How do I determine if a beanstalkd tube is empty? - message-queue

By "empty" I mean there's no job ready to be reserved or being reserved.
I've read the document on github and find that stats is almost what I want except that it gives information about the whole system, not a specific tube.

You will want to run, and parse the output from the stats-tube [tubename] command. It returns the number of jobs in the tube of each type (urgent, ready, reserved, delayed, and others), and other tube-specific information.

Related

FME- Process feature one by one

How to process features in FME one by one For Example:- Take all the data of one country add certain data and write in FGDB, then take data of another country and then process it.
If I understand it correctly, what you're looking for is batch processing different files. In that case I think the easiest approach is tu use a WorkspaceRunner in a parent workspace that calls a child workspace that does the processing. In this FME Community example you can find more information on how to build it: https://community.safe.com/s/article/batch-processing-using-the-workspacerunner-1

Retrieve the EMV Application File Locator without Get Processing Options

I am writing code to extract as much data as possible from an EMV chip card. I can select the application and I have code to send Get Processing Options, but that needs (in some cases) the PDOL to be evaluated and associated data supplied.
The data the PDOL asks for is based on a transaction though, and there will be no transaction in this sequence. Once I have extracted the data then I'm done, so the only reason for GPO would be to get the Application File Locator (AFL).
I suspect the answer here is 'no', but is there any other way to get the AFL? At the moment the only alternative is a brute-force series of Read Record calls with SFI from 1 to 10 and records from 1 to 31. This is slow and, if I can get the AFL, unnecessary so I'm hoping for a more intelligent approach (but one that doesn't need GPO to be used).
As per EMV specifications PDOL if exists is returned in response to SELECT in A5 - FCI Proprietary Template.
PDOL will provide the tag and length of data expected, but since you are not looking in a real transaction perspective, pack all tag data as zeros(make sure of the expected length) and send in GPO. It should return AFL which you could then use in READ RECORDS efficiently.
There is not a single way to retrieve AFL without issuing the GPO command.

News Aggregater of sorts

There is a website that my company uses that updates information about 3 specific things throughout the day. We use the information from 1 of them and what we are wanting to do is pull this information as it is added to their site and add it to a page of our own to view easier. Is this even possible? Can anyone point me in the direction of setting this up? It is all text that we want to pull.
Pick a language (e.g. Perl). Find an HTTP library for it (e.g. LWP). Fetch the page and run it through an HTTP parser (e.g. HTML::TreeBuilder). Pull out the bits you want and shove them into a template (e.g. TT) then dump to a file. Stick the program in cron or Windows Scheduler.

What should I put in header comments at the top of source files?

