DataReader

The Resource, Files and Networking API allows reading of data from various sources.
(From Resource Packs, on-disk file, and data transmitted via HTTP respectively).

One thing they have in common is that these data are nothing but a sequence of bytes. (A file is just a sequence of bytes, a Resource Pack file is just a sequence of bytes, Data transmitted from the network is also just a sequence of bytes).

To turn it into something useful, we have to decode these data depending on the result we want to achieve, which is why all these API returns a DataReader, a common class that allows script developers to decode these bytes into various formats. (e.g. Turn it into String/BufferedImage)

DataReader

A DataReader represents a sequence of bytes data.

Multiple functions are provided allowing you to decode these type of bytes data (Such as converting it into String/BufferedImage):

Functions	Description
DataReader.asString(): String?	Return the file's content as plain text, in UTF-8 encoding. Null if the decoding failed, alongside a console error.
DataReader.asBufferedImage(): BufferImage?	Return the file's content as a BufferedImage. Null if the decoding failed, alongside a console error.
DataReader.asFont(): Font?	Load a custom TTF or OTF font file as an AWT Font. Null if the decoding failed, alongside a console error. Note: Due to the way Java and Minecraft Resource Pack works, new temporary font files are generated on your disk every time you call this function. If you find yourself running out of disk space during the development, you can free up disk space by deleting files starting with +~JF on your system temp directory, or restart your Minecraft/Computer.
DataReader.asByteArray(): byte[]	Return the file's content as a raw byte array.
DataReader.openInputStream(callback: Consumer<InputStream>): void	Opens the underlying InputStream and pass it to callback. The closing of InputStream is automatically done after executing your callback.
DataReader.asInputStream(): InputStream	Return the underlying InputStream. Note: Remember to close the InputStream after use with .close()

Example

/* Files API example (String) */
let mtrConfigFile = Files.read("config", "mtr.json"); // DataReader, or null if the file doesn't exist
if(mtrConfigFile != null) {
    let mtrConfigStr = mtrConfigFile.asString(); // Invoke DataReader.asString() to read it as the string
    let mtrConfig = JSON.parse(mtrConfigStr);
    // ...
}

/* Resources API example (Image) */
let imgAData = Resources.read(Resources.idr("a.png")); // DataReader, or null if the file doesn't exist
if(imgAData != null) {
    let imgA = imgAData.asBufferedImage(); // Invoke DataReader.asBufferedImage() to read it as a BufferedImage
}

/* Network API example (Font) */
/* Note: For illustration only, unless you have really good reason, you shouldn't need to fetch font over the internet... */
let resp = Networking.fetch("https://example.com/a.ttf");
if(resp.ok()) {
    let data = resp.getData(); // DataReader
    let font = data.asFont(); // Invoke DataReader.asFont() to read it as an AWT font
    // ...
}