/gotosocial/internal/log"
 	"github.com/superseriousbusiness/gotosocial/internal/media"
+	"github.com/superseriousbusiness/gotosocial/internal/text"
 	"github.com/superseriousbusiness/gotosocial/internal/uris"
 	"github.com/superseriousbusiness/gotosocial/internal/util"
 )
@@ -684,12 +688,19 @@ func (c *Converter) TagToAPITag(ctx context.Context, t *gtsmodel.Tag, stubHistor
 // (frontend) representation for serialization on the API.
 //
 // Requesting account can be nil.
+//
+// Filter context can be the empty string if these statuses are not being filtered.
+//
+// If there is a matching "hide" filter, the returned status will be nil with a ErrHideStatus error;
+// callers need to handle that case by excluding it from results.
 func (c *Converter) StatusToAPIStatus(
 	ctx context.Context,
 	s *gtsmodel.Status,
 	requestingAccount *gtsmodel.Account,
+	filterContext statusfilter.FilterContext,
+	filters []*gtsmodel.Filter,
 ) (*apimodel.Status, error) {
-	apiStatus, err := c.statusToFrontend(ctx, s, requestingAccount)
+	apiStatus, err := c.statusToFrontend(ctx, s, requestingAccount, filterContext, filters)
 	if err != nil {
 		return nil, err
 	}
@@ -704,6 +715,142 @@ func (c *Converter) StatusToAPIStatus(
 	return apiStatus, nil
 }
 
