Broadcast using LongPoll is failing

Questions / Help
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1

Hi there

I’m currently developing a small webapp using Phoenix to send mails to a bunch of contacts. In there I wanted to use a channel to update the send status (i.e. how many mails have already been sent etc). However when I gave this a try using only long polling, I get this error message every time I try to do a broadcast:

[error] GenServer #PID<0.660.0> terminating
** (FunctionClauseError) no function clause matching in Phoenix.Transports.LongPoll.Server.handle_info/2
    (phoenix) lib/phoenix/transports/long_poll_server.ex:75: Phoenix.Transports.LongPoll.Server.handle_info(%Phoenix.Socket.Broadcast{event: "progress", payload: %{all: 5, done: 1, pending: 4, progress: 20.0}, topic: "mailing:f52c78c8-4148-4c2a-abaf-c91317ffcf7d"}, %{buffer: [], channels: %{"mailing:f52c78c8-4148-4c2a-abaf-c91317ffcf7d" => #PID<0.666.0>}, channels_inverse: %{#PID<0.666.0> => {"mailing:f52c78c8-4148-4c2a-abaf-c91317ffcf7d", "1"}}, client_ref: {#PID<0.622.0>, #Reference<0.3659197968.2859466756.205729>}, last_client_poll: 1527437359083, priv_topic: "phx:lp:oRFiAZoBxO6vqxRk/SFVjA==1527437358904", pubsub_server: Daten.PubSub, serializer: Phoenix.Transports.V2.LongPollSerializer, socket: %Phoenix.Socket{assigns: %{current_user: %Accounts.User{__meta__: #Ecto.Schema.Metadata<:loaded, "user">, account: %Accounts.Account{__meta__: #Ecto.Schema.Metadata<:loaded, "account">, id: "f52c78c8-4148-4c2a-abaf-c91317ffcf7d", inserted_at: #DateTime<2018-05-25 10:42:28.451558Z>, updated_at: #DateTime<2018-05-25 10:42:28.451570Z>}, email: "c@m", id: "f52c78c8-4148-4c2a-abaf-c91317ffcf7d", inserted_at: #DateTime<2018-05-25 10:42:28.456345Z>, name: "clemens", updated_at: #DateTime<2018-05-25 10:42:28.456352Z>, user_password: %Accounts.UserPassword{__meta__: #Ecto.Schema.Metadata<:loaded, "user_password">, id: 2, inserted_at: #DateTime<2018-05-25 10:42:28.457810Z>, password: nil, password_hash: "$argon2i$v=19$m=65536,t=6,p=1$UG2SFHp/2G7mhq+lGXVmgw$AOjJEKsj14GCfjhOWS/pmXCkWqmTWYcSfnV7WGZCbAQ", updated_at: #DateTime<2018-05-25 10:42:28.457817Z>, user: #Ecto.Association.NotLoaded<association :user is not loaded>, user_id: "f52c78c8-4148-4c2a-abaf-c91317ffcf7d"}}}, channel: nil, channel_pid: nil, endpoint: DatenWeb.Endpoint, handler: DatenWeb.UserSocket, id: "mailing:f52c78c8-4148-4c2a-abaf-c91317ffcf7d", join_ref: nil, joined: false, private: %{}, pubsub_server: Daten.PubSub, ref: nil, serializer: Phoenix.Transports.V2.LongPollSerializer, topic: nil, transport: Phoenix.Transports.LongPoll, transport_name: :longpoll, transport_pid: #PID<0.660.0>, vsn: "2.0.0"}, window_ms: 15000})
    (stdlib) gen_server.erl:616: :gen_server.try_dispatch/4
    (stdlib) gen_server.erl:686: :gen_server.handle_msg/6
    (stdlib) proc_lib.erl:247: :proc_lib.init_p_do_apply/3
Last message: %Phoenix.Socket.Broadcast{event: "progress", payload: %{all: 5, done: 1, pending: 4, progress: 20.0}, topic: "mailing:f52c78c8-4148-4c2a-abaf-c91317ffcf7d"}
State: %{buffer: [], channels: %{"mailing:f52c78c8-4148-4c2a-abaf-c91317ffcf7d" => #PID<0.666.0>}, channels_inverse: %{#PID<0.666.0> => {"mailing:f52c78c8-4148-4c2a-abaf-c91317ffcf7d", "1"}}, client_ref: {#PID<0.622.0>, #Reference<0.3659197968.2859466756.205729>}, last_client_poll: 1527437359083, priv_topic: "phx:lp:oRFiAZoBxO6vqxRk/SFVjA==1527437358904", pubsub_server: Daten.PubSub, serializer: Phoenix.Transports.V2.LongPollSerializer, socket: %Phoenix.Socket{assigns: %{current_user: %Accounts.User{__meta__: #Ecto.Schema.Metadata<:loaded, "user">, account: %Accounts.Account{__meta__: #Ecto.Schema.Metadata<:loaded, "account">, id: "f52c78c8-4148-4c2a-abaf-c91317ffcf7d", inserted_at: #DateTime<2018-05-25 10:42:28.451558Z>, updated_at: #DateTime<2018-05-25 10:42:28.451570Z>}, email: "c@m", id: "f52c78c8-4148-4c2a-abaf-c91317ffcf7d", inserted_at: #DateTime<2018-05-25 10:42:28.456345Z>, name: "clemens", updated_at: #DateTime<2018-05-25 10:42:28.456352Z>, user_password: %Accounts.UserPassword{__meta__: #Ecto.Schema.Metadata<:loaded, "user_password">, id: 2, inserted_at: #DateTime<2018-05-25 10:42:28.457810Z>, password: nil, password_hash: "$argon2i$v=19$m=65536,t=6,p=1$UG2SFHp/2G7mhq+lGXVmgw$AOjJEKsj14GCfjhOWS/pmXCkWqmTWYcSfnV7WGZCbAQ", updated_at: #DateTime<2018-05-25 10:42:28.457817Z>, user: #Ecto.Association.NotLoaded<association :user is not loaded>, user_id: "f52c78c8-4148-4c2a-abaf-c91317ffcf7d"}}}, channel: nil, channel_pid: nil, endpoint: DatenWeb.Endpoint, handler: DatenWeb.UserSocket, id: "mailing:f52c78c8-4148-4c2a-abaf-c91317ffcf7d", join_ref: nil, joined: false, private: %{}, pubsub_server: Daten.PubSub, ref: nil, serializer: Phoenix.Transports.V2.LongPollSerializer, topic: nil, transport: Phoenix.Transports.LongPoll, transport_name: :longpoll, transport_pid: #PID<0.660.0>, vsn: "2.0.0"}, window_ms: 15000}

Note that sending the message using a websocket works perfectly, this is just happening when trying to do a long poll. Is this a legitimate bug, or am I missing something regarding how longpolling is implemented?

Thanks a lot

1 Like
2

This seems like a bug, the long poller is not handling the broadcast message, I’d say report it as an issue on github.

3

Thanks, just noticed your reply, I’ll open an issue on github.

4

I ran into this same thing the other day. It seems to be fixed on phoenix master, but not in the current release. Not sure if it’s the same issue or not.

pull from github in your mix.exs file and let us know :slight_smile:

# {:phoenix, "~> 1.3.3"},
{:phoenix, github: "phoenixframework/phoenix", override: true},
5

Thanks, that solved it. Should have thought about checking the current version myself :relaxed: