{
  "parent": {
    "data_source_id": "0a839f17-1b37-4037-a08e-d3a7d2d0dc60"
  },
  "pages": [
    {
      "properties": {
        "Title": "Implementing CLI subcommand with interactive terminal UI (PTY) and git-based username resolution",
        "Category": "Pattern",
        "Tags": "[\"debugging\", \"golang\", \"terminal\"]",
        "Problem Statement": "When creating an `imp claude share-session` CLI command that wraps Python's `prompt_toolkit` (used by `uvx claude-code-transcripts`), the interactive selection UI became malformed when trying to capture output. Standard I/O redirection (`io.MultiWriter`, `bytes.Buffer`, file redirection) caused the terminal control sequences to be duplicated or the UI to not render at all. Additionally, needed to extract GitHub username from git configuration reliably without allowing arbitrary user input.",
        "Outcome": "Solved",
        "date:Date Added:start": "2026-01-09",
        "date:Date Added:is_datetime": 0
      },
      "content": "# Solution\n\n## 1. PTY for Interactive Terminal Apps\n\nWhen wrapping interactive Python tools that use `prompt_toolkit`, use the Unix `script` command to create a proper pseudo-terminal (PTY):\n\n```go\n// Create a temporary file to capture output\ntmpFile, err := os.CreateTemp(\"\", \"uvx-output-*.txt\")\nif err != nil {\n    return \"\", fmt.Errorf(\"failed to create temp file: %w\", err)\n}\ntmpPath := tmpFile.Name()\ntmpFile.Close()\ndefer os.Remove(tmpPath)\n\n// Use script command to create a proper PTY\ncmd := exec.CommandContext(ctx, \"script\", \"-q\", tmpPath, \"uvx\", \"claude-code-transcripts\")\ncmd.Stdin = os.Stdin\ncmd.Stdout = os.Stdout\ncmd.Stderr = os.Stderr\n\n// Run with full terminal access\nerr = cmd.Run()\nif err != nil {\n    return \"\", fmt.Errorf(\"failed to run: %w\", err)\n}\n\n// Read captured output\noutput, err := os.ReadFile(tmpPath)\n```\n\n**Why this works:**\n- `prompt_toolkit` detects terminal capabilities through `isatty()` checks\n- Standard I/O redirection breaks these checks, causing malformed UI\n- `script -q` creates a proper PTY that satisfies terminal detection\n- `-q` flag suppresses \"Script started\" messages\n- Output is still captured to a file for parsing\n\n## 2. Git Email-Based Username Extraction\n\nExtract username from `git config user.email` instead of `git config user.name` to prevent arbitrary user input:\n\n```go\nfunc (o *ShareSessionOptions) getGitHubUsername(ctx context.Context) (string, error) {\n    cmd := exec.CommandContext(ctx, \"git\", \"config\", \"user.email\")\n    output, err := cmd.Output()\n    if err != nil {\n        return \"\", fmt.Errorf(\"failed to get git user email: %w\", err)\n    }\n\n    email := strings.TrimSpace(string(output))\n    \n    // Extract username from email (e.g., \"daniel.roth@imprint.co\" -> \"droth\")\n    parts := strings.Split(email, \"@\")\n    if len(parts) == 0 {\n        return \"\", fmt.Errorf(\"invalid email format: %s\", email)\n    }\n\n    // Split by . and take first letter of first name + last name\n    nameParts := strings.Split(parts[0], \".\")\n    if len(nameParts) >= 2 {\n        username := string(nameParts[0][0]) + nameParts[1]\n        return username, nil\n    }\n\n    // If no dots, use whole part before @\n    return parts[0], nil\n}\n```\n\n**Examples:**\n- `daniel.roth@imprint.co` → `droth`\n- `john.doe.smith@example.com` → `jdoe` (first letter + second part)\n- `admin@example.com` → `admin`\n\n## 3. Config Caching for Expensive Checks\n\nCache expensive prerequisite checks (like `exec.LookPath`) in TOML config:\n\n```go\n// In config struct\ntype Config struct {\n    DisableVersionCheck bool  `toml:\"disable_version_check\"`\n    UVXAvailable        *bool `toml:\"uvx_available,omitempty\"`  // Optional field\n}\n\n// In check function\nfunc (o *ShareSessionOptions) checkUVXAvailable() error {\n    cfg, err := config.Load()\n    if err == nil && cfg.UVXAvailable != nil {\n        if *cfg.UVXAvailable {\n            return nil  // Use cached result\n        }\n    }\n\n    // Perform actual check\n    uvxAvailable := false\n    if _, err := exec.LookPath(\"uvx\"); err == nil {\n        uvxAvailable = true\n    }\n\n    // Cache the result\n    if cfg != nil {\n        cfg.UVXAvailable = &uvxAvailable\n        _ = cfg.Save()\n    }\n\n    return nil\n}\n```\n\n**Key points:**\n- Use pointer types (`*bool`) for optional TOML fields\n- `omitempty` tag prevents writing `false` when nil\n- Still check if cached as unavailable (user may have installed it)\n\n## Related Files\n\n- [share_session.go](https://github.com/Imprint-Tech/imprintctl/blob/main/pkg/cmd/claude/share_session.go) - Full implementation\n- [config.go](https://github.com/Imprint-Tech/imprintctl/blob/main/pkg/config/config.go) - Config caching\n\n## When to Use\n\n- Wrapping any Python tool using `prompt_toolkit` (e.g., `questionary`, `python-prompt-toolkit`)\n- Wrapping interactive TUI tools that use ANSI escape sequences\n- Need to capture output while preserving interactive UI\n- Extracting usernames from standardized email formats"
    }
  ]
}

{
  "parent": {
    "data_source_id": "0a839f17-1b37-4037-a08e-d3a7d2d0dc60"
  },
  "pages": [
    {
      "properties": {
        "Title": "CLI subcommand with interactive terminal UI (PTY) and git-based username",
        "Category": "Pattern",
        "Tags": "[\"debugging\", \"golang\", \"terminal\"]",
        "Problem Statement": "Interactive Python tool (prompt_toolkit) UI became malformed when wrapping in Go CLI. Standard I/O redirection broke terminal control sequences.",
        "Outcome": "Solved",
        "date:Date Added:start": "2026-01-09",
        "date:Date Added:is_datetime": 0
      },
      "content": "# PTY Solution for Interactive Terminal Apps\n\nUse Unix `script` command to create proper PTY:\n\n```go\ncmd := exec.CommandContext(ctx, \"script\", \"-q\", tmpPath, \"uvx\", \"claude-code-transcripts\")\ncmd.Stdin = os.Stdin\ncmd.Stdout = os.Stdout\ncmd.Stderr = os.Stderr\n```\n\n# Git Email Username Extraction\n\n```go\nemail := getGitEmail() // \"daniel.roth@company.com\"\nparts := strings.Split(email, \"@\")\nnameParts := strings.Split(parts[0], \".\")\nusername := string(nameParts[0][0]) + nameParts[1] // \"droth\"\n```\n\n# Config Caching\n\nUse pointer types for optional TOML fields:\n\n```go\ntype Config struct {\n    UVXAvailable *bool `toml:\"uvx_available,omitempty\"`\n}\n```"
    }
  ]
}