Add discord bot example

07_web_endpoints/discord_bot.py

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+# ---
+# lambda-test: false
+# ---
+
+# # Serve a Discord Bot on Modal
+
+# (quick links: [try it out on Discord](https://discord.gg/nR96BxPu))
+
+# In this example we will demonstrate how to build a Discord bot that uses
+# [slash commands](https://discord.com/developers/docs/interactions/application-commands)
+# and serve it from Modal.
+
+# Slash commands send information from Discord server members to a service at a URL.
+# Here, we set up a simple [FastAPI app](https://fastapi.tiangolo.com/)
+# to run that service and deploy it easily and serverlessly using Modal’s
+# [`@asgi_app`](https://modal.com/docs/guide/webhooks#serving-asgi-and-wsgi-apps) decorator.
+
+# As our example application, we build a simple weather service.
+
+# ## Create a Discord app
+
+# To connect our model to a Discord bot, we’re first going to create an
+# application on the Discord Developer Portal.
+
+# 1. Go to the
+#    [Discord Developer Portal](https://discord.com/developers/applications) and
+#    login with your Discord account.
+# 2. On the portal, go to **Applications** and create a new application by
+#    clicking **New Application** in the top right next to your profile picture.
+# 3. [Create a custom Modal secret](https://modal.com/docs/guide/secrets) for your Discord bot.
+#    On Modal's secret creation page, select 'Discord'. Copy your Discord application’s
+#    **Public Key** (in **General Information**) and paste the value of the public key
+#    as the value of the `DISCORD_PUBLIC_KEY` environment variable.
+#    Name this secret `weather-discord-secret`.
+
+# ## Register a Slash Command
+
+# Next, we’re going to register a command for our Discord app via an HTTP
+# endpoint.
+
+# Run the following command in your terminal, replacing the appropriate variable
+# inputs. `BOT_TOKEN` can be found by resetting your token in the application’s
+# **Bot** section, and `CLIENT_ID` is the **Application ID** available in
+# **General Information**.
+
+
+# ``` shell
+# BOT_TOKEN='replace_with_bot_token'
+# CLIENT_ID='replace_with_client_token'
+# curl -X POST \
+# -H 'Content-Type: application/json' \
+# -H "Authorization: Bot $BOT_TOKEN" \
+# -d '{
+#   "name":"get_weather",
+#   "description":"get weather",
+#   "options":[
+#     {
+#       "name":"city",
+#       "description":"The city for which you want to get the weather",
+#       "type":3,
+#       "required":true
+#     }
+#   ]
+# }' "https://discord.com/api/v10/applications/$CLIENT_ID/commands"
+# ```
+
+
+# This will register a Slash Command for your bot named `get_weather`, and has a
+# parameter called `city`. More information about the
+# command structure can be found in the Discord docs
+# [here](https://discord.com/developers/docs/interactions/application-commands).
+
+# ## Defining the asgi app with modal
+
+# We now create a `POST /get_weather` endpoint using [FastAPI](https://fastapi.tiangolo.com/) and Modal's
+# [@asgi_app](https://modal.com/docs/guide/webhooks#serving-asgi-and-wsgi-apps) decorator to handle
+# interactions with our Discord app (so that every time a user does a slash
+# command, we can respond to it).
+
+# Let's get the imports out of the way and define an [`App`](https://modal.com/docs/reference/modal.App)
+
+import json
+
+import modal
+
+app = modal.App("example-discord-weather-bot")
+
+# We define an [Image](https://modal.com/docs/guide/images) that has the [`python-weather`](https://github.com/null8626/python-weather) package and
+# the [FastAPI](https://fastapi.tiangolo.com/) package installed.
+
+image = modal.Image.debian_slim(python_version="3.11").pip_install(
+    "python-weather==2.0.7", "fastapi[standard]==0.115.4", "pynacl==1.5.0"
+)
+
+# We define a function that uses the `python_weather` library to get the weather of a city
+# Note that since Discord requires an interaction response within 3 seconds, we
+# use [`spawn`](https://modal.com/docs/reference/modal.Function#spawn) to kick off
+# `get_weather_for_city`as a background task from the asgi app while returning a `defer` message to
+# Discord within the time limit.
