Questions & Help>Questions

Phoenix custom error doesn't work

/phoenix#troubleshooting#custom-error
shahryarjb

shahryarjb

I have read phoenix documents and edited my code but it didn’t work for me.

my dev config :

config :trangell_html_site_web, TrangellHtmlSiteWeb.Endpoint,
  http: [port: 9991],
  debug_errors: false,
  code_reloader: true,
  check_origin: false,
  watchers: [node: ["node_modules/brunch/bin/brunch", "watch", "--stdin",
                    cd: Path.expand("../assets", __DIR__)]]

my ErrorView :

  def render("404.html", _assigns) do
   "Page not found"
  end

  def render("500.html", _assigns) do
    "Server internal error"
  end

  def template_not_found(template, _assigns) do
    Phoenix.Controller.status_message_from_template(template)
  end

but it shows me :

55%20pm
55%20pm1440×900 123 KB

How can I fix this ?

ref

https://hexdocs.pm/phoenix/errors.html
https://hexdocs.pm/phoenix/views.html#the-errorview

phoenix 1.3 || elixir v1.6.4

13 comments
/phoenix#troubleshooting#custom-error
5547 13

Showing Posts 1 to 10

und0ck3d

und0ck3d

That’s a bit weird, just tested on a new app (generated with phx.new task) and it’s working fine… Only thing I changed was the debug_errors option to false as you did. Can you provide an example repo to reproduce the issue?

1
Post #1
josevalim

josevalim

Creator of Elixir

What is your Elixir version? There is a bug in Elixir before v1.7 where a change of configuration inside the umbrella project was not applying in some cases. If you remove _build at the umbrella root, does the issue still persists?

3
Post #3
shahryarjb

shahryarjb OP

Hello, my elixir ver is v1.6.4, I removed my _build and I saw this which was fixed. thank you , I’ll update this soon to 1.7

3
Post #4
shahryarjb

shahryarjb OP

@josevalim
Unfortunately, I have a problem with this part, I want to redirect to html error page but I can’t

defmodule TrangellHtmlSiteWeb.ErrorView do
  use TrangellHtmlSiteWeb, :view

  # If you want to customize a particular status code
  # for a certain format, you may uncomment below.
  def render("404.html", _assigns) do
  "Page not found"
  end

  def render("500.html", _assigns) do
    "Server internal error"
  end

  # In case no render clause matches or no
  # template is found, let's render it as 500
  def template_not_found(_template, assigns) do
    render "500.html", assigns
  end

  def template_not_found(template, _assigns) do
    Phoenix.Controller.status_message_from_template(template)
  end
end

I edited this to

def render("404.html", _assigns) do
    render "404.html", %{}
end

but it didn’t work, how can I fix this?

0
Post #5
NobbZ

NobbZ

This produces an infinite loop.

1
Post #6
shahryarjb

shahryarjb OP

Then what do I do to fix this? would you mind telling me? Please

1
Post #7
NobbZ

NobbZ

What is it you actually want? If you want some HTML template rendered, then do so. As far as I remember you simply need to provide the template in the template/error folder and then leave off the render clause.

1
Post #8
shahryarjb

shahryarjb OP

Hmm, Im confused, honestly I need it to show my 404.html.eex instead of text, I have created 2 html .eex before, but I can’t use these.

for example:

<!-- /web/templates/error/404.html.eex -->
<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="utf-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1">
    <meta name="description" content="">
    <meta name="author" content="">

    <title>404 - Page Not Found</title>
    <link rel="stylesheet" href="<%= static_path(@conn, "/css/app.css") %>">
  </head>

  <body>
    <h1>404 - Page Not Found</h1>
    <p>This isn't the page you were looking for.</p>
  </body>
</html>

that is my web/templates/error/404.html.eex , but It isn’t shown when I enter broken url. it shows me a text but I want that.

