Dylan M. Taylor
afcc37cf20
The archive half of FigCraft's Penpot import and export (crates/format/src/penpot.rs and penpot/embedded_fonts.rs at 3b9bf8c9): ZIP validation, the manifest, bounded JSON members with the shared byte and value budgets, pages, page shapes, media objects, font signatures, and the archive writer. Members are handed out as the JSON the file holds; mapping shapes stays in the app. Duplicate member names are now refused: the ZIP reader keeps one member per name, so the per-name check FigCraft has never fires. The directory's own member count is compared instead.
4.6 KiB
craft-penpot
A clean-room reader and writer for the Penpot 2.x export container: the .penpot archive
(penpot/export-files, version 1). Offline: no network, no converter, no unsafe.
This crate is the container layer. It validates the ZIP, checks the manifest, and hands out the
members as the JSON the file holds (serde_json::Value) and media objects as bytes; it writes
members back into an archive. What the shapes, components and tokens mean, and how they map onto
an application's document, stays with the caller.
Provenance
Written by FigCraft's contributors (the offline Penpot import and export, first by Guillermo
Bueno) under FigCraft's clean-room rule: behaviour comes from public documentation and from
observing files, no code of another product is copied, and no GPL or AGPL code is used.
FigCraft's own notes say its tests do not establish compatibility with a live Penpot server;
that holds here too. Moved here from figcraft/crates/format/src/penpot.rs (the archive half)
and penpot/embedded_fonts.rs.
The format
A ZIP of JSON members and blobs:
| Member | Holds |
|---|---|
manifest.json |
type (penpot/export-files), version (1), files: each with its id (a UUID) and name |
files/<file>.json |
the file's header: features, version, migrations, options |
files/<file>/pages/<page>.json |
a page: id, name, index, background, guides, flows |
files/<file>/pages/<page>/<shape>.json |
one shape; the root frame has the nil UUID (ROOT_ID) and lists its children in shapes |
files/<file>/components/<id>.json, colors/, typographies/ |
library entries |
files/<file>/tokens.json |
design tokens |
files/<file>/media/<id>.json |
a media record: mediaId names the stored object, mtype its type |
objects/<id>.json, objects/<id>.<ext> |
a stored object's record and its bytes |
Penpot 1.x binary exports are a different format and are not read.
Reading
let mut archive = craft_penpot::Archive::open(&bytes)?;
for file in archive.files.clone() {
let header = archive.json(&format!("files/{}.json", file.id)).ok();
for page in archive.pages(&file.id)? { // sorted by index
let Some(page_id) = page.get("id").and_then(|v| v.as_str()) else { continue };
let shapes = archive.page_shapes(&file.id, page_id)?; // id -> shape JSON
let root = shapes.get(craft_penpot::ROOT_ID);
}
let colors = archive.uuid_members(&format!("files/{}/colors", file.id), 2048);
let image = archive.media(&file.id, media_id, max_bytes); // Option<Vec<u8>>
}
let fonts = archive.embedded_fonts(); // counted by signature
archive.check()?; // no budget was overrun
Members a caller treats as optional return errors it may drop; check then says whether a
budget ran out along the way, so exhaustion is never swallowed.
Writing
let manifest = craft_penpot::manifest("my-app/1.0", &[(file_id, "Name", features)]);
let bytes = craft_penpot::write_archive([("manifest.json", manifest_bytes), (path, member_bytes)])?;
write_archive refuses paths Archive::open would refuse.
Limits
Input is hostile. Nothing panics; every limit has a test.
| Limit | Value |
|---|---|
The archive (MAX_ARCHIVE) |
512 MiB |
ZIP members (MAX_ENTRIES) |
100 000 |
Bytes unpacked, by declared sizes at open and by bytes actually read after (MAX_DECOMPRESSED) |
1 GiB |
A JSON member (MAX_JSON) |
16 MiB |
JSON values and keys, every member together, counted before parsing (MAX_JSON_VALUES) |
4 000 000 |
Shape JSON for one page (MAX_PAGE_SHAPES_BYTES) |
128 MiB |
Shapes on one page (MAX_PAGE_SHAPES) |
50 000 |
Pages in one file (MAX_PAGES) |
500 |
Files in the manifest (MAX_FILES) |
50 |
A media object (MAX_IMAGE; media also takes the caller's own cap) |
128 MiB |
| JSON nesting | serde_json's 128 levels |
Duplicate member names (told by the directory's own member count, since the ZIP reader keeps one
member per name), absolute paths, . and .. parts, backslashes and control characters
fail the archive. Ids are checked to be UUIDs before they are used in a member path.
ZIP
The archive is read with the zip crate directly, with the bounds above applied to each member.
A shared bounded ZIP reader is planned (craft-libs #126); this crate moves to it when it lands.
Not here yet
A typed model of the shapes (frames, groups, paths, text content, fills and strokes, layout, components and variants, tokens, interactions). FigCraft maps the JSON straight onto its own document today; a model mirroring the file's JSON is the next step.