Ready to begin? No? Then grab some coffee or another refreshing beverage. We’ll wait. . .<\/p>\n
Ready now? We hope so! Because we’re getting started.<\/p>\n
<\/p>\n
Install Pre-Requisites<\/h2>\n
In order to complete this tutorial, you will need to set up a development environment. Our tutorial uses a Git<\/a> client to download the code from our Github repository<\/a>, VirtualBox<\/a> to set up a virtual machine, and Vagrant<\/a> to manage the virtual machine. However, all you really need is 1) the code in our repository, and 2) a web server running PHP. If you don’t want to install VirtualBox or Vagrant, you don’t have to, but we highly recommend doing so in case you want to experiment with them.<\/p>\n TIP!<\/strong> Already have a web server and PHP installed somewhere? Then just make certain to install Git<\/a>, then you can download our code from the Github repository<\/a>. You can still follow along with the tutorial, but some URLs and file names may change. We trust that you know what you are doing!<\/p><\/blockquote>\n We will be using the Git command-line client in this tutorial, so head on over to the Git web site, download the command-line client<\/a>, and follow the instructions for installation.<\/p>\n TIP!<\/strong> If you prefer a GUI to the command line, you can also download the GitHub GUI client by visiting the GitHub Git setup page<\/a>, but this tutorial only has instructions for the command line.<\/p><\/blockquote>\n Oracle’s VirtualBox is a powerful environment for running all kinds of virtual machines on Windows, Mac, and Linux. It is very much like Parallels or VMWare, except VirtualBox is free. Visit the VirtualBox downloads page<\/a> to find the software appropriate for your system, download it, and install it.<\/p>\n TIP!<\/strong> If you want, you can also download the Extension Pack, which provides additional functionality.<\/p><\/blockquote>\n Vagrant makes it easy to fire up and provision virtual machines with VirtualBox. Visit the Vagrant downloads page<\/a> to find the software appropriate for your system, download it, and install it.<\/p>\n TIP!<\/strong> To ensure the successful installation of Git, VirtualBox, and Vagrant, please make certain to visit the web sites listed above, and read through the documentation. Some people might call this RTFM<\/strong><\/a>, but we’re too polite to say that.<\/p><\/blockquote>\n Once you have Git, VirtualBox, and Vagrant up and running on your system, you’re ready to start downloading code!<\/p>\n <\/p>\n To get you up and running, we provide you with a Vagrant file and Puppet manifesto to set up your virtual machine (both were generated by the GUI at PuPHPet<\/a>), as well as a Basic LTI library written in PHP (originally found through the Edu Apps Writing LTI Stuff page<\/a>, but, apparently, no longer available). To download this code, you will need to This will download everything from the Git repository and store it in a folder called Once you have downloaded the code, change into the In this directory, you should see several files and folders, including the \n Now you wait. And wait some more. And continue waiting as your virtual environment downloads and fires up.<\/p>\n ACK!What’s all this waiting for? What the Heck is going on?<\/em><\/strong> If you are new to Vagrant and VirtualBox, the command All of this downloading and installing takes a great deal of time.<\/p><\/blockquote>\n As your virtual environment downloads and installs, a tremendous number of log messages and warnings will fly by your screen. Monitor or ignore them as you see fit. Be patient, and the process will eventually return you to the command line. Maybe it’s time to get another cup of coffee or refreshing beverage. . .<\/p>\n ACK! I got a nasty error message, and my VM won’t install. What should I do?<\/em><\/strong> Good question. It really depends on what the error message is. Try Googling it using the keywords “Vagrant” and “VirtualBox” in the search parameters. That might give you a hint.<\/p><\/blockquote>\n Once you are back on the command line, and no errors have occurred, this means that you have your virtual machine up and running, complete with a web server and PHP engine!<\/p>\n Open your favorite web browser and type the following into the address bar:<\/p>\n You should see the following appear in your browser window:<\/p>\n Success! You are running your LTI web server. You can see a sample LTI-compliant LMS running here:<\/p>\n Don’t fill out anything or press any buttons yet. It’s now time to review where you are and what you have.<\/p>\n <\/p>\n If you followed the instructions above, you should be located in your Within the TIP!<\/strong> You might have noticed another The Open up The above is some bare bones PHP that sets some error reporting. Now add the following code:<\/p>\n The above code first loads the Basic LTI library, then instantiates a new LTI object. The parameters of the object indicate, respectively, to set its OAuth secret to ‘secret’, do not set a session, and do not redirect to another application. (If you want to know what all of this really means, it’s best to explore the PHP libraries and see what that code is up to; but it’s not important at the moment.)<\/p>\n Now we will write some more standard PHP and HTML that will begin outputting the web page:<\/p>\n At this point, we want to check if the LTI launch is valid. If so, we print out all the POST parameters associated with this HTTP request:<\/p>\n Finally, if the Basic LTI launch is not valid, we dump an error message. We then close out the HTML:<\/p>\n Taken all together, our code should look like this:<\/p>\n <\/p>\n Open up your favorite browser, and type the following into the address bar:<\/p>\n You should see an error message, which makes sense, since you are not launching the tool with an LTI request (you are simply opening the tool in a web browser):<\/p>\n<\/a>Install Git<\/h3>\n
