Mastodon-compatible webhooks

Signed-off-by: nicole mikołajczyk <git@mkljczk.pl>

changelog.d/webhooks.add

@@ -0,0 +1 @@
+Add support for Mastodon-compatible webhooks

config/config.exs

@@ -926,7 +926,8 @@ config :pleroma, Pleroma.User.Backup,
   timeout: :timer.minutes(30)
 
 config :pleroma, ConcurrentLimiter, [
-  {Pleroma.Search, [max_running: 30, max_waiting: 50]}
+  {Pleroma.Search, [max_running: 30, max_waiting: 50]},
+  {Pleroma.Webhook.Notify, [max_running: 5, max_waiting: 200]}
 ]
 
 config :pleroma, Pleroma.Web.WebFinger, domain: nil, update_nickname_on_user_fetch: true

config/description.exs

@@ -3479,6 +3479,26 @@ config :pleroma, :config_description, [
             suggestion: [5]
           }
         ]
+      },
+      %{
+        key: Pleroma.Webhook.Notify,
+        type: :keyword,
+        description: "Concurrent limits configuration for webhooks.",
+        suggestions: [max_running: 5, max_waiting: 5],
+        children: [
+          %{
+            key: :max_running,
+            type: :integer,
+            description: "Max running concurrently jobs.",
+            suggestion: [5]
+          },
+          %{
+            key: :max_waiting,
+            type: :integer,
+            description: "Max waiting jobs.",
+            suggestion: [5]
+          }
+        ]
       }
     ]
   },

docs/development/API/admin_api.md

@@ -1806,3 +1806,92 @@ Note that this differs from the Mastodon API variant: Mastodon API only returns
 ```json
 {}
 ```
+
+## `GET /api/v1/pleroma/admin/webhooks`
+
+### List webhooks
+
+- Method: `GET`
+- Response:
+
+```json
+[
+  {
+    "enabled": true,
+    "id": "2",
+    "events": ["account.created"],
+    "url": "https://webhook.example/",
+    "secret": "eb85d4ccd8510e78f912743949dc354e8146987d",
+    "updated_at": "2022-10-29T17:44:16.000Z",
+    "created_at": "2022-10-29T17:44:13.000Z"
+  }
+]
+```
+
+## `GET /api/v1/pleroma/admin/webhooks/:id`
+
+### Get an individual webhook
+
+- Method: `GET`
+- Params:
+  - `id`: **string** Webhook ID
+- Response: A webhook
+
+## `POST /api/v1/pleroma/admin/webhooks`
+
+### Create a webhook
+
+- Method: `POST`
+- Params:
+  - `url`: **string** Webhook URL
+  - *optional* `events`: **[string]** Types of events to trigger on (`account.created`, `report.created`)
+  - *optional* `enabled`: **boolean** Whether webhook is enabled
+- Response: A webhook
+
+## `PATCH /api/v1/pleroma/admin/webhooks/:id`
+
+### Update a webhook
+
+- Method: `PATCH`
+- Params:
+  - `id`: **string** Webhook ID
+  - *optional* `url`: **string** Webhook URL
+  - *optional* `events`: **[string]** Types of events to trigger on (`account.created`, `report.created`)
+  - *optional* `enabled`: **boolean** Whether webhook is enabled
+- Response: A webhook
+
+## `DELETE /api/v1/pleroma/admin/webhooks/:id`
+
+### Delete a webhook
+
+- Method: `DELETE`
+- Params:
+  - `id`: **string** Webhook ID
+- Response: A webhook
+
+## `POST /api/v1/pleroma/admin/webhooks/:id/enable`
+
+### Activate a webhook
+
+- Method: `POST`
+- Params:
+  - `id`: **string** Webhook ID
+- Response: A webhook
+
+## `POST /api/v1/pleroma/admin/webhooks/:id/disable`
+
+### Deactivate a webhook
+
+- Method: `POST`
+- Params:
+  - `id`: **string** Webhook ID
+- Response: A webhook
+
+## `POST /api/v1/pleroma/admin/webhooks/:id/rotate_secret`
+
+### Rotate webhook signing secret
+
+- Method: `POST`
+- Params:
+  - `id`: **string** Webhook ID
+- Response: A webhook

lib/pleroma/application.ex

@@ -278,7 +278,8 @@ defmodule Pleroma.Application do
     config = Config.get(ConcurrentLimiter, [])
 
