Mercurial > gemma
view pkg/middleware/json.go @ 4316:3d6a2c6b436c
shape upload stretch import: Store features in database. Still broken [WIP].
author | Sascha L. Teichmann <sascha.teichmann@intevation.de> |
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date | Tue, 03 Sep 2019 19:01:51 +0200 |
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) }) }