[feature] Allow import of following and blocks via CSV (#3150)

* [feature] Import follows + blocks via settings panel

* test import follows

17 files changed, 992 insertions, 35 deletions

diff --git a/internal/api/auth/token_test.go b/internal/api/auth/token_test.go
index c97fce3b9..1c53b5b2e 100644
--- a/internal/api/auth/token_test.go
+++ b/internal/api/auth/token_test.go
@@ -57,7 +57,7 @@ func (suite *TokenTestSuite) TestRetrieveClientCredentialsOK() {
 	testClient := suite.testClients["local_account_1"]
 
 	requestBody, w, err := testrig.CreateMultipartFormData(
-		"", "",
+		nil,
 		map[string][]string{
 			"grant_type":    {"client_credentials"},
 			"client_id":     {testClient.ID},
@@ -103,7 +103,7 @@ func (suite *TokenTestSuite) TestRetrieveAuthorizationCodeOK() {
 	testUserAuthorizationToken := suite.testTokens["local_account_1_user_authorization_token"]
 
 	requestBody, w, err := testrig.CreateMultipartFormData(
-		"", "",
+		nil,
 		map[string][]string{
 			"grant_type":    {"authorization_code"},
 			"client_id":     {testClient.ID},
@@ -148,7 +148,7 @@ func (suite *TokenTestSuite) TestRetrieveAuthorizationCodeNoCode() {
 	testClient := suite.testClients["local_account_1"]
 
 	requestBody, w, err := testrig.CreateMultipartFormData(
-		"", "",
+		nil,
 		map[string][]string{
 			"grant_type":    {"authorization_code"},
 			"client_id":     {testClient.ID},
@@ -180,7 +180,7 @@ func (suite *TokenTestSuite) TestRetrieveAuthorizationCodeWrongGrantType() {
 	testClient := suite.testClients["local_account_1"]
 
 	requestBody, w, err := testrig.CreateMultipartFormData(
-		"", "",
+		nil,
 		map[string][]string{
 			"grant_type":    {"client_credentials"},
 			"client_id":     {testClient.ID},
diff --git a/internal/api/client.go b/internal/api/client.go
index 64f185430..65d4f29d5 100644
--- a/internal/api/client.go
+++ b/internal/api/client.go
@@ -35,6 +35,7 @@ import (
 	filtersV2 "github.com/superseriousbusiness/gotosocial/internal/api/client/filters/v2"
 	"github.com/superseriousbusiness/gotosocial/internal/api/client/followedtags"
 	"github.com/superseriousbusiness/gotosocial/internal/api/client/followrequests"
+	importdata "github.com/superseriousbusiness/gotosocial/internal/api/client/import"
 	"github.com/superseriousbusiness/gotosocial/internal/api/client/instance"
 	"github.com/superseriousbusiness/gotosocial/internal/api/client/interactionpolicies"
 	"github.com/superseriousbusiness/gotosocial/internal/api/client/lists"
@@ -76,6 +77,7 @@ type Client struct {
 	filtersV2           *filtersV2.Module           // api/v2/filters
 	followRequests      *followrequests.Module      // api/v1/follow_requests
 	followedTags        *followedtags.Module        // api/v1/followed_tags
+	importData          *importdata.Module          // api/v1/import
 	instance            *instance.Module            // api/v1/instance
 	interactionPolicies *interactionpolicies.Module // api/v1/interaction_policies
 	lists               *lists.Module               // api/v1/lists
@@ -125,6 +127,7 @@ func (c *Client) Route(r *router.Router, m ...gin.HandlerFunc) {
 	c.filtersV2.Route(h)
 	c.followRequests.Route(h)
 	c.followedTags.Route(h)
+	c.importData.Route(h)
 	c.instance.Route(h)
 	c.interactionPolicies.Route(h)
 	c.lists.Route(h)
@@ -162,6 +165,7 @@ func NewClient(state *state.State, p *processing.Processor) *Client {
 		filtersV2:           filtersV2.New(p),
 		followRequests:      followrequests.New(p),
 		followedTags:        followedtags.New(p),
+		importData:          importdata.New(p),
 		instance:            instance.New(p),
 		interactionPolicies: interactionpolicies.New(p),
 		lists:               lists.New(p),
diff --git a/internal/api/client/accounts/accountdelete_test.go b/internal/api/client/accounts/accountdelete_test.go
index 2f5a25b4b..66a5fa097 100644
--- a/internal/api/client/accounts/accountdelete_test.go
+++ b/internal/api/client/accounts/accountdelete_test.go
@@ -35,7 +35,7 @@ func (suite *AccountDeleteTestSuite) TestAccountDeletePOSTHandler() {
 	// set up the request
 	// we're deleting zork
 	requestBody, w, err := testrig.CreateMultipartFormData(
-		"", "",
+		nil,
 		map[string][]string{
 			"password": {"password"},
 		})
@@ -57,7 +57,7 @@ func (suite *AccountDeleteTestSuite) TestAccountDeletePOSTHandlerWrongPassword()
 	// set up the request
 	// we're deleting zork
 	requestBody, w, err := testrig.CreateMultipartFormData(
-		"", "",
+		nil,
 		map[string][]string{
 			"password": {"aaaaaaaaaaaaaaaaaaaaaaaaaaaa"},
 		})
@@ -79,7 +79,7 @@ func (suite *AccountDeleteTestSuite) TestAccountDeletePOSTHandlerNoPassword() {
 	// set up the request
 	// we're deleting zork
 	requestBody, w, err := testrig.CreateMultipartFormData(
-		"", "",
+		nil,
 		map[string][]string{})
 	if err != nil {
 		panic(err)
diff --git a/internal/api/client/accounts/accountupdate_test.go b/internal/api/client/accounts/accountupdate_test.go
index 09996e998..d0def500c 100644
--- a/internal/api/client/accounts/accountupdate_test.go
+++ b/internal/api/client/accounts/accountupdate_test.go
@@ -51,7 +51,7 @@ func (suite *AccountUpdateTestSuite) updateAccountFromForm(data map[string][]str
 }
 
 func (suite *AccountUpdateTestSuite) updateAccountFromFormData(data map[string][]string, expectedHTTPStatus int, expectedBody string) (*apimodel.Account, error) {
-	requestBody, w, err := testrig.CreateMultipartFormData("", "", data)
+	requestBody, w, err := testrig.CreateMultipartFormData(nil, data)
 	if err != nil {
 		suite.FailNow(err.Error())
 	}
@@ -59,8 +59,8 @@ func (suite *AccountUpdateTestSuite) updateAccountFromFormData(data map[string][
 	return suite.updateAccount(requestBody.Bytes(), w.FormDataContentType(), expectedHTTPStatus, expectedBody)
 }
 