     [
-      Pleroma.Search
+      Pleroma.Search,
+      Pleroma.Webhook.Notify
     ]
     |> Enum.each(fn module ->
       mod_config = Keyword.get(config, module, [])

lib/pleroma/user.ex

@@ -39,6 +39,7 @@ defmodule Pleroma.User do
   alias Pleroma.Web.Endpoint
   alias Pleroma.Web.OAuth
   alias Pleroma.Web.RelMe
+  alias Pleroma.Webhook.Notify
   alias Pleroma.Workers.BackgroundWorker
   alias Pleroma.Workers.DeleteWorker
   alias Pleroma.Workers.UserRefreshWorker
@@ -980,6 +981,7 @@ defmodule Pleroma.User do
   @doc "Inserts provided changeset, performs post-registration actions (confirmation email sending etc.)"
   def register(%Ecto.Changeset{} = changeset) do
     with {:ok, user} <- Repo.insert(changeset) do
+      Notify.trigger_webhooks(user, :"account.created")
       post_register_action(user)
     end
   end

lib/pleroma/web/activity_pub/activity_pub.ex

@@ -30,6 +30,7 @@ defmodule Pleroma.Web.ActivityPub.ActivityPub do
   import Ecto.Query
   import Pleroma.Web.ActivityPub.Utils
   import Pleroma.Web.ActivityPub.Visibility
+  import Pleroma.Webhook.Notify, only: [trigger_webhooks: 2]
 
   require Logger
   require Pleroma.Constants
@@ -415,7 +416,9 @@ defmodule Pleroma.Web.ActivityPub.ActivityPub do
     with flag_data <- make_flag_data(params, additional),
          {:ok, activity} <- insert(flag_data, local),
          _ <- notify_and_stream(activity),
-         :ok <- maybe_federate(activity) do
+         _ <- trigger_webhooks(activity, :"report.created"),
+         :ok <-
+           maybe_federate(activity) do
       User.all_users_with_privilege(:reports_manage_reports)
       |> Enum.filter(fn user -> user.ap_id != actor end)
       |> Enum.filter(fn user -> not is_nil(user.email) end)

lib/pleroma/web/admin_api/controllers/webhook_controller.ex

@@ -0,0 +1,88 @@
+# Pleroma: A lightweight social networking server
+# Copyright © 2017-2022 Pleroma Authors <https://pleroma.social/>
+# SPDX-License-Identifier: AGPL-3.0-only
+
+defmodule Pleroma.Web.AdminAPI.WebhookController do
+  use Pleroma.Web, :controller
+
+  alias Pleroma.Repo
+  alias Pleroma.Web.Plugs.OAuthScopesPlug
+  alias Pleroma.Webhook
+
+  plug(Pleroma.Web.ApiSpec.CastAndValidate)
+
+  plug(
+    OAuthScopesPlug,
+    %{scopes: ["admin:write"]}
+    when action in [:update, :create, :delete, :enable, :disable, :rotate_secret]
+  )
+
+  plug(OAuthScopesPlug, %{scopes: ["admin:read"]} when action in [:index, :show])
+
+  action_fallback(Pleroma.Web.AdminAPI.FallbackController)
+
+  defdelegate open_api_operation(action), to: Pleroma.Web.ApiSpec.Admin.WebhookOperation
+
+  def index(conn, _) do
+    webhooks =
+      Webhook
+      |> Repo.all()
+
+    render(conn, "index.json", webhooks: webhooks)
+  end
+
+  def show(conn, %{id: id}) do
+    with %Webhook{} = webhook <- Webhook.get(id) do
+      render(conn, "show.json", webhook: webhook)
+    else
+      nil -> {:error, :not_found}
+    end
+  end
+
+  def create(%{body_params: params} = conn, _) do
+    with webhook <- Webhook.create(params) do
+      render(conn, "show.json", webhook: webhook)
+    end
+  end
+
+  def update(%{body_params: params} = conn, %{id: id}) do
+    with %Webhook{} = webhook <- Webhook.get(id),
+         webhook <- Webhook.update(webhook, params) do
+      render(conn, "show.json", webhook: webhook)
+    end
+  end
+
+  def delete(conn, %{id: id}) do
+    with %Webhook{} = webhook <- Webhook.get(id),
+         {:ok, webhook} <- Webhook.delete(webhook) do
+      render(conn, "show.json", webhook: webhook)
+    end
+  end
+
+  def enable(conn, %{id: id}) do
+    with %Webhook{} = webhook <- Webhook.get(id),
+         {:ok, webhook} <- Webhook.set_enabled(webhook, true) do
+      render(conn, "show.json", webhook: webhook)
+    else
+      nil -> {:error, :not_found}
+    end
+  end
+
+  def disable(conn, %{id: id}) do
+    with %Webhook{} = webhook <- Webhook.get(id),
+         {:ok, webhook} <- Webhook.set_enabled(webhook, false) do
+      render(conn, "show.json", webhook: webhook)
+    else
+      nil -> {:error, :not_found}
+    end
+  end
+
+  def rotate_secret(conn, %{id: id}) do
+    with %Webhook{} = webhook <- Webhook.get(id),
+         {:ok, webhook} <- Webhook.rotate_secret(webhook) do
+      render(conn, "show.json", webhook: webhook)
+    else
+      nil -> {:error, :not_found}
+    end
+  end
+end

