Great Java - Caffeinated Babblings!

After a decade plus (or longer) using HostGator they doubled my monthly costs with no notification, messed up my account in management tool so I couldn’t see invoices (convenient …). This is a “test post” on the new server to test out things! I can’t say how easy and fast it was to make the move and highly recommend https://www.geekstorage.com!

I recently had a need to write some code for the Kaltura API and the libraries have had a lot of changes since the last time I used them. One thing I found curious was (at least for Java) all API calls are queued making the operation asynchronous. It’s interesting to me that other languages don’t default to this. This may be desirable in some scenarios; however, if you are wanting to take any conditional action, you iI recently had a need to write some code for the Kaltura API, and the libraries have had a lot of changes since the last time I used them. One thing I found curious was that (at least for Java), all API calls are queued, making the operations all asynchronous. It’s interesting to me that other languages don’t default to this. This may be desirable in some scenarios; however, if you are wanting to take any conditional action, you ideally want to wait for the operation to complete. For example, if you want to iterate through the categories and then, depending on the data, take other actions to generate a report, you’re forced to store all the content in memory before processing it. Perhaps you’d prefer to generate your API session ID by logging in rather than using your admin secret, which is highly recommended. The C# examples show all the code using the execute() method with an onComplete method that sets a boolean. The following line after the call does a loop on the boolean with 100 ms of sleep. I’m not sure if the C# API has a queue method; if it does, it seems the developer portal-generated code is wrong and the polling is not required. While I couldn’t find any examples of serial execution of requests in Java, the executor class does have an “execute” method. You just need to massage the code generated by the API tool a bit. It does block until API calls are complete and then returns.

Here is an example of login:

LoginByLoginIdUserBuilder requestBuilder = UserService.loginByLoginId(loginId, password, partnerId, expiry, privileges, otp)
        .setCompletion(new OnCompletion<Response<String>>() {
            @Override
            public void onComplete(Response<String> result) {
                System.out.println(result);
            }
        });

    APIOkRequestsExecutor.getExecutor().queue(requestBuilder.build(client));

// proceed to other API interactions

Obviously you need addition controls here (like C# samples) to know when the request is actually complete prior to doing other API actions. You can rewrite this call to block on completion. This simplifies your code if you have nested logic that iterates through a list of items (each which generate an API call).

Generated Sample Code

LoginByLoginIdUserBuilder requestBuilder = 
 UserService.loginByLoginId(loginId, password, partnerId, expiry, privileges, otp)
        .setCompletion(new OnCompletion<Response<String>>() {
            @Override
            public void onComplete(Response<String> result) {
                System.out.println(result);
            }
        });

    APIOkRequestsExecutor.getExecutor().queue(requestBuilder.build(client));


My Revised Code

LoginByLoginIdUserBuilder userRequestBuilder = UserService.loginByLoginId(loginId, password, partnerId, 86400, "","");
Response <String> userResult = (Response <String>) APIOkRequestsExecutor.getExecutor().execute(userRequestBuilder.build(client));
String ks = userResult.results.toString();

I think the usage pattern is a lot easier, and the code is much more straightforward.

Unfortunately, it seems the code examples, most of the client API, and documentation for the Kaltura developer portal are all code-generated. This allows them to spend less time supporting them, but honestly, I think using the REST endpoints is easier due to the lack of human-readable documents and proper code examples that are tested.

I’ll admit, when I bought the Monoprice Mini Select 3D printer, I knew almost nothing about 3D printing. That won’t get you very far after you unbox the printer. There are some basics you need to learn to get good prints.

Once you have a 3D model in a print file format like STL you still need to put it in a program to tweak for your printer settings that has a slicer that creates a file usable by your printer. Beyond that, many prints require extra work to determine the thickness of walls that will look nice, supports for prints that have large overhangs, and more. It’s not rocket science; you just need to learn how the process works.

Thankfully, this printer has a lot of online help from owners on G+, Facebook, and especially YouTube.

Here’s a print session for a Pi Zero W case I found on thingiverse.com.

Tuning PID for Better Temp Control

Apparently, the out of the box temperatures for printing for this printer can fluctuate a lot. Most control systems use a PID controller to constantly measure the target values and use specific values for this (specified by the letters PID in the acronym). The good news is that you can tweak this printer’s values to get better results. I did this before my first print. Resources below:

• Tuning the headed  bed PID Values
• Tuning the HotEnd PID values

While you can probably put these commands in a.gcode file and print them, I used this software to set the values. http://www.pronterface.com/

Printing Hints I’ve Discovered

• Skip using the SD card and printing from the printer menu. Sometimes prints hang if you don’t upgrade the firmware (wanted to stay out of the box initially). Print from a computer with Pronterface (above) or even better, use Octopi (what I do now). Don’t use Cura on Mac to print; it just pauses every 10 seconds.

• Use a good “slicer” application to create your print files. I do like Cura, and it’s available on Mac and Windows. If longer items can fit sideways, they’ll print faster. Have an item too large for the bed? You might be able to rotate it slightly to fit diagonally.

• Print the first layer SLOW-half speed-on anything long or with quick angle changes.

• Watch the printer. It can go bad. Octopi supports a camera!

• Prints don’t stick without some help. Use a “raft” with your print if it doesn’t cover much surface area, and generally always use a light layer of glue stick on the tape on the bed.

The Octopi interface is great and works from any device anywhere. Why be tethered when you can watch remotely?

My Impressions

While I got some great prints with a little tweaking, I’m a bit concerned that this printer could be a black hole of my time doing mods. Apparently, Monoprice has a new model coming out in a few weeks that has many of these community mods built in, and most importantly, a replaceable hotend. I can already tell I’ll need to reroute the cables under the print bed (not attached correctly), install a stabilizer, and a couple other items. I may take advantage of Monoprice’s 30 day satisfaction guarantee and wait for the upgraded version to save me some time (and money in the long run).

Good luck!