Software Observations
import org.jredis.*
import org.jredis.ri.alphazero.*
import org.jredis.ri.alphazero.support.*
def redis = new JRedisClient();
redis.set("test", "Hello world")
def result = redis.get("test")
assert DefaultCodec.toStr( redis.get("test") ) == "Hello world"
Just a couple of notes to those thinking of using eh-cache for caching their Grails apps.
You may have a situation where you do not want the UIWebView to bounce or scroll when a user touches the view. There are 2 ways to do just that.
1. Embed Javascript function in the page itself
document.onload = function(){ document.ontouchmove = function(e){ e.preventDefault(); } };
2. Set AllowsRubberBanding to NO
[(UIScrollView*)[webview.subviews objectAtIndex:0] setAllowsRubberBanding:NO];
(Discussion here)
A very quick guide on installing Passenger (mod_rails) on a clean install of Ubuntu jaunty 9.04.
Category
apache2-prefork-dev libaprutil1 libaprutil1-devpassenger-install-apache2-moduleJava Tutorial (http://www.mongodb.org/display/DOCS/Java+Tutorial)
Since Groovy is based on Java, you can make use of the Java driver for MongoDB as well as go through the tutorial shown above. The code can be used as-is or modified to look more groovy.
Create a groovy file (mongo.groovy) and place the Java driver in the same directory. Edit it so the code looks like:
this.class.classLoader.rootLoader.addURL(new File("mongo-0.6.jar").toURL())
import com.mongodb.*
DBAddress address = new DBAddress("localhost", "mydb")
Mongo db = new Mongo(address)
db.authenticate('testUser', 'testPassword')
DBCollection coll = db.getCollection("testCollection")
BasicDBObject doc = new BasicDBObject()
doc.put("name", "MongoDB")
doc.put("type", "database")
doc.put("count", 1)
BasicDBObject info = new BasicDBObject()
info.put("x", 203)
info.put("y", 102)
doc.put("info", info)
coll.insert(doc)
for(i in 1..100) {
coll.insert(new BasicDBObject().append("i", i))
}
println coll.getCount()
DBCursor cursor = coll.find()
while(cursor.hasNext()) {
println cursor.next()
}
You can see it's just a rehash of part of the Java tutorial, the output will be a count of the number of inserted objects followed by the objects themselves.
The first line of code loads the jar file, this is useful if you're not looking to put the jar in a classpath or one of groovy's configured library paths like '~/.groovy/lib'.
Running the script is accomplished by 'groovy mongo.groovy' in the terminal. You can also type in 'groovyConsole' to load the console then opening the script and running inside it.
For the installation, I decided to build MongoDB (http://www.mongodb.org/) from source. The documentation regarding this is thorough and getting it running was a cinch. A Javascript engine called Spider Monkey is used and you need to build it with UTF8 support.
The documents referred to:
http://www.mongodb.org/display/DOCS/Building
http://www.mongodb.org/display/DOCS/Building+Spider+Monkey
http://www.mongodb.org/display/DOCS/Building+for+Linux
The all-in-one command line version:
Dependencies:
sudo apt-get install curl tcsh git-core scons g++
sudo apt-get install libpcre++-dev libboost-dev libmozjs-dev
Spider Monkey installation:
curl -O ftp://ftp.mozilla.org/pub/mozilla.org/js/js-1.7.0.tar.gz
tar zxvf js-1.7.0.tar.gz
cd js/src
export CFLAGS="-DJS_C_STRINGS_ARE_UTF8"
make -f Makefile.ref
sudo JS_DIST=/usr make -f Makefile.ref export
MongoDB installation:
git clone git://github.com/mongodb/mongo.git
scons all
sudo scons --prefix=/opt/mongo install
Finishing up:
add /opt/mongo/bin to your path
create a /data/db directory structure and chown it to your user or add read-write permission.
http://www.howtogeek.com/howto/ubuntu/how-to-add-a-program-to-the-ubuntu-startup-list-after-login/
System -> Preferences -> Startup Applications -> Startup Programs
click add, click browse and select /opt/mongo/bin/mongod
add run to the end of the line so that it reads '/opt/mongo/bin/mongod run'
enter name and comment then save
And you're done. mongodb will start up with no authentication as default at localhost:27017, the web information interface is at localhost:28017. You can use mongo to enter the interactive shell, similar to mysql's shell client.
Some links to get you started:
http://www.mongodb.org/display/DOCS/Overview+-+The+MongoDB+Interactive+Shell
http://www.mongodb.org/display/DOCS/File+Based+Configuration
http://www.mongodb.org/display/DOCS/Command+Line+Parameters
http://www.mongodb.org/display/DOCS/Security+and+Authentication
http://www.mongodb.org/display/DOCS/Manual
We've just returned from a trip to Guangzhou where we spent two days working with our partners, Well United, on Groovy, Grails, and PartyTime. It turned out to be a larger group than expected but the more the merrier!