lib/pleroma/web/admin_api/views/webhook_view.ex

@@ -0,0 +1,33 @@
+# Pleroma: A lightweight social networking server
+# Copyright © 2017-2022 Pleroma Authors <https://pleroma.social/>
+# SPDX-License-Identifier: AGPL-3.0-only
+
+defmodule Pleroma.Web.AdminAPI.WebhookView do
+  use Pleroma.Web, :view
+
+  alias Pleroma.Web.CommonAPI.Utils
+
+  def render("index.json", %{webhooks: webhooks}) do
+    render_many(webhooks, __MODULE__, "show.json")
+  end
+
+  def render("show.json", %{webhook: webhook}) do
+    %{
+      id: webhook.id |> to_string(),
+      url: webhook.url,
+      events: webhook.events,
+      secret: webhook.secret,
+      enabled: webhook.enabled,
+      created_at: Utils.to_masto_date(webhook.inserted_at),
+      updated_at: Utils.to_masto_date(webhook.updated_at)
+    }
+  end
+
+  def render("event.json", %{type: type, object: object}) do
+    %{
+      type: type,
+      created_at: Utils.to_masto_date(NaiveDateTime.utc_now()),
+      object: object
+    }
+  end
+end

lib/pleroma/web/api_spec.ex

@@ -105,7 +105,8 @@ defmodule Pleroma.Web.ApiSpec do
               "Report management",
               "Status administration",
               "User administration",
-              "Announcement management"
+              "Announcement management",
+              "Webhooks"
             ]
           },
           %{"name" => "Applications", "tags" => ["Applications", "Push subscriptions"]},

lib/pleroma/web/api_spec/operations/admin/webhook_operation.ex

@@ -0,0 +1,193 @@
+# Pleroma: A lightweight social networking server
+# Copyright © 2017-2022 Pleroma Authors <https://pleroma.social/>
+# SPDX-License-Identifier: AGPL-3.0-only
+
+defmodule Pleroma.Web.ApiSpec.Admin.WebhookOperation do
+  alias OpenApiSpex.Operation
+  alias OpenApiSpex.Schema
+
+  import Pleroma.Web.ApiSpec.Helpers
+
+  def open_api_operation(action) do
+    operation = String.to_existing_atom("#{action}_operation")
+    apply(__MODULE__, operation, [])
+  end
+
+  def index_operation do
+    %Operation{
+      tags: ["Webhooks"],
+      summary: "Retrieve a list of webhooks",
+      operationId: "AdminAPI.WebhookController.index",
+      security: [%{"oAuth" => ["admin:show"]}],
+      responses: %{
+        200 =>
+          Operation.response("Array of webhooks", "application/json", %Schema{
+            type: :array,
+            items: webhook()
+          })
+      }
+    }
+  end
+
+  def show_operation do
+    %Operation{
+      tags: ["Webhooks"],
+      summary: "Retrieve a webhook",
+      operationId: "AdminAPI.WebhookController.show",
+      security: [%{"oAuth" => ["admin:show"]}],
+      parameters: [id_param()],
+      responses: %{
+        200 => Operation.response("Webhook", "application/json", webhook())
+      }
+    }
+  end
+
+  def create_operation do
+    %Operation{
+      tags: ["Webhooks"],
+      summary: "Create a webhook",
+      operationId: "AdminAPI.WebhookController.create",
+      security: [%{"oAuth" => ["admin:write"]}],
+      requestBody:
+        request_body(
+          "Parameters",
+          %Schema{
+            description: "POST body for creating a webhook",
+            type: :object,
+            properties: %{
+              url: %Schema{type: :string, format: :uri, required: true},
+              events: event_type(true),
+              enabled: %Schema{type: :boolean}
+            }
+          }
+        ),
+      responses: %{
+        200 => Operation.response("Webhook", "application/json", webhook())
+      }
+    }
+  end
+
+  def update_operation do
+    %Operation{
+      tags: ["Webhooks"],
+      summary: "Update a webhook",
+      operationId: "AdminAPI.WebhookController.update",
+      security: [%{"oAuth" => ["admin:write"]}],
+      parameters: [id_param()],
+      requestBody:
+        request_body(
+          "Parameters",
+          %Schema{
+            description: "POST body for updating a webhook",
+            type: :object,
+            properties: %{
+              url: %Schema{type: :string, format: :uri},
+              events: event_type(),
+              enabled: %Schema{type: :boolean}
+            }
+          }
+        ),
+      responses: %{
+        200 => Operation.response("Webhook", "application/json", webhook())
+      }
+    }
+  end
+
+  def delete_operation do
+    %Operation{
+      tags: ["Webhooks"],
+      summary: "Delete a webhook",
+      operationId: "AdminAPI.WebhookController.delete",
+      security: [%{"oAuth" => ["admin:write"]}],
+      parameters: [id_param()],
+      responses: %{
+        200 => Operation.response("Webhook", "application/json", webhook())
+      }
+    }
+  end
+
+  def enable_operation do
+    %Operation{
+      tags: ["Webhooks"],
+      summary: "Enable a webhook",
+      operationId: "AdminAPI.WebhookController.enable",
+      security: [%{"oAuth" => ["admin:write"]}],
+      parameters: [id_param()],
+      responses: %{
+        200 => Operation.response("Webhook", "application/json", webhook())
+      }
+    }
+  end
+
+  def disable_operation do
+    %Operation{
+      tags: ["Webhooks"],
+      summary: "Disable a webhook",
+      operationId: "AdminAPI.WebhookController.disable",
+      security: [%{"oAuth" => ["admin:write"]}],
+      parameters: [id_param()],
+      responses: %{
+        200 => Operation.response("Webhook", "application/json", webhook())
+      }
+    }
+  end
+
+  def rotate_secret_operation do
+    %Operation{
+      tags: ["Webhooks"],
+      summary: "Rotate webhook signing secret",
+      operationId: "AdminAPI.WebhookController.rotate_secret",
+      security: [%{"oAuth" => ["admin:write"]}],
+      parameters: [id_param()],
+      responses: %{
+        200 => Operation.response("Webhook", "application/json", webhook())
+      }
+    }
+  end
+
+  defp webhook do
+    %Schema{
+      title: "Webhook",
+      description: "Schema for a webhook",
+      type: :object,
+      properties: %{
+        id: %Schema{type: :string},
+        url: %Schema{type: :string, format: :uri},
+        events: event_type(),
+        secret: %Schema{type: :string},
+        enabled: %Schema{type: :boolean},
+        created_at: %Schema{type: :string, format: :"date-time"},
+        updated_at: %Schema{type: :string, format: :"date-time"}
+      },
+      example: %{
+        "id" => "1",
+        "url" => "https://example.com/webhook",
+        "events" => ["report.created"],
+        "secret" => "d3d8cf4bc11fd9c41fd34dcc38d282e451c8bd34",
+        "enabled" => true,
+        "created_at" => "2022-06-24T16:19:38.523Z",
+        "updated_at" => "2022-06-24T16:19:38.523Z"
+      }
+    }
+  end
+
+  defp event_type(required \\ nil) do
+    %Schema{
+      type: :array,
+      items: %Schema{
+        title: "Event",
+        description: "Event type",
+        type: :string,
+        enum: ["account.created", "report.created"],
+        required: required
+      }
+    }
+  end
+
+  defp id_param do
+    Operation.parameter(:id, :path, :string, "Webhook ID",
+      example: "123",
+      required: true
+    )
+  end
+end

