gem-hunter
Language: Rust
Interact with unix processes/bash the same way as pexpect or Don libes expect does
Spawn, control, and respond to expected patterns of child applications and processes, enabling the automation of interactions and testing. Components include:
The goal is to offer a similar set of functionality as pexpect.
For more examples, check the examples directory.
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)); }
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)); }
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 againuse 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)); }
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