Why

To learn rust!

• This library is used for console based ID3 tagging tool Markdang.

Usage

This is ID3 read and write library.

• Add dependency
• Reding: How to read ID3 information
• Writing: How to write ID3 information
• Rewrite: How to rewrite all ID3 information to version 4
• Getting information of a frame body without property name.

other usecases See tests.

Add dependency

This can be used by adding rtag to your dependencies in your project's Cargo.toml

[dependencies]
rtag = "0.3.5"

and this to your crate root:

extern crate rtag;

Reding: How to read ID3 information

To read a ID3 metadata, you use a MetadataReader and a Unit enum.

and the MetadataReader is implementing the std::iter::Iterator trait, you can use filter, map, fold.. and so on.

Example

// read a frame1
for m in MetadataReader::new("./test-resources/v1-v2.mp3").unwrap() {
    match m {
        Unit::FrameV1(frame) => {
            debug!("v1: {:?}", frame);
            assert_eq!("Artist", frame.artist);
            assert_eq!("!@#$", frame.comment);
            assert_eq!("1", frame.track);
            assert_eq!("137", frame.genre);
        }
        _ => (),
    }
}

// filter a frame v3 having `compression flag`
let mut i = MetadataReader::new(path).unwrap().filter(|m| match m {
    &Unit::FrameV2(FrameHeader::V23(ref header), _) => {
        header.has_flag(FrameHeaderFlag::Compression)
    }
    _ => false,
});

// fold a frame v2
let new_data = MetadataReader::new(path)
    .unwrap()
    .fold(Vec::new(), |mut vec, unit| {
        if let Unit::FrameV2(frame_head, frame_body) = unit {
            let new_frame_body = if let FrameBody::TALB(ref frame) = frame_body {
                let mut new_frame = frame.clone();
                new_frame.text = "Album!".to_string();
                FrameBody::TALB(new_frame)
            } else {
                frame_body.clone()
            };

            vec.push(Unit::FrameV2(frame_head, new_frame_body));
        } else {
            vec.push(unit);
        }

        vec
    });

Writing: How to write ID3 information

To write a ID3 metadata, you pass FrameHeader and FrameBody to MetadataWriter via std::vec::Vec.

Example

let new_data = MetadataReader::new(path)
    .unwrap()
    .fold(Vec::new(), |mut vec, unit| {
        if let Unit::FrameV2(frame_head, frame_body) = unit {
            let new_frame_body = ...
            vec.push(Unit::FrameV2(frame_head, new_frame_body));
        }

        vec
    });

let _ = MetadataWriter::new(path).unwrap().write(new_data, false);

Rewrite: How to rewrite a ID3 information to version 4

To rewrite all the frames to version 4, it is same to above example but second parameter is true.

Note: the frame v1 information is ignored and some frames that are ignored.

• In 2.2 'CRM', 'PIC'.
• In 2.3 'EQUA', 'IPLS', 'RVAD', 'TDAT', 'TIME', 'TORY', 'TRDA', 'TSIZ', 'TYER'

// collect frames having version 2
let frames = MetadataReader::new(path).unwrap().collect::<Vec<Unit>>();
// rewrite to version 4
let _ = MetadataWriter::new(path).unwrap().write(frames, true);
// read a version 4
for unit in MetadataReader::new(path).unwrap() {
    match unit {
        Unit::FrameV2(FrameHeader::V24(head), frame_body) => {
            ...
        },
        _ => (),
    }
}

Getting information of a frame body without property name.

To read value of frame without property name, FrameBody support to_map and inside.

Example

for unit in MetadataReader::new(path).unwrap() {
    match unit {
        Unit::FrameV2(_, ref frame_body) => {
            
            // 1. using to_map();
            let map = frame_body.to_map();
            //{
            //    <key1:&str>: <value1:String>
            //    ...
            //}

            // 2. using inside
            frame_body.inside(|key, value| {
                // key<&str>, value<String>
                ...

                true // if true, look inside next.
            })

        },
        _ => (),
    }
}