From 46e8e4343acba876b9540b9fc77a5c85faa10939 Mon Sep 17 00:00:00 2001
From: Sebastian Silva <sebastian@sugarlabs.org>
Date: Fri, 4 May 2018 05:48:38 -0500
Subject: [PATCH] Fix WebDAV by requesting new ETag. (#3230)

* Fix WebDAV by requesting new ETag conditionally

For me. this was saving only the first time and subsequently failing.
Having revised the requests, I noticed it didn't get a new ETag after saving.
Seems not all WebDAV implementations return a new ETag in PUT requests.

In my WebDAV service (WsgiDAV) - ETag is only served from a HEAD
request.

So if no ETag is found with PUT - we request one with HEAD.

This patch fixes error handling and should also work with servers that
provide ETag directly upon PUT.

* Add tweak from PMario
---
 core/modules/savers/put.js | 50 ++++++++++++++++++++++++--------------
 1 file changed, 32 insertions(+), 18 deletions(-)

diff --git a/core/modules/savers/put.js b/core/modules/savers/put.js
index be9817cf8..e1fd7a8c2 100644
--- a/core/modules/savers/put.js
+++ b/core/modules/savers/put.js
@@ -15,6 +15,24 @@ to the current URL, such as a WebDAV server.
 /*global $tw: false */
 "use strict";
 
+/*
+Retrieve ETag if available
+*/
+var RetrieveETag = function(self) {
+	var headers = { "Accept": "*/*;charset=UTF-8" };
+	$tw.utils.httpRequest({
+		url: self.uri(),
+		type: "HEAD",
+		headers: headers,
+		callback: function(err, data, xhr) {
+			if(!err) {
+				self.etag = xhr.getResponseHeader("ETag").replace(/^W\//,"");
+			}
+		}
+	});
+};
+
+
 /*
 Select the appropriate saver module and set it up
 */
@@ -34,16 +52,7 @@ var PutSaver = function(wiki) {
 			}
 		}
 	});
-	// Retrieve ETag if available
-	$tw.utils.httpRequest({
-		url: uri,
-		type: "HEAD",
-		callback: function(err, data, xhr) {
-			if(!err) {
-				self.etag = xhr.getResponseHeader("ETag");
-			}
-		}
-	});
+	RetrieveETag(this);
 };
 
 PutSaver.prototype.uri = function() {
@@ -69,15 +78,20 @@ PutSaver.prototype.save = function(text, method, callback) {
 		data: text,
 		callback: function(err, data, xhr) {
 			if(err) {
-				callback(err);
-			} else if(xhr.status === 200 || xhr.status === 201) {
-				self.etag = xhr.getResponseHeader("ETag");
-				callback(null); // success
-			} else if(xhr.status === 412) { // edit conflict
-				var message = $tw.language.getString("Error/EditConflict");
-				callback(message);
+				// response is textual: "XMLHttpRequest error code: 412"
+				const status = Number(err.substring(err.indexOf(':') + 2, err.length))
+				if(status === 412) { // edit conflict
+					var message = $tw.language.getString("Error/EditConflict");
+					callback(message);
+				} else {
+					callback(err); // fail
+				}
 			} else {
-				callback(xhr.responseText); // fail
+				self.etag = xhr.getResponseHeader("ETag");
+				if (self.etag == null) {
+					RetrieveETag(self);
+				}
+				callback(null); // success
 			}
 		}
 	});