I understand about the password but it is being hashed somewhere but did not include it coz my problem was the exception being thrown. What is the best way to match it @benwilson512?
greyhwndz
benwilson512
Author of Craft GraphQL APIs in Elixir with Absinthe
Well, let’s think about the control flow you might want. get_user_by_email! uses Repo.get_by!. What happens if it doesn’t return any records? It raises an exception. This means that you’d need to handle it with try / catch in your controller, but this probably isn’t what you want. So I’d get rid of the ! on get_by as well as on get_user_by_email to start with.
So now the question: what does get_by return? Well, it returns either the struct that that you asked for, or nil. So you need to handle the result out of get_user_by_email based on whether the result is nil or not. if is one option, pattern matching on %Library.User{} is another. I’ll leave the actual refactoring of the controller action as an exercise for the reader.
2
greyhwndz
@benwilson512 thanks for the response!
I tried removing the ! at both get_user_by_email and get_by.
I also tried refactoring the SessionController to:
case Library.get_user_by_email(email) do
{user} ->
conn
|> put_view(LibraryApiWeb.SessionView)
|> render("token.json", user: user)
{nil} ->
conn
|> put_status(:unauthorized)
|> put_view(LibraryApiWeb.ErrorView)
|> render("401.json-api", %{detail: "Error logging in a user with that email and password"})
{:error, _reason} ->
conn
|> put_status(:unauthorized)
|> put_view(LibraryApiWeb.ErrorView)
|> render("401.json-api", %{detail: "Error logging in a user with that email and password"})
end
but the following error bugged me:
iex(1)> [info] POST /api/session
iex(1)> [debug] Processing with LibraryApiWeb.SessionController.create/2
Parameters: %{"email" => "maria@hello.com", "password" => "[FILTERED]"}
Pipelines: [:api]
iex(1)> [debug] QUERY OK source="users" db=0.0ms
SELECT u0."id", u0."email", u0."password_hash", u0."username", u0."inserted_at", u0."updated_at" FROM "users" AS u0 WHERE (u0."email" = $1) ["maria@hello.com"]
iex(1)> [info] Converted error {:case_clause, %LibraryApi.Library.User{__meta__: #Ecto.Schema.Metadata<:loaded, "users">, email: "maria@hello.com", id: 4, inserted_at: ~N[2019-05-12 08:41:18], password: nil, password_confirmation: nil, password_hash: "$2b$12$7qHpuOzPJaJShZoO4DCmAe9K/vHvsGwGPRlVmGzHQUlLkCBpgOZ82", updated_at: ~N[2019-05-12 08:41:18], username: "maria"}} to 500 response
iex(1)> [info] Sent 500 in 78ms
iex(1)> [error] #PID<0.451.0> running LibraryApiWeb.Endpoint (connection #PID<0.450.0>, stream id 1) terminated
Server: localhost:4000 (http)
Request: POST /api/session
** (exit) an exception was raised:
** (CaseClauseError) no case clause matching: %LibraryApi.Library.User{__meta__: #Ecto.Schema.Metadata<:loaded, "users">, email: "maria@hello.com", id: 4, inserted_at: ~N[2019-05-12 08:41:18], password: nil, password_confirmation: nil, password_hash: "$2b$12$7qHpuOzPJaJShZoO4DCmAe9K/vHvsGwGPRlVmGzHQUlLkCBpgOZ82", updated_at: ~N[2019-05-12 08:41:18], username: "maria"}
(library_api) lib/library_api_web/controllers/session_controller.ex:7: LibraryApiWeb.SessionController.create/2
(library_api) lib/library_api_web/controllers/session_controller.ex:1: LibraryApiWeb.SessionController.action/2
(library_api) lib/library_api_web/controllers/session_controller.ex:1: LibraryApiWeb.SessionController.phoenix_controller_pipeline/2
