On OSX, the details are stored in the binary file Web Data present in the folder /Library/Application Support/Google/Chrome/. I presume, there would be. In the 'Search engine used in the address bar' drop-down, select Google. Microsoft Edge 44 & lower. Open Microsoft Edge. Go to google.com. At the top right, click Settings and more Settings. In the 'Advanced settings' section, click View Advanced settings. Under 'Search in address bar with,' click Change. Click Google Search Set as default. And deployment of a finished application to Google is a single click away. With the Launcher, you can focus on your app instead of the tools. The Launcher is a true native Mac application. Installing the Google App Engine SDK, embedded in the Launcher, is a drag install. App Engine projects can be added to the Launcher with drag and drop.
Google announced Google App Engine, their long-awaited answer to web services offered by Amazon and others. Google took a different approach to their competitors by including a full application stack for developers. This made App Engine less flexible, by forcing developers to use the programming tools and libraries that Google supplied, but it did have the advantage that you could get your web app up and running very quickly, and easily leverage Google’s infrastructure. An app could scale up with very little work on the part of the developer — in theory.
Although the theory was sound, in practice, developers were quite limited in the resources they had available, and there was no option to increase those resources. Google has now addressed that, allowing developers to pay for resources at rates comparable to Amazon Web Services, so it seems App Engine may finally be ready for prime time.
A couple of months ago, my interest in App Engine was piqued enough to take a closer look. I spent about a week developing a Twitter-like web site called Mental Drain. (The site is fully operational, if a bit rough around the edges. You can try it out by logging in with your Google account.) In the rest of this post, I’ll discuss what’s involved in developing a web app with App Engine, and provide a few examples from the code I wrote for Mental Drain.
![School directory app School directory app](/uploads/1/3/4/2/134296715/199325903.jpg)
Mental Drain For Mac
![Google app engine java Google app engine java](/uploads/1/3/4/2/134296715/141116009.png)
Before we delve into App Engine, it is worth briefly considering the app that I will reference throughout this post: Mental Drain. As mentioned earlier, Mental Drain is based on Twitter, but with a few twists: When using Twitter, you generally follow people you know or admire, and receive all of the messages that they post. With Mental Drain, you receive posts on the topics that interest you, regardless of who posted them. In other words, you subscribe to topics (tags), rather than people. It’s like belonging to many different ad hoc communities, and getting all the messages in a single stream — your mental drain.
What is a Web Application?
Some of you reading this may still be wondering what App Engine actually does. If you don’t have any experience developing for the web, you probably don’t know the difference between a web application and an ‘ordinary’ web site. To get everyone on the same page, a web application is a web site which is interactive, and backed by some sort of database. The web site is dynamically updated based on the data in the store. Nearly every web site you come across these days is in fact a web application, from iTunes to Twitter and Amazon.
What is App Engine?
Google App Engine allows you to develop web applications backed by the mother of all data stores: Big Table. Big Table is Google’s secret sauce, a super-fast, super-scalable store that contains all of the data that makes Google’s search and other services what they are. App Engine opens that power up to outside developers.
App Engine provides a whole range of facilities and frameworks, all based around the scripting language Python. Much of App Engine is based on a web development framework called Django; even where Google have developed their own proprietary code — such as the all-important Datastore API — they seem to have been inspired by Django.
Signing Up and Installing
Signing up as a developer for App Engine is very easy, and free. You simply visit the App Engine site, and use your Google login to create an account. This allows you to write up to 10 applications; free apps are quite restricted in their resource quotas, but for many small sites, they are perfectly adequate. If your site takes off, you will have to decide whether to pay for extra resources, but that is quite a luxurious position to be in.
Free Apps Directory
Installing Google App Engine on your local development machine is also very easy. Google provide native installers for Windows, Mac, and Linux. On the Mac, you simply open the downloaded disk image, and drag the GoogleAppEngineLauncher application to your hard disk. When you launch the app, it will offer to create some symbolic links to make command line usage easier. That’s really all there is to it.
Setting Up a Project
We won’t go into great depth as to how you setup a project. Google provide quite a good introductory tutorial, which is probably the best place to start.
The process is quite straightforward: You create a directory for your project, and you add a configuration file to it called ‘app.yaml’, in the YAML format. Here is the Mental Drain configuration, by way of example.
