Entwicklung

7. July 20227. July 2022

Golang get openid-connect userinfo

It might not be news to you, but this will explain a little bit about Go, making http requests and parsing the result.

OpenID-Connect (oidc) is an identity protocol, you could call it an Oauth2 dialect. It manages your users per realm, well not the protocol but the server does.
Every oidc idp (identity provider aka server) should support the oidc discovery feature.
What is a good OIDC IDP? Keycloak for instance, because it’s free.
Essentially it’s a well known URI that provides information about this IDP or this IDP’s realm in JSON.
The “.well-known/openid-configuration” is appended to the IDP.
To see a live one you could navigate to https://connect.icod.de/auth/realms/testrealm/.well-known/openid-configuration

It lists all the endpoints this server handles and supported grant types and much much more.

I’ve been working with websockets lately and faced the challenge that websockets don’t support passing HTTP headers,
so I had to log in with the token my frontend received by the IDP. And for security reasons this had to be the raw token, not the parsed subject field, because it’s not cryptographically protected.
This means I had to ask the IDP if the token I had received was valid and extract the subject from it.

The below code is the 1st version of how I did it.
It queries the openid-connect discovery document, since the structure was unknown to me, I decoded the response body from the request into a map[string]interface{}.
However in retrospect, I could’ve defined a struct with only the single requested variable in it:

type DiscoveryDocument struct {
	UserinfoEndpoint string `json:"userinfo_endpoint"`
}

type DiscoveryDocument struct {

UserinfoEndpoint string `json:"userinfo_endpoint"`

}

Then this userinfo endpoint is queried with the Accesstoken passed as a Bearer token in the Authorization header.
The result is decoded into the UserInfo struct instance and returned by the function.

I use spew, which is a very helpful tool to display the content of the returned variable.

package main

import (
	"encoding/json"
	"fmt"
	"log"
	"net/http"
	
	"github.com/davecgh/go-spew/spew"
)

type UserInfo struct {
	Subject string `json:"sub"`
	Email string `json:"email"`
	EmailVerified bool `json:"email_verified"`
	Name string `json:"name"`
	FamilyName string `json:"family_name"`
	GivenName string `json:"given_name"`
	PreferredUsername string `json:"preferred_username"`
}

func main() {
		token := "ey...paste your token here"
		discoveryURL := "https://localhost:8080/auth/realms/testrealm/.well-known/openid-configuration"
		userInfo := getUserInfo(token, discoveryURL)
		spew.Dump(userInfo)
}

func getUserInfo(token, discoveryURL string) *UserInfo {
	rsp, e := http.Get(discoveryURL)
	if e != nil {
		log.Println("getUserInfo: could not connect to oidc idp", e.Error())
		return nil
	}
	rspbody := make(map[string]interface{})
	dec := json.NewDecoder(rsp.Body)
	if e := dec.Decode(&rspbody); e != nil {
		log.Println("getUserInfo: decode oidc response body", e.Error())
		return nil
	}
	uie := rspbody["userinfo_endpoint"].(string)
	client := http.DefaultClient
	uireq, e := http.NewRequest(http.MethodGet, uie, nil)
	if e != nil {
		log.Println("getUserInfo: NewRequest error", e.Error())
		return nil
	}
	uireq.Header.Set("Authorization", fmt.Sprintf("Bearer %s", token))
	uirsp, e := client.Do(uireq)
	if e != nil {
		log.Println("getUserInfo: could not connect to oidc userinfo endpoint", e.Error())
		return nil
	}
	userinfo := new(UserInfo)
	uidec := json.NewDecoder(uirsp.Body)
	if e := uidec.Decode(userinfo); e != nil {
		log.Println("getUserInfo: could not connect decode userinfo endpoint response body", e.Error())
		return nil
	}
	return userinfo
}

package main

import (

"encoding/json"

"fmt"

"log"

"net/http"

"github.com/davecgh/go-spew/spew"

)

type UserInfo struct {

Subject string `json:"sub"`

Email string `json:"email"`

EmailVerified bool `json:"email_verified"`

Name string `json:"name"`

FamilyName string `json:"family_name"`

GivenName string `json:"given_name"`

PreferredUsername string `json:"preferred_username"`

}

func main() {

token := "ey...paste your token here"

discoveryURL := "https://localhost:8080/auth/realms/testrealm/.well-known/openid-configuration"

userInfo := getUserInfo(token, discoveryURL)

spew.Dump(userInfo)