lib/pleroma/web/api_spec/operations/notification_operation.ex

@@ -3,7 +3,6 @@
 # SPDX-License-Identifier: AGPL-3.0-only
 
 defmodule Pleroma.Web.ApiSpec.NotificationOperation do
-  alias OpenApiSpex.Operation
   alias OpenApiSpex.Operation
   alias OpenApiSpex.Schema
   alias Pleroma.Web.ApiSpec.Schemas.Account

lib/pleroma/web/mastodon_api/admin/views/account_view.ex

@@ -0,0 +1,65 @@
+# Pleroma: A lightweight social networking server
+# Copyright © 2017-2024 Pleroma Authors <https://pleroma.social/>
+# SPDX-License-Identifier: AGPL-3.0-only
+
+defmodule Pleroma.Web.MastodonAPI.Admin.AccountView do
+  use Pleroma.Web, :view
+
+  alias Pleroma.User
+  alias Pleroma.Web.CommonAPI.Utils
+  alias Pleroma.Web.MastodonAPI
+
+  def render("index.json", %{users: users}) do
+    render_many(users, __MODULE__, "show.json", as: :user)
+  end
+
+  def render("show.json", %{user: user}) do
+    account =
+      MastodonAPI.AccountView.render("show.json", %{user: user, skip_visibility_check: true})
+
+    %{
+      id: user.id,
+      username: username_from_nickname(user.nickname),
+      domain: domain_from_nickname(user.nickname),
+      created_at: Utils.to_masto_date(user.inserted_at),
+      email: user.email,
+      ip: nil,
+      role: role(user),
+      confirmed: user.is_confirmed,
+      sensitized: nil,
+      suspened: nil,
+      silenced: nil,
+      disabled: !user.is_active,
+      approved: user.is_approved,
+      locale: nil,
+      invite_request: user.registration_reason,
+      ips: nil,
+      account: account
+    }
+  end
+
+  defp username_from_nickname(string) when is_binary(string) do
+    hd(String.split(string, "@"))
+  end
+
+  defp username_from_nickname(_), do: nil
+
+  defp domain_from_nickname(string) when is_binary(string) do
+    String.split(string, "@")
+    |> Enum.at(1, nil)
+  end
+
+  defp domain_from_nickname(_), do: nil
+
+  defp role(%User{is_admin: true}) do
+    "admin"
+  end
+
+  defp role(%User{is_moderator: true}) do
+    "moderator"
+  end
+
+  defp role(_user) do
+    nil
+  end
+end

