Delta-upload protocol: negotiate chunks by hash, upload only what changed

Phase 1 of the delta-sync plan, server side. The CDC store already shares
unchanged chunks between file versions after the bytes arrive; these three
stateless endpoints move that detection to the client, so editing a few
bytes of a large file uploads ~1 MiB instead of the whole file:

- POST /api/files/delta/negotiate — given the file's chunk hashes, answer
  which ones the caller must upload. User-scoped and purely advisory.
- PUT  /api/files/delta/chunks — missing chunks as [u32 BE len][bytes]
  frames (streaming parse, ≤1 MiB per frame, chunk_max_bytes per request).
  Every hash is recomputed server-side; chunks land as ref_count=0 orphans
  that a commit pins or the periodic GC sweeps — no session table.
- POST /api/files/delta/commit — pin one reference per distinct chunk with
  a single UPDATE…RETURNING restricted to chunks the caller is entitled
  to (reachable through their own non-trashed files, or unreferenced
  orphans); anything else returns 409 {still_missing} for the client to
  upload and retry. The pinned sequence is then RE-READ and the whole-file
  BLAKE3 recomputed before any manifest exists — a declared file_hash is
  never trusted, because a forged manifest would poison future whole-file
  dedup hits for other users. The manifest accounting is shared with the
  byte path (attach_manifest, extracted from store_from_stream); the file
  row is created (201) or its content swapped by file_id (200). Owners of
  the exact file_hash short-circuit to a pure reference bump.

Supporting pieces: GIN index on chunk_manifests.chunk_hashes (containment
probes were sequential scans), claimable/pin/release/store-loose/verify
primitives on DedupService, update-by-id with Update-permission AuthZ on
FileUploadService, per-caller rate limiter (240/min), audit events with
stable reasons (rate_limited, chunk_verification_failed,
file_hash_mismatch), OpenAPI + docs/delta-upload-protocol.md, framing
parser unit tests and a PG-gated integration suite covering the
entitlement matrix (owned/foreign/orphan/unknown), orphan registration
and the verification read.

Verified end-to-end against PostgreSQL 16 with a node client hashing via
the vendored WASM: a 24 MB file delta-committed in 96 fixed-size chunks;
a 3-byte edit then negotiated missing 1/96 and synced with 278 KB on the
wire vs 24 MB (98.9% saved), downloading byte-identical. A second user
probing the same chunks got nothing (negotiate: all missing; commit: 409
with all 96 still withheld); a forged file_hash returned 400 plus the
audit line; a commit referencing one never-uploaded chunk returned 409
naming exactly that hash; the GIN index serves containment probes
(Bitmap Index Scan) once the planner favors it.

https://claude.ai/code/session_01WdNenpnujNR2sc32XVvwfS
This commit is contained in:
Claude
2026-06-11 14:34:02 +00:00
parent 0fab4ce17d
commit 44967da7f1
11 changed files with 1641 additions and 27 deletions
@@ -0,0 +1,322 @@
//! Delta-upload protocol endpoints — "upload only what changed".
//!
//! Wire surface of [`DeltaUploadService`]; see that module (and
//! `docs/delta-upload-protocol.md`) for the protocol and its security
//! model. These handlers only authenticate, rate-limit and translate
//! the wire formats — every decision lives in the application service.
//!
//! Chunk-frame wire format (`PUT /api/files/delta/chunks`): the body is a
//! sequence of `[u32 big-endian length][length bytes]` frames, one per
//! chunk, with `Content-Type: application/octet-stream`. Frames are capped
//! at the CDC maximum chunk size (1 MiB) and the whole request at the same
//! per-request ceiling as resumable chunk PUTs (`chunk_max_bytes`).
use axum::{
Json,
body::Body,
extract::State,
http::StatusCode,
response::{IntoResponse, Response},
};
use bytes::{Buf, Bytes, BytesMut};
use futures::Stream;
use std::sync::Arc;
use tokio_stream::StreamExt;
use crate::application::services::delta_upload_service::{
DeltaChunksResponse, DeltaCommitOutcome, DeltaCommitRequest, DeltaNegotiateRequest,
DeltaNegotiateResponse,
};
use crate::common::di::AppState;
use crate::common::errors::DomainError;
use crate::infrastructure::services::dedup_service::CDC_MAX_CHUNK;
use crate::interfaces::errors::AppError;
use crate::interfaces::middleware::auth::AuthUser;
use http_body_util::BodyStream;
use serde::Serialize;
use utoipa::ToSchema;
/// 409 body of `POST /api/files/delta/commit` when chunks vanished between
/// negotiate and commit (GC race) or were never claimable: the client
/// uploads exactly these hashes and retries the same commit.
