Add support for dynamic items that parse custom_id for state

examples/views/persistent.py

@@ -2,6 +2,7 @@
 
 from discord.ext import commands
 import discord
+import re
 
 
 # Define a simple View that persists between bot restarts
@@ -29,6 +30,38 @@ class PersistentView(discord.ui.View):
         await interaction.response.send_message('This is grey.', ephemeral=True)
 
 
+# More complicated cases might require parsing state out from the custom_id instead.
+# For this use case, the library provides a `DynamicItem` to make this easier.
+# The same constraints as above apply to this too.
+# For this example, the `template` class parameter is used to give the library a regular
+# expression to parse the custom_id with.
+# These custom IDs will be in the form of e.g. `button:user:80088516616269824`.
+class DynamicButton(discord.ui.DynamicItem[discord.ui.Button], template=r'button:user:(?P<id>[0-9]+)'):
+    def __init__(self, user_id: int) -> None:
+        super().__init__(
+            discord.ui.Button(
+                label='Do Thing',
+                style=discord.ButtonStyle.blurple,
+                custom_id=f'button:user:{user_id}',
+                emoji='\N{THUMBS UP SIGN}',
+            )
+        )
+        self.user_id: int = user_id
+
+    # This is called when the button is clicked and the custom_id matches the template.
+    @classmethod
+    async def from_custom_id(cls, interaction: discord.Interaction, match: re.Match[str], /):
+        user_id = int(match['id'])
+        return cls(user_id)
+
+    async def interaction_check(self, interaction: discord.Interaction) -> bool:
+        # Only allow the user who created the button to interact with it.
+        return interaction.user.id == self.user_id
+
+    async def callback(self, interaction: discord.Interaction) -> None:
+        await interaction.response.send_message('This is your very own button!', ephemeral=True)
+
+
 class PersistentViewBot(commands.Bot):
     def __init__(self):
         intents = discord.Intents.default()
@@ -43,6 +76,8 @@ class PersistentViewBot(commands.Bot):
         # If you have the message_id you can also pass it as a keyword argument, but for this example
         # we don't have one.
         self.add_view(PersistentView())
+        # For dynamic items, we must register the classes instead of the views.
+        self.add_dynamic_items(DynamicButton)
 
     async def on_ready(self):
         print(f'Logged in as {self.user} (ID: {self.user.id})')
@@ -63,4 +98,13 @@ async def prepare(ctx: commands.Context):
     await ctx.send("What's your favourite colour?", view=PersistentView())
 
 
+@bot.command()
+async def dynamic_button(ctx: commands.Context):
+    """Starts a dynamic button."""
+
+    view = discord.ui.View(timeout=None)
+    view.add_item(DynamicButton(ctx.author.id))
+    await ctx.send('Here is your very own button!', view=view)
+
+
 bot.run('token')