The Linux Page


REST hook trigger needs a polling url (ZSE007)

As I'm working on a Zap application (see Zapier). I got this error about my triggers:

REST hook trigger needs a polling url (ZSE007)

So... I understand that they want to have a URL to do a poll and they even have documentation that explains why they want to poll in case of a REST hook Zap: Whenever the user wants to test the Zap, the application will get some data using the polling method. That way they can get that data specifically for one test and not force you to generate an trigger. One problem with testing with an actual trigger is that any other Zap listening to the same trigger ...

Writing a Shell Script from cmake

In cmake, you have a cool feature which allows you to create a file.

First you use a WRITE, then you use the APPEND to add more lines to the file.

That file may be a shell script, though. In that case, you run in a problem whenever you want to write a variable which uses the curly brackets (as in ${TEST}), because cmake sees those as its own variables.

There is an example of script that we use in our Snap! development.

file( WRITE  ${lint_script} "#!${BASH}\n"                                                            )
file( APPEND ${lint_script} "if test \${3##*.} = ...

Apache log says: client denied by server configuration

I work with Apache a lot. It is a really good web server that has many options and features. Unfortunately, maybe it has too many of them!

I ran in a problem where a notification from one server to another would fail with the following error:

[Fri Oct 11 19:43:50 2013] [error] [client] client denied by server configuration: <path to file>

Looking at the error, I was first thinking that my script was generating the error. The fact is that my script does not generate error 403. It has a 400 and 500 but not 403.

So looking at the error I thought, maybe that's an ...

Doxygen does not generate documentation for my C functions (or any global function)

As I write programs, mainly in C++, I document them using the Doxygen tool. This is a very powerful parser that is capable to finding functions, variables, macros, and many other things in the source code and attach the corresponding documentation to those functions, variables, macros, etc.

This is extremly practical when creating large projects or libraries that you want to share with others.

One problem though, by default it seems like global functions (and thus C functions) and variables do not make it to the documentation, when C++ classes work fine.

There are two potential issues:


Using QDateTime to output a date string and UTC

As I'm working on a server I need dates in UTC. By default, the QDateTime object generates dates in local time.

How do you change that? There is a toUTC() but my input data is already UTC so using toUTC() would mess up the date and I'd get the same result anyway.

The idea is actually pretty simple. The toUTC() creates a QDateTime object in UTC mode. This is done like this:

QDateTime utc(QDateTime().toUTC());

Now the utc object is in UTC mode and can be used with your Unix dates as in:


and the string output can be generated with toString() as in:


Designing a rotating wheel to ask users to wait while working in the background

Large version of the waiting wheelAs I'm working on a new feature for our Snap! Website system I wanted to have a turning wheel that asks users to wait while the computer does work.

The graphic is very simple: a rectangle with a border and a background color that rotates. However, I do not have a tool (that I know of) which could create the graphics automatically. So I did it with quite a bit of manual labor, but it was fun to learn a few things along the way.

I use inkscape to create such graphics. First I created the rectangle on the left. With that I had to have it rotated going 360 degrees repeating the rectangle 24 ...

Deleting a database in Synergration

Synergration AccessBooksRT is a tool we use to get a copy of QuickBooks tables in an MS-Access database.

It works great for our purpose and transformed some super sluggish forms into lightning fast forms. We still use QODBC for some of the work (updates) but 99% now goes through the database generated by Synergration instead.

Trace PHP code with xdebug


XDebug "logo"I'm very much working on Drupal and once in a while, I just have no clue what the code does... especially when there are callbacks that call callbacks in forever loops.

PHP Variables and E_NOTICE

Today I learned that not defining a variable in PHP would generate a notice error.

I had been wondering, why it is that so many people in Drupal define their variable or check them with isset()? That's why. In a way it is terrible that you can use a variable that does not exist and just get NULL, on the other hand, quite often that's because you intended to use another variable... (i.e. $create instead of $created, you declare $bool in one function and use it again in another, etc.)

This applies to objects, array indexes, and just plain variables. If you write:

MS-Access: INSERT INTO syntax error

Today I was creating a report and created a table with a column named 'Group'. It looked like it worked just fine so I moved on with it.

Then, at the point I wanted to insert data with a simple INSERT INTO ... statement, it broke. The statement would generate a syntax error. Yes. The simple answer is that GROUP is viewed as a keyword and thus when used as a field name it needs to be escaped (i.e. written between backward quotes: `...`). Not liking the need to escape a field name each time I use it, I just renamed the field which is even better.

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