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Um simples proxy reverso feito em Go
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| package main | |
| import ( | |
| "bytes" | |
| "encoding/json" | |
| "fmt" | |
| "io/ioutil" | |
| "log" | |
| "net/http" | |
| "net/http/httputil" | |
| "net/url" | |
| "os" | |
| "strings" | |
| ) | |
| type Mservice struct { | |
| Hash string `json:"hash"` | |
| Path string `json:"path"` | |
| Name string `json:"name"` | |
| Count int32 `json:"count"` | |
| } | |
| func (e Mservice) toString() string { | |
| return toJson(e) | |
| } | |
| func toJson(p interface{}) string { | |
| bytes, err := json.Marshal(p) | |
| if err != nil { | |
| fmt.Println(err.Error()) | |
| os.Exit(1) | |
| } | |
| return string(bytes) | |
| } | |
| // Get env var or default | |
| func getEnv(key, fallback string) string { | |
| if value, ok := os.LookupEnv(key); ok { | |
| return value | |
| } | |
| return fallback | |
| } | |
| /* | |
| Getters | |
| */ | |
| // Get the port to listen on | |
| func getListenAddress() string { | |
| port := getEnv("PORT", "8000") | |
| return "0.0.0.0:" + port | |
| } | |
| func searchMservice(name string, listaMs []Mservice) Mservice { | |
| fmt.Println("searchMservice name=", name) | |
| var mservice Mservice | |
| for _, elem := range listaMs { | |
| if name == elem.Name { | |
| mservice = elem | |
| break | |
| } | |
| } | |
| return mservice | |
| } | |
| // Get the port to listen on | |
| func getMservice(req *http.Request, listaMs []Mservice) Mservice { | |
| prefix := strings.Split(req.RequestURI, "/") | |
| fmt.Println("prefix", prefix) | |
| return searchMservice(prefix[1], listaMs) | |
| } | |
| /* | |
| Reverse Proxy Logic | |
| */ | |
| // Serve a reverse proxy for a given url | |
| func serveReverseProxy(target string, res http.ResponseWriter, req *http.Request) { | |
| // parse the url | |
| url, _ := url.Parse(target) | |
| // create the reverse proxy | |
| proxy := httputil.NewSingleHostReverseProxy(url) | |
| // Update the headers to allow for SSL redirection | |
| req.URL.Host = url.Host | |
| req.URL.Scheme = url.Scheme | |
| req.Header.Set("X-Forwarded-Host", req.Header.Get("Host")) | |
| req.Host = url.Host | |
| // Note that ServeHttp is non blocking and uses a go routine under the hood | |
| proxy.ServeHTTP(res, req) | |
| } | |
| // Given a request send it to the appropriate url | |
| func handleRequestAndRedirect(res http.ResponseWriter, req *http.Request) { | |
| // requestPayload := parseRequestBody(req) | |
| // url := getProxyUrl(requestPayload.ProxyCondition) | |
| var item Mservice = getMservice(req, listaMs) | |
| url := item.Path | |
| api := strings.Replace(req.RequestURI, "/"+item.Name, "", 1) | |
| req.URL.Path = api | |
| item.Count++ | |
| serveReverseProxy(url, res, req) | |
| } | |
| func handleRegisterMService(res http.ResponseWriter, req *http.Request) { | |
| var tmp Mservice | |
| // Read body | |
| b, err := ioutil.ReadAll(req.Body) | |
| defer req.Body.Close() | |
| if err != nil { | |
| http.Error(res, err.Error(), 500) | |
| return | |
| } | |
| // Unmarshal | |
| err = json.Unmarshal(b, &tmp) | |
| if err != nil { | |
| http.Error(res, err.Error(), 500) | |
| return | |
| } | |
| var novoRegistro Mservice = Mservice{ | |
| Hash: tmp.Hash, | |
| Path: "http://" + req.RemoteAddr, //req.Host, | |
| Name: tmp.Name, | |
| Count: 0, | |
| } | |
| listaMs = append(listaMs, novoRegistro) | |
| res.Write([]byte(listaMs[5].toString())) | |
| } | |
| var listaMs []Mservice | |
| func main() { | |
| settings := os.Getenv("SETTINGS") | |
| file, _ := ioutil.ReadFile(settings) | |
| _ = json.Unmarshal([]byte(file), &listaMs) | |
| // start server | |
| http.HandleFunc("/register", handleRegisterMService) | |
| http.HandleFunc("/", handleRequestAndRedirect) | |
| if err := http.ListenAndServe(getListenAddress(), nil); err != nil { | |
| panic(err) | |
| } | |
| } |
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