[feature] Allow exposing allows, implement `/api/v1/domain_blocks` and `/api/v1/domain_allows` (#4169)

- adds config flags `instance-expose-allowlist` and `instance-expose-allowlist-web` to allow instance admins to expose their allowlist via the web + api.
- renames `instance-expose-suspended` and `instance-expose-suspended-web` to  `instance-expose-blocklist` and `instance-expose-blocklist-web`.
- deprecates the `suspended` filter on `/api/v1/instance/peers` endpoint and adds `blocked` and `allowed` filters
- adds the `flat` query param to `/api/v1/instance/peers` to allow forcing return of a flat list of domains
- implements `/api/v1/instance/domain_blocks` and `/api/v1/instance/domain_allows` endpoints with or without auth depending on config
- rejigs the instance about page to include a general section on domain permissions, with block and allow subsections (and appropriate links)

Closes https://codeberg.org/superseriousbusiness/gotosocial/issues/3847
Closes https://codeberg.org/superseriousbusiness/gotosocial/issues/4150

Prerequisite to https://codeberg.org/superseriousbusiness/gotosocial/issues/3711

Reviewed-on: https://codeberg.org/superseriousbusiness/gotosocial/pulls/4169
Co-authored-by: tobi <tobi.smethurst@protonmail.com>
Co-committed-by: tobi <tobi.smethurst@protonmail.com>

1 files changed, 172 insertions, 0 deletions

diff --git a/internal/api/client/instance/domainperms.go b/internal/api/client/instance/domainperms.go
new file mode 100644
index 000000000..6503388a5
--- /dev/null
+++ b/internal/api/client/instance/domainperms.go
@@ -0,0 +1,172 @@
+// 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 instance
+
+import (
+	"errors"
+	"net/http"
+
+	apiutil "code.superseriousbusiness.org/gotosocial/internal/api/util"
+	"code.superseriousbusiness.org/gotosocial/internal/config"
+	"code.superseriousbusiness.org/gotosocial/internal/gtserror"
+	"github.com/gin-gonic/gin"
+)
+
+// InstanceDomainBlocksGETHandler swagger:operation GET /api/v1/instance/domain_blocks instanceDomainBlocksGet
+//
+// List blocked domains.
+//
+// OAuth token may need to be provided depending on setting `instance-expose-blocklist`.
+//
+//	---
+//	tags:
+//	- instance
+//
+//	produces:
+//	- application/json
+//
+//	security:
+//	- OAuth2 Bearer: []
+//
+//	responses:
+//		'200':
+//			description: List of blocked domains.
+//			schema:
+//				type: array
+//				items:
+//					"$ref": "#/definitions/domain"
+//		'400':
+//			description: bad request
+//		'401':
+//			description: unauthorized
+//		'403':
+//			description: forbidden
+//		'404':
+//			description: not found
+//		'406':
+//			description: not acceptable
+//		'500':
+//			description: internal server error
+func (m *Module) InstanceDomainBlocksGETHandler(c *gin.Context) {
+	authed, errWithCode := apiutil.TokenAuth(c,
+		false, false, false, false,
+	)
+	if errWithCode != nil {
+		apiutil.ErrorHandler(c, errWithCode, m.processor.InstanceGetV1)
+		return
+	}
+
+	if _, err := apiutil.NegotiateAccept(c, apiutil.JSONAcceptHeaders...); err != nil {
+		apiutil.ErrorHandler(c, gtserror.NewErrorNotAcceptable(err, err.Error()), m.processor.InstanceGetV1)
+		return
+	}
+
+	if (authed.Account == nil || authed.User == nil) && !config.GetInstanceExposeBlocklist() {
+		const errText = "domain blocks endpoint requires an authenticated account/user"
+		errWithCode := gtserror.NewErrorUnauthorized(errors.New(errText), errText)
+		apiutil.ErrorHandler(c, errWithCode, m.processor.InstanceGetV1)
+		return
+	}
+
+	data, errWithCode := m.processor.InstancePeersGet(
+		c.Request.Context(),
+		true,  // Include blocked.
+		false, // Don't include allowed.
+		false, // Don't include open.
+		false, // Don't flatten.
+		true,  // Include severity.
+	)
+	if errWithCode != nil {
+		apiutil.ErrorHandler(c, errWithCode, m.processor.InstanceGetV1)
+		return
+	}
+
+	apiutil.JSON(c, http.StatusOK, data)
+}
+
+// InstanceDomainAllowsGETHandler swagger:operation GET /api/v1/instance/domain_allows instanceDomainAllowsGet
+//
+// List explicitly allowed domains.
+//
+// OAuth token may need to be provided depending on setting `instance-expose-allowlist`.
+//
+//	---
+//	tags:
+//	- instance
+//
+//	produces:
+//	- application/json
+//
+//	security:
+//	- OAuth2 Bearer: []
+//
+//	responses:
+//		'200':
+//			description: List of explicitly allowed domains.
+//			schema:
+//				type: array
+//				items:
+//					"$ref": "#/definitions/domain"
+//		'400':
+//			description: bad request
+//		'401':
+//			description: unauthorized
+//		'403':
+//			description: forbidden
+//		'404':
+//			description: not found
+//		'406':
+//			description: not acceptable
+//		'500':
+//			description: internal server error
+func (m *Module) InstanceDomainAllowsGETHandler(c *gin.Context) {
+	authed, errWithCode := apiutil.TokenAuth(c,
+		false, false, false, false,
+	)
+	if errWithCode != nil {
+		apiutil.ErrorHandler(c, errWithCode, m.processor.InstanceGetV1)
+		return
+	}
+
+	if _, err := apiutil.NegotiateAccept(c, apiutil.JSONAcceptHeaders...); err != nil {
+		apiutil.ErrorHandler(c, gtserror.NewErrorNotAcceptable(err, err.Error()), m.processor.InstanceGetV1)
+		return
+	}
+
+	if (authed.Account == nil || authed.User == nil) && !config.GetInstanceExposeAllowlist() {
+		const errText = "domain allows endpoint requires an authenticated account/user"
+		errWithCode := gtserror.NewErrorUnauthorized(errors.New(errText), errText)
+		apiutil.ErrorHandler(c, errWithCode, m.processor.InstanceGetV1)
+		return
+	}
+
+	data, errWithCode := m.processor.InstancePeersGet(
+		c.Request.Context(),
+		false, // Don't include blocked.
+		true,  // Include allowed.
+		false, // Don't include open.
+		false, // Don't flatten.
+		false, // Don't include severity.
+	)
+	if errWithCode != nil {
+		apiutil.ErrorHandler(c, errWithCode, m.processor.InstanceGetV1)
+		return
+	}
+
+	apiutil.JSON(c, http.StatusOK, data)
+}