Skip to main content

A month of Flutter: Stream transforms and failing tests


Originally published on bendyworks.com.
Now that I've got a Post model with mock data and a StreamBuilder for rendering, it all needs to be wired together.
The main changes I'm making are in _MyHomePageState where I'm replacing the stream of ints with a call to the new _loadPosts method.
Stream<List<Post>> _loadPosts(BuildContext context) {
  return DefaultAssetBundle.of(context)
      .loadString('assets/posts.json')
      .then<List<dynamic>>((String value) => json.decode(value))
      .asStream()
      .map(_convertToPosts);
}
_loadPosts uses DefaultAssetBundle.of to get the most appropriate AssetBundle for loading files from the assets directory.
Reading the String contents of a file is asynchronous, after which the JSON contents can be decoded. The loading and decoding will happen as a Futurebut I want to be working on a stream so I'll use asStream to convert the Future to a Stream.
Finally the Stream will then get transformed using map and another new method _convertToPosts.
List<Post> _convertToPosts(List<dynamic> data) {
  return data.map((dynamic item) => Post.fromMap(item)).toList();
}
Every time an event comes down the stream, map will call the convert method on the value. In this case the value is a List of items and List`s map will pass each item to Post.fromMap. Note that map on a List is different from map on a Streammap on a List is lazy so we'll force it to execute with a final toList.
The rest of the changes are going thought the code base and updating List<int> types to be List<Post> types and passing Post instances into the rendering PostItems. I'll also replace the hard coded 'Prim Birb' text with the dynamic username from the Post instances.

As I was updating the tests to use the new mock JSON data, I kept running into failures. I was seeing tests timing out or the PostsList error handling showing errors instead of content. After some digging it turns out that the code in testWidgets can't access files or assets. With CI configured I can't merge code without passing tests so come back tomorrow to see how I fix them.

Code changes

Comments

Popular posts from this blog

Little known @Twitter and @TwitterAPI tips and tricks

Be sure to comeback as new tips and tricks get added. If you know of anything I missed be sure to let me know.

Static URL for profile images based on screen_name:

https://api.twitter.com/1/users/profile_image/abraham

* This performs a http redirect to the actual profile image URL. Currently https redirects to http. You can also add "?size={mini | bigger | normal}" to get specific sizes.

Redirect to profile based on user_id:

https://twitter.com/account/redirect_by_id?id=9436992

In_reply_to_status_id mentions:

https://api.twitter.com/1/statuses/update.json?status=reply+to+@abraham&in_reply_to_status_id=12410413197

* In the web interface new mentions are only replies if they start with @screen_name. By pushing @screen_name further along in the string your followers who do not follow @screen_name will still see the status.

Profile image sizes:

http://a3.twimg.com/profile_images/54160223/chart-black-small.png

* By default you get the original image size you can add _mini, _normal, and …

Installing Storytlr the lifestreaming platform

"Storytlr is an open source lifestreaming and micro blogging platform. You can use it for a single user or it can act as a host for many people all from the same installation."

I've been looking for something like Storytlr for a few months now or at least trying to do it with Drupal. While I love Drupal and FeedAPI I did not want to spend all that time building a lifestream website. So I've been playing around with Storytlr instead and found it very easy. Here is how I got it up and running on a Ubuntu EC2 server. You can also check out the official Storytlr install instructions.

Assumptions:
LAMP stack installed and running.Domain setup for a directory.MySQL database and user ready to go.Lets get started!
Get the code: wget http://storytlr.googlecode.com/files/storytlr-0.9.2.tgz tar -xvzf storytlr-0.9.2.tgzYou can find out the latest stable release on Storytlr's downloads page.

Import the database:
Within protected/install is database.sql. Import this into your empt…

Sync is currently experiencing problems

Update: I now recommend you install Google Chrome and disable the built in Browser as it supports encrypting all synced data.

After picking up a gorgeous Galaxy Nexus yesterday I was running into an issue where my browser data wasn't syncing to the phone. After a little Googling I found this is commonly caused by having all of my synced Chrome data encrypted instead of the default of only encrypting the passwords. These are the steps I went through to get my dat syncing again without losing any of it. The exact error I was getting was "Sync is currently experiencing problems. It will be back shortly."




In Google Chrome open the personal stuff settings page by clicking this link or by opening the wrench menu, and click on "signed in with example@gmail.com".  Hit "disconnect your Google Account" to temporarily disable syncing from your browser.



Visit the Google Dashboard and "Stop sync and delete data from Google". I waited until the stored dat…