65 lines
2.3 KiB
Markdown
65 lines
2.3 KiB
Markdown
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# Gexpect
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Gexpect is a pure golang expect-like module.
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It makes it simpler to create and control other terminal applications.
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child, err := gexpect.Spawn("python")
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if err != nil {
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panic(err)
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}
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child.Expect(">>>")
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child.SendLine("print 'Hello World'")
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child.Interact()
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child.Close()
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## Examples
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`Spawn` handles the argument parsing from a string
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child.Spawn("/bin/sh -c 'echo \"my complicated command\" | tee log | cat > log2'")
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child.ReadLine() // ReadLine() (string, error)
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child.ReadUntil(' ') // ReadUntil(delim byte) ([]byte, error)
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`ReadLine`, `ReadUntil` and `SendLine` send strings from/to `stdout/stdin` respectively
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child, _ := gexpect.Spawn("cat")
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child.SendLine("echoing process_stdin") // SendLine(command string) (error)
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msg, _ := child.ReadLine() // msg = echoing process_stdin
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`Wait` and `Close` allow for graceful and ungraceful termination.
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child.Wait() // Waits until the child terminates naturally.
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child.Close() // Sends a kill command
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`AsyncInteractChannels` spawns two go routines to pipe into and from `stdout`/`stdin`, allowing for some usecases to be a little simpler.
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child, _ := gexpect.Spawn("sh")
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sender, receiver := child.AsyncInteractChannels()
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sender <- "echo Hello World\n" // Send to stdin
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line, open := <- receiver // Recieve a line from stdout/stderr
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// When the subprocess stops (e.g. with child.Close()) , receiver is closed
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if open {
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fmt.Printf("Received %s", line)
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}
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`ExpectRegex` uses golang's internal regex engine to wait until a match from the process with the given regular expression (or an error on process termination with no match).
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child, _ := gexpect.Spawn("echo accb")
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match, _ := child.ExpectRegex("a..b")
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// (match=true)
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`ExpectRegexFind` allows for groups to be extracted from process stdout. The first element is an array of containing the total matched text, followed by each subexpression group match.
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child, _ := gexpect.Spawn("echo 123 456 789")
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result, _ := child.ExpectRegexFind("\d+ (\d+) (\d+)")
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// result = []string{"123 456 789", "456", "789"}
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See `gexpect_test.go` and the `examples` folder for full syntax
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## Credits
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github.com/kballard/go-shellquote
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github.com/kr/pty
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KMP Algorithm: "http://blog.databigbang.com/searching-for-substrings-in-streams-a-slight-modification-of-the-knuth-morris-pratt-algorithm-in-haxe/"
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