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Christian Nennemann 4694a3098b docs: comprehensive update for sprints 1-9

Update README, ROADMAP, and mdBook to reflect all sprint deliverables:
rich messaging, file transfer, disappearing messages, Go/TypeScript SDKs,
C FFI, mesh networking (identity, store-and-forward, broadcast), and
security hardening. Add 6 new mdBook guides (REPL reference, Go SDK,
TypeScript SDK + browser demo, rich messaging, file transfer, mesh
networking). Check off 16 completed ROADMAP items across phases 3-9.

2026-03-04 02:10:20 +01:00

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File Transfer

quicproquo supports encrypted file transfer with chunked upload/download, SHA-256 content addressing, and automatic MIME type detection. Files up to 50 MB are supported.

Sending a file

/send-file /path/to/document.pdf

Or use the short alias:

/sf /path/to/document.pdf

This will:

Read the file and compute its SHA-256 hash
Upload the file in 256 KB chunks via the uploadBlob RPC
Verify the hash on the server side
Send a FileRef message to the active conversation containing the blob ID (SHA-256 hash), filename, file size, and MIME type

A progress bar is displayed during upload.

Downloading a file

/download 7

Or:

/dl 7

Where 7 is the history index of the FileRef message. This will:

Fetch the blob in chunks via the downloadBlob RPC
Verify the SHA-256 hash matches the FileRef's blob ID
Save the file to the current directory using the original filename

If a file with the same name already exists, a suffix is appended (-1, -2, etc.) to avoid overwriting.

How it works

Content-addressable storage

Files are stored on the server by their SHA-256 hash (blob_id). This means identical files are automatically deduplicated — uploading the same file twice reuses the existing blob.

Chunked transfer

Files are split into 256 KB chunks for upload and download. This:

Keeps memory usage bounded for large files
Allows progress reporting
Enables future resumable transfers

FileRef message type

The FileRef (type code 0x08) is sent as a regular MLS-encrypted message:

[blob_id: 32 bytes (SHA-256)]
[filename_len: 2 bytes BE][filename: UTF-8]
[file_size: 8 bytes BE]
[mime_len: 2 bytes BE][mime_type: UTF-8]

The server stores a JSON .meta sidecar alongside each blob with metadata.

MIME type detection

MIME types are detected automatically using the mime_guess crate based on file extension. For example:

report.pdf → application/pdf
photo.jpg → image/jpeg
data.csv → text/csv

Limits

Maximum file size: 50 MB
Chunk size: 256 KB
Hash algorithm: SHA-256

RPC methods

Method	Ordinal	Description
`uploadBlob`	`@21`	Chunked file upload with SHA-256 content addressing
`downloadBlob`	`@22`	Chunked file download with hash verification

Error codes

Code	Meaning
E024	Blob upload failed
E025	Blob download failed
E026	Blob hash mismatch
E027	Blob operation error

Implementation

Server: crates/quicproquo-server/src/node_service/blob_ops.rs
Client REPL: /send-file and /download in crates/quicproquo-client/src/client/repl.rs
Message type: FileRef variant in crates/quicproquo-core/src/app_message.rs

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