-func (suite *AccountUpdateTestSuite) updateAccountFromFormDataWithFile(fieldName string, fileName string, data map[string][]string, expectedHTTPStatus int, expectedBody string) (*apimodel.Account, error) {
-	requestBody, w, err := testrig.CreateMultipartFormData(fieldName, fileName, data)
+func (suite *AccountUpdateTestSuite) updateAccountFromFormDataWithFile(fieldName string, filePath string, data map[string][]string, expectedHTTPStatus int, expectedBody string) (*apimodel.Account, error) {
+	requestBody, w, err := testrig.CreateMultipartFormData(testrig.FileToDataF(fieldName, filePath), data)
 	if err != nil {
 		suite.FailNow(err.Error())
 	}
diff --git a/internal/api/client/admin/emojicreate_test.go b/internal/api/client/admin/emojicreate_test.go
index a687fb0af..9e985459b 100644
--- a/internal/api/client/admin/emojicreate_test.go
+++ b/internal/api/client/admin/emojicreate_test.go
@@ -38,7 +38,7 @@ type EmojiCreateTestSuite struct {
 func (suite *EmojiCreateTestSuite) TestEmojiCreateNewCategory() {
 	// set up the request
 	requestBody, w, err := testrig.CreateMultipartFormData(
-		"image", "../../../../testrig/media/rainbow-original.png",
+		testrig.FileToDataF("image", "../../../../testrig/media/rainbow-original.png"),
 		map[string][]string{
 			"shortcode": {"new_emoji"},
 			"category":  {"Test Emojis"}, // this category doesn't exist yet
@@ -111,7 +111,7 @@ func (suite *EmojiCreateTestSuite) TestEmojiCreateNewCategory() {
 func (suite *EmojiCreateTestSuite) TestEmojiCreateExistingCategory() {
 	// set up the request
 	requestBody, w, err := testrig.CreateMultipartFormData(
-		"image", "../../../../testrig/media/rainbow-original.png",
+		testrig.FileToDataF("image", "../../../../testrig/media/rainbow-original.png"),
 		map[string][]string{
 			"shortcode": {"new_emoji"},
 			"category":  {"cute stuff"}, // this category already exists
@@ -184,7 +184,7 @@ func (suite *EmojiCreateTestSuite) TestEmojiCreateExistingCategory() {
 func (suite *EmojiCreateTestSuite) TestEmojiCreateNoCategory() {
 	// set up the request
 	requestBody, w, err := testrig.CreateMultipartFormData(
-		"image", "../../../../testrig/media/rainbow-original.png",
+		testrig.FileToDataF("image", "../../../../testrig/media/rainbow-original.png"),
 		map[string][]string{
 			"shortcode": {"new_emoji"},
 			"category":  {""},
@@ -257,7 +257,7 @@ func (suite *EmojiCreateTestSuite) TestEmojiCreateNoCategory() {
 func (suite *EmojiCreateTestSuite) TestEmojiCreateAlreadyExists() {
 	// set up the request -- use a shortcode that already exists for an emoji in the database
 	requestBody, w, err := testrig.CreateMultipartFormData(
-		"image", "../../../../testrig/media/rainbow-original.png",
+		testrig.FileToDataF("image", "../../../../testrig/media/rainbow-original.png"),
 		map[string][]string{
 			"shortcode": {"rainbow"},
 		})
diff --git a/internal/api/client/admin/emojiupdate_test.go b/internal/api/client/admin/emojiupdate_test.go
index 073e3cec0..5df43d7ae 100644
--- a/internal/api/client/admin/emojiupdate_test.go
+++ b/internal/api/client/admin/emojiupdate_test.go
@@ -44,7 +44,7 @@ func (suite *EmojiUpdateTestSuite) TestEmojiUpdateNewCategory() {
 
 	// set up the request
 	requestBody, w, err := testrig.CreateMultipartFormData(
-		"", "",
+		nil,
 		map[string][]string{
 			"category": {"New Category"}, // this category doesn't exist yet
 			"type":     {"modify"},
@@ -121,7 +121,7 @@ func (suite *EmojiUpdateTestSuite) TestEmojiUpdateSwitchCategory() {
 
 	// set up the request
 	requestBody, w, err := testrig.CreateMultipartFormData(
-		"", "",
+		nil,
 		map[string][]string{
 			"type":     {"modify"},
 			"category": {"cute stuff"},
@@ -198,7 +198,7 @@ func (suite *EmojiUpdateTestSuite) TestEmojiUpdateCopyRemoteToLocal() {
 
 	// set up the request
 	requestBody, w, err := testrig.CreateMultipartFormData(
-		"", "",
+		nil,
 		map[string][]string{
 			"type":      {"copy"},
 			"category":  {"emojis i stole"},
@@ -276,7 +276,7 @@ func (suite *EmojiUpdateTestSuite) TestEmojiUpdateDisableEmoji() {
 
 	// set up the request
 	requestBody, w, err := testrig.CreateMultipartFormData(
-		"", "",
+		nil,
 		map[string][]string{
 			"type": {"disable"},
 		})
@@ -317,7 +317,7 @@ func (suite *EmojiUpdateTestSuite) TestEmojiUpdateDisableLocalEmoji() {
 
 	// set up the request
 	requestBody, w, err := testrig.CreateMultipartFormData(
-		"", "",
+		nil,
 		map[string][]string{
 			"type": {"disable"},
 		})
@@ -350,7 +350,7 @@ func (suite *EmojiUpdateTestSuite) TestEmojiUpdateModifyRemoteEmoji() {
 
 	// set up the request
 	requestBody, w, err := testrig.CreateMultipartFormData(
-		"image", "../../../../testrig/media/kip-original.gif",
+		testrig.FileToDataF("image", "../../../../testrig/media/kip-original.gif"),
 		map[string][]string{
 			"type": {"modify"},
 		})
@@ -383,7 +383,7 @@ func (suite *EmojiUpdateTestSuite) TestEmojiUpdateModifyNoParams() {
 
 	// set up the request
 	requestBody, w, err := testrig.CreateMultipartFormData(
-		"", "",
+		nil,
 		map[string][]string{
 			"type": {"modify"},
 		})
@@ -416,7 +416,7 @@ func (suite *EmojiUpdateTestSuite) TestEmojiUpdateCopyLocalToLocal() {
 
