minewebgen - transfer.go

     1  package main
     2  
     3  import (
     4  	"errors"
     5  	"io"
     6  	"net/http"
     7  	"os"
     8  
     9  	"golang.org/x/net/websocket"
    10  	"vimagination.zapto.org/byteio"
    11  	"vimagination.zapto.org/minewebgen/internal/data"
    12  )
    13  
    14  var transferFuncs = [...]func(Transfer, string, *byteio.StickyLittleEndianReader, *byteio.StickyLittleEndianWriter, *os.File, int64) error{
    15  	Transfer.server,
    16  	Transfer.maps,
    17  	Transfer.generate,
    18  	Transfer.generator,
    19  }
    20  
    21  type downloadProgress struct {
    22  	io.Reader
    23  	*byteio.StickyLittleEndianWriter
    24  }
    25  
    26  func (d downloadProgress) Read(b []byte) (int, error) {
    27  	n, err := d.Reader.Read(b)
    28  	d.WriteUint8(1)
    29  	d.WriteInt32(int32(n))
    30  	return n, err
    31  }
    32  
    33  type Transfer struct {
    34  	c *Config
    35  }
    36  
    37  func (t Transfer) Websocket(conn *websocket.Conn) {
    38  	conn.PayloadType = websocket.BinaryFrame
    39  	r := byteio.StickyLittleEndianReader{Reader: conn}
    40  	w := byteio.StickyLittleEndianWriter{Writer: conn}
    41  
    42  	err := t.handle(&r, &w)
    43  	if err != nil {
    44  		writeError(&w, err)
    45  	}
    46  }
    47  
    48  func (t Transfer) handle(r *byteio.StickyLittleEndianReader, w *byteio.StickyLittleEndianWriter) error {
    49  	transferType := r.ReadUint8()
    50  
    51  	if transferType>>1 > uint8(len(transferFuncs)) {
    52  		return errors.New("invalid transfer type")
    53  	}
    54  
    55  	f, err := os.CreateTemp("", "mineWebGen")
    56  	if err != nil {
    57  		return err
    58  	}
    59  	var size int64
    60  	if transferType&1 == 0 {
    61  		url := data.ReadString(r)
    62  		if r.Err != nil {
    63  			return err
    64  		}
    65  		resp, err := http.Get(url)
    66  		if err != nil {
    67  			return err
    68  		}
    69  		w.WriteInt32(int32(resp.ContentLength))
    70  		size, err = io.Copy(f, downloadProgress{resp.Body, w})
    71  		resp.Body.Close()
    72  		if err != nil {
    73  			return err
    74  		}
    75  	} else {
    76  		length := r.ReadInt32()
    77  		_, err := io.Copy(f, io.LimitReader(r, int64(length)))
    78  		if err != nil {
    79  			return err
    80  		}
    81  		size = int64(length)
    82  	}
    83  	f.Seek(0, 0)
    84  	name := data.ReadString(r)
    85  	if r.Err != nil {
    86  		return r.Err
    87  	}
    88  	err = transferFuncs[transferType>>1](t, name, r, w, f, size)
    89  	if err != nil {
    90  		return err
    91  	}
    92  	w.WriteUint8(255)
    93  	return nil
    94  }
    95