to-jdbc-uri 0.5.0 released

We just released to-jdbc-uri 0.5.0 with support for URL parameters. Courtesy of Joe Kutner.

I’d like to note, sometimes I hear that the Clojure community doesn’t care about testing, but to-jdbc-uri has a very complete testing suite and so far, this and other contributions came fully tested.


How I found one of the earliest browsers in history

Yesterday, the web celebrated its 25th birthday and to join in, I want a little story. A couple of years ago I found a NeXTcube. I’m not going to say where it is to avoid vandalism (the computer is publicly accessible under some circumstances without much oversight), but this is the story. Sir Tim Berners-Lee coded the earliest version of the web in his NeXTcube workstation when he was working at CERN, so, I was always interested in this machines, from a historical/playful point of view.

The cube that was in front of me was more or less abandoned and I asked the owner if I could play with it. He was very reticent but I was more relentless and I got to play with it. He told me that Next computer belonged, at one point, to CERN and that it has not been used since then. I decided to explore it.

The first interesting thing I found was a file containing a lot of email addresses from people that seemed to work at CERN or be related to CERN in some form or fashion. The owner of the computer decided to be overly professional and deleted the file.

The second interesting thing I found completely blew my mind. There was a folder called WorldWideWeb and inside it several files called WorldWideWeb_0.1.0.tar, 0.1.1.tar, 0.2.0.tar and so on. Could this be? I opened one by one and indeed they were apps. I started with the oldest and executed them one by one.

The first one raised an error as it tried to contact (this Next cube was disconnected) and then it crashed:


I kept on going and eventually one started. It was very plain but I knew what it was. I quickly went back to my terminal, open vi, and wrote a small HTML file, which then I passed as a parameter to the little WorldWideWeb_0.2. It worked… it displayed an h1 as a title!

I was jumping out of my skin. I don’t want to publish the whole picture to avoid releasing private information, but I’m standing, next to the cube, pointing and what could possible be the earliest version of the web browser that still works today, displaying a web site I just coded (it says Hello World):


Then I discovered the browser allowed me to edit the page, directly there, without having to do anything special, and I remembered that Sir Tim Berners-Lee originally designed the web to be read-write, not read-only.

That was one of the most exciting moments of my life. When I got home I wrote an email to Sir Tim Berners-Lee, telling him of my finding and where he could find that computer, just in case he wanted to get ahold of those binaries (I couldn’t find any source code anywhere on that machine). He never replied, I don’t know if he ever got my email. I bet he gets a lot of it and that he’s a very busy man.

Update: explained a bit why I don’t want to reveal where this happened.


How to legally submit an app to Apple’s App Store when it uses encryption (or how to obtain an ERN)

Disclaimer: I am not a lawyer, this is not legal advice. 

Shameless plug: I am available for hire doing Ruby, Clojure, Python or many of my other skills including managing developers.

There’s a lot of conflicting information out there about whether you need an ERN or not to publish an app in the App Store. I spoke to Apple representatives as well as various employees of a couple of US agencies. As painful as it is, if your app is capable of the simplest, most standard, of encryptions such as SSL/HTTPS then you need to answer your export compliance questions like this:

Mac App Store questions and answers about encryption

The conclusion from selecting the above answers:

To make your app available on the App Store, you must submit a copy of your U.S. Encryption Registration (ERN) approval from the U.S. Bureau of Industry (BIS).

In some places, you’ll see CCATS instead of ERN. I’m not 100% sure, but it seems CCATS was a previous more bureaucratic version of the ERN. Right now, what you need is an ERN and this is our journey to get it. We are publishing as much detail as possible so that you can replicate it for your own application. There are some other blog posts that explain how to do it, but we found that over the years, some of the steps changed and we had to find a new path. Since this is going to happen again, we are adding as much information as possible so that should your path be slightly different, you won’t have much trouble finding your way through it.

Starting at the beginning

After being utterly confused by both Apple’s as well as BIS’ FAQ and how to pages, I decided to go the homepage for the Bureau of Industry and Security and see where it took me:

Homepage for the Bureau of Industry and Security

At this point I new SNAP-R was relevant to my needs. I was almost under the impression of needing one, even though I didn’t know what it was. Going through that page I found this:

BIS Would you like to

Yes! I’d like to submit an application (SNAP-R) – fourth item in the list. That takes you to this page:, which defines what a SNAP-R is. It stands for Simplified Network Application Process – Redesign. I think a SNAP-R is sort of an account with the BIS. There’s no mention of ERN in that page, but it says:

You must have a Company Identification Number (CIN) and an active user account to access SNAP-R. The procedures and requirements for obtaining a CIN and user account are set forth below.

