Monthly Archives: August 2017

Tooling Not Craft

August 29, 2017 By in Software Engineering Tags: 3 Comments

For a while, I’ve had the nagging feeling that there’s something missing with the way that many junior developers learn to write software these days. In a way that I suppose makes me a bit of a curmudgeon, I somewhat long for the days before the prevalence of the IDE and the automated unit test framework.   But rationally I know that IDE’s and other specialized tooling have done a lot to both cut grunt work and to eliminate accidental complexity so it’s hard to deny they’re a big step forward from what came before.

And then it occurred to me.  Some of my issue with the modern tendency toward doing everything in the IDE is the tendency that weaker developers have to conflate tooling with craft.  Because Eclipse has the ability to automatically generate getters and setters for each data member of a Java class they simply stop questioning the wisdom of having getters and setters for all the members and merrily march forward–exposing far more data than they should.  The benefit of data hiding, which, after all, was the original benefit of private class members is largely lost because they can’t be bothered to actually think through the wisdom of effectively turning a class into a pseudo-struct.

A long time ago when I first began coding I had a senior developer who mentored me.  I had a bit of a tendency to charge in and start changing code (I am still guilty of that I suppose) without really thinking through the problem.  He wisely counseled me to take a few minutes to think about the problem before I started hacking.  Now I think I understand how he felt.

Don’t get me wrong–better tooling is definitely a good thing.  But don’t let your tooling dictate your craft. And if you want to be a truly better developer focus on learning the craft of building strong code.  The tooling is important, of course, but the underlying craft is much more important.

Some Updates On “LDAP Authentication With Phoenix”

August 7, 2017 By in Elixir, Software Engineering, Tools Leave a comment

There’s an excellent write-up on authenticating users against an LDAP database with Phoenix which was created by Richard Nyström.  For some reason even though it’s barely a year old, there seem to be a few points that are either out of date or simply incorrect. I worked through his example and I wanted to share a few amendments to his original code in the interests of other developers who may want to use LDAP with Phoenix.

First the set up of Phoenix


mix phx.new ldap_example # was mix phoenix.new ldap_example
...
Fetch and install dependencies? [Yn] Y

cd ldap_example

mix ecto.create (configure your db in config/dev.exs if needed)

mix phx.gen.schema User users username:string name:string email:string
# was
# mix phoenix.gen.model User users username:string name:string email:string

mix ecto.migrate

Next change is in the session_controller.ex file:


#was LdapExample.SessionController

defmodule LdapExampleWeb.SessionController do

#was LdapExample.Web, :controller

use LdapExampleWeb, :controller
alias LdapExample.{User, Repo, Ldap}

def new(conn, _params) do
render conn, "new.html", changeset: User.login_changeset
end

def create(conn, %{"user" => params}) do
username = params["username"]
password = params["password"]
case Ldap.authenticate(username, password) do
:ok -> handle_sign_in(conn, username)
_ -> handle_error(conn)
end
end

defp handle_sign_in(conn, username) do
{:ok, user} = insert_or_update_user(username)
conn
|> put_flash(:info, "Logged in.")
|> Guardian.Plug.sign_in(user)
|> redirect(to: page_path(conn, :index))
end

defp insert_or_update_user(username) do
{:ok, ldap_entry} = Ldap.get_by_uid(username)
user_attributes = Ldap.to_map(ldap_entry)
user = Repo.get_by(User, username: username)
changeset =
case user do
nil -> User.changeset(%User{}, user_attributes)
_ -> User.changeset(user, user_attributes)
end
Repo.insert_or_update changeset
end

defp handle_error(conn) do
conn
|> put_flash(:error, "Wrong username or password")
|> redirect(to: page_path(conn, :new))
end

def delete(conn, _params) do
Guardian.Plug.sign_out(conn)
|> put_flash(:info, "Logged out successfully.")
|> redirect(to: "/")
end
end

The changes to user.ex are not made in the web/model/user.ex; rather they’re made in the existing user.ex file.

And finally a change to session_view.ex

#was LdapExample.SessionView

defmodule LdapExampleWeb.SessionView do

use LdapExampleWeb, :view

end