lib/pleroma/web/mastodon_api/admin/views/report_view.ex

@@ -0,0 +1,54 @@
+# Pleroma: A lightweight social networking server
+# Copyright © 2017-2024 Pleroma Authors <https://pleroma.social/>
+# SPDX-License-Identifier: AGPL-3.0-only
+
+defmodule Pleroma.Web.MastodonAPI.Admin.ReportView do
+  use Pleroma.Web, :view
+
+  alias Pleroma.HTML
+  alias Pleroma.Web.AdminAPI.Report
+  alias Pleroma.Web.CommonAPI.Utils
+  alias Pleroma.Web.MastodonAPI.Admin.AccountView
+  alias Pleroma.Web.MastodonAPI.StatusView
+
+  def render("index.json", %{reports: reports}) do
+    reports
+    |> Enum.map(&Report.extract_report_info/1)
+    |> Enum.map(&render(__MODULE__, "show.json", &1))
+  end
+
+  def render("show.json", %{
+        report: report,
+        user: account,
+        account: target_account,
+        statuses: statuses
+      }) do
+    created_at = Utils.to_masto_date(report.data["published"])
+
+    content =
+      unless is_nil(report.data["content"]) do
+        HTML.filter_tags(report.data["content"])
+      else
+        nil
+      end
+
+    %{
+      id: report.id,
+      action_taken: report.data["state"] != "open",
+      category: "other",
+      comment: content,
+      created_at: created_at,
+      updated_at: created_at,
+      account: AccountView.render("show.json", %{user: account}),
+      target_account: AccountView.render("show.json", %{user: target_account}),
+      assigned_account: nil,
+      action_taken_by_account: nil,
+      statuses:
+        StatusView.render("index.json", %{
+          activities: statuses,
+          as: :activity
+        }),
+      rules: []
+    }
+  end
+end

lib/pleroma/web/router.ex

@@ -320,6 +320,15 @@ defmodule Pleroma.Web.Router do
     get("/announcements/:id", AnnouncementController, :show)
     patch("/announcements/:id", AnnouncementController, :change)
     delete("/announcements/:id", AnnouncementController, :delete)
+
+    get("/webhooks", WebhookController, :index)
+    get("/webhooks/:id", WebhookController, :show)
+    post("/webhooks", WebhookController, :create)
+    patch("/webhooks/:id", WebhookController, :update)
+    delete("/webhooks/:id", WebhookController, :delete)
+    post("/webhooks/:id/enable", WebhookController, :enable)
+    post("/webhooks/:id/disable", WebhookController, :disable)
+    post("/webhooks/:id/rotate_secret", WebhookController, :rotate_secret)
   end
 
   # AdminAPI: admins and mods (staff) can perform these actions (if privileged by role)

lib/pleroma/webhook.ex

@@ -0,0 +1,100 @@
+# Pleroma: A lightweight social networking server
+# Copyright © 2017-2022 Pleroma Authors <https://pleroma.social/>
+# SPDX-License-Identifier: AGPL-3.0-only
+
+defmodule Pleroma.Webhook do
+  use Ecto.Schema
+
+  import Ecto.Changeset
+  import Ecto.Query
+
+  alias Pleroma.EctoType.ActivityPub.ObjectValidators
+  alias Pleroma.Repo
+
+  @event_types [:"account.created", :"report.created"]
+
+  schema "webhooks" do
+    field(:url, ObjectValidators.Uri)
+    field(:events, {:array, Ecto.Enum}, values: @event_types, default: [])
+    field(:secret, :string, default: "")
+    field(:enabled, :boolean, default: true)
+
+    timestamps()
+  end
+
+  def get(id), do: Repo.get(__MODULE__, id)
+
+  def get_by_type(type) do
+    __MODULE__
+    |> where([w], ^type in w.events)
+    |> Repo.all()
+  end
+
+  def changeset(%__MODULE__{} = webhook, params) do
+    webhook
+    |> cast(params, [:url, :events, :enabled])
+    |> validate_required([:url, :events])
+    |> unique_constraint(:url)
+    |> strip_events()
+    |> put_secret()
+  end
+
+  def update_changeset(%__MODULE__{} = webhook, params \\ %{}) do
+    webhook
+    |> cast(params, [:url, :events, :enabled])
+    |> unique_constraint(:url)
+    |> strip_events()
+  end
+
+  def create(params) do
+    {:ok, webhook} =
+      %__MODULE__{}
+      |> changeset(params)
+      |> Repo.insert()
+
+    webhook
+  end
+
+  def update(%__MODULE__{} = webhook, params) do
+    {:ok, webhook} =
+      webhook
+      |> update_changeset(params)
+      |> Repo.update()
+
+    webhook
+  end
+
+  def delete(webhook), do: webhook |> Repo.delete()
+
+  def rotate_secret(%__MODULE__{} = webhook) do
+    webhook
+    |> cast(%{}, [])
+    |> put_secret()
+    |> Repo.update()
+  end
+
+  def set_enabled(%__MODULE__{} = webhook, enabled) do
+    webhook
+    |> cast(%{enabled: enabled}, [:enabled])
+    |> Repo.update()
+  end
+
+  defp strip_events(params) do
+    if Map.has_key?(params, :events) do
+      params
+      |> Map.put(:events, Enum.filter(params[:events], &Enum.member?(@event_types, &1)))
+    else
+      params
+    end
+  end
+
+  defp put_secret(changeset) do
+    changeset
+    |> put_change(:secret, generate_secret())
+  end
+
+  defp generate_secret do
+    Base.encode16(:crypto.strong_rand_bytes(20))
+    |> String.downcase()
+  end
+end