You need to obtain a CIN before you can proceed. If you scroll all the way to the bottom of the page, you’ll see:

BIS Obtaining a CIN for a SNAP-R for an ERN

And that link, ladies and gentlemen, is the most promising I’ve seen so far. It takes you to which looks like this:

BIS SNAP-R Company Registration for an ERN

The SNAP-R Company Registration process

After completing and submitting that form you’ll get an email to confirm your email address. I recommend limiting yourself to ASCII characters here, as the é and á in my name got mangled. That email took only a few minutes to arrive but the confirmation page claims the next step might take up to five days:

BIS SNAP-R Email confirmation

Some people claim to have been finished in 30 minutes or even less. I suppose it depends where you or your company is located. In my case, the five days elapsed so I sent them an email and two days later I got a reply telling me to call their support number: +1-202-482-2227 (later on I learned that another phone number that might help is +1-202-482-0707). When I talked to a representative, he said that I should have received the activation email already and just re-triggered it. Maybe calling them after a couple of days would have been a good approach to speed things up. Shortly after my call I got this email:

BIS SNAP-R Account Invitation email - for ERN

That link takes you to a page to set up your log in and password:

BIS SNAP-R Login ID and Password Setup

After entering those details, voila! you have an account:

BIS SNAP-R Login ID and Password Setup - account created

You may now log in:

BIS SNAP-R login in - for ERN

After logging in, you are now in your SNAP-R Home page:

Creating a new work item within your SNAP-R account

The next step is to create a new work item, which you can do from the sidebar. That takes you to a page that looks like this:

BIS SNAP-R Create Work Item

The type of work item that you want, to be able to distribute apps with encryption, is an Encryption Registration:

BIS SNAP-R Create Work Item Type Encryption Registration

Now, about the Reference Number, the question mark next to it sends you to where it says:

Enter a valid reference number for the Work Item. Reference numbers must be in the format “AAA1111”.

which didn’t really answer what a reference number is. I decided to call them again and when I asked the question they put me on hold for 25 minutes. I hung up, called them again and I was speaking with someone else in less than 3 minutes and she answered. The reference number is just something you make up, for yourself. It’s not something you obtain and it seems as long as you follow their convention, it’s fine:

BIS SNAP-R - Create Work Item - Encryption Registration and reference number

After creating the work item, you are invited to edit it. It starts partially populated and it’s straight forward:

BIS SNAP-R Edit Work Item Encryption Registration

Well, it’s straightforward until the last part: Documents. You need to attach the Encryption Registration Supplement No. 5 to Part 742.

Creating the Encryption Registration Supplement

Creating the supplement, thankfully, is easier than it looks; that is, when you know what you have to do. There’s a document number 742 that you can download from and  on page 60 it has the Supplement No. 5: Encryption Registration. These are the contents of that page:


Certain classification requests and self-classification reports for encryption items must be supported by an encryption registration, i.e., the information as described in this Supplement, submitted as a support documentation attachment to an application in accordance with the procedures described in §§ 740.17(b), 740.17(d), 742.15(b), 748.1, 748.3 and Supplement No. 2 to part 748 of the EAR.

(1) Point of Contact Information

(a) Contact Person

(b) Telephone Number

(c) Fax Number

(d) E-mail address

(e) Mailing Address

(2) Company Overview (approximately 100 words).

(3) Identify which of the following categories apply to your companys technology/families of products:

(a) Wireless

(i) 3G cellular

(ii) 4G cellular/WiMax/LTE

(iii) Short-range wireless / WLAN

(iv) Satellite

(v) Radios

(vi) Mobile communications, n.e.s.

