updated Downloader with ifUpdateAvailable (#328)

If the download location is specified (to()), the new (ifUpdateAvailable()) method can be used to trigger a download only if the resource available via the given URL is newer than the local file. It is currently used to avoid repeated downloads of the available Wine versions json.
PhoenicisOrg · Aug 19, 2017 · d86d4bf · d86d4bf
1 parent 7d73400
commit d86d4bf
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Showing 3 changed files with 30 additions and 6 deletions.
diff --git a/Engines/Wine/Engine/Object/script.js b/Engines/Wine/Engine/Object/script.js
@@ -301,13 +301,18 @@ Wine.prototype.kill = function () {
 
 /**
 *
-* @returns {Downloader}
+* @returns available Wine versions
 */
 Wine.prototype.getAvailableVersions = function () {
-    return new Downloader()
+    var versionsFile = this._wineEnginesDirectory + "/availableVersions.json";
+    touch(versionsFile);
+    new Downloader()
         .wizard(this._wizard)
         .url(this._wineWebServiceUrl)
-        .get()
+        .to(versionsFile)
+        .onlyIfUpdateAvailable(true)
+        .get();
+    return cat(versionsFile);
 };
 
 /**

diff --git a/Utils/Functions/Filesystem/Files/script.js b/Utils/Functions/Filesystem/Files/script.js
@@ -33,6 +33,12 @@ var remove = function(filePath) {
     return Bean("fileUtilities").remove(new java.io.File(filePath));
 };
 
+var touch = function(filePath) {
+    if (!fileExists(filePath)) {
+        Bean("fileUtilities").writeToFile(new java.io.File(filePath), "");
+    }
+};
+
 var writeToFile = function(filePath, content) {
     Bean("fileUtilities").writeToFile(new java.io.File(filePath), content);
 };

diff --git a/Utils/Functions/Net/Download/script.js b/Utils/Functions/Net/Download/script.js
@@ -32,6 +32,10 @@ var Downloader = function () {
         that._localFile = localFile;
         return that;
     };
+    that.onlyIfUpdateAvailable = function (onlyIfUpdateAvailable) {
+        that._onlyIfUpdateAvailable = onlyIfUpdateAvailable;
+        return that;
+    }
     that.get = function () {
         if (!that._message) {
             that._message = tr("Please wait while {0} is downloaded ...", that._fetchFileNameFromUrl(that._url));
@@ -41,9 +45,18 @@ var Downloader = function () {
             var progressBar = that._wizard.progressBar(that._message);
         }
 
+        if (that._onlyIfUpdateAvailable) {
+            if (!that._downloader.isUpdateAvailable(that._localFile, that._url)) {
+                print(that._localFile + " already up-to-date.");
+                return;
+            }
+        }
+
         if (that._localFile) {
             that._downloader.get(that._url, that._localFile, function (progressEntity) {
-                progressBar.accept(progressEntity);
+                if (progressBar) {
+                    progressBar.accept(progressEntity);
+                }
             });
 
             if (that._checksum) {
@@ -64,10 +77,10 @@ var Downloader = function () {
             }
         } else {
             return that._downloader.get(that._url, function (progressEntity) {
-                if(progressBar) {
+                if (progressBar) {
                     progressBar.accept(progressEntity);
                 }
             });
         }
     }
-};
+};