{"id":1510,"date":"2019-06-26T16:07:00","date_gmt":"2019-06-26T16:07:00","guid":{"rendered":"https:\/\/hosting.uantwerpen.be\/platformdh\/?p=1510"},"modified":"2020-03-10T14:09:01","modified_gmt":"2020-03-10T14:09:01","slug":"tutorials-iiif-on-a-rpi","status":"publish","type":"post","link":"https:\/\/platformdh.uantwerpen.be\/index.php\/2019\/06\/26\/tutorials-iiif-on-a-rpi\/","title":{"rendered":"Tutorials: IIIF on a RPi"},"content":{"rendered":"\n

First published: 26 June 2019
Last update: 6 August 2019
DOI: http:\/\/dx.doi.org\/10.17613\/6n9b-2n48<\/a><\/p>\n\n\n\n

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This tutorial was developed by Wout Dillen and Joshua Sch\u00e4uble at the Centre for Manuscript Genetics<\/a> (CMG), as part of the IIIF<\/a> courses of the University of Antwerp<\/a>‘s Summer School on Digital Humanities<\/a>. This is a one-week summer school organized by the Antwerp Centre for Digital humanities and literary Criticism<\/a> (ACDC).<\/p>\n\n\n\n

The course was first taught in Antwerp in 2018 (3-7 September), and an adapted version was taught again in 2019 (1-5 July). In the course, students learn how to set up a IIIF-compatible image server (iipimage<\/a>) on a local network of Raspberry Pi<\/a> computers, to ultimately re-use and manipulate each other’s images using the IIIF protocol.<\/p>\n\n\n\n

1. Double-Checking Your Raspberry Pi’s Setup<\/h2>\n\n\n\n

Developed as a classroom instrument, this tutorial assumes that you are a student, and that you have access to a Raspberry Pi (RPi) with the Raspbian Operating System pre-installed on it. While they were preparing your RPi for this course, your tutors will also have checked that they are set up correctly for the course. Still, it is important that we double-check some of their settings, because they are crucial for the rest of this course.<\/p>\n\n\n\n

1.1 Make sure that SSH is enabled on your RPi<\/h3>\n\n\n\n

On your RPi, select the raspberry icon<\/strong> in the top left corner, and navigate to: Preferences > Raspberry Pi Configuration<\/code>. Here, select the tab Interfaces<\/code> and ensure, that SSH is Enabled<\/code>.<\/p>\n\n\n\n

1.2 Ensure that the keyboard layout is set correctly<\/h3>\n\n\n\n

Up until the moment when we are able to SSH into our RPis, we will need to use the keyboard to control them. Go to Preferences\/Mouse and Keyboard Settings<\/code>, select the tab Keyboard<\/code> and there the button Keyboard Layout<\/code>. Select the layout of the keyboard you are using, in our case (at the University of Antwerp) this would be Belgium\/Belgian<\/code>.<\/p>\n\n\n\n

1.3 Ensure that the system language is set to English<\/code><\/h3>\n\n\n\n

We want all RPis to be operated in English. Go to Preferences > Raspberry Pi Configuration<\/code> again, this time select the tab Localisation<\/code>. Click on Set Locale<\/code> and make sure the Language<\/code> is set to English<\/code> and the Character Set <\/code>is UTF-8<\/code>.<\/p>\n\n\n\n

1.4 Set the System Password<\/h3>\n\n\n\n

Although we are in a closed network for this course and do not expect any hacking attempts, it is always good practice to change your RPi’s password. Especially when SSH is enabled, changing the default password (raspberry<\/code>) will prevent others from accessing and controlling your computer without your knowledge. Go to Preferences > Raspberry Pi Configuration<\/code> again, this time select the tab System<\/code> and set the password to your own (unless your tutor provides you with one).<\/p>\n\n\n\n