(b) Mobile applications

(c) Computing platforms

(d) Multimedia over IP

(e) Trusted computing

(f) Network infrastructure

(g) Link layer encryption

(h) Smartcards or other identity management

(i) Computer or network forensics

(j) Software

(i) Operating systems

(ii) Applications

(k) Toolkits / ASICs / components

(l) Information security including secure storage

(m) Gaming

(n) Cryptanalytic tools

(o) “Open cryptographic interface” (or other support for user-supplied or non-standard cryptography)

(p) Other (identify any not listed above)

(q) Not Applicable (Not a producer of encryption or information technology items)

(4) Describe whether the products incorporate or use proprietary, unpublished or non-standard cryptographic functionality, including encryption algorithms or protocols that have not been adopted or approved by a duly recognized international standards body. (If unsure, please explain)

(5) Will your company be exporting “encryption source code”?

(6) Do the products incorporate encryption components produced or furnished by non-U.S. sources or vendors? (If unsure, please explain)

(7) With respect to your companys encryption products, are any of them manufactured outside the United States? If yes, provide manufacturing locations. (Insert “not applicable”, if you are not the principal producer of encryption products)

All you have to do is create a PDF file answering these questions for your application and upload it. I couldn’t find this information anywhere so I called them once again and that’s how I learned that all matters related to encryption were handled by the department… never mind the name, the phone number is +1-202-482-0707. Next time I’m calling them directly – there was no wait, no menu, just a person picking up the phone.

I created a document for my case saying:

Screensaver Ninja Encryption Registration Supplement No. 5 to Part 742

(1) Point of Contact Information

(a) José Pablo Fernández Silva




(e) 20-22 Wenlock Road, London, N1 7GU, United Kingdom

(2) Carousel Apps is a small London based company producing software apps such as Screensaver Ninja. Our main use of encryption (and so far all of it) is the standard SSL (https), OpenSSH, etc. You can learn more about us at

(3) We produce

(j) Software

(ii) Applications

(4) Our products use standard off the shelf encryption libraries and tools, such as https (SSL). We don’t develop or intend to develop any proprietary encryption mechanisms

(5) We don’t plan on exporting “encryption source code”.

(6) Screensaver Ninja uses Apple’s Safari component that allows https encrypted communication. This is provided by Apple. I understand that Apple uses OpenSSL which is an open source project and thus may have contributions from all around the world.

(7) We produce software, so, no manufacturing process are involved. All our software is produced outside the United States. The reason for this application is to distributed an app through Apple’s App store.

I cannot vouch for this content, I’m not sure this is the appropriate file to submit, this is only what I did. The next step is to click on “View and Manage Supporting Documents” which will take you to a page that looks like this:

BIS SNAP-R Document Management Encryption Registration Supplement No. 5 to Part 742

There, click “Upload Supporting Document” and you’ll be greeted by this form:

BIS SNAP-R Upload document for Encryption Registration Supplement No. 5 to Part 742

I just came up with a title and keywords, entered the current date and my name as author. I think the only really important field is the document type:

BIS SNAP-R Upload document for Encryption Registration Supplement No. 5 to Part 742 f

Submitting the ERN

With that document in place and attached, we seem to have passed some sort of automatic verification procedure.

BIS SNAP-R Encryption Registration All party addresses have passed verification

I clicked on “Preview Work Item to Submit” and I was given a last chance to look at the application and verify its correctness:

BIS SNAP-R ERN Application with document

The submission process, triggered by the “Submit” button of course, asks you for your name, in a special format, one more time:

BIS SNAP-R Encryption Registration Submit Work Item

And we you click “Submit Work Item” you are done:

BIS SNAP-R Encryption Registration Submitted - Thank you

Uploading Encryption Registration to Apple

I almost immediately got a message in the SNAP-R website:

Screen Shot 2015-11-19 at 10.36.00

And the message was the acceptance of the application including the ERN code (blacked out):

BIS SNAP-R Encryption Registration Accepted

That is the document you need to upload to Apple. Take a screenshot of that page and save it for your records. Back at Apple’s iTunes connect, when you answer the questions stating that you use encryption, you get an upload box for the document:

iTunes Connect Encryption upload ERN

If the upload button doesn’t appear, this is what an Apple representative suggested: “If you do not see the prompt, there could be a glitch in the website. One possible workaround is to change the answer to question 4 to “Yes”. By doing this the upload field should appear.”

