AL Extensions: Importing and Exporting Media Sets

One of the things that has changed when you are building V2 extensions for a cloud environment is that you cannot access most functions that work with physical files.

This presents a bit of a challenge when it comes to working with the media and media set field types, as the typical approach is to have an import and export function so that a user can get pictures in and out of the field.

An example of this is the Customer Picture fact box that’s on the Customer Card:

WorkingWithMediaFields1

As you can see, the import and export functions in C/Side leverage the FileManagement codeunit in order to transfer the picture image to and from a physical picture file. These functions are now blocked.

So…..we have got to take another approach. Enter streams.

Using the in and out stream types we can recreate the import and export functions without using any of the file based functions.

An import function would look like the following. In this example, the Picture field is defined as a Media Set field.

local procedure ImportPicture();
var
   PicInStream: InStream;
   FromFileName: Text;
   OverrideImageQst: Label 'The existing picture will be replaced. Do you want to continue?', Locked = false, MaxLength = 250;
begin
   if Picture.Count > 0 then
     if not Confirm(OverrideImageQst) then
       exit;

  if UploadIntoStream('Import', '', 'All Files (*.*)|*.*', FromFileName, PicInStream) then begin
    Clear(Picture);
    Picture.ImportStream(PicInStream, FromFileName);
    Modify(true);
  end;
end;

The UploadIntoStream function will prompt the user to choose a local picture file, and from there we upload that into an instream. At no point do we ever put the physical file on the server. Also note that the above example will always override any existing picture. You do not have to do this as media sets allow for multiple pictures. I’m just recreating the original example taken from the Customer Picture page.

For the export we have to write a bit more code. When using a Media Set field, we do not have access to any system function that allows us to export to a stream. To deal with this all we need to do is loop through the media set and get each of the corresponding media records. Once we have that then we can export each of those to a stream.

That would look like this:

local procedure ExportPicture();
var
   PicInStream: InStream;
   Index: Integer;
   TenantMedia: Record "Tenant Media";
   FileName: Text;
begin
   if Picture.Count = 0 then
      exit;

   for Index := 1 to Picture.Count do begin
      if TenantMedia.Get(Picture.Item(Index)) then begin
         TenantMedia.calcfields(Content);
         if TenantMedia.Content.HasValue then begin
            FileName := TableCaption + '_Image' + format(Index) + GetTenantMediaFileExtension(TenantMedia);
            TenantMedia.Content.CreateInStream(PicInstream);
            DownloadFromStream(PicInstream, '', '', '', FileName);
         end;
      end;
   end;
end;

We use the DownloadFromStream function to prompt the user to save each of the pictures in the media set. As in our first example, there are no physical files ever created on the server, so we’re cloud friendly!

You may notice that I use the function GetTenantMediaFileExtension in the export example to populate the extension of the picture file. Since the user can upload a variety of picture file types, we need to make sure we create the file using the correct format.

The function to do this is quite simple, however there is no current function in the product to handle it, so you’ll have to build this yourself for now. Hopefully in the near future this function will be added by Microsoft.

local procedure GetTenantMediaFileExtension(var TenantMedia: Record "Tenant Media"): Text;
begin
   case TenantMedia."Mime Type" of
      'image/jpeg' : exit('.jpg');
      'image/png' : exit('.png');
      'image/bmp' : exit('.bmp');
      'image/gif' : exit('.gif');
      'image/tiff' : exit('.tiff');
      'image/wmf' : exit('.wmf');
   end;
end;

Until next time, happy coding!

 

Advertisements

AL Extensions: Reading JSON info with Powershell

A quick post today on how to read values from a JSON file with PowerShell.

PowerShell contains the commandlet ConvertFrom-Json, which as its name implies, converts a JSON object into a PowerShell object, from which you can then access the values and read them into variables, etc.

Let’s assume we have a file named MyFile.json, which contains the following JSON object:

{
   "id": "123456",
   "name": "MyObjectName"
}

We can convert this into a PowerShell object with the following code:

$JsonObject = Get-Content -Raw -Path .\MyFile.json | ConvertFrom-Json

We can then read the value of  name into a variable like this:

$Name = $JsonObject.Name

SO WHAT?

As the title of this post suggests, we can make use of this handy code with our AL extensions.

In my previous post, I showed you how to create a custom AL extension build task with Visual Studio Code. You can expand on this and launch a PowerShell script to execute the ALC compiler. When you do that, one of the parameters you can supply to the compiler is the output path and resulting app file name. By using the app.json file that is part of every AL extension, you can utilize things such as the extension publisher, name, version, etc. in your compiler process.