1.5 Reboot your RPi<\/h3>\n\n\n\n

Go to your terminal, and enter the following command:<\/p>\n\n\n\n

sudo reboot now<\/pre>\n\n\n\n
2. Connect your RPi to the Internet<\/h2>\n\n\n\n
In the original setup for this tutorial, all RPis are connected to one another (and together to a local router, called IIIFarm<\/code>) via ethernet<\/code>. But we need them to be connected to the actual Internet too \u2013 to download packages etc. For this connection we will use the WiFi. The problem here is, that your RPi will prioritise Ethernet over WiFi for its internet connection. This is not surprising, because ethernet connections are typically much faster and more reliable than WiFi connections. But so in our case, we’ll need to turn this around, so the RPi will always use WiFi for internet connections first, rather than trying to connect through our (local, unconnected) ethernet network.<\/p>\n\n\n\n
2.1 Connect your RPi to the WiFi<\/h3>\n\n\n\n
WiFi network names and passwords will differ depending on where you are following this course, so listen to your tutors, and use the login information they provide.<\/p>\n\n\n\n
2.2 Prioritise WiFi for web requests using nano<\/code><\/h3>\n\n\n\n
So now we want to make sure our RPi uses the WiFi to connect to the internet, rather than its ethernet connection. To change this, we will need to make changes in a configuration file. Open a terminal, and enter:<\/p>\n\n\n\n
sudo nano \/etc\/dhcpcd.conf<\/pre>\n\n\n\n
This will tell the RPi to use the programme nano<\/code>, a shell text editor, to open a file located in the path \/etc\/dhcpcd.conf<\/code>.<\/p>\n\n\n\n
2.3 Assign metric values to your ports<\/h3>\n\n\n\n
Use the arrow-down<\/code> key to move to the end of the configuration file. There, add the following lines:<\/p>\n\n\n\n
interface wlan0\nmetric 202\n\ninterface eth0\nmetric 303\n<\/pre>\n\n\n\n
Hit Ctrl+o<\/code> to save the file and confirm with enter<\/code>. These lines assign metric values to your WiFi and your ethernet ports. The lower the value, the higher its priority. So, since 202<\/code> is lower than 303<\/code>, wlan0<\/code> (your WiFi port) will be rated higher than eth0<\/code> (your ethernet port) and our system will send web requests via wlan0<\/code> instead. Finally, hit Ctrl+x<\/code> to leave nano<\/code>.<\/p>\n\n\n\n
2.4. Reboot your RPi<\/h3>\n\n\n\n
To allow these changes to take effect, you will now have to reboot your RPi again. We will do this using the terminal:<\/p>\n\n\n\n
sudo reboot now<\/pre>\n\n\n\n
2.5 Connect the RPi to the WiFi network again<\/h3>\n\n\n\n
Open the browser. You should be directed to the university’s login page now. This means that assigning the metric values has worked! Each group has received credentials for an account on the guest network. Log in using these access data. Once you are logged in, visit any website to make sure your internet is connected.<\/p>\n\n\n\n
2.6. Double-check the metric values<\/h3>\n\n\n\n
Open a terminal and enter the following command:<\/p>\n\n\n\n
route<\/pre>\n\n\n\n
This command will show you your routing table: a list of all the system’s routing destinations<\/strong> (in the form of IP addresses), that tell the system where to send which data packages. Here you can double-check that the metric value of the wlan0<\/code> interface is now lower than that of the eth0<\/code> interface.<\/p>\n\n\n\n
2.7 Note down your IP Address<\/h3>\n\n\n\n
As mentioned, we will need the IP address that our router has assigned to our RPi to SSH into the RPi via our laptops. We can find the IP address we need by running the following command:<\/p>\n\n\n\n
ifconfig<\/pre>\n\n\n\n
This lists all your network settings. In the list, find the entry that starts with eth0<\/code> (typically the first one), and note down the first IP address that you see, the one that directly follows the word inet<\/code>.<\/p>\n\n\n\n
2.8. No more peeking!<\/h3>\n\n\n\n
Now that we have the IP addresses of our RPis, we can finally access them via SSH, using our laptops. That means we will no longer need to look at its desktop. Turn off the monitor that is connected to your RPi.<\/strong><\/p>\n\n\n\n
3. SSH into your RPi<\/h2>\n\n\n\n
We will now start to control our RPi from a different system (your laptop) using the command line. Since the rest of this tutorial assumes that you know some basic command line commands (and will even ask to write your own commands here and there), this is the point where your tutors will offer you a brief introduction to working in a Linux terminal. At a later point in time, a similar tutorial for training command line basics will be provided and linked here on this website.<\/p>\n\n\n\n
3.1 SSH Connect<\/h3>\n\n\n\n
On your laptop (the one that is connected to the IIIFarm<\/code> WiFi) open a Command Line Interface. Here, enter:<\/p>\n\n\n\n
ssh pi@your.ip.address<\/pre>\n\n\n\n
and confirm with enter<\/code>.<\/p>\n\n\n\n
On your first login to a new resource you will get a security warning. Confirm by typing yes<\/code>. You will be prompted for your RPi’s password. Type in the password that you’ve set up for your RPi, and confirm with enter<\/code>.<\/p>\n\n\n\n
3.2 Creating Files and Directories<\/h3>\n\n\n\n
At this point, your tutors should have either<\/em> already put a folder on your RPi’s Desktop<\/code>, or<\/em> prepared a USB-stick that passes around while you complete this exercise. In the second case, when you get the USB, you can turn your RPi’s monitor on, plug the USB into the RPi, and copy the directory with your RPi’s name onto your Desktop<\/code>. (The whole directory<\/em>, not just the files that are inside). When this is done, turn the monitor off again, and continue with the following exercise.<\/p>\n\n\n\n
3.3 Command Line Exercise<\/h3>\n\n\n\n