如何将`Shell Text`转换为`Shell Line`？及Turtle脚本ssh-add调用问题咨询

Alright, let's break down your two questions with practical, Turtle-specific solutions—no jargon overload, just straight-to-the-point fixes.

First off, let's clarify the difference: in Turtle, Shell Text is a stream of raw text chunks (think unbroken blobs of text), while Shell Line is a stream of text split neatly by newlines. To convert between them, Turtle gives you a ready-made function that does all the line-splitting heavy lifting: textLines.

Here's how to use it in practice:

import Turtle

-- Example: A Shell Text stream from a file
rawTextStream :: Shell Text
rawTextStream = input "my-keyring-output.txt"

-- Convert it to a Shell Line stream (split by newlines)
lineStream :: Shell Line
lineStream = textLines rawTextStream

If you ever need to go the other way (turn Shell Line back into Shell Text), just map lineToText over the stream to unwrap the Line wrapper:

backToRawText :: Shell Text
backToRawText = fmap lineToText lineStream

Let's start by fixing the core logic of your function. I'll walk through common pitfalls people hit with this use case, then share a working example you can adapt to your keyring's format.

First, here's a revised version of the function with explanations for each step:

import Turtle
import qualified Data.Text as T

-- Type alias to make the function signature cleaner
type SshKeyParams = (FilePath, Text)

addSshKeyFromKeyring :: SshKeyParams -> Shell Line -> IO ()
addSshKeyFromKeyring (keyFilePath, searchString) keyRingLines = do
  -- Step 1: Filter lines in the keyring that contain our target search string
  let matchingEntries = filter (T.isInfixOf searchString . lineToText) keyRingLines
  
  -- Step 2: Extract the password from the matching line (ADJUST THIS TO YOUR KEYRING FORMAT!)
  -- Example: If keyring lines look like "ssh-key-name:my-password", split on ":"
  let passwords = fmap extractPassword matchingEntries
  
  -- Step 3: Call ssh-add, passing the password via stdin (ssh-add reads passwords from standard input)
  sh $ passwords >>= \pwd -> proc "ssh-add" [keyFilePath] (pure $ pwd <> "\n")
  where
    extractPassword :: Line -> Text
    extractPassword line = case T.splitOn ":" (lineToText line) of
      [_, password] -> T.strip password  -- Strip extra whitespace just in case
      _ -> error $ "Invalid keyring entry format: " ++ T.unpack (lineToText line)

Common Mistakes We're Fixing: #

• Forgetting to unwrap Line: Line is a wrapper type in Turtle, so you can't run text operations on it directly. We use lineToText to convert it to a Data.Text value before searching or parsing.
• Incorrect password parsing: Your keyring's entry format will vary—maybe it uses a different delimiter, or stores the password in a specific position. The extractPassword function above is an example; tweak it to match how your keyring saves SSH key passwords.
• Not passing the password correctly to ssh-add: ssh-add expects the password to come from standard input (command-line arguments are insecure!). Using proc with the third argument lets us pipe the password directly into ssh-add's stdin.
• Handling multiple matches: If your search string might pull up multiple entries, the function above will try to add the key with each password. If you only expect one match, use Turtle's single function to enforce that (it'll throw a clear error if there's zero or multiple matches):

-- Version for single expected match
addSshKeySingleMatch :: SshKeyParams -> Shell Line -> IO ()
addSshKeySingleMatch (keyFilePath, searchString) keyRingLines = do
  matchingEntry <- single $ filter (T.isInfixOf searchString . lineToText) keyRingLines
  let password = extractPassword matchingEntry
  sh $ proc "ssh-add" [keyFilePath] (pure $ password <> "\n")

Quick Testing Tips: #

• Before running ssh-add, test the filtering step by printing matching lines: sh $ matchingEntries >>= echo
• Verify the password extraction works by printing the parsed password: sh $ passwords >>= echo
• If ssh-add complains about the password, check for extra whitespace—adding T.strip to the password extraction helps catch that.

内容的提问来源于stack exchange，提问作者user4301448