}

func getUserInfo(token, discoveryURL string) *UserInfo {

rsp, e := http.Get(discoveryURL)

if e != nil {

log.Println("getUserInfo: could not connect to oidc idp", e.Error())

return nil

}

rspbody := make(map[string]interface{})

dec := json.NewDecoder(rsp.Body)

if e := dec.Decode(&rspbody); e != nil {

log.Println("getUserInfo: decode oidc response body", e.Error())

return nil

}

uie := rspbody["userinfo_endpoint"].(string)

client := http.DefaultClient

uireq, e := http.NewRequest(http.MethodGet, uie, nil)

if e != nil {

log.Println("getUserInfo: NewRequest error", e.Error())

return nil

}

uireq.Header.Set("Authorization", fmt.Sprintf("Bearer %s", token))

uirsp, e := client.Do(uireq)

if e != nil {

log.Println("getUserInfo: could not connect to oidc userinfo endpoint", e.Error())

return nil

}

userinfo := new(UserInfo)

uidec := json.NewDecoder(uirsp.Body)

if e := uidec.Decode(userinfo); e != nil {

log.Println("getUserInfo: could not connect decode userinfo endpoint response body", e.Error())

return nil

}

return userinfo

}

19. May 20223. June 2022

False Alarm: Serious Bug in MongoDB Go Driver’s Geospatial distance calculation

Final Edit: False Alarm

It’s not MongoDB, It’s not the MongoDB Go driver, it’s something I did.
I was especially careful to double and triple check Long and Lat and still something went wrong.

Continue reading “False Alarm: Serious Bug in MongoDB Go Driver’s Geospatial distance calculation”

1. April 20221. April 2022

The stupidity and ambiguitiy of Vue

Rant mode:

Which idiots name template references “ref” and then name essentially all composition api variables “ref()” as well!?!

YEAH GOOD FUCKING JOB VUE DEVELOPER IDIOTS
It makes searching for answer so much more fucking frustrating! Fucking idiots.

14. March 202214. March 2022

Spring Data JPA fixtures

What are fixtures? Fixed data that is always present in the database. You can think of it as the initial dataset.

application.properties

spring.jpa.hibernate.ddl-auto=create
spring.jpa.generate-ddl=true
spring.jpa.open-in-view=false
spring.sql.init.mode=always
spring.sql.init.data-locations=classpath:db/data.sql
spring.jpa.defer-datasource-initialization=true

spring.jpa.hibernate.ddl-auto=create

spring.jpa.generate-ddl=true

spring.jpa.open-in-view=false

spring.sql.init.mode=always

spring.sql.init.data-locations=classpath:db/data.sql

spring.jpa.defer-datasource-initialization=true

The documentation speaks of “the root classpath”, not knowing Java well I had no idea what that means and an answer on Stackoverflow was of course wrong.
It’s not the “src” dir, but the “resources” dir.

So with the above configuration we set spring.sql.init.data-locations=classpath:db/data.sql
which means we create a directory named “db” under src/main/resources.
Also we create a file named “data.sql”.

If you have spring.jpa.hibernate.ddl-auto=create but not spring.jpa.defer-datasource-initialization=true, data.sql will be executed before the schema is created by JPA and then the tables will be destroyed and created.

data.sql obviously contains sql statements like INSERT INTO profiles (name) VALUES('Darko').
data.sql is only for data, don’t use it for schema.
The location setting for schema is spring.sql.init.schema-locations= e.g. spring.sql.init.schema-locations=classpath:db/schema.sql.
Since you’re using schema.sql you don’t need to defer data initialization.

Details at the Spring Boot JPA reference documentation

14. March 202214. March 2022

Spring Data JPA Postgres UUID @Id

I read lots of outdated info on this matter.

Using PostgreSQL v13+ there is a function called gen_random_uuid().
See the manual page of Postgres UUID.

Here’s an example entity called Page

package de.icod.blog.model;

import javax.persistence.*;
import java.util.UUID;

@Entity
@Table(name = "page")
public class Page {
    @Id
    @GeneratedValue(strategy = GenerationType.AUTO)
    @Column(name = "id", nullable = false, columnDefinition = "UUID default gen_random_uuid()")
    private UUID id;

    public UUID getId() {
        return id;
    }

    public void setId(UUID id) {
        this.id = id;
    }
}

package de.icod.blog.model;

import javax.persistence.*;

import java.util.UUID;

@Entity

@Table(name = "page")

public class Page {

@Id

@GeneratedValue(strategy = GenerationType.AUTO)

@Column(name = "id", nullable = false, columnDefinition = "UUID default gen_random_uuid()")

private UUID id;

public UUID getId() {

return id;

}

public void setId(UUID id) {

this.id = id;

}

As you see you can append the columnDefinition to the @Column annotation. “UUID default gen_random_uuid()”
This translates to following SQL

create table page
(
    id uuid default gen_random_uuid() not null
        constraint "primary"
            primary key
);

create table page

(

id uuid default gen_random_uuid() not null

constraint "primary"

primary key

);

And you don’t have to worry about having an empty ID when inserting records.