cmd/swarm, swarm: cross-platform Content-Type detection (#17782)

- Mime types generator (Standard "mime" package rely on system-settings, see mime.osInitMime)
- Changed swarm/api.Upload:
    - simplify I/O throttling by semaphore primitive and use file name where possible
    - f.Close() must be called in Defer - otherwise panic or future added early return will cause leak of file descriptors
    - one error was suppressed

Makefile

@@ -57,6 +57,9 @@ devtools:
 	@type "solc" 2> /dev/null || echo 'Please install solc'
 	@type "protoc" 2> /dev/null || echo 'Please install protoc'
 
+swarm-devtools:
+	env GOBIN= go install ./cmd/swarm/mimegen
+
 # Cross Compilation Targets (xgo)
 
 geth-cross: geth-linux geth-darwin geth-windows geth-android geth-ios

cmd/swarm/mimegen/generator.go

@@ -0,0 +1,124 @@
+// Copyright 2018 The go-ethereum Authors
+// This file is part of go-ethereum.
+//
+// go-ethereum is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// go-ethereum 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 General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with go-ethereum. If not, see <http://www.gnu.org/licenses/>.
+package main
+
+// Standard "mime" package rely on system-settings, see mime.osInitMime
+// Swarm will run on many OS/Platform/Docker and must behave similar
+// This command generates code to add common mime types based on mime.types file
+//
+// mime.types file provided by mailcap, which follow https://www.iana.org/assignments/media-types/media-types.xhtml
+//
+// Get last version of mime.types file by:
+// docker run --rm -v $(pwd):/tmp alpine:edge /bin/sh -c "apk add -U mailcap; mv /etc/mime.types /tmp"
+
+import (
+	"bufio"
+	"bytes"
+	"flag"
+	"html/template"
+	"io/ioutil"
+	"strings"
+
+	"log"
+)
+
+var (
+	typesFlag   = flag.String("types", "", "Input mime.types file")
+	packageFlag = flag.String("package", "", "Golang package in output file")
+	outFlag     = flag.String("out", "", "Output file name for the generated mime types")
+)
+
+type mime struct {
+	Name string
+	Exts []string
+}
+
+type templateParams struct {
+	PackageName string
+	Mimes       []mime
+}
+
+func main() {
+	// Parse and ensure all needed inputs are specified
+	flag.Parse()
+	if *typesFlag == "" {
+		log.Fatalf("--types is required")
+	}
+	if *packageFlag == "" {
+		log.Fatalf("--types is required")
+	}
+	if *outFlag == "" {
+		log.Fatalf("--out is required")
+	}
+
+	params := templateParams{
+		PackageName: *packageFlag,
+	}
+
+	types, err := ioutil.ReadFile(*typesFlag)
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	scanner := bufio.NewScanner(bytes.NewReader(types))
+	for scanner.Scan() {
+		txt := scanner.Text()
+		if strings.HasPrefix(txt, "#") || len(txt) == 0 {
+			continue
+		}
+		parts := strings.Fields(txt)
+		if len(parts) == 1 {
+			continue
+		}
+		params.Mimes = append(params.Mimes, mime{parts[0], parts[1:]})
+	}
+
+	if err = scanner.Err(); err != nil {
+		log.Fatal(err)
+	}
+
+	result := bytes.NewBuffer([]byte{})
+
+	if err := template.Must(template.New("_").Parse(tpl)).Execute(result, params); err != nil {
+		log.Fatal(err)
+	}
+
+	if err := ioutil.WriteFile(*outFlag, result.Bytes(), 0600); err != nil {
+		log.Fatal(err)
+	}
+}
+
+var tpl = `// Code generated by github.com/ethereum/go-ethereum/cmd/swarm/mimegen. DO NOT EDIT.
+
+package {{ .PackageName }}
+
+import "mime"
+func init() {
+	var mimeTypes = map[string]string{
+{{- range .Mimes -}}
+	{{ $name := .Name -}}
+	{{- range .Exts }}
+		".{{ . }}": "{{ $name | html }}",
+	{{- end }}
+{{- end }}
+	}
+	for ext, name := range mimeTypes {
+		if err := mime.AddExtensionType(ext, name); err != nil {
+			panic(err)
+		}
+	}
+}
+`

cmd/swarm/upload.go

@@ -22,16 +22,15 @@ import (
 	"fmt"
 	"io"
 	"io/ioutil"
-	"mime"
-	"net/http"
 	"os"
 	"os/user"
 	"path"
 	"path/filepath"
 	"strings"
 