(library_api) lib/library_api_web/endpoint.ex:1: LibraryApiWeb.Endpoint.instrument/4
(phoenix) lib/phoenix/router.ex:275: Phoenix.Router.__call__/1
(library_api) lib/library_api_web/endpoint.ex:1: LibraryApiWeb.Endpoint.plug_builder_call/2
(library_api) lib/library_api_web/endpoint.ex:1: LibraryApiWeb.Endpoint.call/2
(phoenix) lib/phoenix/endpoint/cowboy2_handler.ex:33: Phoenix.Endpoint.Cowboy2Handler.init/2
(cowboy) d:/@@@/@gilbertc77/library_api/deps/cowboy/src/cowboy_handler.erl:41: :cowboy_handler.execute/2
(cowboy) d:/@@@/@gilbertc77/library_api/deps/cowboy/src/cowboy_stream_h.erl:296: :cowboy_stream_h.execute/3
(cowboy) d:/@@@/@gilbertc77/library_api/deps/cowboy/src/cowboy_stream_h.erl:274: :cowboy_stream_h.request_process/3
(stdlib) proc_lib.erl:249: :proc_lib.init_p_do_apply/3
There is a line in that iex console dump that catches my eye
iex(1)> [info] Converted error {:case_clause, %LibraryApi.Library.User{__meta__: #Ecto.Schema.Metadata<:loaded, "users">, email: "maria@hello.com", id: 4, inserted_at: ~N[2019-05-12 08:41:18], password: nil, password_confirmation: nil, password_hash: "$2b$12$7qHpuOzPJaJShZoO4DCmAe9K/vHvsGwGPRlVmGzHQUlLkCBpgOZ82", updated_at: ~N[2019-05-12 08:41:18], username: "maria"}} to 500 response
What does Converted error mean?
Also there was a warning before that:
warning: this clause cannot match because a previous clause at line 8 always matches
lib/library_api_web/controllers/session_controller.ex:12
0
greyhwndz
Got already beyond the CaseClauseError by editing the SessionController from:
def create(conn, %{"email" => email, "password" => _password}) do
case Library.get_user_by_email(email) do
{user} ->
conn
|> put_view(LibraryApiWeb.SessionView)
|> render("token.json", user: user)
{nil} ->
conn
|> put_status(:unauthorized)
|> put_view(LibraryApiWeb.ErrorView)
|> render("401.json-api", %{detail: "Error logging in a user with that email and password"})
{:error, _reason} ->
conn
|> put_status(:unauthorized)
|> put_view(LibraryApiWeb.ErrorView)
|> render("401.json-api", %{detail: "Error logging in a user with that email and password"})
end
end
to
def create(conn, %{"email" => email, "password" => _password}) do
case Library.get_user_by_email(email) do
user ->
conn
|> put_view(LibraryApiWeb.SessionView)
|> render("token.json", user: user)
nil ->
conn
|> put_status(:unauthorized)
|> put_view(LibraryApiWeb.ErrorView)
|> render("401.json-api", %{detail: "Error logging in a user with that email and password"})
{:error, _reason} ->
conn
|> put_status(:unauthorized)
|> put_view(LibraryApiWeb.ErrorView)
|> render("401.json-api", %{detail: "Error logging in a user with that email and password"})
end
end
This means my controller is already working and now another error is hounding me concerning JWT using Joken in my SessionView:
def render("token.json", %{user: user}) do
mydata = %{id: user.id, email: user.email, username: user.username}
jwt = %{data: mydata, sub: user.id}
|> Joken.generate_and_sign(nil, Joken.Signer.create("HS512", "SOMESECRETVALUE"))
#IO.inspect jwt
%{token: jwt.token}
end
the error is:
iex(1)> [info] Converted error :badarg to 500 response
iex(1)> [info] Sent 500 in 94ms
iex(1)> [error] #PID<0.449.0> running LibraryApiWeb.Endpoint (connection #PID<0.448.0>, stream id 1) terminated
Server: localhost:4000 (http)
Request: POST /api/session
