| <!-- |
| Copyright (C) Daniel Stenberg, <daniel@haxx.se>, et al. |
| |
| SPDX-License-Identifier: curl |
| --> |
| |
| # Features -- what curl can do |
| |
| ## curl tool |
| |
| - config file support |
| - multiple URLs in a single command line |
| - range "globbing" support: [0-13], {one,two,three} |
| - multiple file upload on a single command line |
| - redirect stderr |
| - parallel transfers |
| |
| ## libcurl |
| |
| - URL RFC 3986 syntax |
| - custom maximum download time |
| - custom lowest download speed acceptable |
| - custom output result after completion |
| - guesses protocol from hostname unless specified |
| - supports .netrc |
| - progress bar with time statistics while downloading |
| - standard proxy environment variables support |
| - have run on 101 operating systems and 28 CPU architectures |
| - selectable network interface for outgoing traffic |
| - IPv6 support on Unix and Windows |
| - happy eyeballs dual-stack IPv4 + IPv6 connects |
| - persistent connections |
| - SOCKS 4 + 5 support, with or without local name resolving |
| - *pre-proxy* support, for *proxy chaining* |
| - supports username and password in proxy environment variables |
| - operations through HTTP proxy "tunnel" (using CONNECT) |
| - replaceable memory functions (malloc, free, realloc, etc) |
| - asynchronous name resolving |
| - both a push and a pull style interface |
| - international domain names (IDN) |
| - transfer rate limiting |
| - stable API and ABI |
| - TCP keep alive |
| - TCP Fast Open |
| - DNS cache (that can be shared between transfers) |
| - non-blocking single-threaded parallel transfers |
| - Unix domain sockets to server or proxy |
| - DNS-over-HTTPS |
| - uses non-blocking name resolves |
| - selectable name resolver backend |
| |
| ## URL API |
| |
| - parses RFC 3986 URLs |
| - generates URLs from individual components |
| - manages "redirects" |
| |
| ## Header API |
| |
| - easy access to HTTP response headers, from all contexts |
| - named headers |
| - iterate over headers |
| |
| ## TLS |
| |
| - selectable TLS backend(s) |
| - TLS False Start |
| - TLS version control |
| - TLS session resumption |
| - key pinning |
| - mutual authentication |
| - Use dedicated CA cert bundle |
| - Use OS-provided CA store |
| - separate TLS options for HTTPS proxy |
| |
| ## HTTP |
| |
| - HTTP/0.9 responses are optionally accepted |
| - HTTP/1.0 |
| - HTTP/1.1 |
| - HTTP/2, including multiplexing and server push |
| - GET |
| - PUT |
| - HEAD |
| - POST |
| - multipart formpost (RFC 1867-style) |
| - authentication: Basic, Digest, NTLM (9) and Negotiate (SPNEGO) |
| to server and proxy |
| - resume transfers |
| - follow redirects |
| - maximum amount of redirects to follow |
| - custom HTTP request |
| - cookie get/send fully parsed |
| - reads/writes the Netscape cookie file format |
| - custom headers (replace/remove internally generated headers) |
| - custom user-agent string |
| - custom referrer string |
| - range |
| - proxy authentication |
| - time conditions |
| - via HTTP proxy, HTTPS proxy or SOCKS proxy |
| - HTTP/2 or HTTP/1.1 to HTTPS proxy |
| - retrieve file modification date |
| - Content-Encoding support for deflate, gzip, brotli and zstd |
| - "Transfer-Encoding: chunked" support in uploads |
| - HSTS |
| - alt-svc |
| - ETags |
| - HTTP/1.1 trailers, both sending and getting |
| |
| ## HTTPS |
| |
| - HTTP/3 |
| - using client certificates |
| - verify server certificate |
| - via HTTP proxy, HTTPS proxy or SOCKS proxy |
| - select desired encryption |
| - select usage of a specific TLS version |
| - ECH |
| |
| ## FTP |
| |
| - download |
| - authentication |
| - Kerberos 5 |
| - active/passive using PORT, EPRT, PASV or EPSV |
| - single file size information (compare to HTTP HEAD) |
| - 'type=' URL support |
| - directory listing |
| - directory listing names-only |
| - upload |
| - upload append |
| - upload via http-proxy as HTTP PUT |
| - download resume |
| - upload resume |
| - custom ftp commands (before and/or after the transfer) |
| - simple "range" support |
| - via HTTP proxy, HTTPS proxy or SOCKS proxy |
| - all operations can be tunneled through proxy |
| - customizable to retrieve file modification date |
| - no directory depth limit |
| |
| ## FTPS |
| |
| - implicit `ftps://` support that use SSL on both connections |
| - explicit "AUTH TLS" and "AUTH SSL" usage to "upgrade" plain `ftp://` |
| connection to use SSL for both or one of the connections |
| |
| ## SSH (both SCP and SFTP) |
| |
| - selectable SSH backend |
| - known hosts support |
| - public key fingerprinting |
| - both password and public key auth |
| |
| ## SFTP |
| |
| - both password and public key auth |
| - with custom commands sent before/after the transfer |
| - directory listing |
| |
| ## TFTP |
| |
| - download |
| - upload |
| |
| ## TELNET |
| |
| - connection negotiation |
| - custom telnet options |
| - stdin/stdout I/O |
| |
| ## LDAP |
| |
| - full LDAP URL support |
| |
| ## DICT |
| |
| - extended DICT URL support |
| |
| ## FILE |
| |
| - URL support |
| - upload |
| - resume |
| |
| ## SMB |
| |
| - SMBv1 over TCP and SSL |
| - download |
| - upload |
| - authentication with NTLMv1 |
| |
| ## SMTP |
| |
| - authentication: Plain, Login, CRAM-MD5, Digest-MD5, NTLM, Kerberos 5 and |
| External |
| - send emails |
| - mail from support |
| - mail size support |
| - mail auth support for trusted server-to-server relaying |
| - multiple recipients |
| - via http-proxy |
| |
| ## SMTPS |
| |
| - implicit `smtps://` support |
| - explicit "STARTTLS" usage to "upgrade" plain `smtp://` connections to use SSL |
| - via http-proxy |
| |
| ## POP3 |
| |
| - authentication: Clear Text, APOP and SASL |
| - SASL based authentication: Plain, Login, CRAM-MD5, Digest-MD5, NTLM, |
| Kerberos 5 and External |
| - list emails |
| - retrieve emails |
| - enhanced command support for: CAPA, DELE, TOP, STAT, UIDL and NOOP via |
| custom requests |
| - via http-proxy |
| |
| ## POP3S |
| |
| - implicit `pop3s://` support |
| - explicit `STLS` usage to "upgrade" plain `pop3://` connections to use SSL |
| - via http-proxy |
| |
| ## IMAP |
| |
| - authentication: Clear Text and SASL |
| - SASL based authentication: Plain, Login, CRAM-MD5, Digest-MD5, NTLM, |
| Kerberos 5 and External |
| - list the folders of a mailbox |
| - select a mailbox with support for verifying the `UIDVALIDITY` |
| - fetch emails with support for specifying the UID and SECTION |
| - upload emails via the append command |
| - enhanced command support for: EXAMINE, CREATE, DELETE, RENAME, STATUS, |
| STORE, COPY and UID via custom requests |
| - via http-proxy |
| |
| ## IMAPS |
| |
| - implicit `imaps://` support |
| - explicit "STARTTLS" usage to "upgrade" plain `imap://` connections to use SSL |
| - via http-proxy |
| |
| ## MQTT |
| |
| - Subscribe to and publish topics using URL scheme `mqtt://broker/topic` |