 	// set up the request
 	requestBody, w, err := testrig.CreateMultipartFormData(
-		"", "",
+		nil,
 		map[string][]string{
 			"type":      {"copy"},
 			"shortcode": {"bottoms"},
@@ -450,7 +450,7 @@ func (suite *EmojiUpdateTestSuite) TestEmojiUpdateCopyEmptyShortcode() {
 
 	// set up the request
 	requestBody, w, err := testrig.CreateMultipartFormData(
-		"", "",
+		nil,
 		map[string][]string{
 			"type":      {"copy"},
 			"shortcode": {""},
@@ -484,7 +484,7 @@ func (suite *EmojiUpdateTestSuite) TestEmojiUpdateCopyNoShortcode() {
 
 	// set up the request
 	requestBody, w, err := testrig.CreateMultipartFormData(
-		"", "",
+		nil,
 		map[string][]string{
 			"type": {"copy"},
 		})
@@ -517,7 +517,7 @@ func (suite *EmojiUpdateTestSuite) TestEmojiUpdateCopyShortcodeAlreadyInUse() {
 
 	// set up the request
 	requestBody, w, err := testrig.CreateMultipartFormData(
-		"", "",
+		nil,
 		map[string][]string{
 			"type":      {"copy"},
 			"shortcode": {"rainbow"},
diff --git a/internal/api/client/import/import.go b/internal/api/client/import/import.go
new file mode 100644
index 000000000..6d85a6b23
--- /dev/null
+++ b/internal/api/client/import/import.go
@@ -0,0 +1,195 @@
+// 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 importdata
+
+import (
+	"errors"
+	"fmt"
+	"net/http"
+	"slices"
+	"strings"
+
+	"github.com/gin-gonic/gin"
+	apimodel "github.com/superseriousbusiness/gotosocial/internal/api/model"
+	apiutil "github.com/superseriousbusiness/gotosocial/internal/api/util"
+	"github.com/superseriousbusiness/gotosocial/internal/gtserror"
+	"github.com/superseriousbusiness/gotosocial/internal/oauth"
+	"github.com/superseriousbusiness/gotosocial/internal/processing"
+)
+
+const (
+	BasePath = "/v1/import"
+)
+
+var types = []string{
+	"following",
+	"blocks",
+}
+
+var modes = []string{
+	"merge",
+	"overwrite",
+}
+
+type Module struct {
+	processor *processing.Processor
+}
+
+func New(processor *processing.Processor) *Module {
+	return &Module{
+		processor: processor,
+	}
+}
+
+func (m *Module) Route(attachHandler func(method string, path string, f ...gin.HandlerFunc) gin.IRoutes) {
+	attachHandler(http.MethodPost, BasePath, m.ImportPOSTHandler)
+}
+
+// ImportPOSTHandler swagger:operation POST /api/v1/import importData
+//
+// Upload some CSV-formatted data to your account.
+//
+// This can be used to migrate data from a Mastodon-compatible CSV file to a GoToSocial account.
+//
+// Uploaded data will be processed asynchronously, and not all entries may be processed depending
+// on domain blocks, user-level blocks, network availability of referenced accounts and statuses, etc.
+//
+//	---
+//	tags:
+//	- import-export
+//
+//	consumes:
+//	- multipart/form-data
+//
+//	produces:
+//	- application/json
+//
+//	parameters:
+//	-
+//		name: data
+//		in: formData
+//		description: The CSV data file to upload.
+//		type: file
+//		required: true
+//	-
+//		name: type
+//		in: formData
+//		description: >-
+//			Type of entries contained in the data file:
+//
+//			- `following` - accounts to follow.
+//			- `blocks` - accounts to block.
+//		type: string
+//		required: true
+//	-
+//		name: mode
+//		in: formData
+//		description: >-
+//			Mode to use when creating entries from the data file:
+//
+//			- `merge` to merge entries in file with existing entries.
+//			- `overwrite` to replace existing entries with entries in file.
+//		type: string
+//		default: merge
+//
+//	security:
+//	- OAuth2 Bearer:
+//		- write:accounts
+//
+//	responses:
+//		'202':
+//			description: Upload accepted.
+//		'400':
+//			description: bad request
+//		'401':
+//			description: unauthorized
+//		'406':
+//			description: not acceptable
+//		'500':
+//			description: internal server error
+func (m *Module) ImportPOSTHandler(c *gin.Context) {
+	authed, err := oauth.Authed(c, true, true, true, true)
+	if err != nil {
+		apiutil.ErrorHandler(c, gtserror.NewErrorUnauthorized(err, err.Error()), m.processor.InstanceGetV1)
+		return
+	}
+
+	if authed.Account.IsMoving() {
+		apiutil.ForbiddenAfterMove(c)
+		return
+	}
+
+	if _, err := apiutil.NegotiateAccept(c, apiutil.JSONAcceptHeaders...); err != nil {
+		apiutil.ErrorHandler(c, gtserror.NewErrorNotAcceptable(err, err.Error()), m.processor.InstanceGetV1)
+		return
+	}
+
+	form := &apimodel.ImportRequest{}
+	if err := c.ShouldBind(form); err != nil {
+		apiutil.ErrorHandler(c, gtserror.NewErrorBadRequest(err, err.Error()), m.processor.InstanceGetV1)
+		return
+	}
+
+	if form.Data == nil {
+		const text = "no data file provided"
+		err := errors.New(text)
+		apiutil.ErrorHandler(c, gtserror.NewErrorBadRequest(err, text), m.processor.InstanceGetV1)
+		return
+	}
+
+	if form.Type == "" {
+		const text = "no type provided"
+		err := errors.New(text)
+		apiutil.ErrorHandler(c, gtserror.NewErrorBadRequest(err, text), m.processor.InstanceGetV1)
+		return
+	}
+
+	form.Type = strings.ToLower(form.Type)
+	if !slices.Contains(types, form.Type) {
+		text := fmt.Sprintf("type %s not recognized, valid types are: %+v", form.Type, types)
+		err := errors.New(text)
+		apiutil.ErrorHandler(c, gtserror.NewErrorBadRequest(err, text), m.processor.InstanceGetV1)
+		return
+	}
+
+	if form.Mode != "" {
+		form.Mode = strings.ToLower(form.Mode)
+		if !slices.Contains(modes, form.Mode) {
+			text := fmt.Sprintf("mode %s not recognized, valid modes are: %+v", form.Mode, modes)
+			err := errors.New(text)
+			apiutil.ErrorHandler(c, gtserror.NewErrorBadRequest(err, text), m.processor.InstanceGetV1)
+			return
+		}
+	}
+	overwrite := form.Mode == "overwrite"
+
+	// Trigger the import.
+	errWithCode := m.processor.Account().ImportData(
+		c.Request.Context(),
+		authed.Account,
+		form.Data,
+		form.Type,
+		overwrite,
+	)
+	if errWithCode != nil {
+		apiutil.ErrorHandler(c, errWithCode, m.processor.InstanceGetV1)
+		return
+	}
+
+	apiutil.JSON(c, http.StatusAccepted, gin.H{"status": "accepted"})
+}
