handle extra slashes for relay url

Closes: https://github.com/damus-io/damus/issues/1766

Signed-off-by: kernelkind <kernelkind@gmail.com>
Reviewed-by: William Casarin <jb55@jb55.com>
Signed-off-by: William Casarin <jb55@jb55.com>

damus/Nostr/Relay.swift

@@ -109,5 +109,13 @@ enum RelayError: Error {
 }
 
 func get_relay_id(_ url: RelayURL) -> String {
-    return url.url.absoluteString
+    let trimTrailingSlashes: (String) -> String = { url in
+        var trimmedUrl = url
+        while trimmedUrl.hasSuffix("/") {
+            trimmedUrl.removeLast()
+        }
+        return trimmedUrl
+    }
+    
+    return trimTrailingSlashes(url.url.absoluteString)
 }

damusTests/RelayPoolTests.swift

@@ -0,0 +1,82 @@
+//
+//  RelayPoolTests.swift
+//  damusTests
+//
+//  Created by kernelkind on 12/16/23.
+//
+
+import Foundation
+
+import XCTest
+@testable import damus
+
+final class RelayPoolTests: XCTestCase {
+    
+    override func setUpWithError() throws {
+    }
+
+    override func tearDownWithError() throws {
+    }
+    
+    func testAddRelay_ValidRelayURL_NoErrors() {
+        testAddRelays(urls: [
+            "wss://relay.damus.io"
+        ])
+    }
+    
+    func testAddRelay_TwoSameURLs_ThrowsRelayAlreadyExists() {
+        testAddRelays(urls: [
+            "wss://relay.damus.io",
+            "wss://relay.damus.io"
+        ], expectedError: .RelayAlreadyExists)
+    }
+    
+    func testAddRelay_OneExtraneousSlashURL_ThrowsRelayAlreadyExists() {
+        testAddRelays(urls: [
+            "wss://relay.damus.io",
+            "wss://relay.damus.io/"
+        ], expectedError: .RelayAlreadyExists)
+    }
+
+    func testAddRelay_MultipleExtraneousSlashURL_ThrowsRelayAlreadyExists() {
+        testAddRelays(urls: [
+            "wss://relay.damus.io",
+            "wss://relay.damus.io///"
+        ], expectedError: .RelayAlreadyExists)
+    }
+    
+    func testAddRelay_ExtraSlashURLFirst_ThrowsRelayAlreadyExists() {
+        testAddRelays(urls: [
+            "wss://relay.damus.io///",
+            "wss://relay.damus.io"
+        ], expectedError: .RelayAlreadyExists)
+    }
+}
+
+func testAddRelays(urls: [String], expectedError: RelayError? = nil) {
+    let ndb = Ndb()!
+    let relayPool = RelayPool(ndb: ndb)
+    let info = RelayInfo(read: true, write: true)
+
+    do {
+        for relay in urls {
+            guard let url = RelayURL(relay) else {
+                XCTFail("Invalid URL encountered: \(relay)")
+                return
+            }
+
+            let descriptor = RelayDescriptor(url: url, info: info)
+            try relayPool.add_relay(descriptor)
+        }
+
+        if expectedError != nil {
+            XCTFail("Expected \(expectedError!) error, but no error was thrown.")
+        }
+    } catch let error as RelayError where expectedError == .RelayAlreadyExists {
+        XCTAssertEqual(error, expectedError!, "Expected RelayAlreadyExists error, got \(error)")
+    } catch {
+        XCTFail("An unexpected error was thrown: \(error)")
+    }
+}
+
+