-	"github.com/ethereum/go-ethereum/cmd/utils"
 	swarm "github.com/ethereum/go-ethereum/swarm/api/client"
+
+	"github.com/ethereum/go-ethereum/cmd/utils"
 	"gopkg.in/urfave/cli.v1"
 )
 
@@ -118,10 +117,9 @@ func upload(ctx *cli.Context) {
 				return "", fmt.Errorf("error opening file: %s", err)
 			}
 			defer f.Close()
-			if mimeType == "" {
-				mimeType = detectMimeType(file)
-			}
+			if mimeType != "" {
 				f.ContentType = mimeType
+			}
 			return client.Upload(f, "", toEncrypt)
 		}
 	}
@@ -161,19 +159,3 @@ func homeDir() string {
 	}
 	return ""
 }
-
-func detectMimeType(file string) string {
-	if ext := filepath.Ext(file); ext != "" {
-		return mime.TypeByExtension(ext)
-	}
-	f, err := os.Open(file)
-	if err != nil {
-		return ""
-	}
-	defer f.Close()
-	buf := make([]byte, 512)
-	if n, _ := f.Read(buf); n > 0 {
-		return http.DetectContentType(buf)
-	}
-	return ""
-}

cmd/swarm/upload_test.go

@@ -32,7 +32,7 @@ import (
 
 	"github.com/ethereum/go-ethereum/log"
 	swarm "github.com/ethereum/go-ethereum/swarm/api/client"
-	colorable "github.com/mattn/go-colorable"
+	"github.com/mattn/go-colorable"
 )
 
 var loglevel = flag.Int("loglevel", 3, "verbosity of logs")

swarm/api/api.go

@@ -16,6 +16,9 @@
 
 package api
 
+//go:generate mimegen --types=./../../cmd/swarm/mimegen/mime.types --package=api --out=gen_mime.go
+//go:generate gofmt -s -w gen_mime.go
+
 import (
 	"archive/tar"
 	"context"
@@ -29,8 +32,6 @@ import (
 	"path"
 	"strings"
 
-	"github.com/ethereum/go-ethereum/swarm/storage/mru/lookup"
-
 	"bytes"
 	"mime"
 	"path/filepath"
@@ -45,7 +46,8 @@ import (
 	"github.com/ethereum/go-ethereum/swarm/spancontext"
 	"github.com/ethereum/go-ethereum/swarm/storage"
 	"github.com/ethereum/go-ethereum/swarm/storage/mru"
-	opentracing "github.com/opentracing/opentracing-go"
+	"github.com/ethereum/go-ethereum/swarm/storage/mru/lookup"
+	"github.com/opentracing/opentracing-go"
 )
 
 var (
@@ -757,9 +759,14 @@ func (a *API) UploadTar(ctx context.Context, bodyReader io.ReadCloser, manifestP
 
 		// add the entry under the path from the request
 		manifestPath := path.Join(manifestPath, hdr.Name)
+		contentType := hdr.Xattrs["user.swarm.content-type"]
+		if contentType == "" {
+			contentType = mime.TypeByExtension(filepath.Ext(hdr.Name))
+		}
+		//DetectContentType("")
 		entry := &ManifestEntry{
 			Path:        manifestPath,
-			ContentType: hdr.Xattrs["user.swarm.content-type"],
+			ContentType: contentType,
 			Mode:        hdr.Mode,
 			Size:        hdr.Size,
 			ModTime:     hdr.ModTime,
@@ -770,10 +777,15 @@ func (a *API) UploadTar(ctx context.Context, bodyReader io.ReadCloser, manifestP
 			return nil, fmt.Errorf("error adding manifest entry from tar stream: %s", err)
 		}
 		if hdr.Name == defaultPath {
+			contentType := hdr.Xattrs["user.swarm.content-type"]
+			if contentType == "" {
+				contentType = mime.TypeByExtension(filepath.Ext(hdr.Name))
+			}
+
 			entry := &ManifestEntry{
 				Hash:        contentKey.Hex(),
 				Path:        "", // default entry
-				ContentType: hdr.Xattrs["user.swarm.content-type"],
+				ContentType: contentType,
 				Mode:        hdr.Mode,
 				Size:        hdr.Size,
 				ModTime:     hdr.ModTime,
@@ -1033,3 +1045,32 @@ func (a *API) ResolveResourceView(ctx context.Context, uri *URI, values mru.Valu
 	}
 	return view, nil
 }
+
+// MimeOctetStream default value of http Content-Type header
+const MimeOctetStream = "application/octet-stream"
+
+// DetectContentType by file file extension, or fallback to content sniff
+func DetectContentType(fileName string, f io.ReadSeeker) (string, error) {
+	ctype := mime.TypeByExtension(filepath.Ext(fileName))
+	if ctype != "" {
+		return ctype, nil
+	}
+
+	// save/rollback to get content probe from begin of file
+	currentPosition, err := f.Seek(0, io.SeekCurrent)
+	if err != nil {
+		return MimeOctetStream, fmt.Errorf("seeker can't seek, %s", err)
+	}
+
+	// read a chunk to decide between utf-8 text and binary
+	var buf [512]byte
+	n, _ := f.Read(buf[:])
+	ctype = http.DetectContentType(buf[:n])
+
+	_, err = f.Seek(currentPosition, io.SeekStart) // rewind to output whole file
+	if err != nil {
+		return MimeOctetStream, fmt.Errorf("seeker can't seek, %s", err)
+	}
+
+	return ctype, nil
+}

