I want to get server's session value when client creates a new request.
But, server returns nil always.
I don't know what is the problem in this case.
Client
package main
import (
"io/ioutil"
"log"
"net/http"
"github.com/gorilla/mux"
"github.com/gorilla/securecookie"
"github.com/gorilla/sessions"
)
var (
store *sessions.CookieStore = sessions.NewCookieStore(securecookie.GenerateRandomKey(64))
session *sessions.Session
SessionName = "client"
)
func main() {
store.Options = &sessions.Options{
Path: "/",
MaxAge: 60 * 15,
Secure: false,
HttpOnly: true,
}
router := mux.NewRouter()
router.HandleFunc("/", cIndex)
router.HandleFunc("/test", cTest)
http.ListenAndServe(":7000", router)
}
func cIndex(w http.ResponseWriter, r *http.Request) {
session, err := store.Get(r, SessionName)
if err != nil {
log.Println("cIndex Session Error : ", err.Error())
return
}
session.Values["foo"] = "bar"
session.Save(r, w)
w.Header().Set("Location", "http://localhost:8080?foo=bar")
w.Header().Set("Content-Type", "application/x-www-form-urlencoded")
w.WriteHeader(http.StatusFound)
}
func cTest(w http.ResponseWriter, r *http.Request) {
req, err := http.NewRequest("GET", "http://localhost:8080/test", nil)
if err != nil {
log.Println("cTest Request Error : ", err.Error())
return
}
req.SetBasicAuth("sample_id", "sample_secret")
req.Header.Set("Content-Type", "application/x-www-form-urlencoded")
c := &http.Client{
Transport: &http.Transport{},
}
resp, err := c.Do(req)
if err != nil {
log.Println("cTest Response Error : ", err.Error())
return
}
defer resp.Body.Close()
body, err := ioutil.ReadAll(resp.Body)
if err != nil {
log.Println("cTest Body Error : ", err.Error())
return
}
log.Println(string(body))
}
Server
package main
import (
"encoding/json"
"log"
"net/http"
"github.com/gorilla/mux"
"github.com/gorilla/securecookie"
"github.com/gorilla/sessions"
)
var (
store *sessions.CookieStore = sessions.NewCookieStore(securecookie.GenerateRandomKey(64))
session *sessions.Session
SessionName = "server"
)
func main() {
store.Options = &sessions.Options{
Path: "/",
MaxAge: 60 * 15,
Secure: false,
HttpOnly: true,
}
router := mux.NewRouter()
router.HandleFunc("/", sIndex)
router.HandleFunc("/test", sTest)
http.ListenAndServe(":8080", router)
}
func sIndex(w http.ResponseWriter, r *http.Request) {
r.ParseForm()
v := r.FormValue("foo")
session, err := store.Get(r, SessionName)
if err != nil {
log.Println("sIndex Session Error : ", err.Error())
return
}
session.Values["foo"] = v
session.Save(r, w)
w.Header().Set("Location", "http://localhost:7000/test")
w.Header().Set("Content-Type", "application/x-www-form-urlencoded")
w.WriteHeader(http.StatusFound)
}
func sTest(w http.ResponseWriter, r *http.Request) {
session, err := store.Get(r, SessionName)
if err != nil {
log.Println("sTest Session Error : ", err.Error())
return
}
v, ok := session.Values["foo"].(string)
if !ok {
log.Printf("foo = %v\n", v)
}
data := struct {
Foo string
}{
v, // I expected v is bar,but v was nil.
}
bytes, err := json.Marshal(data)
if err != nil {
log.Println("sTest JSON Error : ", err.Error())
return
}
w.Header().Set("Content-Type", "application/json")
w.WriteHeader(http.StatusOK)
w.Write(bytes)
}
Details
Client sends request to server with query foo=bar.
Server receives the request and parsing.
Server saves query parameter in session.(I used gorilla/session)
Client makes *http.Client and send new Request to server.
Server receives request, and loads value in session, and set the value at response.
Client receives value bar
In 5, I expected that server can load the value bar from session, but session value was nil.
