How to stop 500 errors when UUID doesn't match

Phoenix Forum Questions / Help
, ,
1

I have an 500 error when my user changes UUID which is relation to Category UUID for inserting post.

** (exit) an exception was raised:
    ** (Ecto.ChangeError) value `"a863228-727c-4cf3-93f5-9b2f79df1288"` for `TrangellCmsService.Cms.Db.Post.cms_post_category_id` in `insert` does not match type :binary_id

How do I prevent an 500 error in client request? I want to show 400 error instead of 500 error , how do ?

my changeset :

def changeset(struct, params \\ %{}) do
        struct
        |> cast(params, @all_fields)
        |> validate_required(@all_fields)
        |> unique_constraint(:seo_alias_link, name: :index_of_post_alias_unique_link, message: "alias link already exists.")
        |> validate_inclusion(:seo_language, ["en", "fa"])
        |> validate_inclusion(:group_acl, ["admin", "actived", "unactived", "blocked"])
        |> validate_inclusion(:post_type, ["article", "shop", "free"])
        |> validate_length(:title, min: 3, max: 100)
        |> validate_length(:description, min: 100)
        |> validate_length(:seo_words, min: 3, max: 100)
        |> validate_length(:seo_description, min: 50, max: 264)
        |> foreign_key_constraint(:cms_post_category_id)
    end

19%20pm
19%20pm1000Ă—621 84.5 KB

1 Like
2

The UUID posted is invalid. I counted only 7 digits in the first group, but there need to be 8.

2 Likes
3

I know that it is invalid, I said that when UUID is invalid , phoenix shows 400 error , not shows 500 error, because my client may send invalid UUID and I don’t want Phoeinix to show 500 error.

4

Have you checked if your changeset is valid before inserting it? If it is in fact valid I’d file a bug for ecto and in the meantime add a regex validation.

If though you haven’t checked for validity, you really should before inserting…

Then if your changeset is invalid you can do any response code you want

5

my code for inserting :

	def insert_post(params) do
		changeset = Post.changeset(%Post{}, params)
		case Repo.insert(changeset) do
			{:ok, post} 				-> 	{:ok, post}
			{:error, changeset} ->  {:error, changeset}
		end
	end

You say I check UUID to validate before inserting? because my Ecto can’t validate it ? my Changesert can’t understand this error.

6

But you do not do a changeset.valid?, you really should…

1 Like
7

@shahryarjb try logging the changset before you insert it and you should see it has a field valid?: false with some more info in the errors field. You can match on these to handle your specific case.

2 Likes
8

What is the reason for checking changeset.valid?? Repo.insert checks if it is valid before inserting.

1 Like
9

Because Changeset isn’t able to validate UUID before inserting, then it shows me an 500 error.

I think , I will need to create a function to check UUID and I put this in my Changeset.

Changeset Custom error

10

It might help to have the controller code… in particular create action.

Do You use fallback controller?

11

I use umbrella project, my controller in Phoenix,

   def create_cms_post(conn, %{"title" => _title, "status" => _status, "post_type" => _post_type, "download_ext_link" => _download_ext_link, "price" => _price, "pic_x1_link" => _pic_x1_link, "pic_x2_link" => _pic_x2_link, "pic_x3_link" => _pic_x3_link, "group_acl" => _group_acl, "description" => _description, "changelog" => _changelog, "changelog_category" => _changelog_category, "plugin" => _plugin, "plugin_category" => _plugin_category, "discourse" => _discourse, "discourse_link" => _discourse_link, "screen_shot" => _screen_shot, "screen_shot_category" => _screen_shot_category, "learn" => _learn, "learn_category" => _learn_category, "seo_tag" => _seo_tag, "seo_alias_link" => _seo_alias_link, "seo_words" => _seo_words, "seo_description" => _seo_description, "seo_language" => _seo_language, "seo_language_link" => _seo_language_link, "cms_post_category_id" => _cms_post_category_id} = allreq) do

      create_cms_posts = case PostQuery.insert_post(allreq) do
         {:ok, _post} 		   -> 
            conn
            |> put_status(200)
            |> json(%{message: "The post has been created."})            
         {:error, changeset}  ->
            IO.inspect changeset
            conn
            |> put_status(403)
            |> json(%{error_code: "403"})
      end
      create_cms_posts 
   end

and my insert function in elixir project :

	def insert_post(params) do
		changeset = Post.changeset(%Post{}, params)
		case Repo.insert(changeset) do
			{:ok, post} 				-> 	{:ok, post}
			{:error, changeset} ->  {:error, changeset}
		end
	end

do you see any problem in this ?

and changeset

    def changeset(struct, params \\ %{}) do
        struct
        |> cast(params, @all_fields)
        |> validate_required(@all_fields)
        |> unique_constraint(:seo_alias_link, name: :index_of_post_alias_unique_link, message: "alias link already exists.")
        |> validate_inclusion(:seo_language, ["en", "fa"])
        |> validate_inclusion(:group_acl, ["admin", "actived", "unactived", "blocked"])
        |> validate_inclusion(:post_type, ["article", "shop", "free"])
        |> validate_length(:title, min: 3, max: 100)
        |> validate_length(:description, min: 100)
        |> validate_length(:seo_words, min: 3, max: 100)
        |> validate_length(:seo_description, min: 50, max: 264)
        |> foreign_key_constraint(:cms_post_category_id)
    end
12

Is the field actually part of @all_fields? The custome type should validate the format during cast or am I missunderstanding the custom type stuff? And how does the schema looks like?

1 Like
13

is in the controller params, so :cms_post_category_id is in @all_fields probably, otherwise I don’t see how it gets into the changeset.

Maybe do |> foreign_key_constraint(:cms_post_category_id) only if the changeset is valid (that is, cms_post_category_id’s uuid is valid). However, it shouldn’t matter. The error (Ecto.ChangeError) seems to come from the changeset anyway (and not from the database). Maybe add a helper function to check for the validity of the uuid before foreign_key_constraint.

1 Like
14

@NobbZ , my schema is : schema.ex · GitHub

My user who is admin in my web service have to comply the rules , especially he should send valid category_id which is UUID.

I user Postgres.

15

If I’m not mistaken, a :binary_id cannot be validated during the changeset process because it can be a different actual type based on the database that you are using. For example, Postgres will use Ecto.UUID as it’s :binary_id type. Whereas mongo will use a BSON.ObjectId.

Edit

This unfortunately leads to a :binary_id being any valid binary. Of course, this isn’t true in practice, but it is the best that can be done.

1 Like
16

Humm… then , how can I validate UUID , do I have a way for this?

17

It can be probably checked on per adapter basis, so postgrex would check for uuid. So @shahryarjb you should try adding a check for it before the actual dumping which I suppose happens either in cast or foreign_key_constraint. You can use the same function https://hexdocs.pm/ecto/Ecto.UUID.html#dump/1 but instead of raising, mark the changeset as invalid.

18

I have heard not to use raise in my project, because it is a time bomb.

19

It most certainly could. I just meant that you cannot do it from Ecto.Changeset.cast/4 alone because it does not know which adapter you are going to be using. A schema is not attached to an adapter.

1 Like
20

I have heard not to use raise in my project, because it is a time bomb.

I actually use raise quite often (“fail fast” and all that). I wouldn’t call it a time bomb …

1 Like