swarm/api/api_test.go

@@ -17,6 +17,7 @@
 package api
 
 import (
+	"bytes"
 	"context"
 	"errors"
 	"flag"
@@ -433,3 +434,69 @@ func TestDecryptOrigin(t *testing.T) {
 		}
 	}
 }
+
+func TestDetectContentType(t *testing.T) {
+	for _, tc := range []struct {
+		file                string
+		content             string
+		expectedContentType string
+	}{
+		{
+			file:                "file-with-correct-css.css",
+			content:             "body {background-color: orange}",
+			expectedContentType: "text/css; charset=utf-8",
+		},
+		{
+			file:                "empty-file.css",
+			content:             "",
+			expectedContentType: "text/css; charset=utf-8",
+		},
+		{
+			file:                "empty-file.pdf",
+			content:             "",
+			expectedContentType: "application/pdf",
+		},
+		{
+			file:                "empty-file.md",
+			content:             "",
+			expectedContentType: "text/markdown; charset=utf-8",
+		},
+		{
+			file:                "empty-file-with-unknown-content.strangeext",
+			content:             "",
+			expectedContentType: "text/plain; charset=utf-8",
+		},
+		{
+			file:                "file-with-unknown-extension-and-content.strangeext",
+			content:             "Lorem Ipsum",
+			expectedContentType: "text/plain; charset=utf-8",
+		},
+		{
+			file:                "file-no-extension",
+			content:             "Lorem Ipsum",
+			expectedContentType: "text/plain; charset=utf-8",
+		},
+		{
+			file:                "file-no-extension-no-content",
+			content:             "",
+			expectedContentType: "text/plain; charset=utf-8",
+		},
+		{
+			file:                "css-file-with-html-inside.css",
+			content:             "<!doctype html><html><head></head><body></body></html>",
+			expectedContentType: "text/css; charset=utf-8",
+		},
+	} {
+		t.Run(tc.file, func(t *testing.T) {
+			detected, err := DetectContentType(tc.file, bytes.NewReader([]byte(tc.content)))
+			if err != nil {
+				t.Fatal(err)
+			}
+
+			if detected != tc.expectedContentType {
+				t.Fatalf("File: %s, Expected mime type %s, got %s", tc.file, tc.expectedContentType, detected)
+			}
+
+		})
+	}
+}

swarm/api/client/client.go

@@ -24,7 +24,6 @@ import (
 	"fmt"
 	"io"
 	"io/ioutil"
-	"mime"
 	"mime/multipart"
 	"net/http"
 	"net/textproto"
@@ -124,10 +123,16 @@ func Open(path string) (*File, error) {
 		f.Close()
 		return nil, err
 	}
+
+	contentType, err := api.DetectContentType(f.Name(), f)
+	if err != nil {
+		return nil, err
+	}
+
 	return &File{
 		ReadCloser: f,
 		ManifestEntry: api.ManifestEntry{
-			ContentType: mime.TypeByExtension(filepath.Ext(path)),
+			ContentType: contentType,
 			Mode:        int64(stat.Mode()),
 			Size:        stat.Size(),
 			ModTime:     stat.ModTime(),

swarm/api/filesystem.go

@@ -21,7 +21,6 @@ import (
 	"context"
 	"fmt"
 	"io"
-	"net/http"
 	"os"
 	"path"
 	"path/filepath"
@@ -97,22 +96,28 @@ func (fs *FileSystem) Upload(lpath, index string, toEncrypt bool) (string, error
 		list = append(list, entry)
 	}
 