I wrote some codes and it moves.
Is it correct way?
Client
func cTest(w http.ResponseWrite, r *http.Request) {
serverURL := "http://localhost:8080/test"
r.Method = http.MethodGet
r.Host = serverURL // server
v, err := url.Parse(serverURL)
if err != nil {
log.Println("url parsing error occurred : ", err.Error())
return
}
c := &http.Client{Transport: &http.Transport{}}
resp, err := c.Transport.RoundTrip(r)
if err != nil {
log.Println("client roundtrip error occurred : ", err.Error())
return
}
defer resp.Body.Close()
body, err := ioutil.ReadAll(resp.Body)
if err != nil {
log.Println("response body reading error occurred : ", err.Error())
return
}
w.Write(body)
}
Related
Hello Everyone, I'm new to Go.
I'm creating a reverse proxy server using Go.
My Server has websocket. I finally get it connected.
Now I want to change websocket message body.
Sorry If my code is weird to you. Forgive me, I'm new to Go 😢
I'm wraping resp.body to NewReadWriteBody() in which contains wrapper for Read, Write and Closer. And I'm modifying message body inside it.
Here is how I'm doing with it:
package rever
// https://blog.joshsoftware.com/2021/05/25/simple-and-powerful-reverseproxy-in-go/
// https://github.com/golang/go/blob/master/src/net/http/httputil/reverseproxy.go
import (
"bytes"
"crypto/tls"
"fmt"
"io"
"io/ioutil"
"log"
"net/http"
"net/http/httputil"
"net/url"
"strconv"
)
type ReadWriteBody struct {
originBody io.ReadWriteCloser
}
func NewReadWriteBody(body io.ReadCloser) *ReadWriteBody {
b := &ReadWriteBody{}
rw, ok := body.(io.ReadWriteCloser)
if !ok {
log.Println("29: error while casting body to ReadWriteCloser")
}
b.originBody = rw
return b
}
func (b *ReadWriteBody) Read(p []byte) (n int, err error) {
buf := make([]byte, len(p))
n, err = b.originBody.Read(buf)
if err != nil {
log.Println("43: ", err.Error())
return n, err
}
buf = bytes.ReplaceAll(buf, []byte("mm.remote"), []byte("mm.local"))
copy(p[:], buf)
return len(p), nil
}
func (b *ReadWriteBody) Write(p []byte) (n int, err error) {
buf := make([]byte, len(p))
n, err = b.originBody.Write(buf)
if err != nil {
log.Println(err.Error())
return n, err
}
buf = bytes.ReplaceAll(buf, []byte("mm.local"), []byte("mm.remote"))
copy(p[:], buf)
return len(p), nil
}
func (b *ReadWriteBody) Close() error {
return b.originBody.Close()
}
type transport struct {
http.RoundTripper
}
func (t *transport) RoundTrip(req *http.Request) (resp *http.Response, err error) {
resp, err = t.RoundTripper.RoundTrip(req)
if err != nil {
log.Println("99: ", err.Error())
return nil, err
}
if resp.StatusCode == http.StatusSwitchingProtocols {
resp.Body = NewReadWriteBody(resp.Body)
return resp, nil
}
b, err := ioutil.ReadAll(resp.Body)
if err != nil {
log.Println("114: ", err.Error())
return nil, err
}
err = resp.Body.Close()
if err != nil {
log.Println("119", err.Error())
return nil, err
}
b = bytes.ReplaceAll(b, []byte("mm.remote"), []byte("mm.local"))
body := ioutil.NopCloser(bytes.NewReader(b))
resp.Body = body
resp.ContentLength = int64(len(b))
resp.Header.Set("Content-Length", strconv.Itoa(len(b)))
return resp, nil
}
var _ http.RoundTripper = &transport{}
// NewProxy takes target host and creates a reverse proxy
func NewProxy(targetHost string) (*httputil.ReverseProxy, error) {
url, err := url.Parse(targetHost)
if err != nil {
log.Println("141: ", err.Error())
return nil, err
}
proxy := httputil.NewSingleHostReverseProxy(url)
originalDirector := proxy.Director
proxy.Director = func(req *http.Request) {
originalDirector(req)
modifyRequest(req)
}
proxy.ErrorHandler = errorHandler()
dt := http.DefaultTransport.(*http.Transport).Clone()