Updated:

now I know, I have to delete all of my codes in My ErrorView except the following line:

def template_not_found(template, _assigns) do
    Phoenix.Controller.status_message_from_template(template)
end

I have 2 questions

q1: when I have 401 or 403 status; What is happens? can I custom them ?
q2: I have a FallbackController please see my code:

defmodule TrangellHtmlSiteWeb.BlogFallbackController do
  use Phoenix.Controller

    def call(conn, {:ok, %HTTPoison.Response{status_code: 404, body: _body}}) do
      conn
      |> put_flash(:info, "متاسفانه صفحه ای که به دنبال آن هستید وجود ندارد.")
      |> render(TrangellHtmlSiteWeb.ErrorView , :"404")
    end
end

I render render(TrangellHtmlSiteWeb.ErrorView , :"404") and it shows me an error in centre of my template, but in the main page if I try like: local.com/404 it just shows me full 404 error page, independently!!

Please see:

pic 1:

21%20pm
21%20pm1440×900 77.7 KB

pic2:

28%20pm
28%20pm1440×900 66.4 KB

how can I redirect it to 404full page with the session which I need?

0
Post #9
shahryarjb

shahryarjb OP

somebody knows what my problem is?
I was forced to use redirect(conn, to: "/404")

path: controllers/blog_fallback_controller.ex

def call(conn, {:ok, %HTTPoison.Response{status_code: 404, body: _body}}) do
      conn
      |> put_flash(:info, "متاسفانه صفحه ای که به دنبال آن هستید وجود ندارد.")
      |> redirect( to: "/404")
 end

and

<!-- /web/templates/error/404.html.eex -->
  <body>
      <%= if Phoenix.Controller.get_flash(@conn, :info) do %>
    <div class="clearfix"> </div>
    <div class="speacer40"></div>
      <div class="alert alert-warning alert-dismissible fade show container rtl-m" role="alert">
        <%= Phoenix.Controller.get_flash(@conn, :info) %>
        <button type="button" class="close" data-dismiss="alert" aria-label="Close">
          <span aria-hidden="true">&times;</span>
        </button>
      </div>
    <% end %>
    <h1>403 - Page Not Found</h1>
    <p>This isn't the page you were looking for.</p>
  </body>

get_flash doesn’t work and I can’t use session, what do I do ?

** (exit) an exception was raised:
    ** (ArgumentError) flash not fetched, call fetch_flash/2
        (phoenix) lib/phoenix/controller.ex:1236: Phoenix.Controller.get_flash/1
        (phoenix) lib/phoenix/controller.ex:1250: Phoenix.Controller.get_flash/2
0
Post #10

Where Next? Top

View thread on forum (has 13 replies!)
phoenix
troubleshooting
custom-error
Home Questions & Help>Questions
13 5418 13
Last post
REPLY VIEW THREAD WITH 13 POSTS

Trending in Questions Top

RSP87
Questions & Help>Questions

Programming Phoenix chat example - iPhone lack of socket updates
I’m working on a project that simulates the bumbl example in the programming phoenix book. It acts almost like an email client. We have a...
/phoenix#troubleshooting
1 950 6
New
nseaSeb
Questions & Help>Questions

What's the approach for handling lists that allows for optimized traversal?
Hello, I know there is an approach for handling lists that allows for optimized traversal, but I can’t recall the specific method (somet...
#learning-elixir#list
13 419 15
New
RemyXRenard
Questions & Help>Questions

Livebook DataTable displaying charlist as list
I’m seeing that a list inside a Kino.DataTable will be interpreted as a charlist, even if the Kino.configure() is set to charlists: :as_l...
/livebook#charlist
2 325 3
New
brecabral
Questions & Help>Questions

Scoped Routes section of the Phoenix guides refers to a problem without explaining what it is ("but there is a problem")
Documentation While reading the Scoped Routes section, I noticed that the documentation currently refers to a problem without explainin...
/phoenix
2 232 2
New
velrest
Questions & Help>Questions

`:erlang.float` vs `value * 1.0`: Which is the prefered way?
So my question is quite simple and i have found no conclusive answer on forum, google or AI. Should we use :erlang.float for Integer to ...
#learning-elixir
12 638 5
New
samoloth
Questions & Help>Questions

Prevent_hijacking? on email change confirmation with magic link strategy
Hi, I’ve just set up an application with ash_authentication. There is only magic link strategy for now, so there is no confirmation add o...
/ash#ash-authentication
0 196 1
New
FlyingNoodle
Questions & Help>Questions