Once you upload it, the “Submit” button will become enabled and you are ready to rock. Click it and your app will be on its way to fame and fortune. Well… that is… after they review your export compliance. For now, your app will be “Waiting for Export Compliance”:

iTunes Connect - Waiting for Export Compliance

From Apple’s version statuses, that means: “Your app is reviewed and ready for sale, but your CCATS file is in review with Export Compliance.” CCATS seems to be an older or bigger version of the ERN and in some places we can still find CCATS instead of ERN. Don’t worry, an ERN is all you need if your situation is similar to mine. When the status reaches to “Waiting for Review”:

mac app waiting for review

Congratulations! Your ERN was accepted.  You are done with this bit of bureaucracy.

If this blog post was useful or you find differences in the process, please, let us know in the comment section.

Picture by Yuri Samoilov


Free-form version 0.2.0 released

We are very happy to announce version 0.2.0 of our form building library Free-form. This version includes:

The Bootstrap 3 support means that you can have whole fields defined as succinctly as:

[:free-form/field {:type        :email
                   :key         :email
                   :label       "Email"}]]




Prerenderer 0.2.0 released

We are proud to announce the release of version 0.2.0 of our ClojureScript library Prerenderer, a library to do server side pre-rendering of single page applications. In this release, we include:

The two first items in the changelog came hand in hand and they are the biggest changes to keep in mind if you are upgrading. We are very happy that we no longer need a fork of re-frame and we would like to extend our gratitude to Mike Thompson for working with us on having the appropriate API to make this happen.

The change in API means that your Prerenderer module now would look something like this:

(ns projectx.node
  (:require [prerenderer.core :as prerenderer]))

(defn render-and-send [page-path send-to-browser]
  (send-to-browser (render page-path)))

(set! *main-cli-fn* (prerenderer/create render-and-send "ProjectX"))

instead of:

(ns projectx.node
  (:require [cljs.nodejs :as nodejs]
            [prerenderer.core :as prerenderer]))

(defn render [req res]
  (let [page-path (.-path (.parse url (.-url (.-query req))))]
    (.send res (render page-path))))

(set! *main-cli-fn* (prerenderer/create render "ProjectX"))



Review of Clojure Exchange 2015 London

I recently attended Clojure Exchange 2015 London, the conference organized by Skills Matter for Clojurians. Like many other attendees I was impressed by the quality of the talks and as a presenter, I was particularly pleased that only a few hours later my presentation, What is a Macro?, was already published, in video form, for everybody to see.

Some presentations I found particularly interesting were:

Yada for RESTfull APIs

Malcolm Sparks presenting Yada in RESTfull web service in Clojure, two different approaches. Yada is a library to create RESTfull APIs that focus on succinctness and on doing as much work for you as possible so you only focus on your business model. Yada is also async-ready and you can stream results. We will consider using it instead of Compojure-API in the future, although we still have to explore how to integrate it with other Clojure components. One limitation it has is that it can only work with Aleph, because the other web services don’t provide back pressure.

Clojurescript: Architecting for Scale

Kris Jenkins presenting his pattern in ClojureScript: Architecting for Scale. Kris shows us how he writes ClojureScript single page applications so he doesn’t end up with a spaghetti of code. The pattern is implemented as a library that he just released for the conference, called Petrol. We are happy to see how close the pattern is to our favorite one, as provided by Re-frame, that we use in Ninja Tools and we plan on using in future projects. Clearly the reactive pattern seems the way to go to write client applications beyond Hello World.

Duct, Covered with James Reeves

James Reeves presenting his aggressively simple framework for writing web applications with Clojure in Duct, Covered. You might know James as weavejester, the author of compojure, environ and so many other super popular libraries. Duct is his take on the web framework arena. It can be said to be similar to Luminus, but its emphasis is in the set up of a componentized system. Something that is easier to ignore at first and comes back to bite you later on. I had a private conversation with James after his presentation and I’m really excited about the future of Duct.

Compared to other conferences I’ve been to, it surprised me how many authors of popular open source libraries and tools we had on stage and that made me wonder how many were in the audience that I didn’t know about. I wished I had better visibility into this as I think cooperation makes for a better ecosystem.

One problem I see in the Clojure world right now is fragmentation; we are all inventing our own ways of doing things instead of compromising a bit, cooperating, and making some ways of doing things faster, better, more tested, friendlier, better documented, and so on.

Saying that, the experience was brilliant and I already bought my ticket for next year’s Clojure Exchange at the bargain price of £95.00+VAT. Do you have yours?


Square peg and a round hole.  Metaphor for a misfit or nonconformist.

A browser in your screensaver is a square peg in a round hole

This blog post was originally published in Screensaver Ninja‘s blog.

