Webware for Python

Author: chrisz
Date: Thu Jan  4 17:53:14 2007
New Revision: 6043

Added:
   Webware/trunk/WebKit/Examples/JSONRPCClient.py   (contents, props changed)
   Webware/trunk/WebKit/Examples/JSONRPCExample.py   (contents, props changed)
   Webware/trunk/WebKit/Examples/jsonrpc.js
   Webware/trunk/WebKit/JSONRPCServlet.py   (contents, props changed)
Modified:
   Webware/trunk/WebKit/Examples/AjaxSuggest.py   (props changed)
   Webware/trunk/WebKit/Properties.py

Log:
Added JSON-RPC base class and usage example. (Suggested by Jean-Francois Pieronne.)

Added: Webware/trunk/WebKit/Examples/JSONRPCClient.py
==============================================================================
--- (empty file)
+++ Webware/trunk/WebKit/Examples/JSONRPCClient.py	Thu Jan  4 17:53:14 2007
@@ -0,0 +1,84 @@
+#
+# JSON-RPC demo client contributed by Christoph Zwerschke
+#
+
+from ExamplePage import ExamplePage
+
+class JSONRPCClient(ExamplePage):
+	"""Demo client for using the JSON-RPC example."""
+
+	def writeJavaScript(self):
+		ExamplePage.writeJavaScript(self)
+		self.write('''\
+			<script type="text/javascript" src="jsonrpc.js"></script>
+			<script type="text/javascript">
+			<!--
+			jsonrpc = new JSONRpcClient("JSONRPCExample");
+			methods = jsonrpc.system.listMethods();
+			function dojsonrpc() {
+				p = document.getElementById("parameter").value;
+				i = document.getElementById("method").selectedIndex;
+				r = jsonrpc[methods[i]](p);
+				document.getElementById("result").value = r;
+			}
+			-->
+			</script>
+		''')
+
+	def writeContent(self):
+		self.write('''\
+			<h3>JSON-RPC Example</h3>
+			<p>This example shows how you can call methods
+			of a <a href="http://json-rpc.org">JSON-RPC</a> servlet
+			built with Webware for Python from your web browser
+			via JavaScript (which has to be activated to run this demo).
+			<noscript><span style="color:red">
+			Unfortunately, JavaScript is not activated.
+			</span></noscript></p>
+			<p>The example uses a JSON-RPC JavaScript client
+			based on Jan-Klaas' "JavaScript o lait" library
+			(<a href="http://jsolait.net">jsolait</a>).
+			You can also use <a href="http://dojotoolkit.org">dojo</a>
+			or <a href="http://pyjamas.pyworks.org">pyjamas</a>
+			for that purpose.</p>
+			<p>In order to run the JSON-RPC servlet,
+			<a href="http://cheeseshop.python.org/pypi/simplejson">simplejson</a>
+			must be installed on your server.''')
+		try:
+			import simplejson
+		except ImportError:
+			self.write(''' <span style="color:red">
+			Unfortunately, simplejson is not installed.</span>''')
+			return
+		self.write('''</p>
+			<p>Type in any example text to be used as input parameter,
+			choose one of the available methods to be invoked by the
+			example servlet and press the button to display the result.</p>
+			<table>
+			<tr align="center">
+			<th>Input parameter</th>
+			<th>Remote method</th>
+			<th>Result</th>
+			</tr><tr align="center">
+			<td>
+			<input id="parameter" type="text" size="20" value="Hello, World!">
+			</td><td>
+			<select id="method" size="1">
+			<script type="text/javascript">
+			<!--
+			for (m in methods)
+				document.writeln('<option>' + methods[m] + '</option>');
+			-->
+			</script>
+			</select>
+			</td><td>
+			<input type="text" size="20" id="result">
+			</td>
+			</tr><tr align="center">
+			<td colspan="3">
+			<input type="button" value="Invoke remote method"
+				onclick="dojsonrpc()">
+			</td>
+			</tr>
+			</table>
+		''')

Added: Webware/trunk/WebKit/Examples/JSONRPCExample.py
==============================================================================
--- (empty file)
+++ Webware/trunk/WebKit/Examples/JSONRPCExample.py	Thu Jan  4 17:53:14 2007
@@ -0,0 +1,31 @@
+#
+# JSON-RPC example servlet contributed by Jean-Francois Pieronne
+#
+
+from WebKit.JSONRPCServlet import JSONRPCServlet
+
+class JSONRPCExample(JSONRPCServlet):
+	"""Example JSON-RPC servlet.
