7 releases (breaking)
new 0.6.0 | Nov 6, 2024 |
---|---|
0.5.0 | Oct 20, 2022 |
0.4.0 | May 25, 2020 |
0.3.0 | Feb 25, 2018 |
0.1.0 | Jul 27, 2017 |
#34 in Unix APIs
20,530 downloads per month
Used in 42 crates
(39 directly)
62KB
863 lines
rexpect
Spawn, control, and respond to expected patterns of child applications and processes, enabling the automation of interactions and testing. Components include:
- session: start a new process and interact with it; primary module of rexpect.
- reader: non-blocking reader, which supports waiting for strings, regex, and EOF.
- process: spawn a process in a pty.
The goal is to offer a similar set of functionality as pexpect.
Examples
For more examples, check the examples directory.
Basic usage
Simple example for interacting via ftp:
use rexpect::spawn;
use rexpect::error::*;
fn do_ftp() -> Result<(), Error> {
let mut p = spawn("ftp speedtest.tele2.net", Some(30_000))?;
p.exp_regex("Name \\(.*\\):")?;
p.send_line("anonymous")?;
p.exp_string("Password")?;
p.send_line("test")?;
p.exp_string("ftp>")?;
p.send_line("cd upload")?;
p.exp_string("successfully changed.\r\nftp>")?;
p.send_line("pwd")?;
p.exp_regex("[0-9]+ \"/upload\"")?;
p.send_line("exit")?;
p.exp_eof()?;
Ok(())
}
fn main() {
do_ftp().unwrap_or_else(|e| panic!("ftp job failed with {}", e));
}
Example with bash and reading from programs
use rexpect::spawn_bash;
use rexpect::error::*;
fn do_bash() -> Result<(), Error> {
let mut p = spawn_bash(Some(2000))?;
// case 1: wait until program is done
p.send_line("hostname")?;
let hostname = p.read_line()?;
p.wait_for_prompt()?; // go sure `hostname` is really done
println!("Current hostname: {}", hostname);
// case 2: wait until done, only extract a few infos
p.send_line("wc /etc/passwd")?;
// `exp_regex` returns both string-before-match and match itself, discard first
let (_, lines) = p.exp_regex("[0-9]+")?;
let (_, words) = p.exp_regex("[0-9]+")?;
let (_, bytes) = p.exp_regex("[0-9]+")?;
p.wait_for_prompt()?; // go sure `wc` is really done
println!("/etc/passwd has {} lines, {} words, {} chars", lines, words, bytes);
// case 3: read while program is still executing
p.execute("ping 8.8.8.8", "bytes of data")?; // returns when it sees "bytes of data" in output
for _ in 0..5 {
// times out if one ping takes longer than 2s
let (_, duration) = p.exp_regex("[0-9. ]+ ms")?;
println!("Roundtrip time: {}", duration);
}
p.send_control('c')?;
Ok(())
}
fn main() {
do_bash().unwrap_or_else(|e| panic!("bash job failed with {}", e));
}
Example with bash and job control
One frequent bitfall with sending ctrl-c and friends is that you need to somehow ensure that the program has fully loaded, otherwise the ctrl-* goes into nirvana. There are two functions to ensure that:
execute
where you need to provide a match string which is present on stdout/stderr when the program is readywait_for_prompt
which waits until the prompt is shown again
use rexpect::spawn_bash;
use rexpect::error::*;
fn do_bash_jobcontrol() -> Result<(), Error> {
let mut p = spawn_bash(Some(1000))?;
p.execute("ping 8.8.8.8", "bytes of data")?;
p.send_control('z')?;
p.wait_for_prompt()?;
// bash writes 'ping 8.8.8.8' to stdout again to state which job was put into background
p.execute("bg", "ping 8.8.8.8")?;
p.wait_for_prompt()?;
p.send_line("sleep 0.5")?;
p.wait_for_prompt()?;
// bash writes 'ping 8.8.8.8' to stdout again to state which job was put into foreground
p.execute("fg", "ping 8.8.8.8")?;
p.send_control('c')?;
p.exp_string("packet loss")?;
Ok(())
}
fn main() {
do_bash_jobcontrol().unwrap_or_else(|e| panic!("bash with job control failed with {}", e));
}
License
Licensed under either of
- Apache License, Version 2.0, (LICENSE-APACHE or http://www.apache.org/licenses/LICENSE-2.0)
- MIT license (LICENSE-MIT or http://opensource.org/licenses/MIT)
at your option.
Contribution
Unless you explicitly state otherwise, any contribution intentionally submitted for inclusion in the work by you, as defined in the Apache-2.0 license, shall be dual licensed as above, without any additional terms or conditions.
Dependencies
~6–15MB
~218K SLoC