#[derive(Debug, Serialize, ToSchema)]
pub struct DeltaStillMissingResponse {
pub still_missing: Vec<String>,
}
/// Per-caller flood guard shared by the three delta endpoints.
fn check_rate_limit(state: &Arc<AppState>, auth_user: &AuthUser) -> Result<(), AppError> {
if state
.delta_upload_rate_limiter
.check_and_increment(&auth_user.id.to_string())
.is_err()
{
tracing::info!(
target: "audit",
event = "delta_upload.rejected",
reason = "rate_limited",
caller_id = %auth_user.id,
"👮🏻‍♂️ Delta upload rejected: per-caller rate limit exceeded",
);
return Err(AppError::new(
StatusCode::TOO_MANY_REQUESTS,
"Too many delta-upload requests; please retry shortly",
"RateLimited",
));
}
Ok(())
}
/// Parse a `[u32 BE length][bytes]` frame sequence from the request body.
///
/// Streaming: peak RAM is one frame (≤ 1 MiB) plus one HTTP frame,
/// regardless of how many chunks the request carries. `max_total` bounds
/// the whole request body.
fn parse_chunk_frames(
body: Body,
max_total: usize,
) -> impl Stream<Item = Result<Bytes, DomainError>> + Send {
async_stream::try_stream! {
let mut body_stream = BodyStream::new(body);
let mut buf = BytesMut::new();
let mut expecting: Option<usize> = None;
let mut total: usize = 0;
loop {
// Drain every complete frame already buffered.
loop {
match expecting {
None => {
if buf.len() < 4 {
break;
}
let len =
u32::from_be_bytes([buf[0], buf[1], buf[2], buf[3]]) as usize;
buf.advance(4);
if len == 0 || len > CDC_MAX_CHUNK {
Err(DomainError::validation_error(format!(
"Chunk frame of {len} bytes out of bounds (1 ..= {CDC_MAX_CHUNK})"
)))?;
}
expecting = Some(len);
}
Some(len) => {
if buf.len() < len {
break;
}
let frame = buf.split_to(len).freeze();
expecting = None;
yield frame;
}
}
}
match body_stream.next().await {
Some(Ok(http_frame)) => {
if let Some(data) = http_frame.data_ref() {
total += data.len();
if total > max_total {
Err(DomainError::validation_error(format!(
"Request body exceeds the {max_total}-byte per-request cap; \
split the chunk upload into several requests"
)))?;
}
buf.extend_from_slice(data);
}
}
Some(Err(e)) => {
Err(DomainError::validation_error(format!(
"Failed to read request body: {e}"
)))?;
}
None => {
if expecting.is_some() || !buf.is_empty() {
Err(DomainError::validation_error(
"Truncated chunk frame at end of body",
))?;
}
break;
}
}
}
}
}
#[utoipa::path(
post,
path = "/api/files/delta/negotiate",
request_body = DeltaNegotiateRequest,
responses(
(status = 200, description = "Chunks the caller must upload (the rest are claimable without bytes)", body = DeltaNegotiateResponse),
(status = 400, description = "Malformed chunk list (hash format, size bounds, count ceiling)"),
(status = 429, description = "Rate limited"),
),
security(("bearerAuth" = [])),
tag = "delta-upload"
)]
pub async fn delta_negotiate(
State(state): State<Arc<AppState>>,
auth_user: AuthUser,
Json(request): Json<DeltaNegotiateRequest>,
) -> Result<impl IntoResponse, AppError> {
check_rate_limit(&state, &auth_user)?;
let response = state
.applications
.delta_upload_service
.negotiate_with_perms(auth_user.id, &request)
.await
.map_err(AppError::from)?;
Ok(Json(response))
}
#[utoipa::path(
put,
path = "/api/files/delta/chunks",
request_body(content_type = "application/octet-stream",
description = "Sequence of [u32 BE length][bytes] frames, one per chunk (each ≤ 1 MiB)"),
responses(
(status = 200, description = "Server-computed identity of every received frame, in order", body = DeltaChunksResponse),
