Elixir - undefined function do_match/4 - ecto

Question

To refactor, I'm trying to move code out of my router into controllers.
I'm getting this error when I do so:
== Compilation error on file lib/api/controllers/product.ex ==
** (CompileError) lib/plug/router.ex:211: undefined function do_match/4
(stdlib) lists.erl:1338: :lists.foreach/2
(stdlib) erl_eval.erl:670: :erl_eval.do_apply/6
controller
defmodule Api.Controllers.Product do
use Plug.Router
import Api.ProductCategory
alias Api.ProductCategory, as: ProductCategory
import Api.Product
import Api.Shop
alias Api.Shop, as: Shop
alias Api.Product, as: Product
import Api.ProductShop
alias Api.ProductShop, as: ProductShop
import Api.Subcategory
alias Api.Subcategory, as: Subcategory
import Api.Category
alias Api.Category, as: Category
import Ecto.Query
import Api.Repo
def put_product(conn) do
errors = {}
# IO.inspect(conn.body_params)
# IO.inspect(conn.query_params["p_id"])
product = Api.Product |> Api.Repo.get(conn.query_params["p_id"])
shop = Api.Shop |> Api.Repo.get(conn.query_params["s_id"])
params = for key <- ~w(image description),
value = conn.body_params[key], into: %{},
do: {key, value}
changeset = Api.Product.changeset(product, params)
case Api.Repo.update(changeset) do
{:ok, product} ->
errors = Tuple.append(errors, "Product updated")
{:error, changeset} ->
errors = Tuple.append(errors, "Product not updated")
end
pid = conn.query_params["p_id"]
sid = conn.query_params["s_id"]
price = conn.body_params["price"]
product_shop = Api.Repo.get_by(ProductShop, s_id: sid, p_id: pid)
IO.inspect(product_shop)
changeset2 = Api.ProductShop.changeset(product_shop, %{price: price})
case Api.Repo.update(changeset2) do
{:ok, product_shop} ->
errors = Tuple.append(errors, "Price updated")
{:error, changeset2} ->
errors = Tuple.append(errors, "Price not updated")
end
IO.inspect(errors)
conn
|> put_resp_content_type("application/json")
|> send_resp(200, Poison.encode!(%{
successs: "success",
errors: Tuple.to_list(errors)
}))
end
end
router.ex
defmodule Api.Router do
use Plug.Router
import Api.ProductCategory
alias Api.ProductCategory, as: ProductCategory
import Api.Product
import Api.Shop
alias Api.Shop, as: Shop
alias Api.Product, as: Product
import Api.ProductShop
alias Api.ProductShop, as: ProductShop
import Api.Subcategory
alias Api.Subcategory, as: Subcategory
import Api.Category
alias Api.Category, as: Category
import Ecto.Query
import Api.Controllers.Product
alias Api.Controllers.Product, as: ProductController
if Mix.env == :dev do
use Plug.Debugger
end
plug :match
plug Plug.Parsers, parsers: [:json],
pass: ["application/json"],
json_decoder: Poison
plug :dispatch
get "/favicon.ico" do
# get_categories(conn)
end
get "/categories/" do
get_categories(conn)
end
options "/categories/" do
get_categories(conn)
end
....
put "/products" do
ProductController.put_product(conn)
end
...
What is causing the error?
Full error:
Benjamins-MacBook-Pro:api Ben$ iex -S mix
Erlang/OTP 19 [erts-8.2] [source] [64-bit] [smp:8:8] [async-threads:10] [hipe] [kernel-poll:false] [dtrace]
Compiling 2 files (.ex)
warning: the variable "errors" is unsafe as it has been set inside a case/cond/receive/if/&&/||. Please explic
itly return the variable value instead. For example:
case int do
1 -> atom = :one
2 -> atom = :two
end
should be written as
atom =
case int do
1 -> :one
2 -> :two
end
Unsafe variable found at:
lib/api/controllers/product.ex:54
warning: the variable "errors" is unsafe as it has been set inside a case/cond/receive/if/&&/||. Please explic
itly return the variable value instead. For example:
case int do
1 -> atom = :one
2 -> atom = :two
end
should be written as
atom =
case int do
1 -> :one
2 -> :two
end
Unsafe variable found at:
lib/api/controllers/product.ex:56
warning: the variable "errors" is unsafe as it has been set inside a case/cond/receive/if/&&/||. Please explic
itly return the variable value instead. For example:
case int do
1 -> atom = :one
2 -> atom = :two
end
should be written as
atom =
case int do
1 -> :one
2 -> :two
end
Unsafe variable found at:
lib/api/controllers/product.ex:59
lib/api/controllers/product.ex:59
warning: the variable "errors" is unsafe as it has been set inside a case/cond/receive/if/&&/||. Please explic
itly return the variable value instead. For example:
case int do
1 -> atom = :one
2 -> atom = :two
end
should be written as
atom =
case int do
1 -> :one
2 -> :two
end
Unsafe variable found at:
lib/api/controllers/product.ex:65
warning: variable "shop" is unused
lib/api/controllers/product.ex:30
warning: variable "product" is unused
lib/api/controllers/product.ex:38
warning: variable "changeset" is unused
lib/api/controllers/product.ex:40
warning: variable "product_shop" is unused
lib/api/controllers/product.ex:53
warning: variable "changeset2" is unused
lib/api/controllers/product.ex:55
== Compilation error on file lib/api/controllers/product.ex ==
** (CompileError) lib/plug/router.ex:211: undefined function do_match/4
(stdlib) lists.erl:1338: :lists.foreach/2
(stdlib) erl_eval.erl:670: :erl_eval.do_apply/6

Answer 1

You're getting the do_match error because your module uses Plug.Router but does not define any route. do_match function clauses are added by the get/post/etc macros in Plug.Router. With no routes, no function clause is ever defined causing that error. Since you don't actually want to define any routes in the module, you can just remove use Plug.Router.
You're also missing an import for the put_resp_content_type/2 function. Adding import Plug.Conn should fix that.