+
+	To try it out, use the JSONRPCClient servlet.
+
+	"""
+
+	def __init__(self):
+		JSONRPCServlet.__init__(self)
+
+	def echo(self, msg):
+		return msg
+
+	def reverse(self, msg):
+		return msg[::-1]
+
+	def uppercase(self, msg):
+		return msg.upper()
+
+	def lowercase(self, msg):
+		return msg.lower()
+
+	def json_methods(self):
+		return JSONRPCServlet.json_methods(self) + [
+			'echo', 'reverse', 'uppercase', 'lowercase']

Added: Webware/trunk/WebKit/Examples/jsonrpc.js
==============================================================================
--- (empty file)
+++ Webware/trunk/WebKit/Examples/jsonrpc.js	Thu Jan  4 17:53:14 2007
@@ -0,0 +1,484 @@
+/*
+ * JSON-RPC JavaScript client
+ *
+ * $Id: jsonrpc.js,v 1.36.2.3 2006/03/08 15:09:37 mclark Exp $
+ *
+ * Copyright (c) 2003-2004 Jan-Klaas Kollhof
+ * Copyright (c) 2005 Michael Clark, Metaparadigm Pte Ltd
+ *
+ * This code is based on Jan-Klaas' JavaScript o lait library (jsolait).
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+
+/* escape a character */
+
+escapeJSONChar =
+function escapeJSONChar(c)
+{
+    if(c == "\"" || c == "\\") return "\\" + c;
+    else if (c == "\b") return "\\b";
+    else if (c == "\f") return "\\f";
+    else if (c == "\n") return "\\n";
+    else if (c == "\r") return "\\r";
+    else if (c == "\t") return "\\t";
+    var hex = c.charCodeAt(0).toString(16);
+    if(hex.length == 1) return "\\u000" + hex;
+    else if(hex.length == 2) return "\\u00" + hex;
+    else if(hex.length == 3) return "\\u0" + hex;
+    else return "\\u" + hex;
+};
+
+
+/* encode a string into JSON format */
+
+escapeJSONString =
+function escapeJSONString(s)
+{
+    /* The following should suffice but Safari's regex is b0rken
+       (doesn't support callback substitutions)
+       return "\"" + s.replace(/([^\u0020-\u007f]|[\\\"])/g,
+       escapeJSONChar) + "\"";
+    */
+
+    /* Rather inefficient way to do it */
+    var parts = s.split("");
+    for(var i=0; i < parts.length; i++) {
+	var c =parts[i];
+	if(c == '"' ||
+	   c == '\\' ||
+	   c.charCodeAt(0) < 32 ||
+	   c.charCodeAt(0) >= 128)
+	    parts[i] = escapeJSONChar(parts[i]);
+    }
+    return "\"" + parts.join("") + "\"";
+};
+
+
+/* Marshall objects to JSON format */
+
+toJSON = function toJSON(o)
+{
+    if(o == null) {
+	return "null";
+    } else if(o.constructor == String) {
+	return escapeJSONString(o);
+    } else if(o.constructor == Number) {
+	return o.toString();
+    } else if(o.constructor == Boolean) {
+	return o.toString();
+    } else if(o.constructor == Date) {
+	return '{javaClass: "java.util.Date", time: ' + o.valueOf() +'}';
+    } else if(o.constructor == Array) {
+	var v = [];
+	for(var i = 0; i < o.length; i++) v.push(toJSON(o[i]));
+	return "[" + v.join(", ") + "]";
+    } else {
+	var v = [];
+	for(attr in o) {
+	    if(o[attr] == null) v.push("\"" + attr + "\": null");
+	    else if(typeof o[attr] == "function"); /* skip */
+	    else v.push(escapeJSONString(attr) + ": " + toJSON(o[attr]));
+	}
+	return "{" + v.join(", ") + "}";
+    }
+};
+
+
+/* JSONRpcClient constructor */
+
+JSONRpcClient =
+function JSONRpcClient_ctor(serverURL, user, pass, objectID)
+{
+    this.serverURL = serverURL;
+    this.user = user;
+    this.pass = pass;
+    this.objectID = objectID;
+
+    /* Add standard methods */