diff --git a/internal/api/client/import/import_test.go b/internal/api/client/import/import_test.go
new file mode 100644
index 000000000..5129f862e
--- /dev/null
+++ b/internal/api/client/import/import_test.go
@@ -0,0 +1,210 @@
+// 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 importdata_test
+
+import (
+	"bytes"
+	"context"
+	"io"
+	"net/http"
+	"net/http/httptest"
+	"testing"
+
+	"github.com/stretchr/testify/suite"
+	importdata "github.com/superseriousbusiness/gotosocial/internal/api/client/import"
+	"github.com/superseriousbusiness/gotosocial/internal/filter/visibility"
+	"github.com/superseriousbusiness/gotosocial/internal/gtsmodel"
+	"github.com/superseriousbusiness/gotosocial/internal/oauth"
+	"github.com/superseriousbusiness/gotosocial/internal/state"
+	"github.com/superseriousbusiness/gotosocial/internal/typeutils"
+	"github.com/superseriousbusiness/gotosocial/testrig"
+)
+
+type ImportTestSuite struct {
+	// Suite interfaces
+	suite.Suite
+	state state.State
+
+	// standard suite models
+	testTokens       map[string]*gtsmodel.Token
+	testClients      map[string]*gtsmodel.Client
+	testApplications map[string]*gtsmodel.Application
+	testUsers        map[string]*gtsmodel.User
+	testAccounts     map[string]*gtsmodel.Account
+
+	// module being tested
+	importModule *importdata.Module
+}
+
+func (suite *ImportTestSuite) SetupSuite() {
+	suite.testTokens = testrig.NewTestTokens()
+	suite.testClients = testrig.NewTestClients()
+	suite.testApplications = testrig.NewTestApplications()
+	suite.testUsers = testrig.NewTestUsers()
+	suite.testAccounts = testrig.NewTestAccounts()
+}
+
+func (suite *ImportTestSuite) SetupTest() {
+	suite.state.Caches.Init()
+
+	testrig.InitTestConfig()
+	testrig.InitTestLog()
+
+	suite.state.DB = testrig.NewTestDB(&suite.state)
+	suite.state.Storage = testrig.NewInMemoryStorage()
+
+	testrig.StartTimelines(
+		&suite.state,
+		visibility.NewFilter(&suite.state),
+		typeutils.NewConverter(&suite.state),
+	)
+
+	testrig.StandardDBSetup(suite.state.DB, nil)
+	testrig.StandardStorageSetup(suite.state.Storage, "../../../../testrig/media")
+
+	mediaManager := testrig.NewTestMediaManager(&suite.state)
+
+	federator := testrig.NewTestFederator(
+		&suite.state,
+		testrig.NewTestTransportController(
+			&suite.state,
+			testrig.NewMockHTTPClient(nil, "../../../../testrig/media"),
+		),
+		mediaManager,
+	)
+
+	processor := testrig.NewTestProcessor(
+		&suite.state,
+		federator,
+		testrig.NewEmailSender("../../../../web/template/", nil),
+		mediaManager,
+	)
+	testrig.StartWorkers(&suite.state, processor.Workers())
+
+	suite.importModule = importdata.New(processor)
+}
+
+func (suite *ImportTestSuite) TriggerHandler(
+	importData string,
+	importType string,
+	importMode string,
+) {
+	// Set up request.
+	recorder := httptest.NewRecorder()
+	ctx, _ := testrig.CreateGinTestContext(recorder, nil)
+
+	// Authorize the request ctx as though it
+	// had passed through API auth handlers.
+	ctx.Set(oauth.SessionAuthorizedAccount, suite.testAccounts["local_account_1"])
+	ctx.Set(oauth.SessionAuthorizedToken, oauth.DBTokenToToken(suite.testTokens["local_account_1"]))
+	ctx.Set(oauth.SessionAuthorizedApplication, suite.testApplications["application_1"])
+	ctx.Set(oauth.SessionAuthorizedUser, suite.testUsers["local_account_1"])
+
+	// Create test request.
+	b, w, err := testrig.CreateMultipartFormData(
+		testrig.StringToDataF("data", "data.csv", importData),
+		map[string][]string{
+			"type": {importType},
+			"mode": {importMode},
+		},
+	)
+	if err != nil {
+		suite.FailNow(err.Error())
+	}
+
+	target := "http://localhost:8080/api/v1/import"
+	ctx.Request = httptest.NewRequest(http.MethodPost, target, bytes.NewReader(b.Bytes()))
+	ctx.Request.Header.Set("Accept", "application/json")
+	ctx.Request.Header.Set("Content-Type", w.FormDataContentType())
+
+	// Trigger handler.
+	suite.importModule.ImportPOSTHandler(ctx)
+
+	if code := recorder.Code; code != http.StatusAccepted {
+		b, err := io.ReadAll(recorder.Body)
+		if err != nil {
+			panic(err)
+		}
+		suite.FailNow("", "expected 202, got %d: %s", code, string(b))
+	}
+}
+
+func (suite *ImportTestSuite) TearDownTest() {
+	testrig.StandardDBTeardown(suite.state.DB)
+	testrig.StandardStorageTeardown(suite.state.Storage)
+	testrig.StopWorkers(&suite.state)
+}
+
+func (suite *ImportTestSuite) TestImportFollows() {
+	var (
+		ctx         = context.Background()
+		testAccount = suite.testAccounts["local_account_1"]
+	)
+
+	// Clear existing follows from Zork.
+	if err := suite.state.DB.DeleteAccountFollows(ctx, testAccount.ID); err != nil {
+		suite.FailNow(err.Error())
+	}
+
+	// Have zork refollow turtle and admin.
+	data := `Account address,Show boosts
+admin@localhost:8080,true
+1happyturtle@localhost:8080,true
+`
+
+	// Trigger the import handler.
+	suite.TriggerHandler(data, "following", "merge")
+
+	// Wait for zork to be
+	// following admin.
+	if !testrig.WaitFor(func() bool {
+		f, err := suite.state.DB.IsFollowing(
+			ctx,
+			testAccount.ID,
+			suite.testAccounts["admin_account"].ID,
+		)
+		if err != nil {
+			suite.FailNow(err.Error())
+		}
+
+		return f
+	}) {
+		suite.FailNow("timed out waiting for zork to follow admin")
+	}
+
+	// Wait for zork to be
+	// follow req'ing turtle.
+	if !testrig.WaitFor(func() bool {
+		f, err := suite.state.DB.IsFollowRequested(
+			ctx,
+			testAccount.ID,
+			suite.testAccounts["local_account_2"].ID,
+		)
+		if err != nil {
+			suite.FailNow(err.Error())
+		}
+
+		return f
+	}) {
+		suite.FailNow("timed out waiting for zork to follow req turtle")
+	}
+}
+
+func TestImportTestSuite(t *testing.T) {
+	suite.Run(t, new(ImportTestSuite))
+}
diff --git a/internal/api/client/instance/instancepatch_test.go b/internal/api/client/instance/instancepatch_test.go
index f12638f82..bb391537e 100644
--- a/internal/api/client/instance/instancepatch_test.go
+++ b/internal/api/client/instance/instancepatch_test.go
@@ -37,7 +37,12 @@ type InstancePatchTestSuite struct {
 }
 
