CODEWITHSUNDEEP
linuxunixsshsftp
Nabil Sham
Nabil Sham

Reputation: 2345

How to confirm SFTP file delivery?

I am sending a file using SFTP and public key for non-root user, looks like the file is sent, but I cant find it on the target folder, maybe due to permission. 

sftp> ls
sftp> put /tmp/testx
Uploading /tmp/testx to /folder1/target_folder
/tmp/testx                                 100%    5     0.0KB/s   00:01
sftp> get testx
Couldn't stat remote file: No such file or directory
File "/folder1/target_folder/testx" not found.
sftp> ls
sftp>

here is the -vvv :

debug3: SSH_FXP_REALPATH . -> /folder1
debug3: Looking up /tmp/file_to_send
debug3: Sent message sender_host 4 T:17 I:2
debug3: Wrote 80 bytes for a total of 2653
debug3: Received stat reply T:105 I:2
debug3: Sent message SSH2_FXP_OPEN I:3 P:/folder1/target_directory/file_to_send
debug3: Wrote 112 bytes for a total of 2765
debug3: Sent message SSH2_FXP_WRITE I:4 O:0 S:6206
debug3: Wrote 6288 bytes for a total of 9053
debug3: SSH2_FXP_STATUS 0

target directory 

 drw-rw-rw-    1  0   0       target_directory

How can I make sure the file is delivered, without server access ?

Upvotes: 5

Views: 20989

Answers (3)

Martin Prikryl
Martin Prikryl

Reputation: 202222

All you can do is to check that there are no errors, when uploading the file. That's all information the SFTP server gives you.

With command-line OpenSSH sftp client, you can check its exit code (you need to use the -b switch).

echo "put file.txt" | sftp -b - user@host
if [ $? -eq 0 ]
then
    echo "File uploaded"
else
    echo "File NOT uploaded"
fi

See also How to perform checksums during a SFTP file transfer for data integrity?

It's perfectly possible that the SFTP server does not allow you to download a file that you have just uploaded.

There are two common reasons for such behavior:

  • Public "upload" directory. This is to prevent you from downloading other user's files.
  • There's some process that immediately picks uploaded file for some processing.

Upvotes: 10

Larry R. Irwin
Larry R. Irwin

Reputation: 121

I know this is an old thread... Here's the best I've been able to come up with for password auth uploading into a blind folder using the openssh sftp client. (It was a lot more exact with ftp...)

SSHPASS=${PASSWORD} sshpass -e sftp -vvv -oStrictHostKeyChecking=no -oBatchMode=no -b - ${LOGON}@${FTPSITE} >${LOB}ftp.log 2>&1 <<EOF
pwd
cd upload
put ${XMTFILE}
quit
EOF
# sftp does not use FTP codes - it only gives the final status of the requested operation
Status=$?
# Not perfect, but sending a single file using -vvv should produce 2 lines containing "debug3: SSH2_FXP_STATUS 0"
Tmp=`grep "debug3: SSH2_FXP_STATUS 0" ${LOB}ftp.log | wc -l`
[ ${Tmp} -ne 2 ] && Status=1 # Override sftp exit value based on log info

Upvotes: 2

Charles Duffy
Charles Duffy

Reputation: 295363

For a completely arbitrary server implementation, this is not possible. It's often desirable to make incoming directories write-only to untrusted users, to prevent abuse of publicly (or otherwise widely) accessible file servers (such as using them to host unrelated content; once upon a time, FTP servers with stolen credentials were often used by pirates -- preventing uploaded content from being downloaded without administrative review prevents this). Thus: If the server administrator chooses not to let you see uploaded files, then, well, you can't see uploaded files.

However -- the SFTP protocol provides a contract: If you tell the server to close a handle after writing to it, and the server says that all involved operations succeeded without error, then if the file wasn't successfully received (whatever the server then decides to do with it, which may or may not include making it accessible for downloads), this is indicative of a server-side bug and is not the fault of your SFTP client.

When I was last implementing a custom SFTP server -- for customer support purposes, implemented using Paramiko -- I sent email notifications after successful uploads; obviously, though, that's an implementation-specific behavior).

Upvotes: 1

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