+    if(this.objectID) {
+	this._addMethods(["listMethods"]);
+	var req = this._makeRequest("listMethods", []);
+    } else {
+	this._addMethods(["system.listMethods"]);
+	var req = this._makeRequest("system.listMethods", []);
+    }
+    var m = this._sendRequest(req);
+    this._addMethods(m);
+};
+
+
+/* JSONRpcCLient.Exception */
+
+JSONRpcClient.Exception =
+function JSONRpcClient_Exception_ctor(code, message, javaStack)
+{
+    this.code = code;
+    var name;
+    if(javaStack) {
+	this.javaStack = javaStack;
+	var m = javaStack.match(/^([^:]*)/);
+	if(m) name = m[0];
+    }
+    if(name) this.name = name;
+    else this.name = "JSONRpcClientException";
+    this.message = message;
+};
+
+JSONRpcClient.Exception.CODE_REMOTE_EXCEPTION = 490;
+JSONRpcClient.Exception.CODE_ERR_CLIENT = 550;
+JSONRpcClient.Exception.CODE_ERR_PARSE = 590;
+JSONRpcClient.Exception.CODE_ERR_NOMETHOD = 591;
+JSONRpcClient.Exception.CODE_ERR_UNMARSHALL = 592;
+JSONRpcClient.Exception.CODE_ERR_MARSHALL = 593;
+
+JSONRpcClient.Exception.prototype = new Error();
+
+JSONRpcClient.Exception.prototype.toString =
+function JSONRpcClient_Exception_toString(code, msg)
+{
+    return this.name + ": " + this.message;
+};
+
+
+/* Default top level exception handler */
+
+JSONRpcClient.default_ex_handler =
+function JSONRpcClient_default_ex_handler(e) { alert(e); };
+
+
+/* Client settable variables */
+
+JSONRpcClient.toplevel_ex_handler = JSONRpcClient.default_ex_handler;
+JSONRpcClient.profile_async = false;
+JSONRpcClient.max_req_active = 1;
+JSONRpcClient.requestId = 1;
+
+
+/* JSONRpcClient implementation */
+
+JSONRpcClient.prototype._createMethod =
+function JSONRpcClient_createMethod(methodName)
+{
+    var fn=function()
+    {
+	var args = [];
+	var callback = null;
+	for(var i=0;i<arguments.length;i++) args.push(arguments[i]);
+	if(typeof args[0] == "function") callback = args.shift();
+	var req = fn.client._makeRequest.call(fn.client, fn.methodName,
+					      args, callback);
+	if(callback == null) {
+	    return fn.client._sendRequest.call(fn.client, req);
+	} else {
+	    JSONRpcClient.async_requests.push(req);
+	    JSONRpcClient.kick_async();
+	    return req.requestId;
+	}
+    };
+    fn.client = this;
+    fn.methodName = methodName;
+    return fn;
+};
+
+JSONRpcClient.prototype._addMethods =
+function JSONRpcClient_addMethods(methodNames)
+{
+    for(var i=0; i<methodNames.length; i++) {
+	var obj = this;
+	var names = methodNames[i].split(".");
+	for(var n=0; n<names.length-1; n++) {
+	    var name = names[n];
+	    if(obj[name]) {
+		obj = obj[name];
+	    } else {
+		obj[name]  = new Object();
+		obj = obj[name];
+	    }
+	}
+	var name = names[names.length-1];
+	if(!obj[name]) {
+	    var method = this._createMethod(methodNames[i]);
+	    obj[name] = method;
+	}
+    }
+};
+
+JSONRpcClient._getCharsetFromHeaders =
+function JSONRpcClient_getCharsetFromHeaders(http)
+{
+    try {
+	var contentType = http.getResponseHeader("Content-type");
+	var parts = contentType.split(/\s*;\s*/);
+	for(var i =0; i < parts.length; i++) {
+	    if(parts[i].substring(0, 8) == "charset=")
+		return parts[i].substring(8, parts[i].length);
+	}
+    } catch (e) {}
+    return "UTF-8"; /* default */
+};
+
+/* Async queue globals */
+JSONRpcClient.async_requests = [];
+JSONRpcClient.async_inflight = {};
