Handle Mongo Connection with Percent-Encoding in Go

connection() : auth error: sasl conversation error: unable to authenticate using mechanism “SCRAM-SHA-1”: (AuthenticationFailed) Authentication failed.

Problem

I was tried to connect with mongo db with simple connection with mongo-go-driver. Here the code main.go :

package main
import (
 "context"
 "fmt"
 "net/url"
"go.mongodb.org/mongo-driver/mongo"
 "go.mongodb.org/mongo-driver/mongo/options"
 "go.mongodb.org/mongo-driver/mongo/readpref"
)
var ctx = context.Background()
func main() {
 driver := "mongodb"
 host := "127.0.0.1"
 port := "27017"
 username := "kecci"
 password := "p@sword%20"
URL := url.URL{
  Scheme: driver,
  Host:   fmt.Sprintf("%s:%s", host, port),
 }
if username != "" || password != "" {
  URL.User = url.UserPassword(username, password)
 }
fmt.Printf("URI: %s \n", URL.String())
 clientOptions := options.Client().ApplyURI(URL.String())
 clientOptions.SetDirect(true)
client, err := mongo.Connect(ctx, clientOptions)
 if err != nil {
  fmt.Printf("error when mongo.Connect(ctx, clientOptions), %v, %v", clientOptions, err)
 }
 err = client.Ping(ctx, readpref.Primary())
 if err != nil {
  fmt.Println(err.Error())
  return
 }
 fmt.Println("ping success")
}

Then I got Error looks like in this output:

mongodb://kecci:p%40sword%2520@127.0.0.1:27017
connection() : auth error: sasl conversation error: unable to authenticate using mechanism “SCRAM-SHA-1”: (AuthenticationFailed) Authentication failed.

My username and password is include symbolic characters. Which it’s use format URL Encode or Percent-Encode by RF3986.

MongoDB Documentation:

MongoDB Documentation for Connection String

I use package net/url to generate URL (ofcourse with URL Encode).

Which mean, I do “Double Encode”

Let’s see how the comparison before, after, and expected format:

Before parsed to URL   : p@sword%20
After parsed to URL    : p%40sword%2520
Expected parsed to URL : p%40sword%20

As you can see the symbol of % parsed to %25. Which is it cause of the Wrong Password.

Which is it cause of the Wrong Password.

Solving

So now I should handle it with url.QueryUnescape from net/url package golang.

And here how I solve it inmain.go :

package main
import (
 "context"
 "fmt"
 "net/url"
"go.mongodb.org/mongo-driver/mongo"
 "go.mongodb.org/mongo-driver/mongo/options"
 "go.mongodb.org/mongo-driver/mongo/readpref"
)
var ctx = context.Background()
func main() {
 driver := "mongodb"
 host := "127.0.0.1"
 port := "27017"
 username, err := url.QueryUnescape("kecci")
 if err != nil {
  username = "kecci"
 }
 password, err := url.QueryUnescape("p@sword%20")
 if err != nil {
  password = "p@sword%20"
 }
URL := url.URL{
  Scheme: driver,
  Host:   fmt.Sprintf("%s:%s", host, port),
 }
if username != "" || password != "" {
  URL.User = url.UserPassword(username, password)
 }
fmt.Printf("URI: %s \n", URL.String())
 clientOptions := options.Client().ApplyURI(URL.String())
 clientOptions.SetDirect(true)
client, err := mongo.Connect(ctx, clientOptions)
 if err != nil {
  fmt.Printf("error when mongo.Connect(ctx, clientOptions), %v, %v", clientOptions, err)
 }
 err = client.Ping(ctx, readpref.Primary())
 if err != nil {
  fmt.Println(err.Error())
  return
 }
 fmt.Println("ping success")
}

output:

mongodb://kecci:p%40sword%20@127.0.0.1:27017
ping success

Conclusion

What I’m trying to do to solve it is :

1. Try to Decode URL / Unescape Query of my password & username. If decode got an error, we re-set the username & password before.
2. After username & password was clear without Encode URL / Percent-Encode. We proceed the URL.String() to get the final format.
3. Done. You can try connect to your mongo db with the right URI.

I also put the code on my github: https://github.com/kecci/mongo-connection-go

That’s all. Have a good day.

Thank You.

Source

• https://docs.mongodb.com/manual/reference/connection-string/#examples
• https://tools.ietf.org/html/rfc3986#section-2.1
• https://en.wikipedia.org/wiki/Percent-encoding