* This is a quick guide on installing the latest Groovy 1.6.1 in Windows for non-Java developers.
1. Download and install Java SDK 1.6.x. Get the latest installer from Sun here. If this is your first time downloading Java, you are going to be confused with the various JDK 6 Updates packages -- JDK 6 Update with JavaFX SDK, JDK Update with Java EE, JDK Update with NetBeans 6.5.x. If unsure just look for the package without any of those extras -- Java 6 Update 13.
2. Download Groovy 1.6.1 installer from Groovy site. We will just use the Windows installer.
3. Double click on the Groovy installer and follow the wizard steps.
4. Use the defaults settings -- create GROOVY_HOME, add to PATH and add to System environment.
5. Make sure you have set JAVA_HOME environment. Right click on "My Computer", select "Properties". Click on the "Advance" tab and then click on the "Environment Variables" at the bottom of the window.
6. Add JAVA_HOME to User Variables. Click "Add" and enter the name as JAVA_HOME and value set to the full path to your Java JDK directory, e.g., C:\Program Files\Java\jdk1.6.0_13.
7. Continue with the Groovy installation wizard -- click next and use the defaults settings for native launcher and use all the Additional Modules.
8. Once finished, you should be able to see a new Groovy menu in Program list.
9. Lets give it a try. Select "Start GroovyConsole" to run GroovyConsole. If all goes well, you should be able to see the GroovyConsole up.
10. There are 2 useful keyboard shortcuts to know for GroovyConsole:
Let's take a brief look at the differences between Grails and Rails in term of persisting domain classes and creating web services. Both Grails and Rails are MVC frameworks and are very similar in terms of code syntax.
1. Domain Class Persistence
In Grails:
class Person {
String firstName
String lastName
String email
Date birthDate
Address address
static constraint = {
firstName(blank:false)
lastName(blank:false)
email(blank:false, email:true) // check if it's really e-mail
}
}
class Address {
String street
String city
String country
Person person
static belongsTo = Person
}
class Person <>
# Expects database schema to have a table "person"
# with columns first_name, last_name, email, birth_datevalidates_presence_of :first_name, :last_name, :email
end
class Address <>has_one :address
belongs_to :person
end
def listAllPeople = {
def pplList = Person.list() // or by query Person.findByLastName("Hewitts")
render pplList as XML
// render pplList as JSON
}
def listAllPeople
@pplList = Person.all # or by query Person.find_by_last_name("Hewitts")
render :xml => @pplList
# render :json => pplList
end
I've finally had it with Xen. We've been using it for QA and infrastructure hosts for a couple of years now (after a brief, bizarre detour with Solaris containers) with pretty good results. But after discovering Xen support had been dropped from the latest version of Ubuntu, I tried out KVM only to discover that its client tools are currently dribbly pieces of poo. I'm sure there's a clever way to compile your own kernel with the Xen patches to create some sort of frankenstein hypervisor, but really all I want is just the thinnest layer possible on top of bare metal in order to run some Linux VMs. Not really all that much to ask for.
The iphone-google-maps-component is a way for you to use Google Maps on the iPhone through the use of an extended UIWebView and an html file on a server somewhere that does the map loading.
The present code overrides the default delegate UIWebViewDelegate with its own, MapWebViewDelegate. You cannot use the setCenterWithLatLng to establish the starting location until the view has finished loading. With the override, the webViewDidFinishLoad delegate method is unavailable.
Going by this post, the following code changes will allow the use of both delegates.
MapWebView.h
1) Change protocol definition.@protocol MapWebViewDelegate < UIWebViewDelegate >
MapWebView.m
2) Remove the synthesize line.//@synthesize delegate;
3) Replace with own methods, to hook into super.delegate.- (id
return (id
}
- (void) setDelegate :(id
super.delegate = delegate;
}
webViewDidFinishLoad should be accessible, as well as the other methods in the UIWebViewDelegate.
Another way of setting the starting location is through the loadMap method in MapWebView.h. The URL string can accept two more variables, latitude and longitude.
Change this:NSString *urlStr = [NSString stringWithFormat:
@"http://www.wenear.com/iphone-test?width=%d&height=%d&zoom=%d",
width, height, DEFAULT_ZOOM_LEVEL];
To this:NSString *urlStr = [NSString stringWithFormat:
@"http://www.wenear.com/iphone-test?width=%d&height=%d&latitude=%f&longitude=%f&zoom=%d",
width, height, location.coordinate.latitude, location.coordinate.longitude, DEFAULT_ZOOM_LEVEL];
Here, location is a CLLocation, part of the CoreLocation framework. The loadMap method is publicly defined in the interface and it accepts location as its variable. The call in didMoveToSuperview should be properly handled.