(status = 400, description = "Malformed framing, oversized frame, or oversized request"),
(status = 429, description = "Rate limited"),
),
security(("bearerAuth" = [])),
tag = "delta-upload"
)]
pub async fn delta_upload_chunks(
State(state): State<Arc<AppState>>,
auth_user: AuthUser,
body: Body,
) -> Result<impl IntoResponse, AppError> {
check_rate_limit(&state, &auth_user)?;
let frames = parse_chunk_frames(body, state.core.config.storage.chunk_max_bytes);
let response = state
.applications
.delta_upload_service
.receive_chunks(frames)
.await
.map_err(AppError::from)?;
Ok(Json(response))
}
#[utoipa::path(
post,
path = "/api/files/delta/commit",
request_body = DeltaCommitRequest,
responses(
(status = 201, description = "File created from the committed chunk sequence", body = crate::application::dtos::file_dto::FileDto),
(status = 200, description = "Existing file's content replaced", body = crate::application::dtos::file_dto::FileDto),
(status = 400, description = "Malformed request, or the declared file_hash does not match the chunk sequence"),
(status = 404, description = "Target folder/file not found or not accessible"),
(status = 409, description = "Chunks not claimable — upload them and retry", body = DeltaStillMissingResponse),
(status = 429, description = "Rate limited"),
(status = 507, description = "Storage quota exceeded"),
),
security(("bearerAuth" = [])),
tag = "delta-upload"
)]
pub async fn delta_commit(
State(state): State<Arc<AppState>>,
auth_user: AuthUser,
Json(request): Json<DeltaCommitRequest>,
) -> Result<Response, AppError> {
check_rate_limit(&state, &auth_user)?;
let outcome = state
.applications
.delta_upload_service
.commit_with_perms(auth_user.id, request)
.await
.map_err(AppError::from)?;
Ok(match outcome {
DeltaCommitOutcome::Done { file, created } => {
let status = if created {
StatusCode::CREATED
} else {
StatusCode::OK
};
(status, Json(file)).into_response()
}
DeltaCommitOutcome::StillMissing(still_missing) => (
StatusCode::CONFLICT,
Json(DeltaStillMissingResponse { still_missing }),
)
.into_response(),
})
}
#[cfg(test)]
mod tests {
use super::*;
/// Encode frames the way a client would.
fn encode(frames: &[&[u8]]) -> Vec<u8> {
let mut out = Vec::new();
for f in frames {
out.extend_from_slice(&(f.len() as u32).to_be_bytes());
out.extend_from_slice(f);
}
out
}
async fn collect(body: Body, max_total: usize) -> Result<Vec<Bytes>, DomainError> {
let stream = parse_chunk_frames(body, max_total);
futures::pin_mut!(stream);
let mut out = Vec::new();
while let Some(item) = stream.next().await {
out.push(item?);
}
Ok(out)
}
#[tokio::test]
async fn roundtrips_frames_in_order() {
let wire = encode(&[b"first", b"second chunk", &[0xAB; 1000]]);
let frames = collect(Body::from(wire), usize::MAX).await.unwrap();
assert_eq!(frames.len(), 3);
assert_eq!(&frames[0][..], b"first");
assert_eq!(&frames[1][..], b"second chunk");
assert_eq!(frames[2].len(), 1000);
}
#[tokio::test]
async fn empty_body_yields_no_frames() {
let frames = collect(Body::empty(), usize::MAX).await.unwrap();
assert!(frames.is_empty());
}
#[tokio::test]
async fn rejects_zero_length_frame() {
let wire = encode(&[b""]);
assert!(collect(Body::from(wire), usize::MAX).await.is_err());
}
#[tokio::test]
async fn rejects_frame_above_cdc_max() {
let mut wire = Vec::new();
wire.extend_from_slice(&((CDC_MAX_CHUNK as u32) + 1).to_be_bytes());
// Header alone is enough — the length is rejected before any data.
