[feature] request blocking by http headers (#2409)

internal/processing/admin/headerfilter.go

@@ -0,0 +1,215 @@
+// 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 admin
+
+import (
+	"context"
+	"errors"
+	"net/textproto"
+	"regexp"
+
+	apimodel "github.com/superseriousbusiness/gotosocial/internal/api/model"
+	"github.com/superseriousbusiness/gotosocial/internal/db"
+	"github.com/superseriousbusiness/gotosocial/internal/gtserror"
+	"github.com/superseriousbusiness/gotosocial/internal/gtsmodel"
+	"github.com/superseriousbusiness/gotosocial/internal/headerfilter"
+	"github.com/superseriousbusiness/gotosocial/internal/id"
+	"github.com/superseriousbusiness/gotosocial/internal/util"
+)
+
+// GetAllowHeaderFilter fetches allow HTTP header filter with provided ID from the database.
+func (p *Processor) GetAllowHeaderFilter(ctx context.Context, id string) (*apimodel.HeaderFilter, gtserror.WithCode) {
+	return p.getHeaderFilter(ctx, id, p.state.DB.GetAllowHeaderFilter)
+}
+
+// GetBlockHeaderFilter fetches block HTTP header filter with provided ID from the database.
+func (p *Processor) GetBlockHeaderFilter(ctx context.Context, id string) (*apimodel.HeaderFilter, gtserror.WithCode) {
+	return p.getHeaderFilter(ctx, id, p.state.DB.GetBlockHeaderFilter)
+}
+
+// GetAllowHeaderFilters fetches all allow HTTP header filters stored in the database.
+func (p *Processor) GetAllowHeaderFilters(ctx context.Context) ([]*apimodel.HeaderFilter, gtserror.WithCode) {
+	return p.getHeaderFilters(ctx, p.state.DB.GetAllowHeaderFilters)
+}
+
+// GetBlockHeaderFilters fetches all block HTTP header filters stored in the database.
+func (p *Processor) GetBlockHeaderFilters(ctx context.Context) ([]*apimodel.HeaderFilter, gtserror.WithCode) {
+	return p.getHeaderFilters(ctx, p.state.DB.GetBlockHeaderFilters)
+}
+
+// CreateAllowHeaderFilter inserts the incoming allow HTTP header filter into the database, marking as authored by provided admin account.
+func (p *Processor) CreateAllowHeaderFilter(ctx context.Context, admin *gtsmodel.Account, request *apimodel.HeaderFilterRequest) (*apimodel.HeaderFilter, gtserror.WithCode) {
+	return p.createHeaderFilter(ctx, admin, request, p.state.DB.PutAllowHeaderFilter)
+}
+
+// CreateBlockHeaderFilter inserts the incoming block HTTP header filter into the database, marking as authored by provided admin account.
+func (p *Processor) CreateBlockHeaderFilter(ctx context.Context, admin *gtsmodel.Account, request *apimodel.HeaderFilterRequest) (*apimodel.HeaderFilter, gtserror.WithCode) {
+	return p.createHeaderFilter(ctx, admin, request, p.state.DB.PutBlockHeaderFilter)
+}
+
+// DeleteAllowHeaderFilter deletes the allowing HTTP header filter with provided ID from the database.
+func (p *Processor) DeleteAllowHeaderFilter(ctx context.Context, id string) gtserror.WithCode {
+	return p.deleteHeaderFilter(ctx, id, p.state.DB.DeleteAllowHeaderFilter)
+}
+
+// DeleteBlockHeaderFilter deletes the blocking HTTP header filter with provided ID from the database.
+func (p *Processor) DeleteBlockHeaderFilter(ctx context.Context, id string) gtserror.WithCode {
+	return p.deleteHeaderFilter(ctx, id, p.state.DB.DeleteBlockHeaderFilter)
+}
+
+// getHeaderFilter fetches an HTTP header filter with
+// provided ID, using given get function, converting the
+// resulting filter to returnable frontend API model.
+func (p *Processor) getHeaderFilter(
+	ctx context.Context,
+	id string,
+	get func(context.Context, string) (*gtsmodel.HeaderFilter, error),
+) (
+	*apimodel.HeaderFilter,
+	gtserror.WithCode,
+) {
+	// Select filter by ID from db.
+	filter, err := get(ctx, id)
+
+	switch {
+	// Successfully found.
+	case err == nil:
+		return toAPIHeaderFilter(filter), nil
+
+	// Filter does not exist with ID.
