FTP和HTTP有什么区别？

Question

HTTP is used to display the info and also can be used to transfer files from one host to another host.

FTP is used to transfer files from one host to another.

So I come to this point that FTP and HTTP both are almost doing the same work. Then what is the exact benefit of using FTP while I can do this with the HTTP?

Correct me if I am wrong.

Thanks

Answer 1

FTP is a File Transfer Protocol, for transferring files.

FTP is significantly older, it is a protocol designed to enable the transfer of files over a long-running session. There are a wide array of commands and the intent is to allow you to navigate and browse a remote file system and retrieve files (originally over a separate data connection).

FTP still sees a lot of use, but many files are actually transferred over HTTP instead.

HTTP The HyperText Transfer Protocol was originally designed to transfer hypertext documents and the various assets needed to render them. In practice, this is the way information is transferred on the web -- html, css, images, data are all transferred between web servers and web browsers, as well as between one server and another this way.

HTTP was designed to retrieve a resource from a URL that may or may not match the remote file system (in many web apps, the structure of the URLs has very little to do with the file locations). There is often only a single request in a single http connection and the data uses the same connection as the request.

Answer 2

So I come to this point that FTP and HTTP both are almost doing the same work.

Not really. FTP can be used for file transfer and not really much more. HTTP is way more flexible since it not only transfers byte streams but also meta data (what kind of data is this), supports implicit compression, client specific responses (like based on supported languages), has more flexible ways for authentication, is tuned for less overhead (ie can be faster) ...

Then what is the exact benefit of using FTP while I can do this with the HTTP?

There is no real benefit of FTP today. In contrary, in contrast to alternatives like HTTP the design of FTP leads to lots of problems in today's infrastructure where NAT is heavily used (ie multiple internal systems behind a single router with public IP address).

FTP remains mostly in places where clients or servers don't support more modern ways for file exchange. A typical example is cheap web hosting where access to the server to update files is often done by FTP since lots of tools have FTP builtin and it is easy to setup on the server too. Alternatives like WebDAV (HTTP based) or SFTP (SSH based) are less used here since they have less support in clients and servers even though they would offer more security and more flexibility and less problems.