lib/pleroma/webhook/notify.ex

@@ -0,0 +1,83 @@
+# Pleroma: A lightweight social networking server
+# Copyright © 2017-2022 Pleroma Authors <https://pleroma.social/>
+# SPDX-License-Identifier: AGPL-3.0-only
+
+defmodule Pleroma.Webhook.Notify do
+  alias Phoenix.View
+  alias Pleroma.Activity
+  alias Pleroma.User
+  alias Pleroma.Web.AdminAPI.Report
+  alias Pleroma.Webhook
+  alias Pleroma.Workers.WebhookWorker
+
+  def trigger_webhooks(%Activity{} = activity, :"report.created" = type) do
+    webhooks = Webhook.get_by_type(type)
+
+    webhooks
+    |> Enum.map(fn webhook ->
+      WebhookWorker.new(%{
+        "op" => "notify",
+        "type" => type,
+        "webhook_id" => webhook.id,
+        "activity_id" => activity.id
+      })
+    end)
+    |> Oban.insert_all()
+  end
+
+  def trigger_webhooks(%User{} = user, :"account.created" = type) do
+    webhooks = Webhook.get_by_type(type)
+
+    webhooks
+    |> Enum.map(fn webhook ->
+      WebhookWorker.new(%{
+        "op" => "notify",
+        "type" => type,
+        "webhook_id" => webhook.id,
+        "user_id" => user.id
+      })
+    end)
+    |> Oban.insert_all()
+  end
+
+  def report_created(%Webhook{} = webhook, %Activity{} = report) do
+    object =
+      View.render(
+        Pleroma.Web.MastodonAPI.Admin.ReportView,
+        "show.json",
+        Report.extract_report_info(report)
+      )
+
+    deliver(webhook, object, :"report.created")
+  end
+
+  def account_created(%Webhook{} = webhook, %User{} = user) do
+    object =
+      View.render(
+        Pleroma.Web.MastodonAPI.Admin.AccountView,
+        "show.json",
+        user: user
+      )
+
+    deliver(webhook, object, :"account.created")
+  end
+
+  defp deliver(%Webhook{url: url, secret: secret}, object, type) do
+    body =
+      View.render_to_string(Pleroma.Web.AdminAPI.WebhookView, "event.json",
+        type: type,
+        object: object
+      )
+
+    headers = [
+      {"Content-Type", "application/json"},
+      {"X-Hub-Signature", "sha256=#{signature(body, secret)}"}
+    ]
+
+    Pleroma.HTTP.post(url, body, headers)
+  end
+
+  defp signature(body, secret) do
+    :crypto.mac(:hmac, :sha256, secret, body) |> Base.encode16()
+  end
+end

lib/pleroma/workers/webhook_worker.ex

@@ -0,0 +1,41 @@
+# Pleroma: A lightweight social networking server
+# Copyright © 2017-2022 Pleroma Authors <https://pleroma.social/>
+# SPDX-License-Identifier: AGPL-3.0-only
+
+defmodule Pleroma.Workers.WebhookWorker do
+  alias Pleroma.Activity
+
+  use Oban.Worker, queue: :background
+
+  @impl true
+  def perform(%Job{
+        args: %{
+          "op" => "notify",
+          "type" => "report.created",
+          "webhook_id" => webhook_id,
+          "activity_id" => report_id
+        }
+      }) do
+    webhook = Pleroma.Webhook.get(webhook_id)
+    report = Activity.get_by_id(report_id)
+
+    Pleroma.Webhook.Notify.report_created(webhook, report)
+  end
+
+  def perform(%Job{
+        args: %{
+          "op" => "notify",
+          "type" => "account.created",
+          "webhook_id" => webhook_id,
+          "user_id" => user_id
+        }
+      }) do
+    webhook = Pleroma.Webhook.get(webhook_id)
+    user = Pleroma.User.get_by_id(user_id)
+
+    Pleroma.Webhook.Notify.account_created(webhook, user)
+  end
+
+  @impl true
+  def timeout(_job), do: :timer.seconds(10)
+end

priv/repo/migrations/20220624104914_create_webhooks.exs

@@ -0,0 +1,20 @@
+# Pleroma: A lightweight social networking server
+# Copyright © 2017-2022 Pleroma Authors <https://pleroma.social/>
+# SPDX-License-Identifier: AGPL-3.0-only
+
+defmodule Pleroma.Repo.Migrations.CreateWebhooks do
+  use Ecto.Migration
+
+  def change do
+    create_if_not_exists table(:webhooks) do
+      add(:url, :string, null: false)
+      add(:events, {:array, :string}, null: false, default: [])
+      add(:secret, :string, null: false, default: "")
+      add(:enabled, :boolean, null: false, default: true)
+
+      timestamps()
+    end
+
+    create_if_not_exists(unique_index(:webhooks, [:url]))
+  end
+end

test/mix/tasks/pleroma/database_test.exs

@@ -416,7 +416,8 @@ defmodule Mix.Tasks.Pleroma.DatabaseTest do
                ["user_invite_tokens"],
                ["user_notes"],
                ["user_relationships"],
-               ["users"]
+               ["users"],
+               ["webhooks"]
              ]
     end
 

