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Firefox needs UTF8 for GeoXml3

2016/01/07


I’m developing an WebAPI2 solution with Angular that receives, from Android devices, GPS points.
So Latitude , Longitude , Speed etc. are saved in a SQL Server 2014 table; from the web site the headquarter would follow the real time navigation.
The chosen approach was to write an KML file from the db data, and show this KML in a GoogleMaps window.
Having local files (not on another domain) the best solution is to use the GeoXml3 library, which is relatively easy to use (examples here and here).
For the javascript part, no problem: there is an simple setTimeout that calls via jQuery an WebAPI2 method that re-write the kml (the name is the record ID), and then adding an random number to the querystring the boss can follow the persons wandering somewhere, seeing the kml line that slowly progress on the map.
But there was an problem: On IE10 , 11, Chrome, Edge all ok; instead on Firefox (Windows or Ubuntu or Android tablet) no kml shown.
Sometimes the things are discovered in a very casual manner…i tried to save the KML with another name using Notepad++ , and change the code in order to not use the API call and instead try to show immediately this second file where i wanted to test some change, in order to understand what was wrong : bingo, KML immediately visible!
This was a real head scratching…the files (the generated from the system, and the one saved from the previous) in Notepad++ was absolutely the same, no visible difference.
So i tried to compare them with WinMerge and surprise, the generated file was full of strange characters before every normal character, immediately i realized “oops, the encoding?” and only after i noticed in Notepad++ that in the Encoding menu the file saved from Notepad++ itself was UTF8 encoded, and the one produced from the C# code was without encoding.
In the WebAPI2 method effectively i used Unicode: so now, all the browsers shows the KML writing the file as:

private async Task WriteTextAsync(string filePath, string text)
{
    //byte[] encodedText = Encoding.Unicode.GetBytes(text);
    byte[] encodedText = Encoding.UTF8.GetBytes(text);
    //
    using (FileStream sourceStream = new FileStream(filePath, FileMode.Append, FileAccess.Write, FileShare.None, bufferSize: 1048576, useAsync: true))
    {
        await sourceStream.WriteAsync(encodedText, 0, encodedText.Length);
    };
}

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