+JSONRpcClient.async_responses = [];
+JSONRpcClient.async_timeout = null;
+JSONRpcClient.num_req_active = 0;
+
+JSONRpcClient._async_handler =
+function JSONRpcClient_async_handler()
+{
+    JSONRpcClient.async_timeout = null;
+
+    while(JSONRpcClient.async_responses.length > 0) {
+	var res = JSONRpcClient.async_responses.shift();
+	if(res.canceled) continue;
+	if(res.profile) res.profile.dispatch = new Date();
+	try {
+	    res.cb(res.result, res.ex, res.profile);
+	} catch(e) {
+	    JSONRpcClient.toplevel_ex_handler(e);
+	}
+    }
+
+    while(JSONRpcClient.async_requests.length > 0 &&
+	  JSONRpcClient.num_req_active < JSONRpcClient.max_req_active) {
+	var req = JSONRpcClient.async_requests.shift();
+	if(req.canceled) continue;
+	req.client._sendRequest.call(req.client, req);
+    }
+};
+
+JSONRpcClient.kick_async =
+function JSONRpcClient_kick_async()
+{
+    if(JSONRpcClient.async_timeout == null)
+	JSONRpcClient.async_timeout =
+	    setTimeout(JSONRpcClient._async_handler, 0);
+};
+
+JSONRpcClient.cancelRequest =
+function JSONRpcClient_cancelRequest(requestId)
+{
+    /* If it is in flight then mark it as canceled in the inflight map
+       and the XMLHttpRequest callback will discard the reply. */
+    if(JSONRpcClient.async_inflight[requestId]) {
+	JSONRpcClient.async_inflight[requestId].canceled = true;
+	return true;
+    }
+
+    /* If its not in flight yet then we can just mark it as canceled in
+       the the request queue and it will get discarded before being sent. */
+    for(var i in JSONRpcClient.async_requests) {
+	if(JSONRpcClient.async_requests[i].requestId == requestId) {
+	    JSONRpcClient.async_requests[i].canceled = true;
+	    return true;
+	}
+    }
+
+    /* It may have returned from the network and be waiting for its callback
+       to be dispatched, so mark it as canceled in the response queue
+       and the response will get discarded before calling the callback. */
+    for(var i in JSONRpcClient.async_responses) {
+	if(JSONRpcClient.async_responses[i].requestId == requestId) {
+	    JSONRpcClient.async_responses[i].canceled = true;
+	    return true;
+	}
+    }
+
+    return false;
+};
+
+JSONRpcClient.prototype._makeRequest =
+function JSONRpcClient_makeRequest(methodName, args, cb)
+{
+    var req = {};
+    req.client = this;
+    req.requestId = JSONRpcClient.requestId++;
+
+    var obj = {};
+    obj.id = req.requestId;
+    if (this.objectID)
+	obj.method = ".obj#" + this.objectID + "." + methodName;
+    else
+	obj.method = methodName;
+    obj.params = args;
+
+    if (cb) req.cb = cb;
+    if (JSONRpcClient.profile_async)
+	req.profile = { "submit": new Date() };
+    req.data = toJSON(obj);
+
+    return req;
+};
+
+JSONRpcClient.prototype._sendRequest =
+function JSONRpcClient_sendRequest(req)
+{
+    if(req.profile) req.profile.start = new Date();
+
+    /* Get free http object from the pool */
+    var http = JSONRpcClient.poolGetHTTPRequest();
+    JSONRpcClient.num_req_active++;
+
+    /* Send the request */
+    if (typeof(this.user) == "undefined") {
+	http.open("POST", this.serverURL, (req.cb != null));
+    } else {
+	http.open("POST", this.serverURL, (req.cb != null), this.user, this.pass);
+    }
+
+    /* setRequestHeader is missing in Opera 8 Beta */
+    try { http.setRequestHeader("Content-type", "text/plain"); } catch(e) {}