dt.TLSClientConfig = &tls.Config{}
dt.ForceAttemptHTTP2 = false
proxy.Transport = &transport{dt}
return proxy, nil
}
func modifyRequest(req *http.Request) {
req.Host = "mm.remote"
req.Header.Set("Accept-Encoding", "identity")
}
func errorHandler() func(http.ResponseWriter, *http.Request, error) {
return func(w http.ResponseWriter, req *http.Request, err error) {
// fmt.Printf("Got error while modifying response: %v \n", err)
}
}
// ProxyRequestHandler handles the http request using proxy
func ProxyRequestHandler(proxy *httputil.ReverseProxy) func(http.ResponseWriter, *http.Request) {
return func(w http.ResponseWriter, r *http.Request) {
proxy.ServeHTTP(w, r)
}
}
func Main() {
// initialize a reverse proxy and pass the actual backend server url here
proxy, err := NewProxy("https://mm.remote")
if err != nil {
log.Println(err.Error())
panic(err)
}
// handle all requests to your server using the proxy
http.HandleFunc("/", ProxyRequestHandler(proxy))
fmt.Println("Server started")
log.Fatal(http.ListenAndServe(":8008", nil))
}
I am trying to do the following.
|Upload file in HTML post file form|
|
⌄
|Server A forwards the multipart request|
|
⌄
|Server B receives and stores the file from the forwarded multipart request|
|
⌄
|Server A receives response from Server B when Server B is done|
Processing the multipart request on Server A is straightforward, but when I try to process the forwarded request on Server B it fails with multipart: NextPart: EOF.
I am trying to create separate frontend/backend services. Frontend only handles UI related processing, while backend will actually do some processing on the file, hence the multipart request forwarding needed.
The forwarding code on Server A is as follows.
The solution has been taken from here.
https://stackoverflow.com/a/34725635/6569715
func forwardRequest(address string, path string, r *http.Request) (interface{}, error) {
body, err := ioutil.ReadAll(r.Body)
if err != nil {
return nil, err
}
r.Body = ioutil.NopCloser(bytes.NewReader(body))
proxyReq, err := http.NewRequest(r.Method, fmt.Sprintf("%s%s", address, path), bytes.NewReader(body))
if err != nil {
return nil, err
}
for header, values := range r.Header {
for _, value := range values {
proxyReq.Header.Add(header, value)
}
}
client := &http.Client{}
resp, err := client.Do(proxyReq)
if err != nil {
return nil, err
}
defer resp.Body.Close()
return resp, nil
}
And the code on Server B to process the forwarded request:
func testMultiPart(w http.ResponseWriter, r *http.Request) {
if err := r.ParseMultipartForm(10 << 20); err != nil {
err = errors.Wrap(errors.WithStack(err), "Backend: Failed to parse form")
w.WriteHeader(http.StatusInternalServerError)
fmt.Fprint(w, fmt.Sprintf("{\"error\":\"%s\"}", err.Error())
return
}
}
Any help is appreciated.
I managed to make it work. I believe it was just my own mistake not filling in the URI properly. In any case I will post my snippets from my solution for future reference.
The client html file form part:
<form action="/test-main/file-test" enctype="multipart/form-data" method="post">
<label for="file-upload">Upload your file :</label>
<input type="file" id="file-upload" name="file-upload" accept="image/*">
</form>
Server A code:
import (
"net/http"
"errors"
"fmt"
"log"
"io/ioutil"
"bytes"
"github.com/gorilla/mux"
)
func fileUpload(w http.ResponseWriter, r *http.Request) {
body, err := ioutil.ReadAll(r.Body)
if err != nil {
return log.Fatal(err)
}
r.Body = ioutil.NopCloser(bytes.NewReader(body))
// If Server A and B are separate docker images, you may need to use their docker subnet IP, like below.