assert!(collect(Body::from(wire), usize::MAX).await.is_err());
}
#[tokio::test]
async fn rejects_truncated_frame() {
let mut wire = encode(&[b"complete"]);
wire.extend_from_slice(&10u32.to_be_bytes());
wire.extend_from_slice(b"only5"); // promises 10, delivers 5
assert!(collect(Body::from(wire), usize::MAX).await.is_err());
}
#[tokio::test]
async fn rejects_request_above_total_cap() {
let wire = encode(&[&[0u8; 600], &[1u8; 600]]);
assert!(collect(Body::from(wire), 1000).await.is_err());
}
#[tokio::test]
async fn accepts_frame_exactly_at_cdc_max() {
let big = vec![7u8; CDC_MAX_CHUNK];
let wire = encode(&[&big]);
let frames = collect(Body::from(wire), usize::MAX).await.unwrap();
assert_eq!(frames.len(), 1);
assert_eq!(frames[0].len(), CDC_MAX_CHUNK);
}
}
+1
View File
@@ -7,6 +7,7 @@ pub mod carddav_handler;
pub mod chunked_upload_handler;
pub mod contacts_handler;
pub mod dedup_handler;
pub mod delta_upload_handler;
pub mod device_auth_handler;
pub mod favorites_handler;
pub mod file_handler;
+10
View File
@@ -81,6 +81,9 @@ use crate::interfaces::api::handlers::file_handler::MoveFilePayload;
handlers::file_handler::list_files_query,
handlers::file_handler::upload_file_with_thumbnails,
handlers::file_handler::create_file_by_hash,
handlers::delta_upload_handler::delta_negotiate,
handlers::delta_upload_handler::delta_upload_chunks,
handlers::delta_upload_handler::delta_commit,
handlers::file_handler::download_file,
handlers::file_handler::get_thumbnail,
handlers::file_handler::upload_thumbnail,
@@ -262,6 +265,13 @@ use crate::interfaces::api::handlers::file_handler::MoveFilePayload;
ResourceContentDto,
// File schemas
FileDto,
// Delta-upload schemas
crate::application::services::delta_upload_service::ChunkRef,
crate::application::services::delta_upload_service::DeltaNegotiateRequest,
crate::application::services::delta_upload_service::DeltaNegotiateResponse,
crate::application::services::delta_upload_service::DeltaChunksResponse,
crate::application::services::delta_upload_service::DeltaCommitRequest,
handlers::delta_upload_handler::DeltaStillMissingResponse,
MoveFilePayload,
PaginationDto,
PaginationRequestDto,
+6
View File
@@ -54,6 +54,9 @@ use crate::interfaces::api::handlers::batch_handler::{self, BatchHandlerState};
use crate::interfaces::api::handlers::chunked_upload_handler::{
cancel_upload, complete_upload, create_upload, get_upload_status, upload_chunk,
};
use crate::interfaces::api::handlers::delta_upload_handler::{
delta_commit, delta_negotiate, delta_upload_chunks,
};
use crate::interfaces::api::handlers::file_handler::{
create_file_by_hash, delete_file, download_file, get_file_metadata, get_thumbnail,
list_files_query, move_file_simple, rename_file, upload_file_with_thumbnails, upload_thumbnail,
@@ -230,6 +233,9 @@ pub fn create_api_routes(app_state: &Arc<AppState>) -> Router<Arc<AppState>> {
.route("/", get(list_files_query))
.route("/upload", post(upload_file_with_thumbnails))
.route("/by-hash", post(create_file_by_hash))
.route("/delta/negotiate", post(delta_negotiate))
.route("/delta/chunks", put(delta_upload_chunks))
.route("/delta/commit", post(delta_commit))
.route("/{id}", get(download_file))
.route(
"/{id}/thumbnail/{size}",