[bugfix] Fix HTML escaping in instance title (#607)

* move caption sanitization -> sanitize.go

* use sanitizeplaintext rather than removehtml

* rename sanitizecaption to sanitizeplaintext

* avoid removing html twice from statuses

* unexport remoteHTML
it's no longer used outside the text package so this
makes it less confusing

* test instance PATCH

internal/api/client/instance/instancepatch_test.go

@@ -0,0 +1,130 @@
+/*
+   GoToSocial
+   Copyright (C) 2021-2022 GoToSocial Authors admin@gotosocial.org
+
+   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_test
+
+import (
+	"io"
+	"net/http"
+	"net/http/httptest"
+	"testing"
+
+	"github.com/stretchr/testify/suite"
+	"github.com/superseriousbusiness/gotosocial/internal/api/client/instance"
+	"github.com/superseriousbusiness/gotosocial/testrig"
+)
+
+type InstancePatchTestSuite struct {
+	InstanceStandardTestSuite
+}
+
+func (suite *InstancePatchTestSuite) TestInstancePatch1() {
+	requestBody, w, err := testrig.CreateMultipartFormData(
+		"", "",
+		map[string]string{
+			"title":            "Example Instance",
+			"contact_username": "admin",
+			"contact_email":    "someone@example.org",
+		})
+	if err != nil {
+		panic(err)
+	}
+	bodyBytes := requestBody.Bytes()
+
+	// set up the request
+	recorder := httptest.NewRecorder()
+	ctx := suite.newContext(recorder, http.MethodPatch, bodyBytes, instance.InstanceInformationPath, w.FormDataContentType())
+
+	// call the handler
+	suite.instanceModule.InstanceUpdatePATCHHandler(ctx)
+
+	// we should have OK because our request was valid
+	suite.Equal(http.StatusOK, recorder.Code)
+
+	result := recorder.Result()
+	defer result.Body.Close()
+
+	b, err := io.ReadAll(result.Body)
+	suite.NoError(err)
+
+	suite.Equal(`{"uri":"http://localhost:8080","title":"Example Instance","description":"","short_description":"","email":"someone@example.org","version":"","registrations":true,"approval_required":true,"invites_enabled":false,"urls":{"streaming_api":"wss://localhost:8080"},"stats":{"domain_count":0,"status_count":16,"user_count":4},"thumbnail":"","contact_account":{"id":"01F8MH17FWEB39HZJ76B6VXSKF","username":"admin","acct":"admin","display_name":"","locked":false,"bot":false,"created_at":"2022-05-17T13:10:59Z","note":"","url":"http://localhost:8080/@admin","avatar":"","avatar_static":"","header":"","header_static":"","followers_count":1,"following_count":1,"statuses_count":4,"last_status_at":"2021-10-20T10:41:37Z","emojis":[],"fields":[]},"max_toot_chars":5000}`, string(b))
+}
+
+func (suite *InstancePatchTestSuite) TestInstancePatch2() {
+	requestBody, w, err := testrig.CreateMultipartFormData(
+		"", "",
+		map[string]string{
+			"title": "<p>Geoff's Instance</p>",
+		})
+	if err != nil {
+		panic(err)
+	}
+	bodyBytes := requestBody.Bytes()
+
+	// set up the request
+	recorder := httptest.NewRecorder()
+	ctx := suite.newContext(recorder, http.MethodPatch, bodyBytes, instance.InstanceInformationPath, w.FormDataContentType())
+
+	// call the handler
+	suite.instanceModule.InstanceUpdatePATCHHandler(ctx)
+
+	// we should have OK because our request was valid
+	suite.Equal(http.StatusOK, recorder.Code)
+
+	result := recorder.Result()
+	defer result.Body.Close()
+
+	b, err := io.ReadAll(result.Body)
+	suite.NoError(err)
+
+	suite.Equal(`{"uri":"http://localhost:8080","title":"Geoff's Instance","description":"","short_description":"","email":"","version":"","registrations":true,"approval_required":true,"invites_enabled":false,"urls":{"streaming_api":"wss://localhost:8080"},"stats":{"domain_count":0,"status_count":16,"user_count":4},"thumbnail":"","max_toot_chars":5000}`, string(b))
+}
+
+func (suite *InstancePatchTestSuite) TestInstancePatch3() {
+	requestBody, w, err := testrig.CreateMultipartFormData(
+		"", "",
+		map[string]string{
+			"short_description": "<p>This is some html, which is <em>allowed</em> in short descriptions.</p>",
+		})
+	if err != nil {
+		panic(err)
+	}
+	bodyBytes := requestBody.Bytes()
+
+	// set up the request
+	recorder := httptest.NewRecorder()
+	ctx := suite.newContext(recorder, http.MethodPatch, bodyBytes, instance.InstanceInformationPath, w.FormDataContentType())
+
+	// call the handler
+	suite.instanceModule.InstanceUpdatePATCHHandler(ctx)
+
+	// we should have OK because our request was valid
+	suite.Equal(http.StatusOK, recorder.Code)
+
+	result := recorder.Result()
+	defer result.Body.Close()
+
+	b, err := io.ReadAll(result.Body)
+	suite.NoError(err)
+
+	suite.Equal(`{"uri":"http://localhost:8080","title":"localhost:8080","description":"","short_description":"\u003cp\u003eThis is some html, which is \u003cem\u003eallowed\u003c/em\u003e in short descriptions.\u003c/p\u003e","email":"","version":"","registrations":true,"approval_required":true,"invites_enabled":false,"urls":{"streaming_api":"wss://localhost:8080"},"stats":{"domain_count":0,"status_count":16,"user_count":4},"thumbnail":"","max_toot_chars":5000}`, string(b))
+}
+
+func TestInstancePatchTestSuite(t *testing.T) {
+	suite.Run(t, &InstancePatchTestSuite{})
+}