+
+    /* Construct call back if we have one */
+    if(req.cb) {
+	var self = this;
+	http.onreadystatechange = function() {
+	    if(http.readyState == 4) {
+		http.onreadystatechange = function () {};
+		var res = { "cb": req.cb, "result": null, "ex": null};
+		if (req.profile) {
+		    res.profile = req.profile;
+		    res.profile.end = new Date();
+		}
+		try { res.result = self._handleResponse(http); }
+		catch(e) { res.ex = e; }
+		if(!JSONRpcClient.async_inflight[req.requestId].canceled)
+		    JSONRpcClient.async_responses.push(res);
+		delete JSONRpcClient.async_inflight[req.requestId];
+		JSONRpcClient.kick_async();
+	    }
+	};
+    } else {
+	http.onreadystatechange = function() {};
+    }
+
+    JSONRpcClient.async_inflight[req.requestId] = req;
+	
+    try {
+	http.send(req.data);
+    } catch(e) {
+	JSONRpcClient.poolReturnHTTPRequest(http);
+	JSONRpcClient.num_req_active--;
+	throw new JSONRpcClient.Exception
+	    (JSONRpcClient.Exception.CODE_ERR_CLIENT, "Connection failed");
+    }
+
+    if(!req.cb) return this._handleResponse(http);
+};
+
+JSONRpcClient.prototype._handleResponse =
+function JSONRpcClient_handleResponse(http)
+{
+    /* Get the charset */
+    if(!this.charset) {
+	this.charset = JSONRpcClient._getCharsetFromHeaders(http);
+    }
+
+    /* Get request results */
+    var status, statusText, data;
+    try {
+	status = http.status;
+	statusText = http.statusText;
+	data = http.responseText;
+    } catch(e) {
+	JSONRpcClient.poolReturnHTTPRequest(http);
+	JSONRpcClient.num_req_active--;
+	JSONRpcClient.kick_async();
+	throw new JSONRpcClient.Exception
+	    (JSONRpcClient.Exception.CODE_ERR_CLIENT, "Connection failed");
+    }
+
+    /* Return http object to the pool; */
+    JSONRpcClient.poolReturnHTTPRequest(http);
+    JSONRpcClient.num_req_active--;
+
+    /* Unmarshall the response */
+    if(status != 200) {
+	throw new JSONRpcClient.Exception(status, statusText);
+    }
+    var obj;
+    try {
+	eval("obj = " + data);
+    } catch(e) {
+	throw new JSONRpcClient.Exception(550, "error parsing result");
+    }
+    if(obj.error)
+	throw new JSONRpcClient.Exception(obj.error.code, obj.error.msg,
+					  obj.error.trace);
+    var res = obj.result;
+
+    /* Handle CallableProxy */
+    if(res && res.objectID && res.JSONRPCType == "CallableReference")
+	return new JSONRpcClient(this.serverURL, this.user,
+				 this.pass, res.objectID);
+
+    return res;
+};
+
+
+/* XMLHttpRequest wrapper code */
+
+/* XMLHttpRequest pool globals */
+JSONRpcClient.http_spare = [];
+JSONRpcClient.http_max_spare = 8;
+
+JSONRpcClient.poolGetHTTPRequest =
+function JSONRpcClient_pool_getHTTPRequest()
+{
+    if(JSONRpcClient.http_spare.length > 0) {
+	return JSONRpcClient.http_spare.pop();
+    }
+    return JSONRpcClient.getHTTPRequest();
+};
+
+JSONRpcClient.poolReturnHTTPRequest =
+function JSONRpcClient_poolReturnHTTPRequest(http)
+{
+    if(JSONRpcClient.http_spare.length >= JSONRpcClient.http_max_spare)
+	delete http;
+    else
+	JSONRpcClient.http_spare.push(http);
+};
+
+JSONRpcClient.msxmlNames = [ "MSXML2.XMLHTTP.5.0",
+			     "MSXML2.XMLHTTP.4.0",
+			     "MSXML2.XMLHTTP.3.0",
+			     "MSXML2.XMLHTTP",
+			     "Microsoft.XMLHTTP" ];
+
+JSONRpcClient.getHTTPRequest =
+function JSONRpcClient_getHTTPRequest()
