path: root/swarm/api/client/client.go

// Copyright 2017 The go-ethereum Authors
// This file is part of the go-ethereum library.
//
// The go-ethereum library is free software: you can redistribute it and/or modify
// it under the terms of the GNU Lesser General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// The go-ethereum library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU Lesser General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public License
// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.

package client

import (
    "archive/tar"
    "bytes"
    "encoding/json"
    "errors"
    "fmt"
    "io"
    "io/ioutil"
    "mime"
    "mime/multipart"
    "net/http"
    "net/textproto"
    "os"
    "path/filepath"
    "strconv"
    "strings"

    "github.com/ethereum/go-ethereum/swarm/api"
)

var (
    DefaultGateway = "http://localhost:8500"
    DefaultClient  = NewClient(DefaultGateway)
)

func NewClient(gateway string) *Client {
    return &Client{
        Gateway: gateway,
    }
}

// Client wraps interaction with a swarm HTTP gateway.
type Client struct {
    Gateway string
}

// UploadRaw uploads raw data to swarm and returns the resulting hash
func (c *Client) UploadRaw(r io.Reader, size int64) (string, error) {
    if size <= 0 {
        return "", errors.New("data size must be greater than zero")
    }
    req, err := http.NewRequest("POST", c.Gateway+"/bzz-raw:/", r)
    if err != nil {
        return "", err
    }
    req.ContentLength = size
    res, err := http.DefaultClient.Do(req)
    if err != nil {
        return "", err
    }
    defer res.Body.Close()
    if res.StatusCode != http.StatusOK {
        return "", fmt.Errorf("unexpected HTTP status: %s", res.Status)
    }
    data, err := ioutil.ReadAll(res.Body)
    if err != nil {
        return "", err
    }
    return string(data), nil
}

// DownloadRaw downloads raw data from swarm
func (c *Client) DownloadRaw(hash string) (io.ReadCloser, error) {
    uri := c.Gateway + "/bzz-raw:/" + hash
    res, err := http.DefaultClient.Get(uri)
    if err != nil {
        return nil, err
    }
    if res.StatusCode != http.StatusOK {
        res.Body.Close()
        return nil, fmt.Errorf("unexpected HTTP status: %s", res.Status)
    }
    return res.Body, nil
}

// File represents a file in a swarm manifest and is used for uploading and
// downloading content to and from swarm
type File struct {
    io.ReadCloser
    api.ManifestEntry
}

// Open opens a local file which can then be passed to client.Upload to upload
// it to swarm
func Open(path string) (*File, error) {
    f, err := os.Open(path)
    if err != nil {
        return nil, err
    }
    stat, err := f.Stat()
    if err != nil {
        f.Close()
        return nil, err
    }
    return &File{
        ReadCloser: f,
        ManifestEntry: api.ManifestEntry{
            ContentType: mime.TypeByExtension(filepath.Ext(path)),
            Mode:        int64(stat.Mode()),
            Size:        stat.Size(),
            ModTime:     stat.ModTime(),
        },
    }, nil
}

// Upload uploads a file to swarm and either adds it to an existing manifest
// (if the manifest argument is non-empty) or creates a new manifest containing
// the file, returning the resulting manifest hash (the file will then be
// available at bzz:/<hash>/<path>)
func (c *Client) Upload(file *File, manifest string) (string, error) {
    if file.Size <= 0 {
        return "", errors.New("file size must be greater than zero")
    }
    return c.TarUpload(manifest, &FileUploader{file})
}

// Download downloads a file with the given path from the swarm manifest with
// the given hash (i.e. it gets bzz:/<hash>/<path>)
func (c *Client) Download(hash, path string) (*File, error) {
    uri := c.Gateway + "/bzz:/" + hash + "/" + path
    res, err := http.DefaultClient.Get(uri)
    if err != nil {
        return nil, err
    }
    if res.StatusCode != http.StatusOK {
        res.Body.Close()
        return nil, fmt.Errorf("unexpected HTTP status: %s", res.Status)
    }
    return &File{
        ReadCloser: res.Body,
        ManifestEntry: api.ManifestEntry{
            ContentType: res.Header.Get("Content-Type"),
            Size:        res.ContentLength,
        },
    }, nil
}

// UploadDirectory uploads a directory tree to swarm and either adds the files
// to an existing manifest (if the manifest argument is non-empty) or creates a
// new manifest, returning the resulting manifest hash (files from the
// directory will then be available at bzz:/<hash>/path/to/file), with
// the file specified in defaultPath being uploaded to the root of the manifest
// (i.e. bzz:/<hash>/)
func (c *Client) UploadDirectory(dir, defaultPath, manifest string) (string, error) {
    stat, err := os.Stat(dir)
    if err != nil {
        return "", err
    } else if !stat.IsDir() {
        return "", fmt.Errorf("not a directory: %s", dir)
    }
    return c.TarUpload(manifest, &DirectoryUploader{dir, defaultPath})
}