-	cnt := len(list)
-	errors := make([]error, cnt)
-	done := make(chan bool, maxParallelFiles)
-	dcnt := 0
-	awg := &sync.WaitGroup{}
+	errors := make([]error, len(list))
+	sem := make(chan bool, maxParallelFiles)
+	defer close(sem)
 
 	for i, entry := range list {
-		if i >= dcnt+maxParallelFiles {
-			<-done
-			dcnt++
-		}
-		awg.Add(1)
-		go func(i int, entry *manifestTrieEntry, done chan bool) {
+		sem <- true
+		go func(i int, entry *manifestTrieEntry) {
+			defer func() { <-sem }()
+
 			f, err := os.Open(entry.Path)
-			if err == nil {
-				stat, _ := f.Stat()
+			if err != nil {
+				errors[i] = err
+				return
+			}
+			defer f.Close()
+
+			stat, err := f.Stat()
+			if err != nil {
+				errors[i] = err
+				return
+			}
+
 			var hash storage.Address
 			var wait func(context.Context) error
 			ctx := context.TODO()
@@ -120,28 +125,21 @@ func (fs *FileSystem) Upload(lpath, index string, toEncrypt bool) (string, error
 			if hash != nil {
 				list[i].Hash = hash.Hex()
 			}
-				err = wait(ctx)
-				awg.Done()
-				if err == nil {
-					first512 := make([]byte, 512)
-					fread, _ := f.ReadAt(first512, 0)
-					if fread > 0 {
-						mimeType := http.DetectContentType(first512[:fread])
-						if filepath.Ext(entry.Path) == ".css" {
-							mimeType = "text/css"
-						}
-						list[i].ContentType = mimeType
-					}
-				}
-				f.Close()
-			}
+			if err := wait(ctx); err != nil {
 				errors[i] = err
-			done <- true
-		}(i, entry, done)
+				return
 			}
-	for dcnt < cnt {
-		<-done
-		dcnt++
+
+			list[i].ContentType, err = DetectContentType(f.Name(), f)
+			if err != nil {
+				errors[i] = err
+				return
+			}
+
+		}(i, entry)
+	}
+	for i := 0; i < cap(sem); i++ {
+		sem <- true
 	}
 
 	trie := &manifestTrie{
@@ -168,7 +166,6 @@ func (fs *FileSystem) Upload(lpath, index string, toEncrypt bool) (string, error
 	if err2 == nil {
 		hs = trie.ref.Hex()
 	}
-	awg.Wait()
 	return hs, err2
 }
 

swarm/api/filesystem_test.go

@@ -60,7 +60,7 @@ func TestApiDirUpload0(t *testing.T) {
 
 		content = readPath(t, "testdata", "test0", "index.css")
 		resp = testGet(t, api, bzzhash, "index.css")
-		exp = expResponse(content, "text/css", 0)
+		exp = expResponse(content, "text/css; charset=utf-8", 0)
 		checkResponse(t, resp, exp)
 
 		addr := storage.Address(common.Hex2Bytes(bzzhash))
@@ -140,7 +140,7 @@ func TestApiDirUploadModify(t *testing.T) {
 
 		content = readPath(t, "testdata", "test0", "index.css")
 		resp = testGet(t, api, bzzhash, "index.css")
-		exp = expResponse(content, "text/css", 0)
+		exp = expResponse(content, "text/css; charset=utf-8", 0)
 		checkResponse(t, resp, exp)
 
 		_, _, _, _, err = api.Get(context.TODO(), nil, addr, "")

swarm/api/http/server.go

@@ -201,6 +201,13 @@ func (s *Server) HandleBzzGet(w http.ResponseWriter, r *http.Request) {
 		defer reader.Close()
 
 		w.Header().Set("Content-Type", "application/x-tar")
+
+		fileName := uri.Addr
+		if found := path.Base(uri.Path); found != "" && found != "." && found != "/" {
+			fileName = found
+		}
+		w.Header().Set("Content-Disposition", fmt.Sprintf("inline; filename=\"%s.tar\"", fileName))
+
 		w.WriteHeader(http.StatusOK)
 		io.Copy(w, reader)
 		return
@@ -616,7 +623,7 @@ func (s *Server) HandleGetResource(w http.ResponseWriter, r *http.Request) {
 
 	// All ok, serve the retrieved update
 	log.Debug("Found update", "view", view.Hex(), "ruid", ruid)
-	w.Header().Set("Content-Type", "application/octet-stream")
+	w.Header().Set("Content-Type", api.MimeOctetStream)
 	http.ServeContent(w, r, "", time.Now(), bytes.NewReader(data))
 }
 
