From ac66eee045e5670f3578717a90d6c0069977c06e Mon Sep 17 00:00:00 2001
From: Chris Lu <chris.lu@gmail.com>
Date: Mon, 18 Nov 2013 23:41:00 -0800
Subject: [PATCH] added download command to download file by fileid

---
 go/weed/download.go | 120 ++++++++++++++++++++++++++++++++++++++++++++
 go/weed/weed.go     |   3 +-
 2 files changed, 122 insertions(+), 1 deletion(-)
 create mode 100644 go/weed/download.go

diff --git a/go/weed/download.go b/go/weed/download.go
new file mode 100644
index 000000000..4f332bd2e
--- /dev/null
+++ b/go/weed/download.go
@@ -0,0 +1,120 @@
+package main
+
+import (
+	"code.google.com/p/weed-fs/go/glog"
+	"code.google.com/p/weed-fs/go/operation"
+	"fmt"
+	"io"
+	"io/ioutil"
+	"net/http"
+	"os"
+	"path"
+	"strings"
+)
+
+var (
+	downloadReplication *string
+	downloadDir         *string
+)
+
+func init() {
+	cmdDownload.Run = runDownload // break init cycle
+	cmdDownload.IsDebug = cmdDownload.Flag.Bool("debug", false, "verbose debug information")
+	server = cmdDownload.Flag.String("server", "localhost:9333", "weedfs master location")
+	downloadDir = cmdDownload.Flag.String("dir", ".", "Download the whole folder recursively if specified.")
+}
+
+var cmdDownload = &Command{
+	UsageLine: "download -server=localhost:9333 -dir=one_directory fid1 [fid2 fid3 ...]",
+	Short:     "download files by file id",
+	Long: `download files by file id.
+  
+  Usually you just need to use curl to lookup the file's volume server, and then download them directly.
+  This download tool combine the two steps into one.
+
+  What's more, if you use "weed upload -maxMB=..." option to upload a big file divided into chunks, you can
+  use this tool to download the chunks and merge them automatically.
+
+  `,
+}
+
+func runDownload(cmd *Command, args []string) bool {
+	for _, fid := range args {
+		filename, content, e := fetchFileId(*server, fid)
+		if e != nil {
+			fmt.Println("Fetch Error:", e)
+			continue
+		}
+		if filename == "" {
+			filename = fid
+		}
+		if strings.HasSuffix(filename, "-list") {
+		  filename = filename[0:len(filename)-len("-list")]
+			fids := strings.Split(string(content), "\n")
+			f, err := os.OpenFile(path.Join(*downloadDir, filename), os.O_WRONLY|os.O_CREATE|os.O_TRUNC, os.ModePerm)
+			if err != nil {
+				fmt.Println("File Creation Error:", e)
+				continue
+			}
+			defer f.Close()
+			for _, partId := range fids {
+				var n int
+				_, part, err := fetchFileId(*server, partId)
+				if err == nil {
+					n, err = f.Write(part)
+				}
+				if err == nil && n < len(part) {
+					err = io.ErrShortWrite
+				}
+				if err != nil {
+					fmt.Println("File Write Error:", err)
+					break
+				}
+			}
+		} else {
+			ioutil.WriteFile(path.Join(*downloadDir, filename), content, os.ModePerm)
+		}
+	}
+	return true
+}
+
+func fetchFileId(server string, fildId string) (filename string, content []byte, e error) {
+	fileUrl, lookupError := operation.LookupFileId(server, fildId)
+	if lookupError != nil {
+		return "", nil, lookupError
+	}
+	filename, content, e = fetchUrl(fileUrl)
+	return
+}
+
+func fetchUrl(fileUrl string) (filename string, content []byte, e error) {
+	response, err := http.Get(fileUrl)
+	if err != nil {
+		return "", nil, err
+	}
+	defer response.Body.Close()
+	contentDisposition := response.Header["Content-Disposition"]
+	if len(contentDisposition) > 0 {
+		glog.V(4).Info("Content-Disposition: ", contentDisposition[0])
+		if strings.HasPrefix(contentDisposition[0], "filename=") {
+			filename = contentDisposition[0][len("filename="):]
+		}
+	} else {
+		glog.V(4).Info("No Content-Disposition!")
+	}
+	content, e = ioutil.ReadAll(response.Body)
+	return
+}
+
+func WriteFile(filename string, data []byte, perm os.FileMode) error {
+	f, err := os.OpenFile(filename, os.O_WRONLY|os.O_CREATE|os.O_TRUNC, perm)
+	if err != nil {
+		return err
+	}
+	n, err := f.Write(data)
+	f.Close()
+	if err == nil && n < len(data) {
+		err = io.ErrShortWrite
+	}
+	return err
+}
diff --git a/go/weed/weed.go b/go/weed/weed.go
index 0b1512636..3d4beac88 100644
--- a/go/weed/weed.go
+++ b/go/weed/weed.go
@@ -22,10 +22,11 @@ var IsDebug *bool
 var server *string
 
 var commands = []*Command{
-  cmdCompact,
+	cmdCompact,
 	cmdFix,
 	cmdMaster,
 	cmdUpload,
+	cmdDownload,
 	cmdShell,
 	cmdVersion,
 	cmdVolume,