CDN
Overview
The cdn package creates URLs without making HTTP requests. It covers user avatars and banners, guild icons, banners, splashes and discovery splashes, member avatars and banners, role icons, stickers, and default avatars. The functions accept string IDs and hashes because a URL builder should not need a REST model to be useful in templates or serializers.
Architecture
BaseURL is https://cdn.discordapp.com; MediaProxyURL is https://media.discordapp.net. Asset functions choose the base from Options.MediaProxy. Options.Extension selects the suffix, Size adds a size query parameter when positive, and Animated adds animated=true. When the extension is empty, hashes beginning with a_ use GIF only when Animated is true; all other empty extensions default to PNG. Sticker and DefaultAvatar always use the CDN base and have their own extension rules.
Quick Start
Every function is pure and returns a string. A zero Options value is useful for ordinary PNG assets.
package main
import (
"fmt"
"github.com/discord-go/discord.go/cdn"
)
func main() {
avatar := cdn.Avatar("123", "a_hash", cdn.Options{Animated: true, Size: 256})
icon := cdn.GuildIcon("456", "icon-hash", cdn.Options{MediaProxy: true})
sticker := cdn.Sticker("789", cdn.ExtensionPNG)
fmt.Println(avatar)
fmt.Println(icon)
fmt.Println(sticker, cdn.DefaultAvatar(2))
}Creating Asset URLs
The asset functions are Avatar, GuildIcon, GuildSplash, DiscoverySplash, GuildBanner, UserBanner, MemberAvatar, MemberBanner, and RoleIcon. Each takes the relevant ID and hash plus an Options value. Sticker(stickerID, extension) defaults an empty extension to ExtensionPNG; DefaultAvatar(index) writes the index verbatim, so validate an index before exposing it to untrusted URL input.
Using Options
The exported extension constants are ExtensionPNG, ExtensionJPEG, ExtensionWebP, ExtensionGIF, and ExtensionJSON. The builder does not validate extension strings, sizes, IDs, or hashes. A zero or negative Size omits the query parameter. Animated affects both the query and the implicit extension, but an explicit extension wins. Query parameters are URL-encoded by net/url, so generated URLs have stable escaped ordering.
Common Patterns
Use users.User.AvatarURL when you already have a user model and need its default-avatar fallback; use this package when you have a raw hash or need member and guild assets. Cache URL strings, not downloaded bytes, when asset freshness is controlled by a hash. Select MediaProxy for media-proxy behavior rather than manually replacing the host.
Best Practices
Treat hashes as opaque values. Keep IDs and hashes separate, and do not construct a path with string concatenation when one of the typed functions exists. Use a supported extension for Discord assets and positive power-of-two sizes accepted by Discord's CDN.
Common Mistakes
MediaProxy is not used by Sticker or DefaultAvatar. An animated hash does not automatically become GIF unless Animated is set. The package does not fetch, authenticate, or check whether an asset exists.
API Walkthrough
The public surface consists of ImageExtension, its five constants, Options, the two base URL constants, and the eleven URL functions described above. No constructor or error return is needed because all functions are deterministic string formatters.
Examples
The Quick Start program is complete and runnable. It demonstrates implicit GIF selection, size parameters, the media proxy, stickers, and default avatars.