// DownloadDirectory downloads the files contained in a swarm manifest under
// the given path into a local directory (existing files will be overwritten)
func (c *Client) DownloadDirectory(hash, path, destDir string) error {
    stat, err := os.Stat(destDir)
    if err != nil {
        return err
    } else if !stat.IsDir() {
        return fmt.Errorf("not a directory: %s", destDir)
    }

    uri := c.Gateway + "/bzz:/" + hash + "/" + path
    req, err := http.NewRequest("GET", uri, nil)
    if err != nil {
        return err
    }
    req.Header.Set("Accept", "application/x-tar")
    res, err := http.DefaultClient.Do(req)
    if err != nil {
        return err
    }
    defer res.Body.Close()
    if res.StatusCode != http.StatusOK {
        return fmt.Errorf("unexpected HTTP status: %s", res.Status)
    }
    tr := tar.NewReader(res.Body)
    for {
        hdr, err := tr.Next()
        if err == io.EOF {
            return nil
        } else if err != nil {
            return err
        }
        // ignore the default path file
        if hdr.Name == "" {
            continue
        }

        dstPath := filepath.Join(destDir, filepath.Clean(strings.TrimPrefix(hdr.Name, path)))
        if err := os.MkdirAll(filepath.Dir(dstPath), 0755); err != nil {
            return err
        }
        var mode os.FileMode = 0644
        if hdr.Mode > 0 {
            mode = os.FileMode(hdr.Mode)
        }
        dst, err := os.OpenFile(dstPath, os.O_WRONLY|os.O_CREATE|os.O_TRUNC, mode)
        if err != nil {
            return err
        }
        n, err := io.Copy(dst, tr)
        dst.Close()
        if err != nil {
            return err
        } else if n != hdr.Size {
            return fmt.Errorf("expected %s to be %d bytes but got %d", hdr.Name, hdr.Size, n)
        }
    }
}

// UploadManifest uploads the given manifest to swarm
func (c *Client) UploadManifest(m *api.Manifest) (string, error) {
    data, err := json.Marshal(m)
    if err != nil {
        return "", err
    }
    return c.UploadRaw(bytes.NewReader(data), int64(len(data)))
}

// DownloadManifest downloads a swarm manifest
func (c *Client) DownloadManifest(hash string) (*api.Manifest, error) {
    res, err := c.DownloadRaw(hash)
    if err != nil {
        return nil, err
    }
    defer res.Close()
    var manifest api.Manifest
    if err := json.NewDecoder(res).Decode(&manifest); err != nil {
        return nil, err
    }
    return &manifest, nil
}

// List list files in a swarm manifest which have the given prefix, grouping
// common prefixes using "/" as a delimiter.
//
// For example, if the manifest represents the following directory structure:
//
// file1.txt
// file2.txt
// dir1/file3.txt
// dir1/dir2/file4.txt
//
// Then:
//
// - a prefix of ""      would return [dir1/, file1.txt, file2.txt]
// - a prefix of "file"  would return [file1.txt, file2.txt]
// - a prefix of "dir1/" would return [dir1/dir2/, dir1/file3.txt]
//
// where entries ending with "/" are common prefixes.
func (c *Client) List(hash, prefix string) (*api.ManifestList, error) {
    res, err := http.DefaultClient.Get(c.Gateway + "/bzz-list:/" + hash + "/" + prefix)
    if err != nil {
        return nil, err
    }
    defer res.Body.Close()
    if res.StatusCode != http.StatusOK {
        return nil, fmt.Errorf("unexpected HTTP status: %s", res.Status)
    }
    var list api.ManifestList
    if err := json.NewDecoder(res.Body).Decode(&list); err != nil {
        return nil, err
    }
    return &list, nil
}

// Uploader uploads files to swarm using a provided UploadFn
type Uploader interface {
    Upload(UploadFn) error
}

type UploaderFunc func(UploadFn) error

func (u UploaderFunc) Upload(upload UploadFn) error {
    return u(upload)
}

// DirectoryUploader uploads all files in a directory, optionally uploading
// a file to the default path
type DirectoryUploader struct {
    Dir         string
    DefaultPath string
}

