X++ code to read CSV files in Dynamics 365 for operations

Reading data from csv files is a very common development requirement for X++ developers. In Dynamics 365 for operations there are some interesting concepts, as opposed to AX2012. The application runs on cloud and the client is in web. In such scenarios the way to read files from local system is a 2 step process.

Step 1: Upload the file from local machine to Microsoft cloud (Azure) storage space called as Azure blob.

Step 2: Read the file from Azure blob to retrieve the data.

 

Microsoft has done an excellent job in creating out of the box classes to run this logic. So we are not required to re-invent the wheel and can leverage the existing API's. The below X++ code can be used to read a CSV file:

 

 

The standard API's are used here do the required magic. I have tried to breakdown the functionality of the calls.
Step 1 is done by the below command where the file is uploaded from local machine to azure blob

 
Step 2 is done by opening the IO stream from the Blob and reading it from the IO class

 

Rest of the job is almost similar to AX2012 pattern.

 

To test the job we create a sample csv file

 
 
On running the job a file picker will be shown, where you can browse the file.



 
The progress of uploading it to cloud space is shown in the progress bar


 
 
 
 
Infolog is shown with the data on the file


 
 

Worth mentioning that there are various other IO classes, provided out of the box which have the below associations

 

 
 
The file upload classes have different strategies and the below classes are available out of the box. For more information refer to nice articles mentioned in the references:

To quickly reuse the code here it goes

class RGReadSample
{       
    ///

    /// Runs the class with the specified arguments.
    ///

    /// The specified arguments.
    public static void main(Args _args)
    {       
        AsciiStreamIo                                   file;
        Array                                           fileLines;
        FileUploadTemporaryStorageResult                fileUpload;
        fileUpload = File::GetFileFromUser() as FileUploadTemporaryStorageResult;
        file = AsciiStreamIo::constructForRead(fileUpload.openResult());
        if (file)
        {
            if (file.status())
            {
                throw error("@SYS52680");
            }
            file.inFieldDelimiter(',');
            file.inRecordDelimiter('\r\n');
        }
        container record;
        while (!file.status())
        {
            record = file.read();
            if (conLen(record))
            {
                info(strFmt("%1 - %2",conPeek(record,1),conPeek(record,2)));
            }
        }
        info("done");
    }
}

Feel free to comment on any feedback/suggestions in case I have missed any important part of this framework  but this code works nicely on reading csv files. Thanks for reading the blog and have a great day.

More references:
https://ax.help.dynamics.com/en/wiki/file-upload-control/
http://dev.goshoom.net/en/2016/03/file-upload-and-download-in-ax-7/