test/pleroma/user_test.exs

@@ -11,12 +11,14 @@ defmodule Pleroma.UserTest do
   alias Pleroma.User
   alias Pleroma.Web.ActivityPub.ActivityPub
   alias Pleroma.Web.CommonAPI
+  alias Pleroma.Webhook.Notify
 
   use Pleroma.DataCase, async: false
   use Oban.Testing, repo: Pleroma.Repo
 
   import Pleroma.Factory
   import ExUnit.CaptureLog
+  import Mock
   import Swoosh.TestAssertions
 
   setup do
@@ -719,6 +721,14 @@ defmodule Pleroma.UserTest do
 
       assert user.is_confirmed
     end
+
+    test_with_mock "triggers webhooks", Notify, trigger_webhooks: fn _, _ -> nil end do
+      cng = User.register_changeset(%User{}, @full_user_data)
+
+      {:ok, registered_user} = User.register(cng)
+
+      assert_called(Notify.trigger_webhooks(registered_user, :"account.created"))
+    end
   end
 
   describe "user registration, with :account_activation_required" do

test/pleroma/web/activity_pub/activity_pub_test.exs

@@ -17,6 +17,7 @@ defmodule Pleroma.Web.ActivityPub.ActivityPubTest do
   alias Pleroma.Web.ActivityPub.Utils
   alias Pleroma.Web.AdminAPI.AccountView
   alias Pleroma.Web.CommonAPI
+  alias Pleroma.Webhook.Notify
 
   import ExUnit.CaptureLog
   import Mock
@@ -1715,6 +1716,29 @@ defmodule Pleroma.Web.ActivityPub.ActivityPubTest do
       assert Repo.aggregate(Object, :count, :id) == 1
       assert Repo.aggregate(Notification, :count, :id) == 0
     end
+
+    test_with_mock "triggers webhooks",
+                   %{
+                     reporter: reporter,
+                     context: context,
+                     target_account: target_account,
+                     reported_activity: reported_activity,
+                     content: content
+                   },
+                   Notify,
+                   [:passthrough],
+                   trigger_webhooks: fn _, _ -> nil end do
+      {:ok, activity} =
+        ActivityPub.flag(%{
+          actor: reporter,
+          context: context,
+          account: target_account,
+          statuses: [reported_activity],
+          content: content
+        })
+
+      assert_called(Notify.trigger_webhooks(activity, :"report.created"))
+    end
   end
 
   test "fetch_activities/2 returns activities addressed to a list " do

test/pleroma/web/admin_api/controllers/webhook_controller_test.exs

@@ -0,0 +1,84 @@
+# Pleroma: A lightweight social networking server
+# Copyright © 2017-2022 Pleroma Authors <https://pleroma.social/>
+# SPDX-License-Identifier: AGPL-3.0-only
+
+defmodule Pleroma.Web.AdminAPI.WebhookControllerTest do
+  use Pleroma.Web.ConnCase, async: true
+
+  import Pleroma.Factory
+
+  alias Pleroma.Webhook
+
+  setup do
+    admin = insert(:user, is_admin: true)
+    token = insert(:oauth_admin_token, user: admin)
+
+    conn =
+      build_conn()
+      |> assign(:user, admin)
+      |> assign(:token, token)
+
+    {:ok, %{admin: admin, token: token, conn: conn}}
+  end
+
+  describe "GET /api/pleroma/admin/webhook" do
+    test "lists existing webhooks", %{conn: conn} do
+      Webhook.create(%{url: "https://example.com/webhook1", events: [:"report.created"]})
+      Webhook.create(%{url: "https://example.com/webhook2", events: [:"account.created"]})
+
+      response =
+        conn
+        |> get("/api/pleroma/admin/webhooks")
+        |> json_response_and_validate_schema(:ok)
+
+      assert length(response) == 2
+    end
+  end
+
+  describe "POST /api/pleroma/admin/webhooks" do
+    test "creates a webhook", %{conn: conn} do
+      %{"id" => id} =
+        conn
+        |> put_req_header("content-type", "application/json")
+        |> post("/api/pleroma/admin/webhooks", %{
+          url: "http://example.com/webhook",
+          events: ["account.created"]
+        })
+        |> json_response_and_validate_schema(:ok)
+
+      assert %{url: "http://example.com/webhook", events: [:"account.created"]} = Webhook.get(id)
+    end
+  end
+
+  describe "PATCH /api/pleroma/admin/webhooks" do
+    test "edits a webhook", %{conn: conn} do
+      %{id: id} =
+        Webhook.create(%{url: "https://example.com/webhook1", events: [:"report.created"]})
+
+      conn
+      |> put_req_header("content-type", "application/json")
+      |> patch("/api/pleroma/admin/webhooks/#{id}", %{
+        events: ["report.created", "account.created"]
+      })
+      |> json_response_and_validate_schema(:ok)
+
+      assert %{events: [:"report.created", :"account.created"]} = Webhook.get(id)
+    end
+  end
+
+  describe "DELETE /api/pleroma/admin/webhooks" do
+    test "deletes a webhook", %{conn: conn} do
+      %{id: id} =
+        Webhook.create(%{url: "https://example.com/webhook1", events: [:"report.created"]})
+
+      conn
+      |> put_req_header("content-type", "application/json")
+      |> delete("/api/pleroma/admin/webhooks/#{id}")
+      |> json_response_and_validate_schema(:ok)
+
+      assert [] =
+               Webhook
+               |> Pleroma.Repo.all()
+    end
+  end
+end

