# Messages & Attachments | EchoHub Documentation

# Messages & Attachments

An EchoHub message is text content plus up to 10 attachments, Discord-style. A plain chat line is just a message with no attachments; a photo dump is one message with several files and an optional caption. This page explains how to attach files, what happens to them on the way to the server, and how other clients receive them.

## Message basics

Limit | Value
--- | ---
Max message length | 2,000 characters
Max newlines per message | 30 (no blank-line runs)
Max attachments per message | 10
Link embeds per message | first 3 URLs

Multiline messages are written with `Ctrl+N` for a newline; `Enter` sends. URLs in a message get link embeds (title, description, theme color) fetched by the server.

## Attaching files

All of these end up in the same place — the staging tray — and are sent together as one message the next time you press `Enter`, with whatever you've typed as the caption:

- Paste a copied file — copy one or several files in your file manager and press `Ctrl+V` in the input. All of them are staged at once.
- Paste an image from the clipboard — copy an image in a browser (right-click → Copy image), take a screenshot (`Win+Shift+S`), or copy from an image editor, then `Ctrl+V`. The image is attached directly as a PNG named `image.png` — no saving to disk first. On Linux this uses `wl-paste` or `xclip`; on macOS it requires `pngpaste` (`brew install pngpaste`).
- Drag & drop — drop a file onto the terminal window; the client recognizes the dropped path and stages the file.
- `/send <filepath>` — stage a file by path (quote paths containing spaces).

The input frame's title shows what's currently staged. `/clear` drops all staged attachments without sending. Sending with an empty input is fine — the message is just the attachments.

    ┌ Message (2 attached: report.pdf, image.png) ──────────────┐
    │ here's the summary and a screenshot_                      │
    └────────────────────────────────────────────────────────────┘

URL sends are different: `/send <https://…>` sends an image URL immediately as its own message — nothing is staged, and it isn't available in end-to-end encrypted rooms (the server would have to fetch the image, which would defeat the encryption).

## Attachment kinds

The kind is detected per attachment, not per message:

Kind | Detected by | Renders as | Default size limit
--- | --- | --- | ---
Image | Magic bytes: JPEG, PNG, GIF, WebP | ASCII-art preview in chat | 10 MB
Audio | Extension: `.mp3` `.wav` `.ogg` `.flac` `.aac` `.m4a` `.wma` | Playable row (▶) | 10 MB
File | Everything else | Downloadable row | 100 MB

Limits are per file and server-configurable — see the `Uploads` section in the configuration guide (`MaxImageSizeMB`, `MaxAudioSizeMB`, `MaxFileSizeMB`, `MaxAttachmentsPerMessage`).

## Image previews (ASCII art)

Images are rendered in chat as half-block ASCII art. You pick the rendering size:

Flag | Size | Feel
--- | --- | ---
`-s` / `/size s` | 40 × 40 | compact
`-m` / `/size m` | 80 × 80 | default
`-l` / `/size l` | 120 × 120 | detailed

`/size` with no argument opens a picker; the choice persists as your default. A one-off `-s|-m|-l` flag on `/send` applies to that message.

## Receiving attachments

Right-click a message (or press `F6` to select one with the arrow keys) for actions:

- Images → save to disk
- Audio → play (in-client playback)
- Files → download

Downloads go to your configured download folder — set it with `/downloadpath` (no argument opens a native folder picker, or pass a path directly).

## Attachments in encrypted rooms

In an end-to-end encrypted room every attachment is encrypted client-side before upload:

    flowchart LR
        F[File bytes] -->|AES-256-GCM with room key| B[Ciphertext blob]
        F -->|if image: render ASCII locally| A[ASCII preview]
        A -->|room-encrypt| AP["$RC1$… preview"]
        B --> S[Server stores blob + name + size]
        AP --> S

The server never sees the file contents or the rendered preview — it stores an opaque blob and broadcasts it to members, who decrypt locally. File names and sizes remain visible to the server so the file list stays usable; don't put secrets in a file name. Pasted clipboard images go through exactly the same pipeline.

## Deleting messages with attachments

Deleting a message also removes its uploaded attachment files from the server. You can always delete your own messages; moderators can delete others' — see Moderation & Roles.