 func (suite *InstancePatchTestSuite) instancePatch(fieldName string, fileName string, extraFields map[string][]string) (code int, body []byte) {
-	requestBody, w, err := testrig.CreateMultipartFormData(fieldName, fileName, extraFields)
+	var dataF testrig.DataF
+	if fieldName != "" && fileName != "" {
+		dataF = testrig.FileToDataF(fieldName, fileName)
+	}
+
+	requestBody, w, err := testrig.CreateMultipartFormData(dataF, extraFields)
 	if err != nil {
 		suite.FailNow(err.Error())
 	}
@@ -499,7 +504,7 @@ func (suite *InstancePatchTestSuite) TestInstancePatch4() {
 
 func (suite *InstancePatchTestSuite) TestInstancePatch5() {
 	requestBody, w, err := testrig.CreateMultipartFormData(
-		"", "",
+		nil,
 		map[string][]string{
 			"short_description": {"<p>This is some html, which is <em>allowed</em> in short descriptions.</p>"},
 		})
diff --git a/internal/api/client/lists/listaccountsadd_test.go b/internal/api/client/lists/listaccountsadd_test.go
index 492996882..7e44eeed3 100644
--- a/internal/api/client/lists/listaccountsadd_test.go
+++ b/internal/api/client/lists/listaccountsadd_test.go
@@ -60,7 +60,7 @@ func (suite *ListAccountsAddTestSuite) postListAccounts(
 	requestPath := config.GetProtocol() + "://" + config.GetHost() + "/api/" + lists.BasePath + "/" + listID + "/accounts"
 
 	// Prepare test body.
-	buf, w, err := testrig.CreateMultipartFormData("", "", map[string][]string{
+	buf, w, err := testrig.CreateMultipartFormData(nil, map[string][]string{
 		"account_ids[]": accountIDs,
 	})
 
diff --git a/internal/api/client/media/mediacreate_test.go b/internal/api/client/media/mediacreate_test.go
index c256d18dc..4c2725681 100644
--- a/internal/api/client/media/mediacreate_test.go
+++ b/internal/api/client/media/mediacreate_test.go
@@ -149,7 +149,7 @@ func (suite *MediaCreateTestSuite) TestMediaCreateSuccessful() {
 	}
 
 	// create the request
-	buf, w, err := testrig.CreateMultipartFormData("file", "../../../../testrig/media/test-jpeg.jpg", map[string][]string{
+	buf, w, err := testrig.CreateMultipartFormData(testrig.FileToDataF("file", "../../../../testrig/media/test-jpeg.jpg"), map[string][]string{
 		"description": {"this is a test image -- a cool background from somewhere"},
 		"focus":       {"-0.5,0.5"},
 	})
@@ -234,7 +234,7 @@ func (suite *MediaCreateTestSuite) TestMediaCreateSuccessfulV2() {
 	}
 
 	// create the request
-	buf, w, err := testrig.CreateMultipartFormData("file", "../../../../testrig/media/test-jpeg.jpg", map[string][]string{
+	buf, w, err := testrig.CreateMultipartFormData(testrig.FileToDataF("file", "../../../../testrig/media/test-jpeg.jpg"), map[string][]string{
 		"description": {"this is a test image -- a cool background from somewhere"},
 		"focus":       {"-0.5,0.5"},
 	})
@@ -317,7 +317,7 @@ func (suite *MediaCreateTestSuite) TestMediaCreateLongDescription() {
 	description := base64.RawStdEncoding.EncodeToString(descriptionBytes)
 
 	// create the request
-	buf, w, err := testrig.CreateMultipartFormData("file", "../../../../testrig/media/test-jpeg.jpg", map[string][]string{
+	buf, w, err := testrig.CreateMultipartFormData(testrig.FileToDataF("file", "../../../../testrig/media/test-jpeg.jpg"), map[string][]string{
 		"description": {description},
 		"focus":       {"-0.5,0.5"},
 	})
@@ -358,7 +358,7 @@ func (suite *MediaCreateTestSuite) TestMediaCreateTooShortDescription() {
 	ctx.Set(oauth.SessionAuthorizedAccount, suite.testAccounts["local_account_1"])
 
 	// create the request
-	buf, w, err := testrig.CreateMultipartFormData("file", "../../../../testrig/media/test-jpeg.jpg", map[string][]string{
+	buf, w, err := testrig.CreateMultipartFormData(testrig.FileToDataF("file", "../../../../testrig/media/test-jpeg.jpg"), map[string][]string{
 		"description": {""}, // provide an empty description
 		"focus":       {"-0.5,0.5"},
 	})
diff --git a/internal/api/client/media/mediaupdate_test.go b/internal/api/client/media/mediaupdate_test.go
index 43b2b6c51..c3a1fb340 100644
--- a/internal/api/client/media/mediaupdate_test.go
+++ b/internal/api/client/media/mediaupdate_test.go
@@ -140,7 +140,7 @@ func (suite *MediaUpdateTestSuite) TestUpdateImage() {
 	ctx.Set(oauth.SessionAuthorizedAccount, suite.testAccounts["local_account_1"])
 