test/pleroma/webhook/notify_test.exs

@@ -0,0 +1,75 @@
+# Pleroma: A lightweight social networking server
+# Copyright © 2017-2022 Pleroma Authors <https://pleroma.social/>
+# SPDX-License-Identifier: AGPL-3.0-only
+
+defmodule Pleroma.Webhook.NotifyTest do
+  use Pleroma.DataCase, async: true
+
+  alias Pleroma.Webhook
+  alias Pleroma.Webhook.Notify
+
+  import Pleroma.Factory
+
+  test "triggers a webhook for a report" do
+    %{id: activity_id} = activity = insert(:report_activity)
+
+    url = "https://example.com/webhook"
+
+    Webhook.create(%{url: url, events: [:"report.created"]})
+
+    Tesla.Mock.mock(fn %{url: ^url, body: body} = _ ->
+      report =
+        body
+        |> Jason.decode!()
+        |> Map.get("object")
+
+      assert %{"id" => ^activity_id} = report
+
+      %Tesla.Env{status: 200, body: ""}
+    end)
+
+    [job] = Notify.trigger_webhooks(activity, :"report.created")
+
+    Pleroma.Workers.WebhookWorker.perform(job)
+  end
+
+  test "triggers a webhook for an account" do
+    %{id: account_id} = user = insert(:user)
+
+    url = "https://example.com/webhook"
+
+    Webhook.create(%{url: url, events: [:"account.created"]})
+
+    Tesla.Mock.mock(fn %{url: ^url, body: body} = _ ->
+      report =
+        body
+        |> Jason.decode!()
+        |> Map.get("object")
+
+      assert %{"id" => ^account_id} = report
+
+      %Tesla.Env{status: 200, body: ""}
+    end)
+
+    [job] = Notify.trigger_webhooks(user, :"account.created")
+
+    Pleroma.Workers.WebhookWorker.perform(job)
+  end
+
+  test "notifies have a valid signature" do
+    activity = insert(:report_activity)
+
+    %{secret: secret} =
+      webhook = Webhook.create(%{url: "https://example.com/webhook", events: [:"report.created"]})
+
+    Tesla.Mock.mock(fn %{url: "https://example.com/webhook", body: body, headers: headers} = _ ->
+      {"X-Hub-Signature", "sha256=" <> signature} =
+        Enum.find(headers, fn {key, _} -> key == "X-Hub-Signature" end)
+
+      assert signature == :crypto.mac(:hmac, :sha256, secret, body) |> Base.encode16()
+      %Tesla.Env{status: 200, body: ""}
+    end)
+
+    Notify.report_created(webhook, activity)
+  end
+end

test/pleroma/webhook_test.exs

@@ -0,0 +1,56 @@
+# Pleroma: A lightweight social networking server
+# Copyright © 2017-2022 Pleroma Authors <https://pleroma.social/>
+# SPDX-License-Identifier: AGPL-3.0-only
+
+defmodule Pleroma.WebhookTest do
+  use Pleroma.DataCase, async: true
+
+  alias Pleroma.Webhook
+
+  test "creating a webhook" do
+    %{id: id} = Webhook.create(%{url: "https://example.com/webhook", events: [:"report.created"]})
+
+    assert %{url: "https://example.com/webhook"} = Webhook.get(id)
+  end
+
+  test "editing a webhook" do
+    %{id: id} =
+      webhook = Webhook.create(%{url: "https://example.com/webhook", events: [:"report.created"]})
+
+    Webhook.update(webhook, %{events: [:"account.created"]})
+
+    assert %{events: [:"account.created"]} = Webhook.get(id)
+  end
+
+  test "filter webhooks by type" do
+    %{id: id1} =
+      Webhook.create(%{url: "https://example.com/webhook1", events: [:"report.created"]})
+
+    %{id: id2} =
+      Webhook.create(%{
+        url: "https://example.com/webhook2",
+        events: [:"account.created", :"report.created"]
+      })
+
+    Webhook.create(%{url: "https://example.com/webhook3", events: [:"account.created"]})
+
+    assert [%{id: ^id1}, %{id: ^id2}] = Webhook.get_by_type(:"report.created")
+  end
+
+  test "change webhook state" do
+    %{id: id, enabled: true} =
+      webhook = Webhook.create(%{url: "https://example.com/webhook", events: [:"report.created"]})
+
+    Webhook.set_enabled(webhook, false)
+    assert %{enabled: false} = Webhook.get(id)
+  end
+
+  test "rotate webhook secrets" do
+    %{id: id, secret: secret} =
+      webhook = Webhook.create(%{url: "https://example.com/webhook", events: [:"report.created"]})
+
+    Webhook.rotate_secret(webhook)
+    %{secret: new_secret} = Webhook.get(id)
+    assert secret != new_secret
+  end
+end