[feature] Federate local account deletion (#431)

* add account delete to API

* model account delete request

* add AccountDeleteLocal

* federate local account deletes

* add DeleteLocal

* update transport (controller) to allow shortcuts

* delete logic + testing

* update swagger docs

* more tests + fixes

6 files changed, 293 insertions, 9 deletions

diff --git a/internal/api/client/account/account.go b/internal/api/client/account/account.go
index c72e9fb5d..c38a8cfb4 100644
--- a/internal/api/client/account/account.go
+++ b/internal/api/client/account/account.go
@@ -71,6 +71,8 @@ const (
 	BlockPath = BasePathWithID + "/block"
 	// UnblockPath is for removing a block of an account
 	UnblockPath = BasePathWithID + "/unblock"
+	// DeleteAccountPath is for deleting one's account via the API
+	DeleteAccountPath = BasePath + "/delete"
 )
 
 // Module implements the ClientAPIModule interface for account-related actions
@@ -90,6 +92,9 @@ func (m *Module) Route(r router.Router) error {
 	// create account
 	r.AttachHandler(http.MethodPost, BasePath, m.AccountCreatePOSTHandler)
 
+	// delete account
+	r.AttachHandler(http.MethodPost, DeleteAccountPath, m.AccountDeletePOSTHandler)
+
 	// get account
 	r.AttachHandler(http.MethodGet, BasePathWithID, m.muxHandler)
 
diff --git a/internal/api/client/account/account_test.go b/internal/api/client/account/account_test.go
index 01c8c9599..e214f7f03 100644
--- a/internal/api/client/account/account_test.go
+++ b/internal/api/client/account/account_test.go
@@ -19,7 +19,6 @@ import (
 	"github.com/superseriousbusiness/gotosocial/internal/media"
 	"github.com/superseriousbusiness/gotosocial/internal/oauth"
 	"github.com/superseriousbusiness/gotosocial/internal/processing"
-	"github.com/superseriousbusiness/gotosocial/internal/typeutils"
 	"github.com/superseriousbusiness/gotosocial/testrig"
 )
 
