Add support for downloading files

We were re-using the `tw-save-wiki` message both for saving the current
wiki and downloading a new wiki. Now we’ll use the separate
`tw-download-file` message for downloading.

Fixes #236

core/modules/savers/andtidwiki.js

@@ -15,7 +15,11 @@ Handles saving changes via the AndTidWiki Android app
 var AndTidWiki = function(wiki) {
 };
 
-AndTidWiki.prototype.save = function(text,callback) {
+AndTidWiki.prototype.save = function(text,method,callback) {
+	// Bail out unless this is a save (rather than a download)
+	if(method !== "save") {
+		return false;
+	}
 	// Get the pathname of this document
 	var pathname = decodeURIComponent(document.location.toString());
 	// Strip the file://

core/modules/savers/download.js

@@ -18,7 +18,7 @@ Select the appropriate saver module and set it up
 var DownloadSaver = function(wiki) {
 };
 
-DownloadSaver.prototype.save = function(text) {
+DownloadSaver.prototype.save = function(text,method,callback) {
 	// Get the current filename
 	var filename = "tiddlywiki.html",
 		p = document.location.pathname.lastIndexOf("/");

core/modules/savers/manualdownload.js

@@ -21,7 +21,7 @@ Select the appropriate saver module and set it up
 var ManualDownloadSaver = function(wiki) {
 };
 
-ManualDownloadSaver.prototype.save = function(text) {
+ManualDownloadSaver.prototype.save = function(text,method,callback) {
 	$tw.modal.display(downloadInstructionsTitle,{
 		downloadLink: "data:text/html," + encodeURIComponent(text)
 	});

core/modules/savers/msdownload.js

@@ -18,7 +18,7 @@ Select the appropriate saver module and set it up
 var MsDownloadSaver = function(wiki) {
 };
 
-MsDownloadSaver.prototype.save = function(text) {
+MsDownloadSaver.prototype.save = function(text,method,callback) {
 	// Get the current filename
 	var filename = "tiddlywiki.html",
 		p = document.location.pathname.lastIndexOf("/");

core/modules/savers/tiddlyfox.js

@@ -15,7 +15,11 @@ Handles saving changes via the TiddlyFox file extension
 var TiddlyFoxSaver = function(wiki) {
 };
 
-TiddlyFoxSaver.prototype.save = function(text,callback) {
+TiddlyFoxSaver.prototype.save = function(text,method,callback) {
+	// Bail out unless this is a save (rather than a download)
+	if(method !== "save") {
+		return false;
+	}
 	var messageBox = document.getElementById("tiddlyfox-message-box");
 	if(messageBox) {
 		// Get the pathname of this document

core/modules/savers/twedit.js

@@ -15,7 +15,11 @@ Handles saving changes via the TWEdit iOS app
 var TWEditSaver = function(wiki) {
 };
 
-TWEditSaver.prototype.save = function(text,callback) {
+TWEditSaver.prototype.save = function(text,method,callback) {
+	// Bail out unless this is a save (rather than a download)
+	if(method !== "save") {
+		return false;
+	}
 	// Bail if we're not running under TWEdit
 	if(typeof DeviceInfo !== "object") {
 		return false;

core/modules/savers/upload.js

@@ -21,7 +21,11 @@ var UploadSaver = function(wiki) {
 	this.wiki = wiki;
 };
 
-UploadSaver.prototype.save = function(text,callback) {
+UploadSaver.prototype.save = function(text,method,callback) {
+	// Bail out unless this is a save (rather than a download)
+	if(method !== "save") {
+		return false;
+	}
 	// Get the various parameters we need
 	var backupDir = ".",
 		username = this.wiki.getTextReference("$:/UploadName"),

core/modules/startup.js

@@ -89,6 +89,13 @@ exports.startup = function() {
 				downloadType: "text/plain"
 			});
 		});
+		$tw.rootWidget.addEventListener("tw-download-file",function(event) {
+			$tw.wiki.saveWiki({
+				method: "download",
+				template: event.param,
+				downloadType: "text/plain"
+			});
+		});
 		// Install the crypto event handlers
 		$tw.rootWidget.addEventListener("tw-set-password",function(event) {
 			$tw.passwordPrompt.createPrompt({

core/modules/wiki.js

@@ -866,15 +866,17 @@ exports.callSaver = function(method /*, args */ ) {
 
 /*
 Save the wiki contents. Options are:
+	method: "save" or "download"
 	template: the tiddler containing the template to save
 	downloadType: the content type for the saved file
 */
 exports.saveWiki = function(options) {
 	options = options || {};
-	var template = options.template || "$:/core/save/all",
+	var method = options.method || "save",
+		template = options.template || "$:/core/save/all",
 		downloadType = options.downloadType || "text/plain";
 	var text = this.renderTiddler(downloadType,template);
-	this.callSaver("save",text,function(err) {
+	this.callSaver("save",text,method,function(err) {
 		if(err) {
 			alert("Error while saving:\n\n" + err);
 		} else {

editions/tw5.com/tiddlers/Download.tid

@@ -7,8 +7,8 @@ title: Download
 
 ! Download Single File Editions
 
-|<$button message="tw-save-wiki" param="$:/editions/tw5.com/save-empty" class="btn-big-green">Save Empty {{$:/core/images/save-button}}</$button>|Get started with an empty wiki |
-|<$button message="tw-save-wiki" param="$:/core/save/all" class="btn-big-green">Save Full {{$:/core/images/save-button}}</$button>|Download a full copy of this site, including all the documentation |
+|<$button message="tw-download-file" param="$:/editions/tw5.com/save-empty" class="btn-big-green">Download Empty {{$:/core/images/save-button}}</$button>|Get started with an empty wiki |
+|<$button message="tw-download-file" param="$:/core/save/all" class="btn-big-green">Download Full {{$:/core/images/save-button}}</$button>|Download a full copy of this site, including all the documentation |
 
 ! Download Node.js Edition