proxyReq, err := http.NewRequest(r.Method, fmt.Sprintf("http://172.18.0.2:8082%s", r.RequestURI), bytes.NewReader(body))
if err != nil {
return log.Fatal(err)
}
for header, values := range r.Header {
for _, value := range values {
proxyReq.Header.Add(header, value)
}
}
client := &http.Client{}
resp, err := client.Do(proxyReq)
if err != nil {
return log.Fatal(err)
}
defer resp.Body.Close()
respBody, err := ioutil.ReadAll(resp.Body)
if err != nil {
return log.Fatal(err)
}
// Process Server B response
// ...
}
func createRouter() *mux.Router {
r := mux.NewRouter()
testPath := r.PathPrefix("/test-main").Subrouter()
testPath.HandleFunc("/file-test", fileUpload)
return r
}
func main() {
// Create Server and Route Handlers
srv := &http.Server{
Handler: createRouter(),
Addr: ":8081",
ReadTimeout: 30 * time.Second,
WriteTimeout: 30 * time.Second,
}
// Start Server
go func() {
log.Println("Starting Server")
if err := srv.ListenAndServe(); err != nil {
log.Fatal(err)
}
}()
}
And Server B code:
import (
"encoding/json"
"fmt"
"io/ioutil"
"net/http"
"github.com/gorilla/mux"
)
func uploadFile(w http.ResponseWriter, r *http.Request) {
if err := r.ParseMultipartForm(10 << 20); err != nil {
log.Fatal(err)
}
file, handler, err := r.FormFile("file-upload")
if err == http.ErrMissingFile {
return nil
}
if err != nil {
log.Fatal(err)
}
fmt.Printf("Uploaded File: %+v\n", handler.Filename)
fmt.Printf("File Size: %+v\n", handler.Size)
fmt.Printf("MIME Header: %+v\n", handler.Header)
defer file.Close()
// Create file
dst, err := os.Create(fmt.Sprintf("/some-destination-folder/%s", handler.Filename))
if err != nil {
log.Fatal(err)
}
// Copy the uploaded file to the created file on the file system.
if _, err := io.Copy(dst, file); err != nil {
if err2 := dst.Close(); err2 != nil {
log.Fatal(err)
}
log.Fatal(err)
}
dst.Close()
return nil
}
func (c *Controller) createRouter() *mux.Router {
r := mux.NewRouter()
testPath := r.PathPrefix("/test-main").Subrouter()
testPath.HandleFunc("/file-test", uploadFile)
return r
}
func main() {
// Create Server and Route Handlers
srv := &http.Server{
Handler: createRouter(),
Addr: ":8082",
ReadTimeout: 30 * time.Second,
WriteTimeout: 30 * time.Second,
}
// Start Server
go func() {
log.Println("Starting Server")
if err := srv.ListenAndServe(); err != nil {
log.Fatal(err)
}
}()
}
Good luck for future readers.
I'm writing a small package which does a GET request to an external API every 2 seconds. It takes the value from this request and passes it into a channel. I have made this channel available to a http.handler (chi router) which upgrades to a websocket where the front-end will grab the value in realtime. the panic error is a lot of lines but i guess the most important is this:
2018/11/14 16:47:55 http: response.WriteHeader on hijacked connection
2018/11/14 16:47:55 http: response.Write on hijacked connection
Aside from that I'm sure there is a better way of doing this. Any experienced Gophers out there have any pointers to help a noob such as myself improve this?