@@ -27,7 +26,6 @@ type AccountStandardTestSuite struct {
 	// standard suite interfaces
 	suite.Suite
 	db           db.DB
-	tc           typeutils.TypeConverter
 	storage      *kv.KVStore
 	mediaManager media.Manager
 	federator    federation.Federator
diff --git a/internal/api/client/account/accountdelete.go b/internal/api/client/account/accountdelete.go
new file mode 100644
index 000000000..2aae2afa0
--- /dev/null
+++ b/internal/api/client/account/accountdelete.go
@@ -0,0 +1,90 @@
+/*
+   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 account
+
+import (
+	"net/http"
+
+	"github.com/sirupsen/logrus"
+
+	"github.com/gin-gonic/gin"
+	"github.com/superseriousbusiness/gotosocial/internal/api/model"
+	"github.com/superseriousbusiness/gotosocial/internal/oauth"
+)
+
+// AccountDeletePOSTHandler swagger:operation POST /api/v1/accounts/delete accountDelete
+//
+// Delete your account.
+//
+// ---
+// tags:
+// - accounts
+//
+// consumes:
+// - multipart/form-data
+//
+// parameters:
+// - name: password
+//   in: formData
+//   description: Password of the account user, for confirmation.
+//   type: string
+//   required: true
+//
+// security:
+// - OAuth2 Bearer:
+//   - write:accounts
+//
+// responses:
+//   '202':
+//     description: "The account deletion has been accepted and the account will be deleted."
+//   '400':
+//      description: bad request
+//   '401':
+//      description: unauthorized
+func (m *Module) AccountDeletePOSTHandler(c *gin.Context) {
+	l := logrus.WithField("func", "AccountDeletePOSTHandler")
+	authed, err := oauth.Authed(c, true, true, true, true)
+	if err != nil {
+		l.Debugf("couldn't auth: %s", err)
+		c.JSON(http.StatusUnauthorized, gin.H{"error": err.Error()})
+		return
+	}
+	l.Tracef("retrieved account %+v", authed.Account.ID)
+
+	form := &model.AccountDeleteRequest{}
+	if err := c.ShouldBind(&form); err != nil {
+		c.JSON(http.StatusBadRequest, gin.H{"error": err.Error()})
+		return
+	}
+
+	if form.Password == "" {
+		c.JSON(http.StatusBadRequest, gin.H{"error": "no password provided in account delete request"})
+		return
+	}
+
+	form.DeleteOriginID = authed.Account.ID
+
+	if errWithCode := m.processor.AccountDeleteLocal(c.Request.Context(), authed, form); errWithCode != nil {
+		l.Debugf("could not delete account: %s", errWithCode.Error())
+		c.JSON(errWithCode.Code(), gin.H{"error": errWithCode.Safe()})
+		return
+	}
+
+	c.JSON(http.StatusAccepted, gin.H{"message": "accepted"})
+}
diff --git a/internal/api/client/account/accountdelete_test.go b/internal/api/client/account/accountdelete_test.go
new file mode 100644
index 000000000..78348eabc
--- /dev/null
+++ b/internal/api/client/account/accountdelete_test.go
@@ -0,0 +1,101 @@
+/*
+   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 account_test
+
+import (
+	"net/http"
+	"net/http/httptest"
+	"testing"
+
+	"github.com/stretchr/testify/suite"
+	"github.com/superseriousbusiness/gotosocial/internal/api/client/account"
+	"github.com/superseriousbusiness/gotosocial/testrig"
+)
+
+type AccountDeleteTestSuite struct {
+	AccountStandardTestSuite
+}
+
+func (suite *AccountDeleteTestSuite) TestAccountDeletePOSTHandler() {
+	// set up the request
+	// we're deleting zork
+	requestBody, w, err := testrig.CreateMultipartFormData(
+		"", "",
+		map[string]string{
+			"password": "password",
+		})
+	if err != nil {
+		panic(err)
+	}
+	bodyBytes := requestBody.Bytes()
+	recorder := httptest.NewRecorder()
+	ctx := suite.newContext(recorder, http.MethodPost, bodyBytes, account.DeleteAccountPath, w.FormDataContentType())
+
+	// call the handler
+	suite.accountModule.AccountDeletePOSTHandler(ctx)
+
+	// 1. we should have Accepted because our request was valid
+	suite.Equal(http.StatusAccepted, recorder.Code)
+}
+
+func (suite *AccountDeleteTestSuite) TestAccountDeletePOSTHandlerWrongPassword() {
+	// set up the request
+	// we're deleting zork
+	requestBody, w, err := testrig.CreateMultipartFormData(
+		"", "",
+		map[string]string{
+			"password": "aaaaaaaaaaaaaaaaaaaaaaaaaaaa",
+		})
+	if err != nil {
+		panic(err)
+	}
+	bodyBytes := requestBody.Bytes()
+	recorder := httptest.NewRecorder()
+	ctx := suite.newContext(recorder, http.MethodPost, bodyBytes, account.DeleteAccountPath, w.FormDataContentType())
+
+	// call the handler
+	suite.accountModule.AccountDeletePOSTHandler(ctx)
+
+	// 1. we should have Forbidden because we supplied the wrong password
+	suite.Equal(http.StatusForbidden, recorder.Code)
+}
+
+func (suite *AccountDeleteTestSuite) TestAccountDeletePOSTHandlerNoPassword() {
+	// set up the request
+	// we're deleting zork
+	requestBody, w, err := testrig.CreateMultipartFormData(
+		"", "",
+		map[string]string{})
+	if err != nil {
+		panic(err)
+	}
+	bodyBytes := requestBody.Bytes()
+	recorder := httptest.NewRecorder()
+	ctx := suite.newContext(recorder, http.MethodPost, bodyBytes, account.DeleteAccountPath, w.FormDataContentType())
+
+	// call the handler
+	suite.accountModule.AccountDeletePOSTHandler(ctx)
+
+	// 1. we should have StatusBadRequest because our request was invalid
+	suite.Equal(http.StatusBadRequest, recorder.Code)
+}
+
+func TestAccountDeleteTestSuite(t *testing.T) {
+	suite.Run(t, new(AccountDeleteTestSuite))
+}
diff --git a/internal/api/model/account.go b/internal/api/model/account.go
index 712640367..4ff229589 100644
--- a/internal/api/model/account.go
+++ b/internal/api/model/account.go
@@ -187,3 +187,14 @@ type AccountFollowRequest struct {
 	// Notify when this account posts.
 	Notify *bool `form:"notify" json:"notify" xml:"notify"`
 }
+
+// AccountDeleteRequest models a request to delete an account.
+//
+// swagger:ignore
+type AccountDeleteRequest struct {
+	// Password of the account's user, for confirmation.
+	Password string `form:"password" json:"password" xml:"password"`
+	// The origin of the delete account request.
+	// Can be the ID of the account owner, or the ID of an admin account.
+	DeleteOriginID string `form:"-" json:"-" xml:"-"`
+}
diff --git a/internal/api/s2s/user/userget_test.go b/internal/api/s2s/user/userget_test.go
index a764f6993..a2e1b0806 100644
--- a/internal/api/s2s/user/userget_test.go
+++ b/internal/api/s2s/user/userget_test.go
@@ -25,13 +25,15 @@ import (
 	"net/http"
 	"net/http/httptest"
 	"testing"
+	"time"
 