+// statusToAPIFilterResults applies filters to a status and returns an API filter result object.
+// The result may be nil if no filters matched.
+// If the status should not be returned at all, it returns the ErrHideStatus error.
+func (c *Converter) statusToAPIFilterResults(
+	ctx context.Context,
+	s *gtsmodel.Status,
+	requestingAccount *gtsmodel.Account,
+	filterContext statusfilter.FilterContext,
+	filters []*gtsmodel.Filter,
+) ([]apimodel.FilterResult, error) {
+	if filterContext == "" || len(filters) == 0 || s.AccountID == requestingAccount.ID {
+		return nil, nil
+	}
+
+	filterResults := make([]apimodel.FilterResult, 0, len(filters))
+
+	now := time.Now()
+	for _, filter := range filters {
+		if !filterAppliesInContext(filter, filterContext) {
+			// Filter doesn't apply to this context.
+			continue
+		}
+		if !filter.ExpiresAt.IsZero() && filter.ExpiresAt.Before(now) {
+			// Filter is expired.
+			continue
+		}
+
+		// List all matching keywords.
+		keywordMatches := make([]string, 0, len(filter.Keywords))
+		fields := filterableTextFields(s)
+		for _, filterKeyword := range filter.Keywords {
+			wholeWord := util.PtrValueOr(filterKeyword.WholeWord, false)
+			wordBreak := ``
+			if wholeWord {
+				wordBreak = `\b`
+			}
+			re, err := regexp.Compile(`(?i)` + wordBreak + regexp.QuoteMeta(filterKeyword.Keyword) + wordBreak)
+			if err != nil {
+				return nil, err
+			}
+			var isMatch bool
+			for _, field := range fields {
+				if re.MatchString(field) {
+					isMatch = true
+					break
+				}
+			}
+			if isMatch {
+				keywordMatches = append(keywordMatches, filterKeyword.Keyword)
+			}
+		}
+
+		// A status has only one ID. Not clear why this is a list in the Mastodon API.
+		statusMatches := make([]string, 0, 1)
+		for _, filterStatus := range filter.Statuses {
+			if s.ID == filterStatus.StatusID {
+				statusMatches = append(statusMatches, filterStatus.StatusID)
+				break
+			}
+		}
+
+		if len(keywordMatches) > 0 || len(statusMatches) > 0 {
+			switch filter.Action {
+			case gtsmodel.FilterActionWarn:
+				// Record what matched.
+				apiFilter, err := c.FilterToAPIFilterV2(ctx, filter)
+				if err != nil {
+					return nil, err
+				}
+				filterResults = append(filterResults, apimodel.FilterResult{
+					Filter:         *apiFilter,
+					KeywordMatches: keywordMatches,
+					StatusMatches:  statusMatches,
+				})
+
+			case gtsmodel.FilterActionHide:
+				// Don't show this status. Immediate return.
+				return nil, statusfilter.ErrHideStatus
+			}
+		}
+	}
+
+	return filterResults, nil
+}
+
+// filterableTextFields returns all text from a status that we might want to filter on:
+// - content
+// - content warning
+// - media descriptions
+// - poll options
+func filterableTextFields(s *gtsmodel.Status) []string {
+	fieldCount := 2 + len(s.Attachments)
+	if s.Poll != nil {
+		fieldCount += len(s.Poll.Options)
+	}
+	fields := make([]string, 0, fieldCount)
+
+	if s.Content != "" {
+		fields = append(fields, text.SanitizeToPlaintext(s.Content))
+	}
+	if s.ContentWarning != "" {
+		fields = append(fields, s.ContentWarning)
+	}
+	for _, attachment := range s.Attachments {
+		if attachment.Description != "" {
+			fields = append(fields, attachment.Description)
+		}
+	}
+	if s.Poll != nil {
+		for _, option := range s.Poll.Options {
+			if option != "" {
+				fields = append(fields, option)
+			}
+		}
+	}
+
+	return fields
+}
+
+// filterAppliesInContext returns whether a given filter applies in a given context.
+func filterAppliesInContext(filter *gtsmodel.Filter, filterContext statusfilter.FilterContext) bool {
+	switch filterContext {
+	case statusfilter.FilterContextHome:
+		return util.PtrValueOr(filter.ContextHome, false)
+	case statusfilter.FilterContextNotifications:
+		return util.PtrValueOr(filter.ContextNotifications, false)
+	case statusfilter.FilterContextPublic:
+		return util.PtrValueOr(filter.ContextPublic, false)
+	case statusfilter.FilterContextThread:
+		return util.PtrValueOr(filter.ContextThread, false)
+	case statusfilter.FilterContextAccount:
+		return util.PtrValueOr(filter.ContextAccount, false)
+	}
+	return false
+}
+
 // StatusToWebStatus converts a gts model status into an
 // api representation suitable for serving into a web template.
 //
@@ -713,7 +860,7 @@ func (c *Converter) StatusToWebStatus(
 	s *gtsmodel.Status,
 	requestingAccount *gtsmodel.Account,
 ) (*apimodel.Status, error) {
-	webStatus, err := c.statusToFrontend(ctx, s, requestingAccount)
+	webStatus, err := c.statusToFrontend(ctx, s, requestingAccount, statusfilter.FilterContextNone, nil)
 	if err != nil {
 		return nil, err
 	}
@@ -815,6 +962,8 @@ func (c *Converter) statusToFrontend(
 	ctx context.Context,
 	s *gtsmodel.Status,
 	requestingAccount *gtsmodel.Account,
+	filterContext statusfilter.FilterContext,
+	filters []*gtsmodel.Filter,
 ) (*apimodel.Status, error) {
 	// Try to populate status struct pointer fields.
 	// We can continue in many cases of partial failure,
@@ -913,7 +1062,11 @@ func (c *Converter) statusToFrontend(
 	}
 
 	if s.BoostOf != nil {
-		reblog, err := c.StatusToAPIStatus(ctx, s.BoostOf, requestingAccount)
+		reblog, err := c.StatusToAPIStatus(ctx, s.BoostOf, requestingAccount, filterContext, filters)
+		if errors.Is(err, statusfilter.ErrHideStatus) {
+			// If we'd hide the original status, hide the boost.
+			return nil, err
+		}
 		if err != nil {
 			return nil, gtserror.Newf("error converting boosted status: %w", err)
 		}
@@ -977,6 +1130,13 @@ func (c *Converter) statusToFrontend(
 		s.URL = s.URI
 	}
 
+	// Apply filters.
+	filterResults, err := c.statusToAPIFilterResults(ctx, s, requestingAccount, filterContext, filters)
+	if err != nil {
+		return nil, fmt.Errorf("error applying filters: %w", err)
+	}
+	apiStatus.Filtered = filterResults
+
 	return apiStatus, nil
 }
 