You can do something like the following…

$JsonObject = Get-Content -Raw -Path .\app.json | ConvertFrom-Json

$ExtensionName = $JsonObject.Publisher + '_' + $JsonObject.Name + '_' + $JsonObject.Version + '.app'

$CompilerPath = 'C:\Users\<username>\.vscode\extensions\Microsoft.al-0.10.13928\bin'

$ALProjectFolder = 'C:\MyProjectFolder'
$ALPackageCachePath = Join-Path -Path $ALProjectFolder -ChildPath '.alPackages'
$AlPackageOutFilePath = Join-Path -Path 'C:\MyCustomOutputFolder' -ChildPath $ExtensionName

Set-Location -Path $CompilerPath
.\alc.exe /project:$ALProjectFolder /packagecachepath:$ALPackageCachePath /out:$AlPackageOutFilePath

…which would replicate the same file name that the out of box compile process does, but will still allow you to direct the file to be output to a custom path. For example, maybe a shared AL package cache that you use for multiple developers.

Until next time, happy coding!

AL Extensions: Custom Build Process Using Visual Studio Code Tasks

I recently discovered the Tasks menu in Visual Studio Code and after a bit of wondering why I’ve not seen it after using VS Code for many months, I then took a quick look into what it was all about.

Turns out VS Code has yet another amazing feature called Tasks, which let’s you automate things such as builds, packaging, deployment, and probably whatever else you can think of. You can read all about tasks in detail here.

This got me thinking, I wonder if I can use this to make my own build process for AL extensions? Turns out this is quite easy…and here’s how you can do it.

Open up your AL extension folder and select Tasks > Configure Tasks.

TasksConfigureTasks

In the command palette select Create tasks.json from template.

CommandBoxConfigureTasks

In the command palette select Others.

CommandBoxSelectOthers

You’ll now see a tasks.json file create in the .vscode folder of your AL project.

tasksJsonFile

In the tasks.json file you’ll see some default settings like this:

{
    // See https://go.microsoft.com/fwlink/?LinkId=733558
    // for the documentation about the tasks.json format
    "version": "2.0.0",
    "tasks": [
        {
            "taskName": "echo",
            "type": "shell",
            "command": "echo Hello"
        }
    ]
}

We need to change the task command so that we build our AL extension. When you install the AL Language extension, behind the scenes is installed a command line compiler (alc.exe). The alc compiler accepts 3 parameters:

  1. project: The path to the AL project folder
  2. packagecachepath: The path to the folder containing the reference packages
  3. out: The path to output the packaged extension app file to. This parameter is optional. If it’s not specified then the compiler will output the app file in the project folder with the default name of <Publisher>_<Name>_<Version>.app

For example, in order to build our AL extension with the default output and name, we’d need a command such as this:

C:\Users\<username>\.vscode\extensions\Microsoft.al-0.10.13928\bin\alc.exe /project:C:\ALProject1 /packagecachepath:C:\ALProject1\.alpackages

One more quick thing before we continue. Within VS Code tasks, you have access to some predefined variables. You can read about what they are here. For our task, we’re interested in the ${workspaceFolder} variable, which will give us the path to the workspace folder of the project.

Back to the VS Code task. We need to update the tasks.json file now. We’ll change the taskName property to a more meaningful name, and we’ll update the command property to execute our alc compiler. Make sure to note the double slashes and that you replace the <username> and AL Language extension version number with the correct one as per your environment.

{
    // See https://go.microsoft.com/fwlink/?LinkId=733558
    // for the documentation about the tasks.json format
    "version": "2.0.0",
    "tasks": [
        {
            "taskName": "Offline Build",
            "type": "shell",
            "command": "C:\\Users\\<username>\\.vscode\\extensions\\Microsoft.al-0.10.13928\\bin\\alc.exe /project:${workspaceFolder} /packagecachepath:${workspaceFolder}\\.alpackages"
        }
    ]
}

Now that we’ve updated the task file, you need to set this task as the default build command. To do that you select Tasks > Configure Default Build Task from the menu. Doing this will not change the existing F5 or Ctrl+F5 commands that Microsoft delivers with the AL Language extension.

TasksConfigureDefaultBuildTask.png

In the command palette select the name of the task you created above. In my case, I’ve named the task Offline Build.

CommandBoxSelectTaskName

The following lines were just added to your tasks.json file:

"group": {
    "kind": "build",
    "isDefault": true
}

You can close and save the tasks.json file now if you still have it open. You’re ready to use your new build task in the following ways:

  1. Tasks > Run Task
    • With this method you can select to run any task that you’ve created.
  2. Tasks > Run Build Task
    • This will work only if you’ve made your task the default build task.
  3. Ctrl+Shift+B
    • This will work only if you’ve made your task the default build task.

No matter what method you choose to execute the task, you can monitor it for errors in the VS Code terminal window.

TerminalWindowOutput

That’s it! Now you’ve got a way to build your extension without having to deploy it at the same time.

Pretty sure I’ve only scratched the surface on what VS Code tasks can do, so I’m excited to see how else I can make use of them in my AL development.

Until next time…..happy coding!