+{
+    /* Mozilla XMLHttpRequest */
+    try {
+	JSONRpcClient.httpObjectName = "XMLHttpRequest";
+	return new XMLHttpRequest();
+    } catch(e) {}
+
+    /* Microsoft MSXML ActiveX */
+    for (var i=0;i < JSONRpcClient.msxmlNames.length; i++) {
+	try {
+	    JSONRpcClient.httpObjectName = JSONRpcClient.msxmlNames[i];
+	    return new ActiveXObject(JSONRpcClient.msxmlNames[i]);
+	} catch (e) {}
+    }
+
+    /* None found */
+    JSONRpcClient.httpObjectName = null;
+    throw new JSONRpcClient.Exception(0, "Can't create XMLHttpRequest object");
+};
+

Added: Webware/trunk/WebKit/JSONRPCServlet.py
==============================================================================
--- (empty file)
+++ Webware/trunk/WebKit/JSONRPCServlet.py	Thu Jan  4 17:53:14 2007
@@ -0,0 +1,75 @@
+#
+# JSON-RPC servlet class written by Jean-Francois Pieronne
+#
+
+import traceback
+import simplejson # http://cheeseshop.python.org/pypi/simplejson
+import cStringIO as StringIO
+
+from WebKit.HTTPContent import HTTPContent
+
+debug = 0
+
+class JSONRPCServlet(HTTPContent):
+	"""A superclass for Webware servlets using JSON-RPC techniques.
+
+	JSONRPCServlet can be used to make coding JSON-RPC applications easier.
+
+	Subclasses should override the method json_methods() which returns a list
+	of method names. These method names refer to Webware Servlet methods that
+	are able to be called by an JSON-RPC-enabled web page. This is very similar
+	in functionality to Webware's actions.
+
+	"""
+
+	def __init__(self):
+		HTTPContent.__init__(self)
+
+	def defaultAction(self):
+		self.json_call()
+
+	def actions(self):
+		actions = HTTPContent.actions(self)
+		actions.append('json_call')
+		return actions
+
+	def json_methods(self):
+		return []
+
+	def json_call(self):
+		"""Execute method with arguments on the server side.
+
+		Returns Javascript function to be executed by the client immediately.
+
+		"""
+		request = self.request()
+		data = simplejson.loads(request.rawInput().read())
+		id, call, params = data["id"], data["method"], data["params"]
+		self.id = id
+		if call == 'system.listMethods':
+			result = self.json_methods()
+			self.write(simplejson.dumps({'id': id, 'result': result}))
+		elif call in self.json_methods():
+			try:
+				method = getattr(self, call)
+			except AttributeError:
+				cmd = self.error('%s, although an approved method,'
+					' was not found' % call)
+			else:
+				try:
+					if debug:
+						self.log("json call %s(%s)" % (call, params))
+					result = method(*params)
+					self.write(simplejson.dumps({'id': id, 'result': result}))
+				except Exception:
+					err = StringIO.StringIO()
+					traceback.print_exc(file=err)
+					e = err.getvalue()
+					cmd = self.error('%s was called,'
+						' but encountered an error: %s' % (call, e))
+					err.close()
+		else:
+			self.error('%s is not an approved method' % call)
+
+	def error(self, msg):
+		self.write(simplejson.dumps({'id': self.id, 'code': -1, 'error': msg}))

Modified: Webware/trunk/WebKit/Properties.py
==============================================================================
--- Webware/trunk/WebKit/Properties.py	(original)
+++ Webware/trunk/WebKit/Properties.py	Thu Jan  4 17:53:14 2007
@@ -35,5 +35,6 @@
 		'RequestInformation',
 		'Image',
 		'AjaxSuggest',
+		'JSONRPCClient',
 	]
 }