From 81e40ba76d9df6cd0e4119166d5304e640c7f526 Mon Sep 17 00:00:00 2001
From: abraunegg <alex.braunegg@gmail.com>
Date: Wed, 3 Mar 2021 11:12:27 +1100
Subject: [PATCH] Update 429 retry-after response handling (#1305)

* Always check the response headers when a 429 response is returned from OneDrive, so that the 'retry-after' value is correctly consumed and used
---
 src/onedrive.d | 45 ++++++++++++++++++++++++++++++---------------
 1 file changed, 30 insertions(+), 15 deletions(-)

diff --git a/src/onedrive.d b/src/onedrive.d
index d66d3cdb..40996f68 100644
--- a/src/onedrive.d
+++ b/src/onedrive.d
@@ -979,6 +979,8 @@ final class OneDriveApi
 			try {
 				// try and catch any curl error
 				http.perform();
+				// Check the HTTP Response headers - needed for correct 429 handling
+				// check will be performed in checkHttpCode()
 				writeln();
 				// Reset onProgress to not display anything for next download done using exit scope
 			} catch (CurlException e) {
@@ -991,12 +993,14 @@ final class OneDriveApi
 			try {
 				// try and catch any curl error
 				http.perform();
+				// Check the HTTP Response headers - needed for correct 429 handling
+				// check will be performed in checkHttpCode()
 			} catch (CurlException e) {
 				displayOneDriveErrorMessage(e.msg, getFunctionName!({}));
 			}
 		}
 		
-		// Check the HTTP response code
+		// Check the HTTP response code, which, if a 429, will also check response headers
 		checkHttpCode();
 	}
 
@@ -1029,6 +1033,7 @@ final class OneDriveApi
 		http.url = url;
 		addAccessTokenHeader();
 		auto response = perform(postData);
+		// Check the HTTP response code, which, if a 429, will also check response headers
 		checkHttpCode();
 		return response;
 	}
@@ -1105,19 +1110,8 @@ final class OneDriveApi
 		
 		try {
 			http.perform();
-			// Get the HTTP Response headers - needed for correct 429 handling
-			auto responseHeaders = http.responseHeaders();
-			// HTTP Server Response Headers Debugging if --https-debug is being used
-			if (.debugResponse){
-				log.vdebug("onedrive.perform() => HTTP Response Headers: ", responseHeaders);
-			}
-			// is retry-after in the response headers
-			if ("retry-after" in http.responseHeaders) {
-				// Set the retry-after value
-				log.vdebug("onedrive.perform() => Received a 'Retry-After' Header Response with the following value: ", http.responseHeaders["retry-after"]);
-				log.vdebug("onedrive.perform() => Setting retryAfterValue to: ", http.responseHeaders["retry-after"]);
-				.retryAfterValue = to!ulong(http.responseHeaders["retry-after"]);
-			}
+			// Check the HTTP Response headers - needed for correct 429 handling
+			checkHTTPResponseHeaders();
 		} catch (CurlException e) {
 			// Parse and display error message received from OneDrive
 			log.vdebug("onedrive.perform() Generated a OneDrive CurlException");
@@ -1150,6 +1144,8 @@ final class OneDriveApi
 					}
 					try {
 						http.perform();
+						// Check the HTTP Response headers - needed for correct 429 handling
+						checkHTTPResponseHeaders();
 						// no error from http.perform() on re-try
 						log.log("Internet connectivity to Microsoft OneDrive service has been restored");
 						retrySuccess = true;
@@ -1187,6 +1183,23 @@ final class OneDriveApi
 		}
 		return json;
 	}
+	
+	private void checkHTTPResponseHeaders()
+	{
+		// Get the HTTP Response headers - needed for correct 429 handling
+		auto responseHeaders = http.responseHeaders();
+		if (.debugResponse){
+			log.vdebug("http.perform() => HTTP Response Headers: ", responseHeaders);
+		}
+		
+		// is retry-after in the response headers
+		if ("retry-after" in http.responseHeaders) {
+			// Set the retry-after value
+			log.vdebug("http.perform() => Received a 'Retry-After' Header Response with the following value: ", http.responseHeaders["retry-after"]);
+			log.vdebug("http.perform() => Setting retryAfterValue to: ", http.responseHeaders["retry-after"]);
+			.retryAfterValue = to!ulong(http.responseHeaders["retry-after"]);
+		}
+	}
 
 	private void checkHttpCode()
 	{
@@ -1303,10 +1316,12 @@ final class OneDriveApi
 			//  429 - Too Many Requests
 			case 429:
 				// Too many requests in a certain time window
+				// Check the HTTP Response headers - needed for correct 429 handling
+				checkHTTPResponseHeaders();
 				// https://docs.microsoft.com/en-us/sharepoint/dev/general-development/how-to-avoid-getting-throttled-or-blocked-in-sharepoint-online
 				log.vlog("OneDrive returned a 'HTTP 429 - Too Many Requests' - gracefully handling error");
 				throw new OneDriveException(http.statusLine.code, http.statusLine.reason);
-			
+				
 			// Server side (OneDrive) Errors
 			//  500 - Internal Server Error
 			// 	502 - Bad Gateway