The app.yaml file describes the app’s structure, including its version number and runtime environment. It also tells App Engine how to handle requests for URLs. For example, the Mental Drain project has subdirectories for static content like images, stylesheets, and scripts. As you can see, the app.yaml file maps URLs matching certain patterns to these directories. Any URL that begins with
/images
will be treated as a request for static data, and will be resolved to the images
subdirectory. (Note that although the URL and directory names are the same in this example, that is not a requirement.) Anything not matching these particular cases is matched by the last entry, which includes a wild card, and is resolved to the main application script: mentaldrain.py
.Controllers
App Engine, like nearly all modern web development environments, is based on the Model-View-Controller (MVC) paradigm. The model is the data in the data store, the view is what appears in the user’s browser, and the controller is the code that binds the two together.
The controller code for Mental Drain, which receives requests and decides what to do with them, is mostly concentrated in a single file:
mentaldrain.py
. We saw that most requests are directed to this script due to the configuration in app.yaml
. A controller script usually begins by importing a bunch of useful App Engine modules.The modules you need in your app will vary, but the ones listed above are quite common. We’ll see them in use as we go.
Somewhere in the controller file, usually toward the bottom, a
WSGIApplication
object will be created, and initialized.The application object maps URLs to particular handler classes, which are usually defined in the same controller file. In the example above, if a URL begins with
/postnugget
, it will be handled by the NuggetFactory
class. Note that a single class can handle multiple types of URLs, as is the case for TopicHandler
.The handler classes themselves must be subclasses of
webapp.RequestHandler
. They can handle both HTTP get and post requests, simply by implementing the get
and post
methods, respectively.For example, the
TopicHandler
class handles post requests for a user to subscribe to one or more topics (tags) in a string, or a get request to add or remove a particular topic from a user’s follow list.Getting the parameters passed with the request is trivial using the
request
dictionary. The string passed in the topics
argument is retrieved like thisApp Engine supplies many different APIs: in the code above, you can see examples of retrieving the current user
and redirecting the browser to a different URL
Another very common aspect of handling requests in a controller is returning HTML from the request, to be displayed in the user’s browser. This amounts to writing data to the request output stream, as in the following piece of code from Mental Drain
Although you can simply write out HTML strings directly, it is more common to separate the HTML from the controller code in template files. This snippet shows how a template is located in the ‘templates’ subdirectory, and then instantiated with a particular URL argument. The resulting string is written to
self.response.out
, the request’s output stream, which results in it appearing in the user’s browser.Views
We already started to consider the View of MVC in the controller section above. The View is what appears in the user’s browser, and is usually generated by App Engine using HTML template files. The template engine in App Engine is from the Django framework. Here is a relatively simple template for the info page of Mental Drain.
It looks a lot like ordinary HTML, but has embedded directives and variables. The code
{{ url }}
, for example, will be substituted with the string supplied for the url
variable when instantiating the template. The template engine can also handle many other operations common to programming, such as conditional branching and looping.Django templates can be arranged into an inheritance hierarchy much like in Object-Oriented Programming (OOP) languages. The page above extends the file
base.html
, which includes repetitive code such as the head section, with links to CSS and Javascript files.Two blocks have been defined, for the main content, and the sidebar content. These override blocks defined in
base.html
. Put simply, the blocks replace the blocks of the same name from the base.html
file in the generated output. Here is the base.html
file:Even if you aren’t using App Engine, a template engine like Django’s provides a powerful way to avoid repetitive coding, keep program logic and presentation code separate, and structure a web site much more cleanly.
Models
The model layer is about how data is stored in Big Table. Google doesn’t give you direct access to Big Table; you get indirect access through the Datastore API.
The Datastore API is similar to Core Data framework on the Mac, in that you define entities and relationships between those entities. When you use Core Data, you do this with a graphical tool; for App Engine, you define Python classes and add entity properties as class members. For example, the
Nugget
entity in Mental Drain, which represents a single post, begins like thisEntity classes generally derive from the
db.Model
class, and contain class members for each property. The created
property, for example, is a date, so it is assigned to a DateTimeProperty
object. content
is the textual content of the post, so this is a TextProperty
. There are many other property types available, including generic data blobs, which can be used for storing images and files.The
teacher
property is somewhat different, in that it defines a relationship to another entity: Teacher
. A teacher in Mental Drain is just a user — we are all teachers in ‘the drain’ — and this property maps a particular post (nugget) back to the user that posted it. A ReferenceProperty
is used to create such a relationship.Relationships can of course take many forms: one-to-one, one-to-many, many-to-many. The relationship of a nugget to its teacher is actually many-to-one, because a teacher can post many nuggets, so where is the ‘many’ side of the relationship?