We were recently challenged by someone who asked what was so special about adding websites into a screensaver. Perhaps, at first, this doesn’t seem like a tough task but after months of challenging work, I can confirm it is. I realized I never shared exactly why yet, so here it is. Putting a browser into your screensaver is like putting a square peg in a round hole.

Chromium on Mac

Screensaver Ninja for Mac is already out there. It’s working and it’s robust, but getting there wasn’t without its pains. Initially, we wanted the Mac and Windows versions to have the exact same rendering engine and thus, we went for Chrome’s WebKit, packaged as Chromium Embedded Framework, or CEF for short.

open-package-contentsChromium, the open source version of Chrome, follows the same structure as Chrome to handle page isolation: by running it in different processes. On Mac, applications are distributed as bundles which you may know as .app files. They are actually directories and you can inspect the contents by right‐clicking or control‐clicking on it and then choosing Show Package Contents. (Warning: if you change anything the app will likely not work anymore.) When you use CEF, you end up with a secondary bundle application inside your application. This is sort‐of supported, but weird and not without issues.

In Mac OS X, screensavers are dynamic libraries that are loaded by a special screensaver program. When you make a screensaver, you are not in control of the running program, you just have a few entry points to start doing your animation. The Mac OS X screensaver framework doesn’t like it at all when you have a secondary app bundle that you trigger from your library.

During this research, we found a bunch of issues, many of which were not clear‐cut as solving it for us might break it for other people. We still needed those issues solved so we wrote scripts that would pre-process CEF and solve them for us. Ultimately we ended up dropping CEF; more on that later.


We decided to use Swift for our project. It’s the new way and we prefer higher level languages whenever possible. Swift saves us a bit of pain with memory management, syntax and other things. But we inadvertently caused ourselves quite a bit of pain. The Mac screensaver framework is still an Objective-C application and since we are not building an app, but a library, we need to write and compile Swift with Objective-C binary compatibility. This is not commonly done so it took us quite a bit of bumping our head against a brick wall to figure it out. Furthermore, not being in control of the program loading our library made getting error messages tricky at best.

Apple’s WebKit

When we dropped CEF, our alternative was Apple’s WebKit, which was so much easier to integrate and have running, despite the fact that there are two of them; one that works out of the box, but it’s deprecated, called WebView, and a new one that’s not so well supported, called KWWebView. We played a lot with both and both had the same problem: cookies shared with Safari.

Apple decided that all users of a web view must share cookies with Safari. This was not acceptable for us because we want to have separate independent sessions and in the future we are even planning on having separate cookie jars per site so that you can, for example, be logged in into two different Twitter accounts at the same time. We contacted Apple about it, paying our tech support fee, and the answer was a resounding “can’t be done, we’ll add it to the list of things that we’ll consider in the future”.

Challenge accepted Mr Apple! We embarked on a quest to achieve this anyway that took us into the dark innards of the Cookie Jar, debugging it at the assembly level to understand its interface and workings:


I have to admit it, that was fun. After understanding Apple’s cookie jar’s implementation, we wrote a test suite that was exercising it all, as far as we know, including bits that we believe are abandoned. After that we wrote our own implementation that stored the cookies separately and used the same test suite to make sure our implementation was equivalent to Apple’s. This code had to be done in a mix of C and Objective-C. Then we used method swizzling to replace Apple’s with our own and ta-da! Cookie separation.

Windows events

The Windows version of Screensaver Ninja is of course not done yet, but we’ve already started working on it and we are partly there. One interesting problem that we run into is that Windows doesn’t help you at all with the workflow of a screensaver. It is of paramount importance to us that while the screensaver is running, nobody should be able to interact with those websites. We don’t want any keystrokes, mouse moves, mouse clicks, etc to reach the pages, otherwise it would be a breach of our security approach to dashboards.

Windows has a long history all the way back to Windows 1.0 that ran as a little program on top of MS DOS. Awww, good old days. Through the decades, ways to code Windows applications have changed radically and thus the way events travel through applications also did. That means that there’s a lot of different ways for an app to get keystrokes, mouse events, etc. Finding them all and plugging all those holes was not trivial and since we are talking about security this required a lot of testing.

I’m sure that as we go along, we are going to find many more issues like those in the Windows environment, and we are going to solve them and we are going to strive for elegant, stable, robust code.