// Upload performs the upload of the directory and default path
func (d *DirectoryUploader) Upload(upload UploadFn) error {
    if d.DefaultPath != "" {
        file, err := Open(d.DefaultPath)
        if err != nil {
            return err
        }
        if err := upload(file); err != nil {
            return err
        }
    }
    return filepath.Walk(d.Dir, func(path string, f os.FileInfo, err error) error {
        if err != nil {
            return err
        }
        if f.IsDir() {
            return nil
        }
        file, err := Open(path)
        if err != nil {
            return err
        }
        relPath, err := filepath.Rel(d.Dir, path)
        if err != nil {
            return err
        }
        file.Path = filepath.ToSlash(relPath)
        return upload(file)
    })
}

// FileUploader uploads a single file
type FileUploader struct {
    File *File
}

// Upload performs the upload of the file
func (f *FileUploader) Upload(upload UploadFn) error {
    return upload(f.File)
}

// UploadFn is the type of function passed to an Uploader to perform the upload
// of a single file (for example, a directory uploader would call a provided
// UploadFn for each file in the directory tree)
type UploadFn func(file *File) error

// TarUpload uses the given Uploader to upload files to swarm as a tar stream,
// returning the resulting manifest hash
func (c *Client) TarUpload(hash string, uploader Uploader) (string, error) {
    reqR, reqW := io.Pipe()
    defer reqR.Close()
    req, err := http.NewRequest("POST", c.Gateway+"/bzz:/"+hash, reqR)
    if err != nil {
        return "", err
    }
    req.Header.Set("Content-Type", "application/x-tar")

    // use 'Expect: 100-continue' so we don't send the request body if
    // the server refuses the request
    req.Header.Set("Expect", "100-continue")

    tw := tar.NewWriter(reqW)

    // define an UploadFn which adds files to the tar stream
    uploadFn := func(file *File) error {
        hdr := &tar.Header{
            Name:    file.Path,
            Mode:    file.Mode,
            Size:    file.Size,
            ModTime: file.ModTime,
            Xattrs: map[string]string{
                "user.swarm.content-type": file.ContentType,
            },
        }
        if err := tw.WriteHeader(hdr); err != nil {
            return err
        }
        _, err = io.Copy(tw, file)
        return err
    }

    // run the upload in a goroutine so we can send the request headers and
    // wait for a '100 Continue' response before sending the tar stream
    go func() {
        err := uploader.Upload(uploadFn)
        if err == nil {
            err = tw.Close()
        }
        reqW.CloseWithError(err)
    }()

    res, err := http.DefaultClient.Do(req)
    if err != nil {
        return "", err
    }
    defer res.Body.Close()
    if res.StatusCode != http.StatusOK {
        return "", fmt.Errorf("unexpected HTTP status: %s", res.Status)
    }
    data, err := ioutil.ReadAll(res.Body)
    if err != nil {
        return "", err
    }
    return string(data), nil
}

// MultipartUpload uses the given Uploader to upload files to swarm as a
// multipart form, returning the resulting manifest hash
func (c *Client) MultipartUpload(hash string, uploader Uploader) (string, error) {
    reqR, reqW := io.Pipe()
    defer reqR.Close()
    req, err := http.NewRequest("POST", c.Gateway+"/bzz:/"+hash, reqR)
    if err != nil {
        return "", err
    }

    // use 'Expect: 100-continue' so we don't send the request body if
    // the server refuses the request
    req.Header.Set("Expect", "100-continue")

    mw := multipart.NewWriter(reqW)
    req.Header.Set("Content-Type", fmt.Sprintf("multipart/form-data; boundary=%q", mw.Boundary()))

    // define an UploadFn which adds files to the multipart form
    uploadFn := func(file *File) error {
        hdr := make(textproto.MIMEHeader)
        hdr.Set("Content-Disposition", fmt.Sprintf("form-data; name=%q", file.Path))
        hdr.Set("Content-Type", file.ContentType)
        hdr.Set("Content-Length", strconv.FormatInt(file.Size, 10))
        w, err := mw.CreatePart(hdr)
        if err != nil {
            return err
        }
        _, err = io.Copy(w, file)
        return err
    }

    // run the upload in a goroutine so we can send the request headers and
    // wait for a '100 Continue' response before sending the multipart form
    go func() {
        err := uploader.Upload(uploadFn)
        if err == nil {
            err = mw.Close()
        }
        reqW.CloseWithError(err)
    }()

    res, err := http.DefaultClient.Do(req)
    if err != nil {
        return "", err
    }
    defer res.Body.Close()
    if res.StatusCode != http.StatusOK {
        return "", fmt.Errorf("unexpected HTTP status: %s", res.Status)
    }
    data, err := ioutil.ReadAll(res.Body)
    if err != nil {
        return "", err
    }
    return string(data), nil
}