@@ -1252,7 +1412,7 @@ func (c *Converter) RelationshipToAPIRelationship(ctx context.Context, r *gtsmod
 }
 
 // NotificationToAPINotification converts a gts notification into a api notification
-func (c *Converter) NotificationToAPINotification(ctx context.Context, n *gtsmodel.Notification) (*apimodel.Notification, error) {
+func (c *Converter) NotificationToAPINotification(ctx context.Context, n *gtsmodel.Notification, filters []*gtsmodel.Filter) (*apimodel.Notification, error) {
 	if n.TargetAccount == nil {
 		tAccount, err := c.state.DB.GetAccountByID(ctx, n.TargetAccountID)
 		if err != nil {
@@ -1293,7 +1453,7 @@ func (c *Converter) NotificationToAPINotification(ctx context.Context, n *gtsmod
 		}
 
 		var err error
-		apiStatus, err = c.StatusToAPIStatus(ctx, n.Status, n.TargetAccount)
+		apiStatus, err = c.StatusToAPIStatus(ctx, n.Status, n.TargetAccount, statusfilter.FilterContextNotifications, filters)
 		if err != nil {
 			return nil, fmt.Errorf("NotificationToapi: error converting status to api: %s", err)
 		}
@@ -1446,7 +1606,7 @@ func (c *Converter) ReportToAdminAPIReport(ctx context.Context, r *gtsmodel.Repo
 		}
 	}
 	for _, s := range r.Statuses {
-		status, err := c.StatusToAPIStatus(ctx, s, requestingAccount)
+		status, err := c.StatusToAPIStatus(ctx, s, requestingAccount, statusfilter.FilterContextNone, nil)
 		if err != nil {
 			return nil, fmt.Errorf("ReportToAdminAPIReport: error converting status with id %s to api status: %w", s.ID, err)
 		}
@@ -1687,6 +1847,55 @@ func (c *Converter) FilterKeywordToAPIFilterV1(ctx context.Context, filterKeywor
 	}
 	filter := filterKeyword.Filter
 
+	return &apimodel.FilterV1{
+		// v1 filters have a single keyword each, so we use the filter keyword ID as the v1 filter ID.
+		ID:           filterKeyword.ID,
+		Phrase:       filterKeyword.Keyword,
+		Context:      filterToAPIFilterContexts(filter),
+		WholeWord:    util.PtrValueOr(filterKeyword.WholeWord, false),
+		ExpiresAt:    filterExpiresAtToAPIFilterExpiresAt(filter.ExpiresAt),
+		Irreversible: filter.Action == gtsmodel.FilterActionHide,
+	}, nil
+}
+
+// FilterToAPIFilterV2 converts one GTS model filter into an API v2 filter.
+func (c *Converter) FilterToAPIFilterV2(ctx context.Context, filter *gtsmodel.Filter) (*apimodel.FilterV2, error) {
+	apiFilterKeywords := make([]apimodel.FilterKeyword, 0, len(filter.Keywords))
+	for _, filterKeyword := range filter.Keywords {
+		apiFilterKeywords = append(apiFilterKeywords, apimodel.FilterKeyword{
+			ID:        filterKeyword.ID,
+			Keyword:   filterKeyword.Keyword,
+			WholeWord: util.PtrValueOr(filterKeyword.WholeWord, false),
+		})
+	}
+
+	apiFilterStatuses := make([]apimodel.FilterStatus, 0, len(filter.Keywords))
+	for _, filterStatus := range filter.Statuses {
+		apiFilterStatuses = append(apiFilterStatuses, apimodel.FilterStatus{
+			ID:       filterStatus.ID,
+			StatusID: filterStatus.StatusID,
+		})
+	}
+
+	return &apimodel.FilterV2{
+		ID:           filter.ID,
+		Title:        filter.Title,
+		Context:      filterToAPIFilterContexts(filter),
+		ExpiresAt:    filterExpiresAtToAPIFilterExpiresAt(filter.ExpiresAt),
+		FilterAction: filterActionToAPIFilterAction(filter.Action),
+		Keywords:     apiFilterKeywords,
+		Statuses:     apiFilterStatuses,
+	}, nil
+}
+
+func filterExpiresAtToAPIFilterExpiresAt(expiresAt time.Time) *string {
+	if expiresAt.IsZero() {
+		return nil
+	}
+	return util.Ptr(util.FormatISO8601(expiresAt))
+}
+
+func filterToAPIFilterContexts(filter *gtsmodel.Filter) []apimodel.FilterContext {
 	apiContexts := make([]apimodel.FilterContext, 0, apimodel.FilterContextNumValues)
 	if util.PtrValueOr(filter.ContextHome, false) {
 		apiContexts = append(apiContexts, apimodel.FilterContextHome)
@@ -1703,21 +1912,17 @@ func (c *Converter) FilterKeywordToAPIFilterV1(ctx context.Context, filterKeywor
 	if util.PtrValueOr(filter.ContextAccount, false) {
 		apiContexts = append(apiContexts, apimodel.FilterContextAccount)
 	}
+	return apiContexts
+}
 