Should change and preparation modules validate arguments?
If a change or preparation module uses Ash.Changeset.get_argument/2 or Ash.Query.get_argument/2 (or any of the other get_argument functio...
/ash
1 138 1
New

Other Trending Topics Top

mudasobwa
Chat & Discussions>Discussions

Cure - a new language compiled to BEAM
I am happy to introduce the very α version of the new programming language compiled to BEAM. Welcome Cure. It has literally three kille...
#static-types#type-checking#types#fsm
168 5507 69
New
marciok
News>Announcing

Gust - A task orchestration system built in Elixir
Hi there! We created Gust: A task orchestrator inspired by Airflow. For those who have never heard about Aiflow, it’s a Python-based wor...
/phoenix/oban#library#workflow#background_job#reactor
111 4469 40
New
jimsynz
News>Announcing

Beam Bots - Resilient Robotics on the BEAM
Beam Bots (or just BB for short) is a framework for building fault-tolerant robotics applications in Elixir using familiar OTP patterns. ...
/beam-bots#library#robotics#bb
119 2916 28
New
Dmk
News>Announcing

Xamal - Deploy Elixir releases to bare metal servers via SSH
Xamal is a deployment tool for Elixir apps that deploys native releases to bare metal servers over SSH. It’s a port of GitHub - basecamp/...
#library#deployment#deploy#deployments#xamal
75 2512 33
New
netoum
News>Announcing

Corex - Accessible and unstyled UI Phoenix components
Corex is an accessible, unstyled UI component library for Phoenix that integrates Zag.js state machines using Vanilla JavaScript and Live...
/phoenix#library#ui#liveview#hooks#accessibility#component#tableau
63 2662 20
New
webofbits
Chat & Discussions>AI / LLMs

How much do you still code yourself?
With AI doing more of the implementation work, I’ve been wondering how much coding I should deliberately keep doing myself. My main conc...
#ai
202 1626 84
New
Back to top

Latest Phoenix Threads

Phoenix Forum ❯

Questions & Help>Questions

Questions Questions ❯

Latest on Elixir Forum

Elixir Forum ❯

Sponsor Spotlight

AppSignal

Catch errors, track performance, monitor hosts and more.

Our Sponsors

EEF

Supporting innovation across the BEAM ecosystem.

Coders51

We build reliable cloud platforms for business-critical systems.

AppSignal

Catch errors, track performance, monitor hosts and more.

Honeybadger

Error tracking, logs, uptime, and Just Enough APM. Built for developers.

Code Sync

Elixir, Erlang & BEAM conferences from Code Sync - join us in 2026!

Manning

Master modern tools, write cleaner code, and tackle real-world challenges.

WyeWorks

**Building the future of software with AI, trust, and human connection.**

Potions

The deployment platform built for Elixir: PaaS ease, VPS control.

Software Mansion

The team behind Membrane, Popcorn, LiveDebugger. Available for hire.

Pragmatic Studio

Courses that'll move you from confusion to "Aha, now I get it!"

View all our sponsors ❯

Categories:

Sub Categories:

Forums

Popular Tags

Our Sponsors

EEF

Supporting innovation across the BEAM ecosystem.

Coders51

We build reliable cloud platforms for business-critical systems.

AppSignal

Catch errors, track performance, monitor hosts and more.

Honeybadger

Error tracking, logs, uptime, and Just Enough APM. Built for developers.

Code Sync

Elixir, Erlang & BEAM conferences from Code Sync - join us in 2026!

Manning

Master modern tools, write cleaner code, and tackle real-world challenges.

WyeWorks

**Building the future of software with AI, trust, and human connection.**

Potions

The deployment platform built for Elixir: PaaS ease, VPS control.

Software Mansion

The team behind Membrane, Popcorn, LiveDebugger. Available for hire.

Pragmatic Studio

Courses that'll move you from confusion to "Aha, now I get it!"

View all our sponsors ❯

We're in Beta

About us Mission Statement

Options

Thread Display Mode




Thread Preview

Skip Thread Previews