The latitude and longitude are doubles and can be hardcoded instead.
Found this very insightful diagram of how Android SDK churns out Dalvik .dex files from Android java files here.
For anyone parsing an XML file and wondering what in the world an org.xml.sax.SAXParseException: Invalid byte 1 of 1-byte UTF-8 sequence error message is, check to see whether the XML file has any special characters like the copyright symbol, ©. The default encoding of UTF-8 will choke on these.
Solved my woes by changing the encoding to <?xml version="1.0" encoding="iso-8859-1"?> to get the character to display correctly. You can also filter it out or replace the symbol with its character reference.
A quick note on how to inject Service objects -- or for that matter any object -- via Spring.
Grails has always been able to support the injection of objects via Spring whether using XML or Spring DSL. A good scenario of using Spring DSL is to swap implementations easily.
In our project, Party Time, we use a lot of services. Most of these services implement Java interfaces and may be changed in the future. To be flexible in the changing of these service implementation, we auto-wire the services via Spring DSL.
For example, we have a Service class, LocalCDNService that implements the ICDNProvider interface. We configure the implementation by specifying in grails-app/conf/spring/resources.groovy:
beans = {
cdnProvider(LocalCDNService)
}
class ExampleController {
def cdnProvider
...
}
class ExampleController {
def localCdnService
}
beans = {
cdnProvider(AWSCDNService)
}
Just finished the first day of Sun Tech Days 2009 -- in summary I give it 4 stars out of 5.
Arrived early and saw a huge crowd of people queuing up for registration. The registration process was efficient -- I got my badge, orange goodie bag, and was quickly shown the way to the foyer. I'll be frank, I was expecting a light breakfast. No breakfast, only coffee and tea. Well as long as they serve coffee I am happy.
The welcoming ceremony started at around 9:10 am. Man, it was hilarious to see the big guys dressed as some Chinese gods. Check out some pictures and video in Arun's blog.
We were given a small Chinese rattle drum on the way into the hall. It's cool to use those small drums instead of clapping. This drum rattling event was supposed to be in Singapore's Book of Records for largest number of developers drumming away. Well whatever floats their boat.
Next thing I remember is seeing Mr Jeff Jackson taking on the stage to coordinate a few demo sessions. Between the sessions I remember lots of mentions of Glassfish, social networking, Google, YouTube, Ruby, OpenSolaris, etc.
Notable demos in the technology showcase:
This is what I did to start consuming RSS feeds with Groovy within 20 minutes!
1. Download Rome.
2. Download Rome Fetcher.
3. Download JDOM is you haven't done so.
4. Extract rome-x.jar, rom-fetcher-x.jar and jdom.jar to a tmp directory -- I placed them in lib/.
5. Start your Groovy console with the classpath set to the jar files, like this:
$ groovyConsole -cp lib/rome-1.0RC1.jar:lib/rome-fetcher-0.9.jar:lib/jdom.jar
6. Use the code below:
import com.sun.syndication.fetcher.*
import com.sun.syndication.fetcher.impl.*
import com.sun.syndication.feed.synd.SyndFeed
FeedFetcherCache feedInfoCache = HashMapFeedInfoCache.getInstance();
FeedFetcher feedFetcher = new HttpURLFeedFetcher(feedInfoCache);
SyndFeed feed = feedFetcher.retrieveFeed(new URL("http://feeds.digg.com/digg/topic/programming/popular.rss"));
feed.entries.each {
println " -> ${it} "
}
println " == ${feed.entries?.size()}"
Testing Grails service classes is easy if the service does not call any domain persistence methods. Meaning if your service class does cause some domain object to persist to database, it's going to be painful to try to mock the calls and check the result. And I'm not even sure if it's worth it to try.
The problem is that grails-testing newbies like me will want to try to do unit testing for services. In short, don't do that unless your service classes are simple and easy. (Keep this in mind when you start your project -- you won't see this unless you've experienced the pain before).
The best way that I found so far is to make service tests into integration tests. This mean putting service tests into the "integration" folder under the test directory. For more explanation on the difference between Unit Testing and Integration Testing in Grails, go here.
Testing Service classes is easy once you understand that it is:
class FooServiceTests extends GroovyTestCase {A couple of helpful points as indicated by the numbers above:
def fooService
void setUp() {
fooService = new FooService // *1
fooService.otherService = new OtherService() // *2
}
void testServiceCall() {
def user = new User(name:"Test", email:"test@name.com")
user.save(flush:true) // *3
fooService.doSomething(user) // *4
assertEquals user.result, "expected result"
}
}