+
+
+@app.function(image=image)
+async def get_weather_forecast_for_city(
+    city: str, interaction_token, application_id
+):
+    import aiohttp
+    from python_weather import IMPERIAL, Client, Error, RequestError
+
+    interaction_url = f"https://discord.com/api/v10/webhooks/{application_id}/{interaction_token}/messages/@original"
+    async with Client(unit=IMPERIAL) as client:
+        try:
+            weather = await client.get(city)
+            daily_forecasts = "\n".join(
+                [
+                    f"Date: {daily.date}, Highest temperature: {daily.highest_temperature}°F, Lowest Temperature: {daily.lowest_temperature}°F"
+                    for daily in weather
+                ]
+            )
+            message = f"The forecast for {weather.location} is as follows:\n{daily_forecasts}"
+        except RequestError:
+            message = "An error occurred, issue with connecting to weather api"
+        except Error:
+            message = "An error occurred, please check city name"
+
+    json_payload = {"content": message}
+    async with aiohttp.ClientSession() as session:
+        async with session.patch(interaction_url, json=json_payload) as resp:
+            print(await resp.text())
+
+
+# We now define an asgi app using the Modal ASGI syntax [@asgi_app](https://modal.com/docs/guide/webhooks#serving-asgi-and-wsgi-apps).
+
+
+@app.function(
+    secrets=[modal.Secret.from_name("weather-discord-secret")],
+    keep_warm=1,  # eliminates risk of container startup making discord ack time too long
+    image=image,
+)
+@modal.asgi_app()
+def web_app():
+    from fastapi import FastAPI, HTTPException, Request
+    from fastapi.middleware.cors import CORSMiddleware
+
+    web_app = FastAPI()
+
+    # allow CORS
+    web_app.add_middleware(
+        CORSMiddleware,
+        allow_origins=["*"],
+        allow_credentials=True,
+        allow_methods=["*"],
+        allow_headers=["*"],
+    )
+
+    @web_app.post("/get_weather_forecast")
+    async def get_weather_forecast_api(request: Request):
+        import os
+
+        from nacl.exceptions import BadSignatureError
+        from nacl.signing import VerifyKey
+
+        # Verify the request using the Discord public key
+        public_key = os.getenv("DISCORD_PUBLIC_KEY")
+        verify_key = VerifyKey(bytes.fromhex(public_key))
+
+        signature = request.headers.get("X-Signature-Ed25519")
+        timestamp = request.headers.get("X-Signature-Timestamp")
+        body = await request.body()
+
+        message = timestamp.encode() + body
+
+        try:
+            verify_key.verify(message, bytes.fromhex(signature))
+        except BadSignatureError:
+            raise HTTPException(status_code=401, detail="Invalid request")
+
+        # Parse request
+        data = json.loads(body.decode())
+        if data.get("type") == 1:  # ack ping from Discord
+            return {"type": 1}
+
+        if data.get("type") == 2:  # triggered by slash command interaction
+            options = data["data"]["options"]
+            for option in options:
+                name = option["name"]
+                if name == "city":
+                    city = option["value"]
+
+            app_id = data["application_id"]
+            interaction_token = data["token"]
+
+            # Kick off request asynchronously, send value when we have it
+            get_weather_forecast_for_city.spawn(city, interaction_token, app_id)
+
+            # respond immediately with defer message
+            return {"type": 5}
+
+        raise HTTPException(status_code=400, detail="Bad request")
+
+    return web_app
+
+
+# ## Deploy on Modal
+
+# You can deploy this app by running the following command:
+
+# ``` shell
+# modal deploy discord_bot.py
+# ```
+
+# Copy the Modal URL that is printed in the output and go back to your
+# application's **General Information** section on the
+# [Discord Developer Portal](https://discord.com/developers/applications). Paste
+# the URL, making sure to append the path of your `POST` route, in the
+# **Interactions Endpoint URL** field, then click **Save Changes**. If your
+# endpoint is valid, it will properly save and you can start receiving
+# interactions via this web endpoint.
+
+# ## Finish setting up Discord bot
+
+# To start using the Slash Command you just set up, you need to invite the bot to
+# a Discord server. To do so, go to your application's **OAuth2** section on the
+# [Discord Developer Portal](https://discord.com/developers/applications). Select
+# `applications.commands` as the scope of your bot and copy the invite URL that is
+# generated at the bottom of the page.
+
+# Paste this URL in your browser, then select your desired server (create a new
+# server if needed) and click **Authorize**. Now you can open your Discord server
+# and type `/{name of your slash command}` - your bot should be connected and
+# ready for you to use!