How To Bind An Interface To An Implementation In Laravel

Binding an interface to an implementation promotes good coding practices. As a result the code is less coupled, more maintainable, and testable.

Why might someone want to bind an interface using Laravel? To put an abstraction between the application and the concretion. A concretion is a class that implements the interface. It is a specific implementation, in our example it will be Amazon S3 file storage provider. The application doesn’t care which implementation it receives just that it receives an implementation with the guaranteed functions.

Lets build functionality to interact with files on a storage provider such as Amazon S3. Initially all files will be uploaded and deleted on S3 only. There are other ways to accomplish this and the main goal is to demonstrate how to bind an interface to an implementation and not so much the actual code to upload to a storage provider.

Create An Interface

The interface will determine which functions are available on the concrete implementation through the binding.

Create The Concrete Implementation

The concretion is an Amazon S3 file storage provider. This file is where Amazon specific upload/delete functionality goes.

Create The Laravel Service Provider

The Laravel service provider is the mechanism that binds the FileStorageInterface to the S3FileStorage class implementation. This means if we use dependency injection for the FileStorageInterface or use App:make it will automatically resolve to the S3FileStorage class.

Using The Interface

In the below example we are not using the implementation directly. Instead it is automatically resolved through the service provider which returns the concrete implementation. Laravel will automatically resolve dependencies if they are in the __construct() functions. We can see below that the controller doesn’t know about Amazon and nor should it. I am only using the controller in this example to provide a demonstration. There are other places where we would use the storage provider that might better organize the code.

Final Thoughts

If we wanted to swap out for Dropbox or some other provider the impact is minimal, create a Dropbox implementation and change the provider. The application would now use the Dropbox implementation instead of the Amazon S3 implementation.

Following this pattern can also help separate the application from Laravel which could make reusing this code in other projects easier than if the Amazon S3 code were included in a model directly. Definitely think about how to best structure your code and not to fall into the framework convenience trap of putting everything in a model, controller or view. In most cases there are better places for code than those 3 areas.

Laravel 4 Project On Shared Hosting

Laravel 4 is capable of running on a shared hosting environment. It’s a lot easier than you probably think.

  1. Login to your host and go to your home directory. This does not mean your public home directory, they are separate.
  2. Upload all the contents Laravel project EXCEPT the public folder to your home directory.
  3. Upload the contents of your Laravel public directory to your public directory on your host. The public directory is sometimes called public_html.
  4. Edit file paths.php located in the bootstrap folder so the public path matches the path to your public directory on your host.

After completing each of those steps you should now have a working Laravel 4 project on a shared hosting environment. This assumes the shared host has all the PHPmodules required to run Laravel as well. I was able to accomplish this on HostGator.

If you have any questions feel free to ask.

PHP Pages Displaying Code And Not Rendering Code

For some reason my server started displaying code instead of actually processing or rendering the code.

After playing around with the server I noticed the php5 module was missing from Apache.

If your code is displaying and not rendering you may have the same issue.

To install and enable it run the following command.

sudo apt-get install libapache2-mod-php5
sudo a2enmod php5

Then restart your apache. The restart command is different depending on the distro you’re using.
A simple Google search will help you.

 

This is the forum post that helped me fix my issue.

http://ubuntuforums.org/showthread.php?t=1546116&p=9681081#post9681081

Mod Rewrite Enabled But Not Working

If you find that your mod rewrite is enabled, but doesn’t seem to be working you may need to add this little bit of code to your httpd.conf file.

AllowOverride All

It’s possible your file might have the following:

AllowOverride None

If your AllowOverride was set to none then your .htaccess files in your project directory are not able to set their own settings including url rewriting.

Make sure to restart Apache after applying this change to your httpd.conf file.

 

The following link helped me solve my problem.

http://stackoverflow.com/questions/17772962/laravel-4-simple-route-not-working-using-mod-rewrite-and-htaccess

Xampp Send Email Issues

After upgrading my xampp installation I had issues sending email.

I wrote a small test PHP page and it was saying my emails were being sent, but I never received them. Obviously something was misconfigured.

I thought I correctly edited my php.ini file, but it turns out all the tinkering I did with it may have caused the issues.

Search your php.ini file for [mail function].

  1. Remove the comment on smtp and smtp_port by removing the semi colons before them.
  2. Add smtp server, port number. I’m using my ISP smtp server. Find your ISP smtp settings by searching google.
  3. sendmail_from needs to be set only if you don’t specify a from header in your PHP code. This can be set to any email address.
; XAMPP: Comment out this if you want to work with an SMTP Server like Mercury
SMTP = examplesmtpserver.com
smtp_port = 25

; For Win32 only.
; http://php.net/sendmail-from
sendmail_from = email you want to send from (ex: [email protected]). This needs to be set or a from header must be added in the php mail code

 

Here is test PHP code that I used. You’ll have to edit the “to” variable to your email address.

$to = "your email here";
$subject = "Test Email";
$body = "Email for testing Xampp";

if (mail($to, $subject, $body)){
	echo("Message successfully sent!");
} 
else{
	echo("Message delivery failed…");
}

After visiting your created PHP page the page should tell you whether PHP sent your email. Please note that just because PHP says it sent the mail doesn’t actually mean the email will be delivered  While I was having issues PHP still said it successfully sent, but I wasn’t receiving emails. If you’re still having problems after it says email successfully sent you’ll have to do more digging.

Contact me if you have questions I’ll do my best to assist [email protected].

 

 

Build Email Message Dynamically From Submitted Form

I wrote some code to dynamically generate an email message based on the names of form elements being sent through post.
In this post I’ll describe how it’s done.

The foreach loop grabs the keys from the post array. An example key for this  $_POST[‘Name’] would be “Name”. It’s important to put in the name of the field how you want it to show in the email. So if you want uppercase letters or spaces put them in.

The $keywos (key without spaces) gets the current key in the foreach loop and replaces the underscores that are automatically put in if the name from the HTML form elements had spaces when posting and replaces them with spaces.

Copy the post array to values array

If the current value for a particular key doesn’t have information in it don’t add it to the email message. This means the user hasn’t typed in any information in the input or selected an option.

If the key isn’t equal to submit then add it to the email messages. The submit button doesn’t need to be added to the email message.

 

Have questions? Email me at [email protected].