I've got lots of source code files written in various languages, but none of them have a standard comment at the top (sometimes even across the same project). Some of them don't have any header comment at all :-)
I've been thinking about creating a standard template that I can use at the top of my source files, and was wondering what fields I should include.
I know I want to include my name and a short description of what the file contains/does. Should I also include the date created? The date last modified? The programmer who last modified the file? What other fields have you found to be useful?
Any tips and comments welcome.
Thanks,
Cameron
This seems to be a dying practice.
Some people here on StackOverflow are against code comments altogether (reasoning that code should be written to be self explanatory) While I wouldn't go that far, some of the points of the anti-comment crowd make sense, such as the fact that comments tend to be out of date.
Header blocks of comments suffer from these symptoms even more so. Every organization I've been with that has had these header blocks, they are out of date. They have a author name of some guy who doesnt even work there any more, a description that does not match the code at all (assuming it ever did) and a last modified date, that once compared with version control history, seems to have missed its last dozen updates.
In my personal opinion, keep comments close to the code. If you want to know purpose of, and/or history of, a code file, use your version control system.
Date created, date modified and author who last changed the file should be stored in your source control software.
I usually put:
The main purpose of the file and things within the file.
The project/module the file belongs to.
The license associated with the file (and a LICENSE file in the project root).
Who is responsible for the file (either the team, person, or both)
Back in 2002, when I was straight out of college and jobs were few and far between after the dot-com bust, I joined a service company which used to create software customized for their clients in Java. I had to sit in the office of a client (which was a ramshackle room in an electric sub-station rigged with an AC to keep the servers running), sharing chairs/PCs with other guys in the team. The other engineers (if I can call them engineers ;) in the group used to make changes ad-hoc to the source code, compile the files and put them into production.
No way to figure out who made what change.
No way to figure out why any change was made.
No way to go to previous version of code, unless the engineer "remembered" what he modified.
Backup: Copy over files from the production server, which were replaced with new files.
Location of backup: Home directory of engineer copying over files to production server.
Reports of production servers going down due to botched attempts of copying over files to the server (missed a file to be copied over, backups getting lost or wrong files being copied over or not all files being copied over) were met with shrugs (oh no, is it down? let's see what happened; hey who changed what recently...? ummm...).
During those days, after spending several frustrating days trying to figure out the whos and whys behind the code, I had devised a system for comments in a list in the header of the source file which detailed the following:
Date of change made
Who made the change
Why was the change made
Two months later when the list threatened to challenge the size of the source code in the file, the manager had the bright idea of getting a source version control system.
I have never needed to put any comments in headers of source files (except for copyright notices) in any company I worked since. In my current company, everything else is mostly self-evident by looking at the code, or going to the bug reporting system which is integrated with the source version control system.
What fields do you need? If you have to ask whether to put some info there, you don't really need that info. Unless you are forced, by some bureaucratic incompetence of your employer, I don't see why you should go looking for more info than you already feel should be there.\
In most organizations, all source files have to begin with a legal blurb. If you're really lucky, it's just a one-liner, but in most cases it's a really long block of legalese. As a result, few people ever read these. Our eye just travels to the first program element and then goes up to its documentation.
So if you want to write anything, write it in association with the topmost program element, not the file.
Any other bookkeeping information should generally be part of your version control, not maintained (poorly) in the file itself.
In addition to the comment above stating license, the project that it belongs to, etc I also tend to put the "weird" requirements at the top as well (such as "built with version X of library Y") so you, or the person who picks it up after you won't change something that the program relies on without realizing it (or, if they do, they will at least know what to change back)
A lot depends on whether you're using an auto-documentation generation tool or not.
While I agree with many of the comments, if you're using JavaDoc or some other documentation generating tool that depends on comments, you'll obviously need to include the things it wants to see.
You did not mention that you are using a version control system and your comment in Neil N's answer confirms this for your older code. While using version control is the best way to go I also have experienced many situations where the cost of doing so for older code would not be paid for by the project's sponsor. If you do not have a centralized change history for the project then the change history can be put in the modules. It is good that you are using a version control system for your new code.
Your company name
All rights reserved (c) year - or reference to appropriate license
Project or library this file is for
Module it belongs to
Description of what it contains
History
-------
01/08/2010 - Programmer - version
Initial creation.
01/09/2010 - Programmer - version
Change description.
01/10/2010 - Programmer - version
Change description.
Those useful fields that you mentioned are good ones. Who modified the file and when.
Your version control software should allow for the embedding of keywords within comments. For example, in CVS, the $Id$ will resolve to the file, date/time modified, and user that modified the file. It will automatically be kept up to date with each check-in.
Include the following information:
What this file is for. That's a very useful piece of knowledge and it's more important than anything else. You should tell the reader, why there is such a file, why did you group functions in a separate file/package/module and why they are used. Maybe briefly, one or two lines, but that should be there.
Legal stuff, if appplicant.
Leave the place for special commands of console editors, such as of Emacs.
Add special commands that your auto-documenting system requires.
Things things you shouldn not include are
Who created the file
When it was created
Who modified it the last time
When it was last modified
What was added by the latest modification
You can--and should--retrieve it via the version control system, where it's constantly and automatically kept up-to-date. Let alone that most of these points are just useless.
Who created the file
When it was created
Who modified it the last time
When it was last modified
What was added by the latest modification

Recommendations for a programmable drivers license scanner? [closed]