+	case errors.Is(err, db.ErrNoEntries):
+		const text = "filter not found"
+		return nil, gtserror.NewErrorNotFound(errors.New(text), text)
+
+	// Any other error type.
+	default:
+		err := gtserror.Newf("error selecting from database: %w", err)
+		return nil, gtserror.NewErrorInternalError(err)
+	}
+}
+
+// getHeaderFilters fetches all HTTP header filters
+// using given get function, converting the resulting
+// filters to returnable frontend API models.
+func (p *Processor) getHeaderFilters(
+	ctx context.Context,
+	get func(context.Context) ([]*gtsmodel.HeaderFilter, error),
+) (
+	[]*apimodel.HeaderFilter,
+	gtserror.WithCode,
+) {
+	// Select all filters from DB.
+	filters, err := get(ctx)
+
+	if err != nil && !errors.Is(err, db.ErrNoEntries) {
+		// Only handle errors other than not-found types.
+		err := gtserror.Newf("error selecting from database: %w", err)
+		return nil, gtserror.NewErrorInternalError(err)
+	}
+
+	// Convert passed header filters to apimodel filters.
+	apiFilters := make([]*apimodel.HeaderFilter, len(filters))
+	for i := range filters {
+		apiFilters[i] = toAPIHeaderFilter(filters[i])
+	}
+
+	return apiFilters, nil
+}
+
+// createHeaderFilter inserts the given HTTP header
+// filter into database, marking as authored by the
+// provided admin, using the given insert function.
+func (p *Processor) createHeaderFilter(
+	ctx context.Context,
+	admin *gtsmodel.Account,
+	request *apimodel.HeaderFilterRequest,
+	insert func(context.Context, *gtsmodel.HeaderFilter) error,
+) (
+	*apimodel.HeaderFilter,
+	gtserror.WithCode,
+) {
+	// Convert header key to canonical mime header format.
+	request.Header = textproto.CanonicalMIMEHeaderKey(request.Header)
+
+	// Validate incoming header filter.
+	if errWithCode := validateHeaderFilter(
+		request.Header,
+		request.Regex,
+	); errWithCode != nil {
+		return nil, errWithCode
+	}
+
+	// Create new database model with ID.
+	var filter gtsmodel.HeaderFilter
+	filter.ID = id.NewULID()
+	filter.Header = request.Header
+	filter.Regex = request.Regex
+	filter.AuthorID = admin.ID
+	filter.Author = admin
+
+	// Insert new header filter into the database.
+	if err := insert(ctx, &filter); err != nil {
+		err := gtserror.Newf("error inserting into database: %w", err)
+		return nil, gtserror.NewErrorInternalError(err)
+	}
+
+	// Finally return API model response.
+	return toAPIHeaderFilter(&filter), nil
+}
+
+// deleteHeaderFilter deletes the HTTP header filter
+// with provided ID, using the given delete function.
+func (p *Processor) deleteHeaderFilter(
+	ctx context.Context,
+	id string,
+	delete func(context.Context, string) error,
+) gtserror.WithCode {
+	if err := delete(ctx, id); err != nil && !errors.Is(err, db.ErrNoEntries) {
+		err := gtserror.Newf("error deleting from database: %w", err)
+		return gtserror.NewErrorInternalError(err)
+	}
+	return nil
+}
+
+// toAPIFilter performs a simple conversion of database model HeaderFilter to API model.
+func toAPIHeaderFilter(filter *gtsmodel.HeaderFilter) *apimodel.HeaderFilter {
+	return &apimodel.HeaderFilter{
+		ID:        filter.ID,
+		Header:    filter.Header,
+		Regex:     filter.Regex,
+		CreatedBy: filter.AuthorID,
+		CreatedAt: util.FormatISO8601(filter.CreatedAt),
+	}
+}
+
+// validateHeaderFilter validates incoming filter's header key, and regular expression.
+func validateHeaderFilter(header, regex string) gtserror.WithCode {
+	// Check header validity (within our own bound checks).
+	if header == "" || len(header) > headerfilter.MaxHeaderValue {
+		const text = "invalid request header key (empty or too long)"
+		return gtserror.NewErrorBadRequest(errors.New(text), text)
+	}
+
+	// Ensure this is compilable regex.
+	_, err := regexp.Compile(regex)
+	if err != nil {
+		return gtserror.NewErrorBadRequest(err, err.Error())
+	}
+
+	return nil
+}