Rob Allen's DevNotes – Developing software in the Real World

Converting JSON to a struct in Go

I'm in the process of writing a little command line app in Go that uploads images to Flickr. It's called Rodeo and it's working well as a project with which to learn Go in 2020. Rodeo uses ExifTool to interrogate an image file for meta data. ExifTool is wonderful and very comprehensive and with the -j switch can return JSON. Today I want to note down what I learned about dealing with JSON.

$ exiftool -j -iptc:* -exif:* RKA-glorious.jpeg
[{
  "SourceFile": "RKA-glorious.jpeg",
  "Country-PrimaryLocationName": "United Kingdom",
  "Caption-Abstract": "On a wet gala weekend, Glorious returns after its 2018-19 restoration",
  "Keywords": ["diesel","50 033","Severn Valley Railway","Glorious","railway"],
  "ObjectName": "Glorious Sunrise",
  "ImageDescription": "On a wet gala weekend, Glorious returns after its 2018-19 restoration",
  "Make": "FUJIFILM",
  "Model": "X-T3",
  "ISO": 500,
  "DateTimeOriginal": "2019:10:04 11:50:40",
  "ShutterSpeedValue": "1/1000",
  "ApertureValue": 4.0,
  ...
}]

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

$ exiftool -j -iptc:* -exif:* RKA-glorious.jpeg

[{

"SourceFile": "RKA-glorious.jpeg",

"Country-PrimaryLocationName": "United Kingdom",

"Caption-Abstract": "On a wet gala weekend, Glorious returns after its 2018-19 restoration",

"Keywords": ["diesel","50 033","Severn Valley Railway","Glorious","railway"],

"ObjectName": "Glorious Sunrise",

"ImageDescription": "On a wet gala weekend, Glorious returns after its 2018-19 restoration",

"Make": "FUJIFILM",

"Model": "X-T3",

"ISO": 500,

"DateTimeOriginal": "2019:10:04 11:50:40",

"ShutterSpeedValue": "1/1000",

"ApertureValue": 4.0,

...

}]

(For… continue reading.

Posted on 3 June 2020 in Go View all 4 comments

Validating default PHP session ID values

I recently needed to validate the value created by PHP for its session ID. After a bit of research, I realised that there are two interesting php.ini config settings that relate to this value: session.sid_length is the number of characters in the ID session.sid_bits_per_character controls the set of characters used. From the manual: The possible values are '4' (0-9, a-f), '5' (0-9, a-v), and '6' (0-9, a-z, A-Z, "-", ","). Therefore, to validate the session… continue reading.

Posted on 13 February 2020 in PHP View all 7 comments

Turn off foreign key checks when restoring a mysql file dump

I recently received a MySQL dump file where the various tables in it had foreign keys to each other. I usually restore with this command: mysql –login-path=rob < dump.sql but this generated the error: ERROR 1217 (23000) at line 288805: Cannot delete or update a parent row: a foreign key constraint fails It turns out that the easiest way to solve this is to use the –init-command switch to set foreign keys off for this… continue reading.

Posted on 29 January 2020 in Database, Development Leave a comment

A logo for rst2pdf

All projects seem to have a logo these days, so I asked my friend Jane of iD to create a logo for rst2pdf and she came up with this: This met what I was looking for with a clear design that is related to the what the application does, so thank you Jane. I've set the profile icon for the GitHub organisation and Twitter accounts and we'll be using this in other places as we… continue reading.

Posted on 24 January 2020 in rst2pdf Leave a comment

Creating collections with the Lightroom Classic SDK

I currently organise my photo library in Lightroom Classic with one folder per day for my images and then I extensively use collection sets, collections and smart collections to manage the photos that represent an "event", regardless of whether the project is a single day, such as a family BBQ, a multi-day event such as a conference or a multi-month thing such as my Project 365 or mainline railway photos. The nice thing about using… continue reading.

Posted on 15 January 2020 in Lightroom, Lua Leave a comment

Writing a Lightroom Classic plug-in

As part of my migration to Lightroom Classic from Photos, I needed to recreate my folder and album structure. In Photos, folders container albums (or other folders) and albums contain photos. An album cannot contain a folder. This maps directly to Lightroom Classic which has "collection sets" for folders and "collections" for albums. To transfer the folder and album information over to Lightroom Classic, I wrote an Apple Script for Photos that added a keyword… continue reading.

Posted on 6 January 2020 in Lightroom, Lua, Photography One comment so far

2019 in Pictures

As we reach the end of 2019, I again get the opportunity to look back at my year through the photos that I took as I have done every year since 2009. I have been doing a Project 365 for a good few years which acts as a diary too, so I have the opportunity to appreciate what happened this year in my life. January Early in January, I spent an afternoon taking photos with… continue reading.

Posted on 31 December 2019 in Me, Year in Pictures Leave a comment

Migrating to Lightroom Classic from Apple Photos

I recently moved over to Adobe's Lightroom Classic from Apple's Photos in order to have more flexible non-destructive editing features – in particular local brushes. Rather confusingly, there's also another Adobe product called Lightroom which is a new build for cloud-based storage which doesn't (yet?) have all the features of Lightroom Classic. In particular, the lack of virtual copies and smart collection sets make Lightroom feel like a step backwards from Photos, while Lightroom Classic… continue reading.

Posted on 30 December 2019 in AppleScript, Lightroom, Photography View all 3 comments

Routing in Slim 4

Routing in Slim 4 works pretty much exactly the same as in Slim 3. They are used to map a URL that the browser requests to a specific handler that executes the code for that particular page or API endpoint. You can also attach middleware that will only be run when that route is matched. The route in the slim4-starter looks like this:

$app->get('/[{name}]', HomePageHandler::class);

1	$app->get('/[{name}]', HomePageHandler::class);

It is made up of the method, the pattern and the… continue reading.

Posted on 18 December 2019 in PHP, Slim Framework 4 View all 3 comments

Keyboard shortcut to mirror displays on a Touch Bar Mac

One feature of the 16" MacBook Pro that was new to me is the Touch Bar. This thing replaces the F-keys with a touch pad that adjusts itself to the app in use in order to provide useful shortcuts you can just touch. This is all well and good, but when presenting, I use the cmd+F1 keyboard shortcut to toggle display mirroring. A useful Stack Overflow answer tells me that I can use cmd+{dim brightness}… continue reading.

Posted on 13 December 2019 in Computing, Keyboard Maestro, Software View all 3 comments