abzcoding/hget

package main

import (
    "encoding/json"
    "io/ioutil"
    "os"
    "path/filepath"
)

var dataFolder = ".hget/"
var stateFileName = "state.json"

// State holds information about url Parts
type State struct {
    URL   string
    Parts []Part
}

// Part represents a chunk of downloaded file
type Part struct {
    Index     int64
    URL       string
    Path      string
    RangeFrom int64
    RangeTo   int64
}

// Save stores downloaded file into disk
func (s *State) Save() error {
    //make temp folder
    //only working in unix with env HOME
    folder := FolderOf(s.URL)
    Printf("Saving current download data in %s\n", folder)
    if err := MkdirIfNotExist(folder); err != nil {
        return err
    }

    //move current downloading file to data folder
    for _, part := range s.Parts {
        os.Rename(part.Path, filepath.Join(folder, filepath.Base(part.Path)))
    }

    //save state file
    j, err := json.Marshal(s)
    if err != nil {
        return err
    }
    return ioutil.WriteFile(filepath.Join(folder, stateFileName), j, 0644)
}

// Read loads data about the state of downloaded files
func Read(task string) (*State, error) {
    file := filepath.Join(os.Getenv("HOME"), dataFolder, task, stateFileName)
    Printf("Getting data from %s\n", file)
    bytes, err := ioutil.ReadFile(file)
    if err != nil {
        return nil, err
    }

    s := new(State)
    err = json.Unmarshal(bytes, s)
    return s, err
}