package currencyticker
import (
"bitbucket.org/special/api/config"
"encoding/json"
"fmt"
"github.com/go-chi/chi"
"github.com/go-chi/render"
"github.com/gorilla/websocket"
"github.com/leekchan/accounting"
"io/ioutil"
"log"
"math/big"
"net/http"
"time"
)
var (
ac = accounting.Accounting{Precision: 2}
from = "USD"
to = "EUR,SWK"
url = "https://min-api.currencyapi.com/data/price?fsym=" + from + "&tsyms=" + to
messages = make(chan float64)
)
var wsupgrader = websocket.Upgrader{
ReadBufferSize: 1024,
WriteBufferSize: 1024,
CheckOrigin: func(r *http.Request) bool {
return true // Disable CORS for testing
},
}
// Config - init
type Config struct {
*config.Config
}
type result map[string]float64
// New - init the configs
func New(configuration *config.Config) *Config {
return &Config{configuration}
}
// Routes - api urls
func (config *Config) Routes() *chi.Mux {
router := chi.NewRouter()
router.Use(
render.SetContentType(render.ContentTypeHTML), // Set content-Type headers as application/json
)
router.Get("/", config.GetPrice) // subscribe to new tweets
return router
}
func (config *Config) GetPrice(w http.ResponseWriter, r *http.Request) {
conn, err := wsupgrader.Upgrade(w, r, nil)
if err != nil {
fmt.Println(fmt.Printf("Failed to set websocket upgrade: %+v ", err))
return
}
for {
time.Sleep(1 * time.Second)
price := <-messages
w, err := conn.NextWriter(websocket.TextMessage)
if err != nil {
fmt.Println("ws error", err)
}
currVal := ac.FormatMoneyBigFloat(big.NewFloat(price))
if _, err := w.Write([]byte(currVal)); err != nil {
fmt.Printf("w.Write() returned %v", err)
}
w.Close()
}
}
// start getting the price of ether as soon as they ap starts
func init() {
go startPollingPriceAPI()
}
// Go Routine to start polling
func startPollingPriceAPI() {
for {
time.Sleep(2 * time.Second)
go getPriceFromAPI()
}
}
func getPriceFromAPI() {
w := http.Client{
// Timeout: time.Second * 3,
}
req, _ := http.NewRequest(http.MethodGet, url, nil)
res, err := w.Do(req)
if err != nil {
log.Println("err getting price [req]: ", err)
}
body, err := ioutil.ReadAll(res.Body)
if err != nil {
log.Println("err getting price [io-read]: ", err)
}
r := result{}
if jsonErr := json.Unmarshal(body, &r); jsonErr != nil {
log.Println("err getting price [json]: ", jsonErr)
}
fmt.Println("1 Dollar = €", r["EUR"])
messages <- r["EUR"]
}
How I can implement this kind of scenario:
1.I have LoginHandler which receives some user data - email and signedXml:
func LoginHandler(c *gin.Context) {
var (
err error
data LoginPost
)
if err = c.BindJSON(&data); err != nil {
c.JSON(http.StatusBadRequest, gin.H{"status": "error"})
return
}
...
c.JSON(http.StatusOK, gin.H{"status": "ok"})
}
2.I need to send signedXml to another server via websocket
3.Save result (success or error)
4.Close connection
Every HTTP request will open connection, send 1 message, get 1 result and finally close socket. I was trying with channel, but no success. Is this possible to implement my case?
UPDATE
package main
import (
"log"
"net/url"
"github.com/gorilla/mux"
"github.com/gorilla/websocket"
"net/http"
)
func indexHandler(w http.ResponseWriter, r *http.Request) {
message := r.FormValue("message")
w.Write([]byte(message))
}
func postHandler(w http.ResponseWriter, r *http.Request) {
var (
message = r.FormValue("message")
u = url.URL{Scheme: "ws", Host: "echo.websocket.org", Path: "/"}
err error
out []byte
conn *websocket.Conn
)
log.Printf("message: %s\n", message)
log.Printf("connecting to %s\n", u.String())
conn, _, err = websocket.DefaultDialer.Dial(u.String(), nil)
if err != nil {
log.Fatal("dial:", err)
}
log.Println("write")
if err = conn.WriteMessage(websocket.TextMessage, []byte(message)); err != nil {
log.Fatal("write:", err)
}
log.Println("read")
if _, out, err = conn.ReadMessage(); err != nil {
log.Fatal("read:", err)
}
w.Write(out)
log.Println("close")
conn.Close()
}
func main() {
r := mux.NewRouter()
r.HandleFunc("/", indexHandler).Methods("GET")
r.HandleFunc("/post", postHandler).Methods("POST")
http.Handle("/", r)
http.ListenAndServe(":8080", nil)
}
Call Dial, WriteMessage, ReadMessage and Close in sequence.
c, _, err := websocket.DefaultDialer.Dial(url, nil)
if err != nil {
// handle error
}
err := c.WriteMessage(websocket.TextMessage, signedXML)
if err != nil {
// handle error
}
_, p, err := c.ReadMessage()
if err != nil {
// handle error
}
c.Close()
// p is a []byte with the first received message.