 	// create the request
-	buf, w, err := testrig.CreateMultipartFormData("", "", map[string][]string{
+	buf, w, err := testrig.CreateMultipartFormData(nil, map[string][]string{
 		"id":          {toUpdate.ID},
 		"description": {"new description!"},
 		"focus":       {"-0.1,0.3"},
@@ -201,7 +201,7 @@ func (suite *MediaUpdateTestSuite) TestUpdateImageShortDescription() {
 	ctx.Set(oauth.SessionAuthorizedAccount, suite.testAccounts["local_account_1"])
 
 	// create the request
-	buf, w, err := testrig.CreateMultipartFormData("", "", map[string][]string{
+	buf, w, err := testrig.CreateMultipartFormData(nil, map[string][]string{
 		"id":          {toUpdate.ID},
 		"description": {"new description!"},
 		"focus":       {"-0.1,0.3"},
diff --git a/internal/api/client/polls/polls_vote_test.go b/internal/api/client/polls/polls_vote_test.go
index 01bd941d3..54f98c192 100644
--- a/internal/api/client/polls/polls_vote_test.go
+++ b/internal/api/client/polls/polls_vote_test.go
@@ -107,7 +107,7 @@ func (suite *PollCreateTestSuite) formVoteInPoll(
 		choicesStrs = append(choicesStrs, strconv.Itoa(choice))
 	}
 
-	body, w, err := testrig.CreateMultipartFormData("", "", map[string][]string{
+	body, w, err := testrig.CreateMultipartFormData(nil, map[string][]string{
 		"choices[]": choicesStrs,
 	})
 
diff --git a/internal/api/model/exportimport.go b/internal/api/model/exportimport.go
index d87ed8cd3..88ea5489d 100644
--- a/internal/api/model/exportimport.go
+++ b/internal/api/model/exportimport.go
@@ -17,6 +17,8 @@
 