Install VirtualBox<\/h3>\n
Install Vagrant<\/h3>\n
Download Our Code<\/h2>\n
clone<\/code> it using Git. First, create and change into a directory where you want to stash the code. Once you do so, type in the following command:<\/p>\ngit clone https:\/\/github.com\/Harvard-ATG\/workshop-lti-basic.git
\n<\/code><\/p><\/blockquote>\nworkshop-lti-basic<\/code>.<\/p>\nStart Up Your Virtual Environment<\/h2>\n
workshop-lti-basic<\/code> folder:<\/p>\ncd path\/to\/workshop-lti-basic<\/code><\/p><\/blockquote>\nLICENSE<\/code> file, the README.md<\/code> file, a .git<\/code> folder, and a demo<\/code> folder. Run the following commands:<\/p>\ncd demo
\nvagrant up
\n<\/code><\/p><\/blockquote>\nvagrant up<\/code> does the following things:<\/p>\n\n
Test Your Virtual Environment<\/h2>\n
http:\/\/localhost:8080\/<\/code><\/p><\/blockquote>\n![\"tlt_lti_screenshot_index\"](\"http:\/\/blogs.law.harvard.edu\/acts\/files\/2014\/07\/tlt_lti_screenshot_index-1024x465.png\")
<\/a><\/p>\nhttp:\/\/localhost:8080\/lms.php<\/code><\/p><\/blockquote>\n![\"tlt_lti_screenshot_lms\"](\"http:\/\/blogs.law.harvard.edu\/acts\/files\/2014\/07\/tlt_lti_screenshot_lms.png\")
<\/a><\/p>\nExploring the Code<\/h2>\n
demo<\/code> folder. List out its contents. At this point, you should see a file called Vagrantfile<\/code> and a puphpet<\/code> folder. You can ignore these for now–they are responsible for setting up and running your virtual environment. Instead, change into the html<\/code> folder that is present.<\/p>\nhtml<\/code> folder are several .php<\/code> files, an index.html<\/code> file, and several folders. You can ignore most of the folders–they contain images and css files–but note the ims-blti<\/code> folder. Your Basic LTI libraries are stored in there.<\/p>\nhtml<\/code> folder and a default<\/code> folder among all those other files and folders. These folders were automatically created by your virtual machine and can be safely ignored.<\/p><\/blockquote>\n.php<\/code> files include lms.php<\/code> (the sample LMS you fired up earlier), misc.php<\/code> (some miscellaneous code used by the sample LMS), and tool-helloworld.php<\/code>. The latter file is the one you will be writing!<\/p>\nLet’s Write Some Code<\/h2>\n
tool-helloworld.php<\/code> in your favorite text editor. It should be beautifully blank, so type in the following:<\/p>\n\n
\r\n<?php\r\nerror_reporting(E_ALL & ~E_NOTICE);\r\nini_set("display_errors", 1);\r\n\r\n<\/pre>\n<\/blockquote>\n\n
\r\nrequire_once 'ims-blti\/blti.php';\r\n$lti = new BLTI("secret", false, false);\r\n\r\n<\/pre>\n<\/blockquote>\n\n
\r\nsession_start();\r\nheader('Content-Type: text\/html; charset=utf-8'); \r\n?>\r\n\r\n<!DOCTYPE html>\r\n<html>\r\n <head>\r\n <meta charset="UTF-8" \/>\r\n <title>Building Tools With The Learning Tools Operability Specification<\/title>\r\n <\/head>\r\n \r\n <body>\r\n<\/pre>\n<\/blockquote>\n\n
\r\n <?php\r\n if ($lti->valid) {\r\n ?>\r\n <h2>Hello, World!<\/h2>\r\n <p>We have implemented a basic LTI tool!<\/p>\r\n <h3>A basic dump of POST parameters:<\/h3>\r\n <pre> \r\n <?php\r\n foreach($_POST as $key => $value) {\r\n print "$key=$value\\n";\r\n }\r\n ?>\r\n <\/pre>\r\n<\/pre>\n<\/blockquote>\n\n
\r\n <?php\r\n } else {\r\n ?>\r\n <h2>This was not a valid LTI launch<\/h2>\r\n <p>Error message: <?= $lti->message ?><\/p>\r\n <?php\r\n }\r\n ?>\r\n <\/body>\r\n \r\n<\/html>\r\n<\/pre>\n<\/blockquote>\n\r\n<?php\r\nerror_reporting(E_ALL & ~E_NOTICE);\r\nini_set("display_errors", 1);\r\n \r\nrequire_once 'ims-blti\/blti.php';\r\n$lti = new BLTI("secret", false, false);\r\n\r\nsession_start();\r\nheader('Content-Type: text\/html; charset=utf-8'); \r\n?>\r\n \r\n<!DOCTYPE html>\r\n<html>\r\n <head>\r\n <meta charset="UTF-8" \/>\r\n <title>Building Tools With The Learning Tools Operability Specification<\/title>\r\n <\/head>\r\n \r\n <body>\r\n <?php\r\n if ($lti->valid) {\r\n ?>\r\n <h2>Hello, World!<\/h2>\r\n <p>We have implemented a basic LTI tool!<\/p>\r\n <h3>A basic dump of POST parameters:<\/h3>\r\n <pre> \r\n <?php\r\n foreach($_POST as $key => $value) {\r\n print "$key=$value\\n";\r\n }\r\n ?>\r\n <\/pre>\r\n <?php\r\n } else {\r\n ?>\r\n <h2>This was not a valid LTI launch<\/h2>\r\n <p>Error message: <?= $lti->message ?><\/p>\r\n <?php\r\n }\r\n ?>\r\n <\/body>\r\n \r\n<\/html>\r\n<\/pre>\nLet’s Run The Code<\/h2>\n
http:\/\/localhost:8080\/tool-helloworld.php<\/code><\/p><\/blockquote>\n
![\"tlt_lti_screenshot_invalid_02\"](\"http:\/\/blogs.law.harvard.edu\/acts\/files\/2014\/07\/tlt_lti_screenshot_invalid_02.png\")
<\/a><\/p>\n![\"tlt_lti_screenshot_success\"](\"http:\/\/blogs.law.harvard.edu\/acts\/files\/2014\/07\/tlt_lti_screenshot_success.png\")
<\/a><\/p>\n