Closed. This question does not meet Stack Overflow guidelines. It is not currently accepting answers.
We don’t allow questions seeking recommendations for books, tools, software libraries, and more. You can edit the question so it can be answered with facts and citations.
Closed 3 years ago.
Improve this question
Our motor pool wants to scan drivers’ licenses and have the data imported into our custom system. We're looking for something that will allow us to programmatically get the data from the scanner (including the picture) and let us insert it into our application. I was wondering if anyone has had experience with this type of system and could recommend one or tell us which ones to avoid. Our application is written in PowerBuilder and uses a DB2 database.
Try solutions by idScan.net (www.idScan.net)
There is SDK that will allow drivers license parsing for all states in the USA and Canadian provinces. You can also purchase hardware such as ID scanner E-seek m250 that reads both 2D barcode and magnetic stripes (software is included).
Good luck!
We support something similar in our records management software. Our application is designed to work with a wedge reader, since they are the easiest to get up and running (no special drivers needed). When a card is swiped, the reader sends keystrokes to the OS for each character that is encoded on the magnetic stripe, with a simulated Enter keypress between each track (an AAMVA-compliant license has 3 data tracks).
It's slightly annoying because it behaves exactly as if someone was typing out the data by hand, so there is no easy way to tell when you have all the data (you could just wait to get 3 lines of information, but then it's difficult to detect invalid cards, such as when someone tries to swipe a student ID card, which might have fewer than 3 tracks encoded; in this case, the application hangs forever waiting for the non-existent third track to be received). To deal with this, we use a "fail-fast" approach: each time we get an Enter keypress, we immediately process the current line, keeping a record of which track we are expecting at that point (1, 2, or 3). If the current track cannot be processed (for example, a different start character appears on the track that what is documented for an AAMVA format driver's license), we assume the user must have swiped something other than a driver's license.
I'm not sure if the reader we use supports reading image data or not. It can be programmed to return a subset of the data on the card, but we just use the factory default setting, which appears to return only the first three data tracks (and actually I believe image data is encoded in the 2D barcode found on some licenses, not on the magnetic stripe, but I could be wrong).
For more on the AAMVA track format that is used on driver's license magstripes, see Annex F in the current standard.
The basic approach we use is:
Display a modal dialog that has a hidden textbox, which is given focus. The dialog box simply tells the user to swipe the card through the reader.
The user swipes the card, and the reader starts sending keydown events to the hidden textbox.
The keydown event handler for the textbox watches for Enter keypresses. When one is detected, we grab the last line currently stored in the textbox, and pass it to a track parser that attempts to parse the track according to the AAMVA format.
If this "fail-fast" parsing step fails for the current track, we change the dialog's status message to a message telling the user the card could not be read. At this point, the textbox will still receive additional keydown events, but it's OK because subsequent tracks have a high enough chance of also failing that the user will still see the error message whenever the reader stops sending data.
If the parsing is successful, we increment a counter that tells the parser what track it should process next.
If the current track count is greater than 3, we know we've processed 3 tracks. At this point we parse the 3 tracks (which have already split most of the fields up but everything is still stored as strings at this point) into a more usable DriversLicense object, which does additional checks on the track data, and makes it more consumable from our application (converting the DOB field from a string into a real Date object, parsing out the subfields in the AAMVA Name field into first name, middle name, last name, name suffix, etc.). If this second parsing phase fails, we tell the user to reswipe the card. If it succeeds, we close the dialog and pass the DriversLicense object to our main application for further processing.
If your scanner is "twain compliant", You will then be able to manage it from your app through an ActiveX control you can buy on the net like this one. You'll be able to manage your basic scan parameters (quality, color, single/multiple pages can, output format, etc), start the scan from your app, save the result as a file and transfer this file wherever needed. We have been using it with VB code for the last 2 years. It works.
Maybe you want to use magnetic stripe reader, to get driver license info from the card. As I remember most of the Driver licenses just have the data in plain text on those stripes, so it is relatively stright forward programming-wise.
MagStripe readers are also cheap now days.
You can try something from this list: http://www.adams1.com/plugins.html
I have not used them myself, though.
I wrote a parser in C#, and while it's "ok" it's still far from perfect.
I can't seem to find it but a Wikipedia entry used to exist that has the patterns to look for (trust me, parsing this yourself is a pain without any help).
Be aware that different states have different laws for what you can and can't use government issued ID's for. Texas has one.
We use a dell card reader and it inputs it exactly as though it were being typed through a keyboard, followed by the enter key. This made programming /very/ easy because then you just send focus to the text box and wait for enter. The main keys which break it in to chunks is the carrot '^'. Break that and you'll have your basic chunks.
You can also use InfoScan SDK. You can find it on www.scan-monitor.com the system allows you to use any scanner and does not make you purchase a specific scanner.