Move Webhook regex check to its own method

Sources/Discord/Discord.swift

@@ -331,7 +331,7 @@ public class Bot {
         for addedListener in listeners {
             let currentListenerNames = self.listeners.map({ $0.name })
             if currentListenerNames.contains(addedListener.name) {
-                throw DiscordError.generic("An event listener with the name '\(addedListener.name)' has already been added")
+                throw DiscordError.generic("an event listener with the name '\(addedListener.name)' has already been added")
             } else {
                 self.listeners.append(addedListener)
             }
@@ -607,19 +607,12 @@ public class Bot {
         return try await http.getWebhook(webhookId: id)
     }
 
-    /// Request a webhook by its URL. Unlike ``requestWebhookFrom(id:)``, this does not require authentification. Meaning this can be called prior to connecting to Discord via ``connect()``.
+    /// Request a webhook by its URL. Unlike ``requestWebhookFrom(id:)``, this does not require authentification. Meaning this can be called prior to connecting to Discord.
     /// - Parameter url: The webhooks URL.
     /// - Returns: The webhook matching the given URL.
     public func requestWebhookFrom(url: String) async throws -> Webhook {
-        let webhookUrlRegex = #/https://discord\.com/api/webhooks/[0-9]{17,20}/\S+/#
-        guard let _ = url.wholeMatch(of: webhookUrlRegex) else {
-            throw DiscordError.generic("Invalid webhook URL")
-        }
-        let split = Array(url.split(separator: "/").suffix(2))
-        let webhookId = split[0].description
-        let webhookToken = split[1].description
-
-        return try await http.getWebhookWithToken(webhookId: webhookId, webhookToken: webhookToken)
+        let info = try Webhook.extractFromURL(url)
+        return try await http.getWebhookWithToken(webhookId: info.id, webhookToken: info.token!)
     }
 
     /// Connect to Discord and blocks the app from exiting.

Sources/Discord/Http.swift

@@ -1619,7 +1619,7 @@ class HTTPClient {
 
     /// Same as ``getWebhook()``, except this call does not require authentication and returns no user in the webhook object.
     /// https://discord.com/developers/docs/resources/webhook#get-webhook-with-token
-    func getWebhookWithToken(webhookId: String, webhookToken: String) async throws -> Webhook {
+    func getWebhookWithToken(webhookId: Snowflake, webhookToken: String) async throws -> Webhook {
         let data = try await request(.GET, route("/webhooks/\(webhookId)/\(webhookToken)")) as! JSON
         return .init(bot: bot, webhookData: data)
     }

Sources/Discord/Models/Webhook.swift

@@ -80,6 +80,22 @@ public struct Webhook : Object {
         url = token == nil ? nil : "https://discord.com/api/webhooks/\(id)/\(token!)"
     }
 
+    static func extractFromURL(_ url: String) throws -> (id: Snowflake, token: String?) {
+        let webhookUrlRegex = #/https://discord\.com/api/webhooks/[0-9]{17,20}/\S+/#
+        let invalid = "invalid webhook URL"
+        guard let _ = url.wholeMatch(of: webhookUrlRegex) else {
+            throw DiscordError.generic(invalid)
+        }
+        let split = Array(url.split(separator: "/").suffix(2))
+        // Verify the first element are all numbers (the ID)
+        if !split[0].allSatisfy(\.isNumber) {
+            throw DiscordError.generic(invalid)
+        }
+        let webhookId = split[0].description
+        let webhookToken = split.count > 1 ? split[1].description : nil
+        return (Conversions.snowflakeToUInt(webhookId), webhookToken)
+    }
+
     /// Deletes the webhook.
     public func delete() async throws {
         try await bot!.http.deleteWebhook(webhookId: id)