add option to retry on internal server error

Signed-off-by: Adam Ratzman <adam@adamratzman.com>

Author: adamint

src/commonMain/kotlin/com.adamratzman.spotify/Builder.kt

@@ -846,6 +846,8 @@ public class SpotifyUserAuthorization(
  * @param requiredScopes Scopes that your application requires to function (only applicable to [SpotifyClientApi] and [SpotifyImplicitGrantApi]).
  * @param proxyBaseUrl Provide if you have a proxy base URL that you would like to use instead of the Spotify API base
  * (https://api.spotify.com/v1).
+ * @param retryIfInternalServerError Whether to retry once if an internal server error (500..599) has been received
+ *
  */
 public data class SpotifyApiOptions(
     public var useCache: Boolean = true,
@@ -861,5 +863,6 @@ public data class SpotifyApiOptions(
     public var refreshTokenProducer: (suspend (GenericSpotifyApi) -> Token)? = null,
     public var onTokenRefresh: (suspend (GenericSpotifyApi) -> Unit)? = null,
     public var requiredScopes: List<SpotifyScope>? = null,
-    public var proxyBaseUrl: String? = null
+    public var proxyBaseUrl: String? = null,
+    public var retryIfInternalServerError: Boolean = true
 )

src/commonMain/kotlin/com.adamratzman.spotify/http/Endpoints.kt

@@ -87,9 +87,10 @@ public abstract class SpotifyEndpoint(public val api: GenericSpotifyApi) {
             return withTimeout(api.spotifyApiOptions.requestTimeoutMillis ?: 100 * 1000L) {
                 try {
                     val document = createConnection(url, body, method, contentType).execute(
-                        cacheState?.eTag?.let {
+                        additionalHeaders = cacheState?.eTag?.let {
                             listOf(HttpHeader("If-None-Match", it))
-                        }
+                        },
+                        retryIfInternalServerError = api.spotifyApiOptions.retryIfInternalServerError
                     )
 
                     handleResponse(document, cacheState, spotifyRequest, retry202) ?: execute(
@@ -100,7 +101,7 @@ public abstract class SpotifyEndpoint(public val api: GenericSpotifyApi) {
                         contentType
                     )
                 } catch (e: BadRequestException) {
-                    if (e.statusCode?.equals(401) == true && !attemptedRefresh) {
+                    if (e.statusCode == 401 && !attemptedRefresh) {
                         api.refreshToken()
 
                         execute(
@@ -147,7 +148,7 @@ public abstract class SpotifyEndpoint(public val api: GenericSpotifyApi) {
             }
         }
 
-        if (document.responseCode / 200 != 1 /* Check if status is not 2xx or 3xx */) {
+        if (document.responseCode !in 200..399 /* Check if status is not 2xx or 3xx */) {
             val response = try {
                 document.body.toObject(ErrorResponse.serializer(), api, api.spotifyApiOptions.json)
             } catch (e: Exception) {

src/commonMain/kotlin/com.adamratzman.spotify/http/HttpConnection.kt

@@ -85,23 +85,23 @@ public class HttpConnection constructor(
 
     public suspend fun execute(
         additionalHeaders: List<HttpHeader>? = null,
-        retryIf502: Boolean = true
+        retryIfInternalServerError: Boolean = true
     ): HttpResponse {
         val httpRequest = buildRequest(additionalHeaders)
 
         try {
             return HttpClient().request<io.ktor.client.statement.HttpResponse>(httpRequest).let { response ->
                 val respCode = response.status.value
 
-                if (respCode == 502 && retryIf502) {
+                if (respCode in 500..599 && retryIfInternalServerError) {
                     api?.logger?.logError(
                         false,
-                        "Received 502 (Invalid response) for URL $url and $this (${response.readText()})\nRetrying..",
+                        "Received $respCode (Internal Server Error) for URL $url and $this (${response.readText()})\nRetrying..",
                         null
                     )
-                    return@let execute(additionalHeaders, retryIf502 = false)
-                } else if (respCode == 502 && !retryIf502) {
-                    api?.logger?.logWarning("Recieved 502 (Invalid response) for URL $url and $this\nNot retrying")
+                    return@let execute(additionalHeaders, retryIfInternalServerError = false)
+                } else if (respCode in 500..599 && !retryIfInternalServerError) {
+                    api?.logger?.logWarning("Received $respCode (Internal Server Error) for URL $url and $this\nNot retrying")
                 }
 
                 if (respCode == 429) {
@@ -114,7 +114,7 @@ public class HttpConnection constructor(
                         )
 
                         delay(ratelimit * 1000)
-                        return@let execute(additionalHeaders, retryIf502 = retryIf502)
+                        return@let execute(additionalHeaders, retryIfInternalServerError = retryIfInternalServerError)
                     } else throw SpotifyRatelimitedException(ratelimit)
                 }
 
@@ -125,7 +125,7 @@ public class HttpConnection constructor(
                     api.refreshToken()
                     val newAdditionalHeaders = additionalHeaders?.toMutableList() ?: mutableListOf()
                     newAdditionalHeaders.add(0, HttpHeader("Authorization", "Bearer ${api.token.accessToken}"))
-                    return execute(newAdditionalHeaders, retryIf502)
+                    return execute(newAdditionalHeaders, retryIfInternalServerError)
                 }
 
                 return HttpResponse(