ftp: remove libcurl dependency

This splits out sftp into a separate binary that *does* depend on
libcurl. However, ftp now uses the same socket code as gopher.

ftps is dropped, because I've never even tested it. Maybe I'll add
it back when we have working OpenSSL bindings.

This is still "doing the easy part first", now I have no clue how to
handle sftp because my initial plan ("just use the sftp binary") doesn't
work - sftp batch mode doesn't accept passwords. libssh2 remains the
sole candidate, but that's what libcurl wraps anyway.

1 files changed, 15 insertions, 11 deletions

diff --git a/doc/protocols.md b/doc/protocols.md
index 0d670797..7d23d22c 100644
--- a/doc/protocols.md
+++ b/doc/protocols.md
@@ -14,6 +14,7 @@ this document.
 
 * [HTTP](#http)
 * [FTP](#ftp)
+* [SFTP](#sftp)
 * [Gopher](#gopher)
 * [Gemini](#gemini)
 * [Finger](#finger)
@@ -34,7 +35,7 @@ to use passed userinfo data (`https://username:password@example.org`), and
 returns all headers and response body it receives from libcurl without
 exception.
 
-It is possible to build these adapters using
+It is possible to build the HTTP adapter using
 [curl-impersonate](https://github.com/lwthiker/curl-impersonate) by setting
 the compile-time variable CURLLIBNAME to `libcurl-impersonate.so`. Note that
 for curl-impersonate to work, you must set `network.default-headers = {}`
@@ -49,17 +50,20 @@ not work.
 
 ## FTP
 
-Chawan supports FTP through the `adapter/protocol/ftp.nim` libcurl adapter. For
-directory listings, it assumes UNIX output style, and will probably break
-horribly on receiving anything else. Otherwise, the directory listing view
-is identical to the file:// directory listing.
+Chawan supports FTP through the `adapter/protocol/ftp.nim` adapter. Only
+passive mode is supported.
 
-SFTP "works" too, but YMMV. Note that if an IdentityFile declaration is found in
-your ssh config, then it will prompt for the identity file password, but there
-is no way to tell whether it is really asking for that. Also, settings covered
-by the Match field are ignored.
+For directory listings, it assumes UNIX output style, and will probably
+break horribly on receiving anything else. Otherwise, the directory
+listing view is identical to the file:// directory listing.
 
-In theory, FTPS should work too, but it is completely untested.
+## SFTP
+
+The sftp adapter wraps libcurl. It works for me, but YMMV. Note that if
+an IdentityFile declaration is found in your ssh config, then it will
+prompt for the identity file password, but there is no way to tell
+whether it is really asking for that. Also, settings covered by the
+Match field are ignored.
 
 ## Gopher
 
@@ -78,7 +82,7 @@ case may end up with `application/octet-stream`.
 Chawan's gemini adapter (in `adapter/protocol/gmifetch.c`) is a C program. It
 requires OpenSSL to work.
 
-Currently, it still has some limitations:
+It still has some limitations:
 
 * It does not support proxies yet.
 * It does not support sites that require private key authentication.