@@ -690,11 +697,9 @@ func (s *Server) HandleGet(w http.ResponseWriter, r *http.Request) {
 	case uri.Raw():
 		// allow the request to overwrite the content type using a query
 		// parameter
-		contentType := "application/octet-stream"
 		if typ := r.URL.Query().Get("content_type"); typ != "" {
-			contentType = typ
+			w.Header().Set("Content-Type", typ)
 		}
-		w.Header().Set("Content-Type", contentType)
 		http.ServeContent(w, r, "", time.Now(), reader)
 	case uri.Hash():
 		w.Header().Set("Content-Type", "text/plain")
@@ -850,8 +855,17 @@ func (s *Server) HandleGetFile(w http.ResponseWriter, r *http.Request) {
 		return
 	}
 
+	if contentType != "" {
 		w.Header().Set("Content-Type", contentType)
-	http.ServeContent(w, r, "", time.Now(), newBufferedReadSeeker(reader, getFileBufferSize))
+	}
+
+	fileName := uri.Addr
+	if found := path.Base(uri.Path); found != "" && found != "." && found != "/" {
+		fileName = found
+	}
+	w.Header().Set("Content-Disposition", fmt.Sprintf("inline; filename=\"%s\"", fileName))
+
+	http.ServeContent(w, r, fileName, time.Now(), newBufferedReadSeeker(reader, getFileBufferSize))
 }
 
 // The size of buffer used for bufio.Reader on LazyChunkReader passed to

swarm/api/http/server_test.go

@@ -32,6 +32,7 @@ import (
 	"net/http"
 	"net/url"
 	"os"
+	"path"
 	"strconv"
 	"strings"
 	"testing"
@@ -764,6 +765,16 @@ func testBzzTar(encrypted bool, t *testing.T) {
 	}
 	defer resp2.Body.Close()
 
+	if h := resp2.Header.Get("Content-Type"); h != "application/x-tar" {
+		t.Fatalf("Content-Type header expected: application/x-tar, got: %s", h)
+	}
+
+	expectedFileName := string(swarmHash) + ".tar"
+	expectedContentDisposition := fmt.Sprintf("inline; filename=\"%s\"", expectedFileName)
+	if h := resp2.Header.Get("Content-Disposition"); h != expectedContentDisposition {
+		t.Fatalf("Content-Disposition header expected: %s, got: %s", expectedContentDisposition, h)
+	}
+
 	file, err := ioutil.TempFile("", "swarm-downloaded-tarball")
 	if err != nil {
 		t.Fatal(err)
@@ -1099,7 +1110,7 @@ func TestModify(t *testing.T) {
 			res, body := httpDo(testCase.method, testCase.uri, reqBody, testCase.headers, testCase.verbose, t)
 
 			if res.StatusCode != testCase.expectedStatusCode {
-				t.Fatalf("expected status code %d but got %d", testCase.expectedStatusCode, res.StatusCode)
+				t.Fatalf("expected status code %d but got %d, %s", testCase.expectedStatusCode, res.StatusCode, body)
 			}
 			if testCase.assertResponseBody != "" && !strings.Contains(body, testCase.assertResponseBody) {
 				t.Log(body)
@@ -1213,16 +1224,22 @@ func TestBzzGetFileWithResolver(t *testing.T) {
 		addr                string
 		path                string
 		expectedStatusCode  int
+		expectedContentType string
+		expectedFileName    string
 	}{
 		{
 			addr:                string(swarmHash),
 			path:                fileNames[0],
 			expectedStatusCode:  http.StatusOK,
+			expectedContentType: "text/plain",
+			expectedFileName:    path.Base(fileNames[0]),
 		},
 		{
 			addr:                "somebogusensname",
 			path:                fileNames[0],
 			expectedStatusCode:  http.StatusOK,
+			expectedContentType: "text/plain",
+			expectedFileName:    path.Base(fileNames[0]),
 		},
 	} {
 		req, err := http.NewRequest("GET", fmt.Sprintf(srv.URL+"/bzz:/%s/%s", v.addr, v.path), nil)
@@ -1237,6 +1254,16 @@ func TestBzzGetFileWithResolver(t *testing.T) {
 		if serverResponse.StatusCode != v.expectedStatusCode {
 			t.Fatalf("expected %d, got %d", v.expectedStatusCode, serverResponse.StatusCode)
 		}
+
+		if h := serverResponse.Header.Get("Content-Type"); h != v.expectedContentType {
+			t.Fatalf("Content-Type header expected: %s, got %s", v.expectedContentType, h)
+		}
+
+		expectedContentDisposition := fmt.Sprintf("inline; filename=\"%s\"", v.expectedFileName)
+		if h := serverResponse.Header.Get("Content-Disposition"); h != expectedContentDisposition {
+			t.Fatalf("Content-Disposition header expected: %s, got: %s", expectedContentDisposition, h)
+		}
+
 	}
 }