In Core Data, this would be made explicit by adding an inverse property,
nuggets
, to the Teacher
entity, but in App Engine, nothing is added to Teacher
at all. Instead, an implicit property is created behind-the-scenes called nuggets
; this property is not a list or array of nuggets, as you might expect, but a query that can be used to retrieve all of the nuggets that belong to the teacher from the data store.Although all of this works fine once you get used to it, I think I prefer having an explicit property added to the
Teacher
class — it certainly makes reading the code simpler.Fetching and Saving Data
We mentioned you can use queries to retrieve objects from the store. This is analogous to using ‘fetch requests’ in Core Data, or an SQL query for a relational database. App Engine even supports an SQL like query language called GQL, but for many queries, you can use a simplified syntax. For example, here is how Mental Drain checks if a particular user already exists in the store
The
all
class method returns a query for all Teacher
instances in the data store. This is then modified by the filter
method to only look for those Teachers
where the user
property is equal to a particular user. Finally, the get
method returns the user, if there is one, and None
otherwise. (If you are looking for more than one object, you use the fetch
method instead of get
.)School Directory App
Whenever you create a new object, you need to make sure it is saved. The
put
method ensures that the data is persisted in the data store.Notebooks by Alfons Schmid is an iOS and Mac notebook app that has excellent organizational tools on iOS and the Mac. With solid search, sorting and sync options, your notebooks and documents are always readily available to you, which makes it a great research tool, especially on iOS. Mac notebooks app review. Zoho Notebook is a free Mac app that makes note-taking simple, but to be really useful, it needs a web version and better organizational features. MSRP Free PCMag editors select and review.
Testing
Google have gone to quite a lot of trouble to make working with App Engine a pleasure. You can test your app on your local machine with a test store before uploading it to the Google servers. You can even login with different fictional user names to test your app for multiple users. You can start the test server using the GoogleAppEngineLauncher app, or on the command line:
Mac Google App Engine Directory Windows 10
Your app will then be available at the address
http://localhost:8080
.Deploying an App
Mac Google App Engine Directory Search
Once an app is ready for prime time, it is just as easy to deploy it as it is to test. Again, you can use GoogleAppEngineLauncher to upload the app, or you can use the command line:
Gotchas
There are a few gotchas to be aware of. For one, you have no direct access to your app’s data. If you want to perform a migration, or other manipulation of that data, you will need to do so by writing application code, and running that via URL requests.
To complicate matters somewhat, Google have placed a limit on the number of items you can retrieve from the store with one query, and that is currently set at 1000. If you have a million items in the store, you need to develop a script to iterate through those items 1000 at a time.
Finally, you have to be aware that there are limits on how long a single request can run, so if your data transformation takes a considerable amount of time, you will have to break it up into a chain of contiguous URL requests. The App Engine documentation explains how you best can do this.
Advanced Stuff
This has been a very high-level look at App Engine. The objective was to give you an idea of the scope of the project, some of its advantages, and some of its disadvantages. We haven’t touched on anything particularly advanced, but that doesn’t mean it can’t be done. For example, Mental Drain uses Ajax techniques for updating data without reloading the page, and the Memcache API to improve performance.
Mac Google App Engine Directory Download
While I was writing scenario applications to test Google App Engine, I had the following idea: If BBEdit, Dreamweaver, CSSEdit, and TextMate were at a party, what kind of application would be welcomed to help with App Engine development? As silly as this sounds, it led me to think more about workflow. I used:
- a few applications for Python, CSS, HTML, and JavaScript.
- the command line to run applications and to view logs.
- a browser to test locally and to access the local developer console.
- the command line to deploy the application.
- a browser to view a live application's dashboard.
I began to think about how unfriendly command line interfaces can be, and how much repetitive typing I had been doing to test and deploy applications. With that said, I worked with John Grabowski of the Google Mac team and Brett Slatkin, an engineer on App Engine, on a 20% project to make Google App Engine Launcher for Mac OS X.
Free Phone Directory App
Now, App Engine Launcher is not a replacement for your code editor or your IDE. It improves your App Engine development experience by managing a list of your applications. With a few clicks you can run, browse, deploy, and view logs for your applications. It also has some added sugar thrown in like drag and drop, integration with your editor, and quick links to the local developer console and the live application dashboard.
Trackartist - Tracktitle.flac.When creating your music library, tick the checkbox ‘Use embedded tags’I have a whole library worth of Flacs. The whole point of plex is that the server adjusts the content for the client automatically.So demetri90, rip them as Flac, tag them meticulously with at leastArtist, Tracktitle, Albumartist, Tracknumber, Discnumberput them into a folder structurelike /Albumartist/Albumartist - Albumtitle1. Best mac app to rip cds. Trackartist - Tracktitle.flac2.
Download it now. If it's missing a feature that you'd like to see (like scripting, a Windows or Linux version, human-level AI ;), let us know in the Discussion Group.