** (exit) an exception was raised:
** (ArgumentError) argument error
:erlang.apply({:ok, "eyJhbGciOiJIUzUxMiIsInR5cCI6IkpXVCJ9.e30.OcmgLBuda2S8amZVN2V7ux2RdWJJKZiSZAv2IBndBQjuiWyoHmge8bmufXrA92wPCZLO0xXEA-b41fy7oOWNOg", %{}}, :token, [])
(library_api) lib/library_api_web/views/session_view.ex:10: LibraryApiWeb.SessionView.render/2
(phoenix) lib/phoenix/view.ex:399: Phoenix.View.render_to_iodata/3
(phoenix) lib/phoenix/controller.ex:729: Phoenix.Controller.__put_render__/5
(phoenix) lib/phoenix/controller.ex:746: Phoenix.Controller.instrument_render_and_send/4
(library_api) lib/library_api_web/controllers/session_controller.ex:1: LibraryApiWeb.SessionController.action/2
(library_api) lib/library_api_web/controllers/session_controller.ex:1: LibraryApiWeb.SessionController.phoenix_controller_pipeline/2
(library_api) lib/library_api_web/endpoint.ex:1: LibraryApiWeb.Endpoint.instrument/4
(phoenix) lib/phoenix/router.ex:275: Phoenix.Router.__call__/1
(library_api) lib/library_api_web/endpoint.ex:1: LibraryApiWeb.Endpoint.plug_builder_call/2
(library_api) lib/library_api_web/endpoint.ex:1: LibraryApiWeb.Endpoint.call/2
(phoenix) lib/phoenix/endpoint/cowboy2_handler.ex:33: Phoenix.Endpoint.Cowboy2Handler.init/2
(cowboy) d:/@@@/@gilbertc77/library_api/deps/cowboy/src/cowboy_handler.erl:41: :cowboy_handler.execute/2
(cowboy) d:/@@@/@gilbertc77/library_api/deps/cowboy/src/cowboy_stream_h.erl:296: :cowboy_stream_h.execute/3
(cowboy) d:/@@@/@gilbertc77/library_api/deps/cowboy/src/cowboy_stream_h.erl:274: :cowboy_stream_h.request_process/3
(stdlib) proc_lib.erl:249: :proc_lib.init_p_do_apply/3
How can I extract the token from the jwt?
0
benwilson512
Author of Craft GraphQL APIs in Elixir with Absinthe
Use IO.inspect on the jwt value to figure out what its shape is if you can’t determine that from the error message. Then, based on its shape, consider how you might want to change jwt = so that jwt is bound to just the token string and not the entire return result.
1
greyhwndz
@benwilson512 thanks I have the following code now for my SessionView:
defmodule LibraryApiWeb.SessionView do
use LibraryApiWeb, :view
def render("token.json", %{user: user}) do
data = %{id: user.id, email: user.email, username: user.username}
jwt = %{data: data, sub: user.id}
theToken = Joken.generate_and_sign!(jwt, nil, Joken.Signer.create("HS512", "SOMESECRETVALUE"))
%{token: theToken}
end
end
The current problem that I am facing is that the generated token is invalid.
What could I be doing wrong with Joken this time?
0
benwilson512
Author of Craft GraphQL APIs in Elixir with Absinthe
You have a variable here theToken. Do you understand what it is? What type of datastructure is it? A string? A map? A tuple?
1
greyhwndz
It is a string @benwilson512.
That last line produces:
{
"token": "eyJhbGciOiJIUzUxMiIsInR5cCI6IkpXVCJ9.e30.OcmgLBuda2S8amZVN2V7ux2RdWJJKZiSZAv2IBndBQjuiWyoHmge8bmufXrA92wPCZLO0xXEA-b41fy7oOWNOg"
}
0
benwilson512
Author of Craft GraphQL APIs in Elixir with Absinthe
Ah yes, that is correct now, you changed from Joken.generate_and_sign which you had in the previous post to Joken.generate_and_sign!. Joken.generate_and_sign returns a tuple, Joken.generate_and_sign! returns a string. However if you changed that it shoul dhave solved yout :erlang.apply error, so what’s the new error you have?
2
greyhwndz
There are no more errors @benwilson512!
Only that the generated token seems to not have a payload when I paste it into the debugger in http://jwt.io.
I might be doing something wrong along the way. Something like a logical error
0