-	var expiresAt *string
-	if !filter.ExpiresAt.IsZero() {
-		expiresAt = util.Ptr(util.FormatISO8601(filter.ExpiresAt))
+func filterActionToAPIFilterAction(m gtsmodel.FilterAction) apimodel.FilterAction {
+	switch m {
+	case gtsmodel.FilterActionWarn:
+		return apimodel.FilterActionWarn
+	case gtsmodel.FilterActionHide:
+		return apimodel.FilterActionHide
 	}
-
-	return &apimodel.FilterV1{
-		// v1 filters have a single keyword each, so we use the filter keyword ID as the v1 filter ID.
-		ID:           filterKeyword.ID,
-		Phrase:       filterKeyword.Keyword,
-		Context:      apiContexts,
-		WholeWord:    util.PtrValueOr(filterKeyword.WholeWord, false),
-		ExpiresAt:    expiresAt,
-		Irreversible: filter.Action == gtsmodel.FilterActionHide,
-	}, nil
+	return apimodel.FilterActionNone
 }
 
 // convertEmojisToAPIEmojis will convert a slice of GTS model emojis to frontend API model emojis, falling back to IDs if no GTS models supplied.

internal/typeutils/internaltofrontend_test.go

@@ -25,6 +25,7 @@
 	"github.com/stretchr/testify/suite"
 	"github.com/superseriousbusiness/gotosocial/internal/config"
 	"github.com/superseriousbusiness/gotosocial/internal/db"
+	statusfilter "github.com/superseriousbusiness/gotosocial/internal/filter/status"
 	"github.com/superseriousbusiness/gotosocial/internal/gtsmodel"
 	"github.com/superseriousbusiness/gotosocial/testrig"
 )
@@ -427,7 +428,7 @@ func (suite *InternalToFrontendTestSuite) TestLocalInstanceAccountToFrontendBloc
 func (suite *InternalToFrontendTestSuite) TestStatusToFrontend() {
 	testStatus := suite.testStatuses["admin_account_status_1"]
 	requestingAccount := suite.testAccounts["local_account_1"]
-	apiStatus, err := suite.typeconverter.StatusToAPIStatus(context.Background(), testStatus, requestingAccount)
+	apiStatus, err := suite.typeconverter.StatusToAPIStatus(context.Background(), testStatus, requestingAccount, statusfilter.FilterContextNone, nil)
 	suite.NoError(err)
 
 	b, err := json.MarshalIndent(apiStatus, "", "  ")
@@ -537,11 +538,186 @@ func (suite *InternalToFrontendTestSuite) TestStatusToFrontend() {
 }`, string(b))
 }
 
