RustyFIT
Rewrite of FIT SDK for Go in Rust.
Current State
This project serves as an exercise for me to learn Rust. I believe the fastest way to learn something new is by reinventing the wheel or rewriting something that already exists. Although this is a learning project, this library generally works, is usable, and quite fast.
Missing features, test completeness, and more robust documentation may be added later through release iteration.
Usage
Decoding
Decode
Decoder's decode allows us to interact with FIT files directly through their original protocol messages' structure.
First call will return either Ok(Some(fit)) or Err(err), never Ok(None).
On next call, it may return Ok(None) to indicate that no more FIT sequence in the file.
use rustyfit::{Decoder, profile::{mesgdef, typedef}};
use std::{error::Error, fs::File, io::BufReader};
fn main() -> Result<(), Box<dyn Error>> {
let name = "Activity.fit";
let f = File::open(name)?;
let br = BufReader::new(f);
let mut dec = Decoder::new(br);
let fit = dec.decode()?.unwrap();
println!("file_header's data_size: {}", fit.file_header.data_size);
println!("messages count: {}", fit.messages.len());
for field in &fit.messages[0].fields {
if field.num == mesgdef::FileId::TYPE {
println!("file type: {}", typedef::File(field.value.as_u8()));
}
}
Ok(())
}
The decode method can be invoked multiple times to decode chained FIT file until it return Ok(None) or Err(err).
We can decode chained FIT file using while let, e.g:
while let Some(fit) = dec.decode()? {
println!("file_header's data_size: {}", fit.file_header.data_size);
println!("messages count: {}", fit.messages.len());
for field in &fit.messages[0].fields {
if field.num == mesgdef::FileId::TYPE {
println!("file type: {}", typedef::File(field.value.as_u8()));
}
}
}
Decode with Closure
Decoder's decode_with allow us to retrieve event data (FileHeader, MessageDefinition, Message, CRC) as soon as it is being decoded.
This way, users can have fine-grained control on how to interact with the data.
use rustyfit::{Decoder, DecoderEvent,profile::{mesgdef, typedef}};
use std::{error::Error, fs::File, io::BufReader};
fn main() -> Result<(), Box<dyn Error>> {
let name = "Activity.fit";
let f = File::open(name)?;
let br = BufReader::new(f);
let mut dec = Decoder::new(br);
dec.decode_with(|event| match event {
DecoderEvent::FileHeader(_) => {},
DecoderEvent::MessageDefinition(_) => {},
DecoderEvent::Message(mesg) => {
if mesg.num == typedef::MesgNum::SESSION {
let ses = mesgdef::Session::from(mesg);
println!(
"session:\n start_time: {}\n sport: {}\n num_laps: {}",
ses.start_time.0, ses.sport, ses.num_laps
);
}
}
DecoderEvent::Crc(_) => {}
})?;
Ok(())
}
The decode_with method can be invoked multiple times to decode chained FIT file until it return Ok(false) or Err(err).
while dec.decode_with(|event| {
if let DecoderEvent::Message(mesg) = event {
if mesg.num == typedef::MesgNum::SESSION {
let ses = mesgdef::Session::from(mesg);
println!(
"session:\n start_time: {}\n sport: {}\n num_laps: {}",
ses.start_time.0, ses.sport, ses.num_laps
);
}
}
})? {}
DecoderBuilder
Create Decoder instance with options using DecoderBuilder.
let mut dec: Decoder = DecoderBuilder::new(br)
.checksum(false)
.expand_components(false)
.build();
Encoding
Encode
Here is the example of manually encode FIT protocol using this library to give the idea how it works.
use std::{error::Error, fs::File, io::{BufWriter, Write}};
use rustyfit::{Encoder, profile::{ProfileType, mesgdef, typedef::{self}}, proto::{FIT, Field, Message, Value}};
fn main() -> Result<(), Box<dyn Error>> {
let fout_name = "output.fit";
let fout = File::create(fout_name)?;
let mut bw = BufWriter::new(fout);
let mut enc = Encoder::new(&mut bw);
let mut fit = FIT {
messages: vec![
Message {
num: typedef::MesgNum::FILE_ID,
fields: vec![
Field {
num: mesgdef::FileId::MANUFACTURER,
profile_type: ProfileType::MANUFACTURER,
value: Value::Uint16(typedef::Manufacturer::GARMIN.0),
is_expanded: false,
},
Field {
num: mesgdef::FileId::PRODUCT,
profile_type: ProfileType::UINT16,
value: Value::Uint16(typedef::GarminProduct::FENIX8_SOLAR.0),
is_expanded: false,
},
Field {
num: mesgdef::FileId::TYPE,
profile_type: ProfileType::UINT8,
value: Value::Uint8(typedef::File::ACTIVITY.0),
is_expanded: false,
},
],
..Default::default()
},
Message {
num: typedef::MesgNum::RECORD,
fields: vec![
Field {
num: mesgdef::Record::DISTANCE,
profile_type: ProfileType::UINT32,
value: Value::Uint32(100 * 100), is_expanded: false,
},
Field {
num: mesgdef::Record::HEART_RATE,
profile_type: ProfileType::UINT8,
value: Value::Uint8(70), is_expanded: false,
},
Field {
num: mesgdef::Record::SPEED,
profile_type: ProfileType::UINT16,
value: Value::Uint16(2 * 1000), is_expanded: false,
},
],
..Default::default()
},
],
..Default::default()
};
enc.encode(&mut fit)?;
bw.flush()?;
Ok(())
}
Encode using mesgdef module
Alternatively, users can create messages using the mesgdef module for convenience.
use std::{error::Error, fs::File, io::{BufWriter, Write}};
use rustyfit::{Encoder, profile::{mesgdef, typedef::{self}}, proto::{FIT, Message}};
fn main() -> Result<(), Box<dyn Error>> {
let fout_name = "output.fit";
let fout = File::create(fout_name)?;
let mut bw = BufWriter::new(fout);
let mut enc = Encoder::new(&mut bw);
let mut fit = FIT {
messages: vec![
{
let mut file_id = mesgdef::FileId::new();
file_id.manufacturer = typedef::Manufacturer::GARMIN;
file_id.product = typedef::GarminProduct::FENIX8_SOLAR.0;
file_id.r#type = typedef::File::ACTIVITY;
Message::from(file_id)
},
{
let mut record = mesgdef::Record::new();
record.distance = 100 * 100; record.heart_rate = 70; record.speed = 2 * 1000; Message::from(record)
},
],
..Default::default()
};
enc.encode(&mut fit)?;
bw.flush()?;
Ok(())
}
EncoderBuilder
Create Encoder instance with options using EncoderBuilder.
let mut enc: Encoder = EncoderBuilder::new(&mut bw)
.endianness(Endianness::BigEndian)
.protocol_version(ProtocolVersion::V2)
.header_option(HeaderOption::Compressed(3))
.build();