 package model
 
+import "mime/multipart"
+
 // AccountExportStats models an account's stats
 // specifically for the purpose of informing about
 // export sizes at the /api/v1/exports/stats endpoint.
@@ -58,3 +60,23 @@ type AccountExportStats struct {
 	// example: 11
 	MutesCount int `json:"mutes_count"`
 }
+
+// AttachmentRequest models media attachment creation parameters.
+//
+// swagger: ignore
+type ImportRequest struct {
+	// The CSV data to upload.
+	Data *multipart.FileHeader `form:"data" binding:"required"`
+	// Type of entries contained in the data file.
+	//
+	//	- `following` - accounts to follow.
+	//	- `lists` - lists of accounts.
+	//	- `blocks` - accounts to block.
+	//	- `mutes` - accounts to mute.
+	//	- `bookmarks` - statuses to bookmark.
+	Type string `form:"type" binding:"required"`
+	// Mode to use when creating entries from the data file:
+	//	- `merge` to merge entries in file with existing entries.
+	//	- `overwrite` to replace existing entries with entries in file.
+	Mode string `form:"mode"`
+}
diff --git a/internal/processing/account/import.go b/internal/processing/account/import.go
new file mode 100644
index 000000000..200d971b8
--- /dev/null
+++ b/internal/processing/account/import.go
@@ -0,0 +1,374 @@
+// 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 account
+
+import (
+	"context"
+	"encoding/csv"
+	"errors"
+	"fmt"
+	"mime/multipart"
+
+	apimodel "github.com/superseriousbusiness/gotosocial/internal/api/model"
+	"github.com/superseriousbusiness/gotosocial/internal/gtserror"
+	"github.com/superseriousbusiness/gotosocial/internal/gtsmodel"
+	"github.com/superseriousbusiness/gotosocial/internal/log"
+)
+
+func (p *Processor) ImportData(
+	ctx context.Context,
+	requester *gtsmodel.Account,
+	data *multipart.FileHeader,
+	importType string,
+	overwrite bool,
+) gtserror.WithCode {
+	switch importType {
+
+	case "following":
+		return p.importFollowing(
+			ctx,
+			requester,
+			data,
+			overwrite,
+		)
+
+	case "blocks":
+		return p.importBlocks(
+			ctx,
+			requester,
+			data,
+			overwrite,
+		)
+
+	default:
+		const text = "import type not yet supported"
+		return gtserror.NewErrorUnprocessableEntity(errors.New(text), text)
+	}
+}
+
+func (p *Processor) importFollowing(
+	ctx context.Context,
+	requester *gtsmodel.Account,
+	followingData *multipart.FileHeader,
+	overwrite bool,
+) gtserror.WithCode {
+	file, err := followingData.Open()
+	if err != nil {
+		err := fmt.Errorf("error opening following data file: %w", err)
+		return gtserror.NewErrorBadRequest(err, err.Error())
+	}
+	defer file.Close()
+
+	// Parse records out of the file.
+	records, err := csv.NewReader(file).ReadAll()
+	if err != nil {
+		err := fmt.Errorf("error reading following data file: %w", err)
+		return gtserror.NewErrorBadRequest(err, err.Error())
+	}
+
+	// Convert the records into a slice of barebones follows.
+	//
+	// Only TargetAccount.Username, TargetAccount.Domain,
+	// and ShowReblogs will be set on each Follow.
+	follows, err := p.converter.CSVToFollowing(ctx, records)
+	if err != nil {
+		err := fmt.Errorf("error converting records to follows: %w", err)
+		return gtserror.NewErrorBadRequest(err, err.Error())
+	}
+
+	// Do remaining processing of this import asynchronously.
+	f := importFollowingAsyncF(p, requester, follows, overwrite)
+	p.state.Workers.Processing.Queue.Push(f)
+
+	return nil
+}
+
+func importFollowingAsyncF(
+	p *Processor,
+	requester *gtsmodel.Account,
+	follows []*gtsmodel.Follow,
+	overwrite bool,
+) func(context.Context) {
+	return func(ctx context.Context) {
+		// Map used to store wanted
+		// follow targets (if overwriting).
+		var wantedFollows map[string]struct{}
+
+		if overwrite {
+			// If we're overwriting, we need to get current
+			// follow(-req)s owned by requester *before*
+			// making any changes, so that we can remove
+			// unwanted follows after we've created new ones.
+			prevFollows, err := p.state.DB.GetAccountFollows(ctx, requester.ID, nil)
+			if err != nil {
+				log.Errorf(ctx, "db error getting following: %v", err)
+				return
+			}
+
+			prevFollowReqs, err := p.state.DB.GetAccountFollowRequesting(ctx, requester.ID, nil)
+			if err != nil {
+				log.Errorf(ctx, "db error getting follow requesting: %v", err)
+				return
+			}
+
+			// Initialize new follows map.
+			wantedFollows = make(map[string]struct{}, len(follows))
+
+			// Once we've created (or tried to create)
+			// the required follows, go through previous
+			// follow(-request)s and remove unwanted ones.
+			defer func() {
+
+				// AccountIDs to unfollow.
+				toRemove := []string{}
+
+				// Check previous follows.
+				for _, prev := range prevFollows {
+					username := prev.TargetAccount.Username
+					domain := prev.TargetAccount.Domain
+
+					_, wanted := wantedFollows[username+"@"+domain]
+					if !wanted {
+						toRemove = append(toRemove, prev.TargetAccountID)
+					}
+				}
+
+				// Now any pending follow requests.
+				for _, prev := range prevFollowReqs {
+					username := prev.TargetAccount.Username
+					domain := prev.TargetAccount.Domain
+
+					_, wanted := wantedFollows[username+"@"+domain]
+					if !wanted {
+						toRemove = append(toRemove, prev.TargetAccountID)
+					}
+				}
+
+				// Remove each discovered
+				// unwanted follow.
+				for _, accountID := range toRemove {
+					if _, errWithCode := p.FollowRemove(
+						ctx,
+						requester,
+						accountID,
+					); errWithCode != nil {
+						log.Errorf(ctx, "could not unfollow account: %v", errWithCode.Unwrap())
+						continue
+					}
+				}
+			}()
+		}
+
+		// Go through the follows parsed from CSV
+		// file, and create / update each one.
+		for _, follow := range follows {
+			var (
+				// Username of the target.
+				username = follow.TargetAccount.Username
+
+				// Domain of the target.
+				// Empty for our domain.
+				domain = follow.TargetAccount.Domain
+
+				// Show reblogs on
+				// the new follow.
+				showReblogs = follow.ShowReblogs
+			)
+
+			if overwrite {
+				// We'll be overwriting, so store
+				// this new follow in our handy map.
+				wantedFollows[username+"@"+domain] = struct{}{}
+			}
+
+			// Get the target account, dereferencing it if necessary.
+			targetAcct, _, err := p.federator.Dereferencer.GetAccountByUsernameDomain(
+				ctx,
+				requester.Username,
+				username,
+				domain,
+			)
+			if err != nil {
+				log.Errorf(ctx, "could not retrieve account: %v", err)
+				continue
+			}
+
+			// Use the processor's FollowCreate function
+			// to create or update the follow. This takes
+			// account of existing follows, and also sends
+			// the follow to the FromClientAPI processor.
+			if _, errWithCode := p.FollowCreate(
+				ctx,
+				requester,
+				&apimodel.AccountFollowRequest{
+					ID:      targetAcct.ID,
+					Reblogs: showReblogs,
+				},
+			); errWithCode != nil {
+				log.Errorf(ctx, "could not follow account: %v", errWithCode.Unwrap())
+				continue
+			}
+		}
+	}
+}
+
+func (p *Processor) importBlocks(
+	ctx context.Context,
+	requester *gtsmodel.Account,
+	blocksData *multipart.FileHeader,
+	overwrite bool,
+) gtserror.WithCode {
+	file, err := blocksData.Open()
+	if err != nil {
+		err := fmt.Errorf("error opening blocks data file: %w", err)
+		return gtserror.NewErrorBadRequest(err, err.Error())
+	}
+	defer file.Close()
+
+	// Parse records out of the file.
+	records, err := csv.NewReader(file).ReadAll()
+	if err != nil {
+		err := fmt.Errorf("error reading blocks data file: %w", err)
+		return gtserror.NewErrorBadRequest(err, err.Error())
+	}
+
+	// Convert the records into a slice of barebones blocks.
+	//
+	// Only TargetAccount.Username and TargetAccount.Domain,
+	// will be set on each Block.
+	blocks, err := p.converter.CSVToBlocks(ctx, records)
+	if err != nil {
+		err := fmt.Errorf("error converting records to blocks: %w", err)
+		return gtserror.NewErrorBadRequest(err, err.Error())
+	}
+
+	// Do remaining processing of this import asynchronously.
+	f := importBlocksAsyncF(p, requester, blocks, overwrite)
+	p.state.Workers.Processing.Queue.Push(f)
+
+	return nil
+}
+
+func importBlocksAsyncF(
+	p *Processor,
+	requester *gtsmodel.Account,
+	blocks []*gtsmodel.Block,
+	overwrite bool,
+) func(context.Context) {
+	return func(ctx context.Context) {
+		// Map used to store wanted
+		// block targets (if overwriting).
+		var wantedBlocks map[string]struct{}
+
+		if overwrite {
+			// If we're overwriting, we need to get current
+			// blocks owned by requester *before* making any
+			// changes, so that we can remove unwanted blocks
+			// after we've created new ones.
+			var (
+				prevBlocks []*gtsmodel.Block
+				err        error
+			)
+
+			prevBlocks, err = p.state.DB.GetAccountBlocks(ctx, requester.ID, nil)
+			if err != nil {
+				log.Errorf(ctx, "db error getting blocks: %v", err)
+				return
+			}
+
+			// Initialize new blocks map.
+			wantedBlocks = make(map[string]struct{}, len(blocks))
+
+			// Once we've created (or tried to create)
+			// the required blocks, go through previous
+			// blocks and remove unwanted ones.
+			defer func() {
+				for _, prev := range prevBlocks {
+					username := prev.TargetAccount.Username
+					domain := prev.TargetAccount.Domain
+
+					_, wanted := wantedBlocks[username+"@"+domain]
+					if wanted {
+						// Leave this
+						// one alone.
+						continue
+					}
+
+					if _, errWithCode := p.BlockRemove(
+						ctx,
+						requester,
+						prev.TargetAccountID,
+					); errWithCode != nil {
+						log.Errorf(ctx, "could not unblock account: %v", errWithCode.Unwrap())
+						continue
+					}
+				}
+			}()
+		}
+
+		// Go through the blocks parsed from CSV
+		// file, and create / update each one.
+		for _, block := range blocks {
+			var (
+				// Username of the target.
+				username = block.TargetAccount.Username
+
+				// Domain of the target.
+				// Empty for our domain.
+				domain = block.TargetAccount.Domain
+			)
+
+			if overwrite {
+				// We'll be overwriting, so store
+				// this new block in our handy map.
+				wantedBlocks[username+"@"+domain] = struct{}{}
+			}
+
+			// Get the target account, dereferencing it if necessary.
+			targetAcct, _, err := p.federator.Dereferencer.GetAccountByUsernameDomain(
+				ctx,
+				// Provide empty request user to use the
+				// instance account to deref the account.
+				//
+				// It's pointless to make lots of calls
+				// to a remote from an account that's about
+				// to block that account.
+				"",
+				username,
+				domain,
+			)
+			if err != nil {
+				log.Errorf(ctx, "could not retrieve account: %v", err)
+				continue
+			}
+
+			// Use the processor's BlockCreate function
+			// to create or update the block. This takes
+			// account of existing blocks, and also sends
+			// the block to the FromClientAPI processor.
+			if _, errWithCode := p.BlockCreate(
+				ctx,
+				requester,
+				targetAcct.ID,
+			); errWithCode != nil {
+				log.Errorf(ctx, "could not block account: %v", errWithCode.Unwrap())
+				continue
+			}
+		}
+	}
+}
diff --git a/internal/typeutils/csv.go b/internal/typeutils/csv.go
index 2ef56cb0c..063e31d54 100644
--- a/internal/typeutils/csv.go
+++ b/internal/typeutils/csv.go
@@ -26,6 +26,7 @@ import (
 	"github.com/superseriousbusiness/gotosocial/internal/gtscontext"
 	"github.com/superseriousbusiness/gotosocial/internal/gtserror"
 	"github.com/superseriousbusiness/gotosocial/internal/gtsmodel"
+	"github.com/superseriousbusiness/gotosocial/internal/util"
 )
 