 	"github.com/gin-gonic/gin"
-	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/suite"
 	"github.com/superseriousbusiness/activity/streams"
 	"github.com/superseriousbusiness/activity/streams/vocab"
+	apimodel "github.com/superseriousbusiness/gotosocial/internal/api/model"
 	"github.com/superseriousbusiness/gotosocial/internal/api/s2s/user"
+	"github.com/superseriousbusiness/gotosocial/internal/oauth"
 	"github.com/superseriousbusiness/gotosocial/testrig"
 )
 
@@ -80,24 +82,101 @@ func (suite *UserGetTestSuite) TestGetUser() {
 	result := recorder.Result()
 	defer result.Body.Close()
 	b, err := ioutil.ReadAll(result.Body)
-	assert.NoError(suite.T(), err)
+	suite.NoError(err)
 
 	// should be a Person
 	m := make(map[string]interface{})
 	err = json.Unmarshal(b, &m)
-	assert.NoError(suite.T(), err)
+	suite.NoError(err)
 
 	t, err := streams.ToType(context.Background(), m)
-	assert.NoError(suite.T(), err)
+	suite.NoError(err)
 
 	person, ok := t.(vocab.ActivityStreamsPerson)
-	assert.True(suite.T(), ok)
+	suite.True(ok)
 
 	// convert person to account
 	// since this account is already known, we should get a pretty full model of it from the conversion
 	a, err := suite.tc.ASRepresentationToAccount(context.Background(), person, false)
-	assert.NoError(suite.T(), err)
-	assert.EqualValues(suite.T(), targetAccount.Username, a.Username)
+	suite.NoError(err)
+	suite.EqualValues(targetAccount.Username, a.Username)
+}
+
+// TestGetUserPublicKeyDeleted checks whether the public key of a deleted account can still be dereferenced.
+// This is needed by remote instances for authenticating delete requests and stuff like that.
+func (suite *UserGetTestSuite) TestGetUserPublicKeyDeleted() {
+	targetAccount := suite.testAccounts["local_account_1"]
+
+	// first delete the account, as though zork had deleted himself
+	authed := &oauth.Auth{
+		Application: suite.testApplications["local_account_1"],
+		User:        suite.testUsers["local_account_1"],
+		Account:     suite.testAccounts["local_account_1"],
+	}
+	suite.processor.AccountDeleteLocal(context.Background(), authed, &apimodel.AccountDeleteRequest{
+		Password:       "password",
+		DeleteOriginID: targetAccount.ID,
+	})
+
+	// now wait just a sec for it to go through....
+	time.Sleep(1 * time.Second)
+
+	// the dereference we're gonna use
+	derefRequests := testrig.NewTestDereferenceRequests(suite.testAccounts)
+	signedRequest := derefRequests["foss_satan_dereference_zork_public_key"]
+
+	tc := testrig.NewTestTransportController(testrig.NewMockHTTPClient(nil), suite.db)
+	federator := testrig.NewTestFederator(suite.db, tc, suite.storage, suite.mediaManager)
+	emailSender := testrig.NewEmailSender("../../../../web/template/", nil)
+	processor := testrig.NewTestProcessor(suite.db, suite.storage, federator, emailSender, suite.mediaManager)
+	userModule := user.New(processor).(*user.Module)
+
+	// setup request
+	recorder := httptest.NewRecorder()
+	ctx, _ := gin.CreateTestContext(recorder)
+	ctx.Request = httptest.NewRequest(http.MethodGet, targetAccount.PublicKeyURI, nil) // the endpoint we're hitting
+	ctx.Request.Header.Set("accept", "application/activity+json")
+	ctx.Request.Header.Set("Signature", signedRequest.SignatureHeader)
+	ctx.Request.Header.Set("Date", signedRequest.DateHeader)
+
+	// we need to pass the context through signature check first to set appropriate values on it
+	suite.securityModule.SignatureCheck(ctx)
+
+	// normally the router would populate these params from the path values,
+	// but because we're calling the function directly, we need to set them manually.
+	ctx.Params = gin.Params{
+		gin.Param{
+			Key:   user.UsernameKey,
+			Value: targetAccount.Username,
+		},
+	}
+
+	// trigger the function being tested
+	userModule.UsersGETHandler(ctx)
+
+	// check response
+	suite.EqualValues(http.StatusOK, recorder.Code)
+
+	result := recorder.Result()
+	defer result.Body.Close()
+	b, err := ioutil.ReadAll(result.Body)
+	suite.NoError(err)
+
+	// should be a Person
+	m := make(map[string]interface{})
+	err = json.Unmarshal(b, &m)
+	suite.NoError(err)
+
+	t, err := streams.ToType(context.Background(), m)
+	suite.NoError(err)
+
+	person, ok := t.(vocab.ActivityStreamsPerson)
+	suite.True(ok)
+
+	// convert person to account
+	a, err := suite.tc.ASRepresentationToAccount(context.Background(), person, false)
+	suite.NoError(err)
+	suite.EqualValues(targetAccount.Username, a.Username)
 }
 
 func TestUserGetTestSuite(t *testing.T) {