I'm trying to create login with google api authentication with oauth2.
I'm getting response from google api (response.body) as:
{
"id": "received ID",
"email": "EMAIL",
"verified_email": true,
"name": "Name",
}
How can I access that data inside go program so that I can store it in database?
package main
import (
"fmt"
"io/ioutil"
"log"
"net/http"
"net/url"
"strings"
"golang.org/x/oauth2"
"golang.org/x/oauth2/google"
"encoding/json"
)
var (
oauthConf = &oauth2.Config{
ClientID: "CLIENTID",
ClientSecret: "Secret",
RedirectURL: "http://localhost:8011/showprofile",
//Scopes: []string{"https://www.googleapis.com/auth/plus.login"},
Scopes:[]string{"profile","email"},
Endpoint: google.Endpoint,
}
oauthStateString = "thisshouldberandom"
)
const htmlIndex = `<html><body>
Logged in with facebook
</body></html>
`
func handleMain(w http.ResponseWriter, r *http.Request) {
w.Header().Set("Content-Type", "text/html; charset=utf-8")
w.WriteHeader(http.StatusOK)
w.Write([]byte(htmlIndex))
}
func handleGoogleLogin(w http.ResponseWriter, r *http.Request) {
Url, err := url.Parse(oauthConf.Endpoint.AuthURL)
if err != nil {
log.Fatal("Parse: ", err)
}
parameters := url.Values{}
parameters.Add("client_id", oauthConf.ClientID)
parameters.Add("scope", strings.Join(oauthConf.Scopes, " "))
parameters.Add("redirect_uri", oauthConf.RedirectURL)
parameters.Add("response_type", "code")
parameters.Add("state", oauthStateString)
Url.RawQuery = parameters.Encode()
url := Url.String()
fmt.Println("URL" + url)
http.Redirect(w, r, url, http.StatusTemporaryRedirect)
}
func handleGoogleCallback(w http.ResponseWriter, r *http.Request) {
fmt.Println("Call back working")
state := r.FormValue("state")
if state != oauthStateString {
fmt.Printf("invalid oauth state, expected '%s', got '%s'\n", oauthStateString, state)
http.Redirect(w, r, "/", http.StatusTemporaryRedirect)
return
}
code := r.FormValue("code")
token, err := oauthConf.Exchange(oauth2.NoContext, code)
if err != nil {
fmt.Printf("oauthConf.Exchange() failed with '%s'\n", err)
http.Redirect(w, r, "/", http.StatusTemporaryRedirect)
return
}
resp,err:= http.Get("https://www.googleapis.com/oauth2/v2/userinfo?access_token=" + token.AccessToken)
if err != nil {
fmt.Printf("Get: %s\n", err)
http.Redirect(w, r, "/", http.StatusTemporaryRedirect)
return
}
fmt.Println(resp.Body)
defer resp.Body.Close()
response, err := ioutil.ReadAll(resp.Body)
if err != nil {
fmt.Printf("ReadAll: %s\n", err)
http.Redirect(w, r, "/showprofile", http.StatusTemporaryRedirect)
return
}
log.Printf("parseResponseBody: %s\n", string(response))
http.Redirect(w, r, "/showprofile", http.StatusTemporaryRedirect)
}
func main() {
http.HandleFunc("/", handleMain)
http.HandleFunc("/login", handleGoogleLogin)
http.HandleFunc("/showprofile", handleGoogleCallback)
fmt.Print("Started running on http://localhost:8011\n")
log.Fatal(http.ListenAndServe(":8011", nil))
}
Fixed it by using json.Unmarshal.