feat: add channel name resolution and canvas support

[brianevanmiller]

Summary

This PR adds two major features to slackcli:

1. Channel Name Resolution

• Channels can now be referenced by name (general, #general) instead of requiring IDs
• Works in both conversations read and messages send commands
• Automatically paginates through workspace channels to find matches

2. Canvas Support

New canvases command group for reading Slack canvas documents:

• slackcli canvases list - List all canvases in the workspace
• slackcli canvases read <id> - Read canvas content as markdown
• --channel <name> - Read a channel's associated canvas
• --raw - Output raw HTML instead of parsed markdown
• --include-comments - Include threaded comments from all shares

Note: The Slack API does not provide a public method to read canvas content directly. This implementation uses the files API to download the HTML export and converts it to markdown using node-html-parser.

New Usage Examples

# Channel names now work everywhere
slackcli conversations read general --limit 5
slackcli conversations read "#random" --limit 5
slackcli messages send --recipient-id general --message "Hello"

# Canvas commands
slackcli canvases list
slackcli canvases read F0123456789
slackcli canvases read --channel general
slackcli canvases read F0123456789 --include-comments

Test plan

• Verify channel name resolution works for public and private channels
• Test canvas listing returns expected results
• Test canvas content is correctly converted to markdown
• Test --include-comments fetches threaded replies
• Test --raw outputs HTML directly

🤖 Generated with Claude Code

[shahariaazam]

Required Before Merge

1. Rebase on main - Currently based on v0.1.1, main is now v0.2.0
2. Update CHANGELOG.md - Add v0.3.0 section with these features
3. Update README.md - Document canvas commands and channel name resolution
4. Complete test plan checklist

Key Issues

See inline comments for details on:

• Channel resolution performance (no caching)
• Type safety issues (client: any)
• Missing file size limits
• Input validation needed

Great features overall! Just needs documentation and some refinements.

[shahariaazam]

See inline comments for specific issues to address.

[shahariaazam]

Performance issue: No caching. Every command re-fetches all channels with pagination.

Add caching:

private channelCache = new Map<string, {id: string, expires: number}>();

async resolveChannel(channelOrName: string): Promise<string> {
  const cached = this.channelCache.get(channelOrName);
  if (cached && cached.expires > Date.now()) return cached.id;
  // ... existing logic ...
  this.channelCache.set(channelName, {
    id: match.id,
    expires: Date.now() + 300000
  });
  return match.id;
}

[shahariaazam]

Type safety: Change client: any to proper type.

import type { SlackClient } from '../lib/slack-client.ts';

async function fetchAndDisplayComments(
  client: SlackClient,
  file: SlackFile,
  spinner: ReturnType<typeof ora>
): Promise<void>

[shahariaazam]

Missing size limit: Large files can cause OOM.

const contentLength = response.headers.get('content-length');
const MAX_SIZE = 10 * 1024 * 1024; // 10MB
if (contentLength && parseInt(contentLength) > MAX_SIZE) {
  throw new Error('Canvas too large (max: 10MB)');
}
return response.text();

[shahariaazam]

No input validation:

const limit = parseInt(options.limit);
if (isNaN(limit) || limit <= 0 || limit > 1000) {
  throw new Error('Limit must be 1-1000');
}

[shahariaazam]

Additional review comments on documentation and testing.

[shahariaazam]

Dependency pinning: Using ^7.0.2 allows minor version updates that could introduce breaking changes.

For CLI tools, consider tighter pinning:

"node-html-parser": "~7.0.2"

[shahariaazam]

Nested lists not supported: This only handles direct children with :scope > li.

Consider testing with canvases containing nested lists to see if recursion is needed.

[shahariaazam]

Hard-coded limit: Why 100? Extract to constant:

const MAX_COMMENT_REPLIES = 100;

Also consider what happens if there are >100 comments.

[shahariaazam]

Documentation Required

README.md - Missing documentation for:

• Canvas commands (canvases list, canvases read)
• Channel name resolution feature (now works in conversations read and messages send)
• Examples showing general vs #general vs C1234567890

CHANGELOG.md - Missing v0.3.0 section with:

• Channel name resolution feature
• Canvas support (list, read, comments)
• New dependency: node-html-parser

Note: PR is based on v0.1.1, but main is now v0.2.0. Rebase needed.