+// Test that a status which is filtered with a warn filter by the requesting user has `filtered` set correctly.
+func (suite *InternalToFrontendTestSuite) TestWarnFilteredStatusToFrontend() {
+	testStatus := suite.testStatuses["admin_account_status_1"]
+	testStatus.Content += " fnord"
+	testStatus.Text += " fnord"
+	requestingAccount := suite.testAccounts["local_account_1"]
+	expectedMatchingFilter := suite.testFilters["local_account_1_filter_1"]
+	expectedMatchingFilterKeyword := suite.testFilterKeywords["local_account_1_filter_1_keyword_1"]
+	expectedMatchingFilterKeyword.Filter = expectedMatchingFilter
+	expectedMatchingFilter.Keywords = []*gtsmodel.FilterKeyword{expectedMatchingFilterKeyword}
+	requestingAccountFilters := []*gtsmodel.Filter{expectedMatchingFilter}
+	apiStatus, err := suite.typeconverter.StatusToAPIStatus(
+		context.Background(),
+		testStatus,
+		requestingAccount,
+		statusfilter.FilterContextHome,
+		requestingAccountFilters,
+	)
+	suite.NoError(err)
+
+	b, err := json.MarshalIndent(apiStatus, "", "  ")
+	suite.NoError(err)
+
+	suite.Equal(`{
+  "id": "01F8MH75CBF9JFX4ZAD54N0W0R",
+  "created_at": "2021-10-20T11:36:45.000Z",
+  "in_reply_to_id": null,
+  "in_reply_to_account_id": null,
+  "sensitive": false,
+  "spoiler_text": "",
+  "visibility": "public",
+  "language": "en",
+  "uri": "http://localhost:8080/users/admin/statuses/01F8MH75CBF9JFX4ZAD54N0W0R",
+  "url": "http://localhost:8080/@admin/statuses/01F8MH75CBF9JFX4ZAD54N0W0R",
+  "replies_count": 1,
+  "reblogs_count": 0,
+  "favourites_count": 1,
+  "favourited": true,
+  "reblogged": false,
+  "muted": false,
+  "bookmarked": true,
+  "pinned": false,
+  "content": "hello world! #welcome ! first post on the instance :rainbow: ! fnord",
+  "reblog": null,
+  "application": {
+    "name": "superseriousbusiness",
+    "website": "https://superserious.business"
+  },
+  "account": {
+    "id": "01F8MH17FWEB39HZJ76B6VXSKF",
+    "username": "admin",
+    "acct": "admin",
+    "display_name": "",
+    "locked": false,
+    "discoverable": true,
+    "bot": false,
+    "created_at": "2022-05-17T13:10:59.000Z",
+    "note": "",
+    "url": "http://localhost:8080/@admin",
+    "avatar": "",
+    "avatar_static": "",
+    "header": "http://localhost:8080/assets/default_header.png",
+    "header_static": "http://localhost:8080/assets/default_header.png",
+    "followers_count": 1,
+    "following_count": 1,
+    "statuses_count": 4,
+    "last_status_at": "2021-10-20T10:41:37.000Z",
+    "emojis": [],
+    "fields": [],
+    "enable_rss": true,
+    "role": {
+      "name": "admin"
+    }
+  },
+  "media_attachments": [
+    {
+      "id": "01F8MH6NEM8D7527KZAECTCR76",
+      "type": "image",
+      "url": "http://localhost:8080/fileserver/01F8MH17FWEB39HZJ76B6VXSKF/attachment/original/01F8MH6NEM8D7527KZAECTCR76.jpg",
+      "text_url": "http://localhost:8080/fileserver/01F8MH17FWEB39HZJ76B6VXSKF/attachment/original/01F8MH6NEM8D7527KZAECTCR76.jpg",
+      "preview_url": "http://localhost:8080/fileserver/01F8MH17FWEB39HZJ76B6VXSKF/attachment/small/01F8MH6NEM8D7527KZAECTCR76.jpg",
+      "remote_url": null,
+      "preview_remote_url": null,
+      "meta": {
+        "original": {
+          "width": 1200,
+          "height": 630,
+          "size": "1200x630",
+          "aspect": 1.9047619
+        },
+        "small": {
+          "width": 256,
+          "height": 134,
+          "size": "256x134",
+          "aspect": 1.9104477
+        },
+        "focus": {
+          "x": 0,
+          "y": 0
+        }
+      },
