Add request deduplication for Bungie API client (#108)

Co-authored-by: seer-by-sentry[bot] <157164994+seer-by-sentry[bot]@users.noreply.github.com>
Co-authored-by: Owen <98496129+owens1127@users.noreply.github.com>

Author: seer-by-sentry[bot]

src/integrations/bungie/client.ts

@@ -13,68 +13,91 @@ const inMemoryCache = new Map<
     }
 >()
 
+const inFlightRequests = new Map<string, Promise<unknown>>()
+
 export const bungiePlatformHttp = (opts: { ttl: number }) => ({
     fetch: async <T>(config: BungieFetchConfig) => {
         const cacheKey = config.url.toString()
+        
+        // Check cache first
         if (inMemoryCache.has(cacheKey)) {
             return inMemoryCache.get(cacheKey)!.data as T
         }
 
-        const apiKey = process.env.BUNGIE_API_KEY
-        if (!apiKey) {
-            throw new Error("Missing Bungie API Key")
+        // Check if request is already in-flight
+        if (inFlightRequests.has(cacheKey)) {
+            return inFlightRequests.get(cacheKey)! as Promise<T>
         }
 
-        const headers = new Headers(config.headers)
-        headers.append("X-API-KEY", apiKey)
-        headers.append("User-Agent", `RaidHub-API/${apiVersion} (contact=admin@raidhub.io)`)
+        // Create the request promise
+        const requestPromise = (async () => {
+            const apiKey = process.env.BUNGIE_API_KEY
+            if (!apiKey) {
+                throw new Error("Missing Bungie API Key")
+            }
 
-        const response = await fetch(config.url, {
-            method: config.method,
-            headers: headers,
-            body: config.body
-        })
+            const headers = new Headers(config.headers)
+            headers.append("X-API-KEY", apiKey)
+            headers.append("User-Agent", `RaidHub-API/${apiVersion} (contact=admin@raidhub.io)`)
 
-        if (response.headers.get("content-type")?.includes("application/json")) {
-            const data = (await response.json()) as BungieNetResponse<unknown>
+            const response = await fetch(config.url, {
+                method: config.method,
+                headers: headers,
+                body: config.body
+            })
 
-            if (!("ErrorCode" in data)) {
-                throw new Error("Invalid JSON response", {
-                    cause: data
-                })
-            }
+            if (response.headers.get("content-type")?.includes("application/json")) {
+                const data = (await response.json()) as BungieNetResponse<unknown>
 
-            if (data.ErrorCode !== 1) {
-                throw new BungieApiError({
-                    cause: data,
-                    url: config.url
-                })
-            } else {
-                // This is needed because we could have fired multiple requests to the same URL simultaneously
-                if (inMemoryCache.has(cacheKey)) {
-                    clearTimeout(inMemoryCache.get(cacheKey)!.timer)
+                if (!("ErrorCode" in data)) {
+                    throw new Error("Invalid JSON response", {
+                        cause: data
+                    })
                 }
-                inMemoryCache.set(cacheKey, {
-                    data,
-                    timer: setTimeout(() => {
-                        inMemoryCache.delete(cacheKey)
-                    }, opts.ttl)
-                })
 
-                return data as T
-            }
-        } else {
-            const body = await response.text()
-            const match = body.match(htmlRegex)
-            if (match) {
-                throw new Error(`Invalid HTML response (${response.status}): ${match[1]}`, {
-                    cause: body
-                })
+                if (data.ErrorCode !== 1) {
+                    throw new BungieApiError({
+                        cause: data,
+                        url: config.url
+                    })
+                } else {
+                    // This is needed because we could have fired multiple requests to the same URL simultaneously
+                    if (inMemoryCache.has(cacheKey)) {
+                        clearTimeout(inMemoryCache.get(cacheKey)!.timer)
+                    }
+                    inMemoryCache.set(cacheKey, {
+                        data,
+                        timer: setTimeout(() => {
+                            inMemoryCache.delete(cacheKey)
+                        }, opts.ttl)
+                    })
+
+                    return data as T
+                }
             } else {
-                throw new Error(`Invalid response (${response.status}): ${response.statusText}`, {
-                    cause: body
-                })
+                const body = await response.text()
+                const match = body.match(htmlRegex)
+                if (match) {
+                    throw new Error(`Invalid HTML response (${response.status}): ${match[1]}`, {
+                        cause: body
+                    })
+                } else {
+                    throw new Error(`Invalid response (${response.status}): ${response.statusText}`, {
+                        cause: body
+                    })
+                }
             }
+        })()
+
+        // Track the in-flight request
+        inFlightRequests.set(cacheKey, requestPromise)
+
+        try {
+            const result = await requestPromise
+            return result
+        } finally {
+            // Clean up in-flight request tracker
+            inFlightRequests.delete(cacheKey)
         }
     }
 })