Mercurial > gemma
view pkg/middleware/json.go @ 5095:e21cbb9768a2
Prevent duplicate fairway areas
In principal, there can be only one or no fairway area at each point
on the map. Since polygons from real data will often be topologically
inexact, just disallow equal geometries. This will also help to
avoid importing duplicates with concurrent imports, once the history
of fairway dimensions will be preserved.
author | Tom Gottfried <tom@intevation.de> |
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date | Wed, 25 Mar 2020 18:10:02 +0100 |
parents | 4394daeea96a |
children | 6270951dda28 |
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// This is Free Software under GNU Affero General Public License v >= 3.0 // without warranty, see README.md and license for details. // // SPDX-License-Identifier: AGPL-3.0-or-later // License-Filename: LICENSES/AGPL-3.0.txt // // Copyright (C) 2019 by via donau // – Österreichische Wasserstraßen-Gesellschaft mbH // Software engineering by Intevation GmbH // // Author(s): // * Sascha L. Teichmann <sascha.teichmann@intevation.de> package middleware import ( "context" "encoding/json" "io" "net/http" ) type jsonInputKeyType int const jsonInputKey jsonInputKeyType = 0 // DefaultLimit limits the incoming JSON payload to 2K to // prevent flooding the server. const DefaultLimit = 2048 // GetJSONInput returns the deserialized JSON data from // the incoming request if any. func GetJSONInput(req *http.Request) interface{} { return req.Context().Value(jsonInputKey) } // JSONMiddleware is a middleware to deserialize the incomming // request body to a object to be created by a given input function // and stores the result into the context. // GetJSONInput can be used to receive the deserialized data. // limit limits the size of the incoming body to prevent // flooding the server. func JSONMiddleware(next http.Handler, input func(*http.Request) interface{}, limit int64) http.Handler { return http.HandlerFunc(func(rw http.ResponseWriter, req *http.Request) { dst := input(req) defer req.Body.Close() var r io.Reader switch { case limit == 0: r = io.LimitReader(req.Body, DefaultLimit) case limit > 0: r = io.LimitReader(req.Body, limit) default: r = req.Body } if err := json.NewDecoder(r).Decode(dst); err != nil { http.Error(rw, "error: "+err.Error(), http.StatusBadRequest) return } parent := req.Context() ctx := context.WithValue(parent, jsonInputKey, input) req = req.WithContext(ctx) next.ServeHTTP(rw, req) }) }