+      "description": "Black and white image of some 50's style text saying: Welcome On Board",
+      "blurhash": "LNJRdVM{00Rj%Mayt7j[4nWBofRj"
+    }
+  ],
+  "mentions": [],
+  "tags": [
+    {
+      "name": "welcome",
+      "url": "http://localhost:8080/tags/welcome"
+    }
+  ],
+  "emojis": [
+    {
+      "shortcode": "rainbow",
+      "url": "http://localhost:8080/fileserver/01AY6P665V14JJR0AFVRT7311Y/emoji/original/01F8MH9H8E4VG3KDYJR9EGPXCQ.png",
+      "static_url": "http://localhost:8080/fileserver/01AY6P665V14JJR0AFVRT7311Y/emoji/static/01F8MH9H8E4VG3KDYJR9EGPXCQ.png",
+      "visible_in_picker": true,
+      "category": "reactions"
+    }
+  ],
+  "card": null,
+  "poll": null,
+  "text": "hello world! #welcome ! first post on the instance :rainbow: ! fnord",
+  "filtered": [
+    {
+      "filter": {
+        "id": "01HN26VM6KZTW1ANNRVSBMA461",
+        "title": "fnord",
+        "context": [
+          "home",
+          "public"
+        ],
+        "expires_at": null,
+        "filter_action": "warn",
+        "keywords": [
+          {
+            "id": "01HN272TAVWAXX72ZX4M8JZ0PS",
+            "keyword": "fnord",
+            "whole_word": true
+          }
+        ],
+        "statuses": []
+      },
+      "keyword_matches": [
+        "fnord"
+      ],
+      "status_matches": []
+    }
+  ]
+}`, string(b))
+}
+
+// Test that a status which is filtered with a hide filter by the requesting user results in the ErrHideStatus error.
+func (suite *InternalToFrontendTestSuite) TestHideFilteredStatusToFrontend() {
+	testStatus := suite.testStatuses["admin_account_status_1"]
+	testStatus.Content += " fnord"
+	testStatus.Text += " fnord"
+	requestingAccount := suite.testAccounts["local_account_1"]
+	expectedMatchingFilter := suite.testFilters["local_account_1_filter_1"]
+	expectedMatchingFilter.Action = gtsmodel.FilterActionHide
+	expectedMatchingFilterKeyword := suite.testFilterKeywords["local_account_1_filter_1_keyword_1"]
+	expectedMatchingFilterKeyword.Filter = expectedMatchingFilter
+	expectedMatchingFilter.Keywords = []*gtsmodel.FilterKeyword{expectedMatchingFilterKeyword}
+	requestingAccountFilters := []*gtsmodel.Filter{expectedMatchingFilter}
+	_, err := suite.typeconverter.StatusToAPIStatus(
+		context.Background(),
+		testStatus,
+		requestingAccount,
+		statusfilter.FilterContextHome,
+		requestingAccountFilters,
+	)
+	suite.ErrorIs(err, statusfilter.ErrHideStatus)
+}
+
 func (suite *InternalToFrontendTestSuite) TestStatusToFrontendUnknownAttachments() {
 	testStatus := suite.testStatuses["remote_account_2_status_1"]
 	requestingAccount := suite.testAccounts["admin_account"]
 
-	apiStatus, err := suite.typeconverter.StatusToAPIStatus(context.Background(), testStatus, requestingAccount)
+	apiStatus, err := suite.typeconverter.StatusToAPIStatus(context.Background(), testStatus, requestingAccount, statusfilter.FilterContextNone, nil)
 	suite.NoError(err)
 
 	b, err := json.MarshalIndent(apiStatus, "", "  ")
@@ -774,7 +950,7 @@ func (suite *InternalToFrontendTestSuite) TestStatusToFrontendUnknownLanguage()
 	*testStatus = *suite.testStatuses["admin_account_status_1"]
 	testStatus.Language = ""
 	requestingAccount := suite.testAccounts["local_account_1"]
-	apiStatus, err := suite.typeconverter.StatusToAPIStatus(context.Background(), testStatus, requestingAccount)
+	apiStatus, err := suite.typeconverter.StatusToAPIStatus(context.Background(), testStatus, requestingAccount, statusfilter.FilterContextNone, nil)
 	suite.NoError(err)
 
 	b, err := json.MarshalIndent(apiStatus, "", "  ")