 func (c *Converter) AccountToExportStats(
@@ -383,3 +384,137 @@ func (c *Converter) MutesToCSV(
 
 	return records, nil
 }
+
+// CSVToFollowing converts a slice of CSV records
+// to a slice of barebones *gtsmodel.Follow's,
+// ready for further processing.
+//
+// Only TargetAccount.Username, TargetAccount.Domain,
+// and ShowReblogs will be set on each Follow.
+func (c *Converter) CSVToFollowing(
+	ctx context.Context,
+	records [][]string,
+) ([]*gtsmodel.Follow, error) {
+	// We need to know our own domain for this.
+	// Try account domain, fall back to host.
+	var (
+		thisHost          = config.GetHost()
+		thisAccountDomain = config.GetAccountDomain()
+		follows           = make([]*gtsmodel.Follow, 0, len(records))
+	)
+
+	for _, record := range records {
+		if len(record) != 2 {
+			// Badly formatted,
+			// skip this one.
+			continue
+		}
+
+		namestring := record[0]
+		if namestring == "" {
+			// Badly formatted,
+			// skip this one.
+			continue
+		}
+
+		// Prepend with "@"
+		// if not included.
+		if namestring[0] != '@' {
+			namestring = "@" + namestring
+		}
+
+		username, domain, err := util.ExtractNamestringParts(namestring)
+		if err != nil {
+			// Badly formatted,
+			// skip this one.
+			continue
+		}
+
+		if domain == thisHost || domain == thisAccountDomain {
+			// Clear the domain,
+			// since it's ours.
+			domain = ""
+		}
+
+		showReblogs, err := strconv.ParseBool(record[1])
+		if err != nil {
+			// Badly formatted,
+			// skip this one.
+			continue
+		}
+
+		// Looks good, whack it in the slice.
+		follows = append(follows, &gtsmodel.Follow{
+			TargetAccount: &gtsmodel.Account{
+				Username: username,
+				Domain:   domain,
+			},
+			ShowReblogs: &showReblogs,
+		})
+	}
+
+	return follows, nil
+}
+
+// CSVToBlocks converts a slice of CSV records
+// to a slice of barebones *gtsmodel.Block's,
+// ready for further processing.
+//
+// Only TargetAccount.Username and TargetAccount.Domain
+// will be set on each Block.
+func (c *Converter) CSVToBlocks(
+	ctx context.Context,
+	records [][]string,
+) ([]*gtsmodel.Block, error) {
+	// We need to know our own domain for this.
+	// Try account domain, fall back to host.
+	var (
+		thisHost          = config.GetHost()
+		thisAccountDomain = config.GetAccountDomain()
+		blocks            = make([]*gtsmodel.Block, 0, len(records))
+	)
+
+	for _, record := range records {
+		if len(record) != 1 {
+			// Badly formatted,
+			// skip this one.
+			continue
+		}
+
+		namestring := record[0]
+		if namestring == "" {
+			// Badly formatted,
+			// skip this one.
+			continue
+		}
+
+		// Prepend with "@"
+		// if not included.
+		if namestring[0] != '@' {
+			namestring = "@" + namestring
+		}
+
+		username, domain, err := util.ExtractNamestringParts(namestring)
+		if err != nil {
+			// Badly formatted,
+			// skip this one.
+			continue
+		}
+
+		if domain == thisHost || domain == thisAccountDomain {
+			// Clear the domain,
+			// since it's ours.
+			domain = ""
+		}
+
+		// Looks good, whack it in the slice.
+		blocks = append(blocks, &gtsmodel.Block{
+			TargetAccount: &gtsmodel.Account{
+				Username: username,
+				Domain:   domain,
+			},
+		})
+	}
+
+	return blocks, nil
+}
diff --git a/internal/workers/workers.go b/internal/workers/workers.go
index 377a9d899..657522903 100644
--- a/internal/workers/workers.go
+++ b/internal/workers/workers.go
@@ -49,6 +49,11 @@ type Workers struct {
 	// for asynchronous dereferencer jobs.
 	Dereference FnWorkerPool
 
+	// Processing provides a worker pool
+	// for asynchronous processing jobs,
+	// eg., import tasks, admin tasks.
+	Processing FnWorkerPool
+
 	// prevent pass-by-value.
 	_ nocopy
 }
@@ -81,6 +86,10 @@ func (w *Workers) Start() {
 	n = 4 * maxprocs
 	w.Dereference.Start(n)
 	log.Infof(nil, "started %d dereference workers", n)
+
+	n = 4 * maxprocs
+	w.Processing.Start(n)
+	log.Infof(nil, "started %d processing workers", n)
 }
 
 // Stop will stop all of the contained
@@ -101,6 +110,9 @@ func (w *Workers) Stop() {
 
 	w.Dereference.Stop()
 	log.Info(nil, "stopped dereference workers")
+
+	w.Processing.Stop()
+	log.Info(nil, "stopped processing workers")
 }
 
 // nocopy when embedded will signal linter to