mirror of
https://github.com/superseriousbusiness/gotosocial.git
synced 2025-10-31 18:32:25 -05:00
91 lines
2.7 KiB
Go
91 lines
2.7 KiB
Go
// GoToSocial
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// Copyright (C) GoToSocial Authors admin@gotosocial.org
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// SPDX-License-Identifier: AGPL-3.0-or-later
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//
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// This program is free software: you can redistribute it and/or modify
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// it under the terms of the GNU Affero General Public License as published by
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// the Free Software Foundation, either version 3 of the License, or
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// (at your option) any later version.
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//
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// This program is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU Affero General Public License for more details.
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//
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// You should have received a copy of the GNU Affero General Public License
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// along with this program. If not, see <http://www.gnu.org/licenses/>.
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package transport
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import (
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"context"
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"net/http"
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"net/url"
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apiutil "code.superseriousbusiness.org/gotosocial/internal/api/util"
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"code.superseriousbusiness.org/gotosocial/internal/gtserror"
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"codeberg.org/gruf/go-bytesize"
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"codeberg.org/gruf/go-iotools"
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"github.com/temoto/robotstxt"
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)
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func (t *transport) DereferenceRobots(ctx context.Context, protocol string, host string) (*robotstxt.RobotsData, error) {
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robotsIRI := &url.URL{
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Scheme: protocol,
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Host: host,
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Path: "robots.txt",
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}
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// Build IRI just once
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iriStr := robotsIRI.String()
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// Prepare new HTTP request to endpoint
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req, err := http.NewRequestWithContext(ctx, "GET", iriStr, nil)
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if err != nil {
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return nil, err
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}
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// We want text/plain utf-8 encoding.
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//
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// https://www.rfc-editor.org/rfc/rfc9309.html#name-access-method
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req.Header.Add("Accept", apiutil.TextPlain)
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req.Header.Add("Accept-Charset", apiutil.UTF8)
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// Perform the HTTP request
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rsp, err := t.GET(req)
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if err != nil {
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return nil, err
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}
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// Ensure a non-error status response.
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if rsp.StatusCode != http.StatusOK {
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err := gtserror.NewFromResponse(rsp)
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_ = rsp.Body.Close() // close early.
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return nil, err
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}
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// Ensure that the incoming request content-type is expected.
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if ct := rsp.Header.Get("Content-Type"); !apiutil.TextPlainContentType(ct) {
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err := gtserror.Newf("non text/plain response: %s", ct)
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_ = rsp.Body.Close() // close early.
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return nil, gtserror.SetMalformed(err)
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}
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// Limit the robots.txt size to 500KiB
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//
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// https://www.rfc-editor.org/rfc/rfc9309.html#name-limits
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const maxsz = int64(500 * bytesize.KiB)
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// Check body claims to be within size limit.
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if rsp.ContentLength > maxsz {
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_ = rsp.Body.Close() // close early.
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sz := bytesize.Size(maxsz) //nolint:gosec
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return nil, gtserror.Newf("robots.txt body exceeds max size %s", sz)
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}
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// Update response body with maximum size.
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rsp.Body, _, _ = iotools.UpdateReadCloserLimit(rsp.Body, maxsz)
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defer rsp.Body.Close()
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return robotstxt.FromResponse(rsp)
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}
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