implement ajax-like functionality for zk docs

www/common/cryptget.js

@@ -0,0 +1,59 @@
+define([
+    '/customize/messages.js?app=read',
+    '/bower_components/chainpad-crypto/crypto.js',
+    '/bower_components/chainpad-netflux/chainpad-netflux.js',
+    '/common/cryptpad-common.js',
+], function (Messages, Crypto, Realtime, Cryptpad) {
+    var Crypt = {};
+
+    var finish = function (Session, err, doc) {
+        if (Session.done) { return; }
+        Session.cb(err, doc);
+        Session.done = true;
+
+        var abort = Cryptpad.find(Session,
+            ['realtime', 'realtime', 'abort']);
+        if (typeof(abort) === 'function') { abort(); }
+    };
+
+    var get = Crypt.get = function (hash, cb, opt) {
+        if (typeof(cb) !== 'function') {
+            throw new Error('Crypt.get expects a callback');
+        }
+
+        var Session = {
+            cb: cb,
+        };
+        opt = opt || {};
+        var secret = Session.secret = Cryptpad.getSecrets(hash);
+
+        var config = {
+            websocketURL: Cryptpad.getWebsocketURL(),
+            channel: secret.channel,
+            crypto: Crypto.createEncryptor(secret.keys),
+            logLevel: 0,
+        };
+
+        var onError = config.onError = function () {
+            finish(Session, Messages.websocketError);
+        };
+        var onAbort = config.onAbort = function () {
+            finish(Session, Messages.disconnectAlert);
+        };
+
+        var onReady = config.onReady = function (info) {
+            var realtime = Session.realtime = info.realtime;
+            finish(Session, void 0, realtime.getUserDoc());
+        };
+
+        var onConnectionChange = config.onConnectionChange = function (info) {
+            if (info.state) { return; }
+            finish(Session, Messages.disconnectAlert);
+        };
+        Object.keys(opt).forEach(function (k) { config[k] = opt[k]; });
+
+        return (Session.realtime = Realtime.start(config));
+    };
+
+    return Crypt;
+});