eantyshev commented on code in PR #23349: URL: https://github.com/apache/beam/pull/23349#discussion_r982437891
########## learning/tour-of-beam/backend/middleware.go: ########## @@ -0,0 +1,79 @@ +// Licensed to the Apache Software Foundation (ASF) under one +// or more contributor license agreements. See the NOTICE file +// distributed with this work for additional information +// regarding copyright ownership. The ASF licenses this file +// to you under the Apache License, Version 2.0 (the +// "License"); you may not use this file except in compliance +// with the License. You may obtain a copy of the License at +// +// http://www.apache.org/licenses/LICENSE-2.0 +// +// Unless required by applicable law or agreed to in writing, +// software distributed under the License is distributed on an +// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY +// KIND, either express or implied. See the License for the +// specific language governing permissions and limitations +// under the License. + +package tob + +import ( + "log" + "net/http" + + tob "beam.apache.org/learning/tour-of-beam/backend/internal" +) + +// Middleware-maker for setting a header +// We also make this less generic: it works with HandlerFunc's +// so that to be convertible to func(w http ResponseWriter, r *http.Request) +// and be accepted by functions.HTTP. +func AddHeader(header, value string) func(http.HandlerFunc) http.HandlerFunc { + return func(next http.HandlerFunc) http.HandlerFunc { + return func(w http.ResponseWriter, r *http.Request) { + w.Header().Add(header, value) + next(w, r) + } + } +} + +// Middleware to check http method. +func EnsureMethod(method string) func(http.HandlerFunc) http.HandlerFunc { + return func(next http.HandlerFunc) http.HandlerFunc { + return func(w http.ResponseWriter, r *http.Request) { + if r.Method == method { + next(w, r) + } else { + w.WriteHeader(http.StatusMethodNotAllowed) + } + } + } +} + +// Helper common AIO middleware +func Common(next http.HandlerFunc) http.HandlerFunc { + addContentType := AddHeader("Content-Type", "application/json") + addCORS := AddHeader("Access-Control-Allow-Origin", "*") + ensureGet := EnsureMethod(http.MethodGet) + + return ensureGet(addCORS(addContentType(next))) +} + +// HandleFunc enriched with sdk. +type HandlerFuncWithSdk func(w http.ResponseWriter, r *http.Request, sdk tob.Sdk) + +// middleware to parse sdk query param and pass it as additional handler param. +func ParseSdkParam(next HandlerFuncWithSdk) http.HandlerFunc { + return func(w http.ResponseWriter, r *http.Request) { + sdkStr := r.URL.Query().Get("sdk") + sdk := tob.ParseSdk(sdkStr) + + if sdk == tob.SDK_UNDEFINED { + log.Printf("Bad sdk: %v", sdkStr) + finalizeErrResponse(w, http.StatusBadRequest, BAD_FORMAT, "unknown sdk") Review Comment: Just realized that it makes no sense responding with SDK value to the client: it has just given it as a query parameter -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: [email protected] For queries about this service, please contact Infrastructure at: [email protected]
