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A lexicon-driven AppView for ATProto.
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Rust
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use crate::db::{DatabaseBackend, adapt_sql, now_rfc3339};use crate::error::AppError;use crate::plugin::encryption::{decrypt, encrypt};use crate::spaces::credential::{ DEFAULT_CREDENTIAL_TTL_SECS, SpaceCredentialClaims, make_jti, sign_credential,};use crate::spaces::types::{AppAccess, MintPolicy, Space};
pub struct IssuedCredential { pub token: String, pub expires_at: String,}
#[allow(clippy::too_many_arguments)]pub async fn issue_credential( pool: &sqlx::AnyPool, backend: DatabaseBackend, http: &reqwest::Client, encryption_key: &[u8; 32], space: &Space, subject_did: &str, client_id: Option<&str>, authority_did: &str,) -> Result<IssuedCredential, AppError> { check_app_access(space, client_id)?; check_mint_policy(http, space, subject_did, client_id, authority_did).await?;
let private_jwk = get_or_create_signing_key(pool, backend, encryption_key, space).await?;
let now = std::time::SystemTime::now() .duration_since(std::time::UNIX_EPOCH) .unwrap() .as_secs(); let exp = now + DEFAULT_CREDENTIAL_TTL_SECS;
let claims = SpaceCredentialClaims { iss: space.authority_did.clone(), sub: format!( "at://{}/space/{}/{}", space.did, space.type_nsid, space.skey ), iat: now, exp, jti: make_jti(), };
let token = sign_credential(&claims, &private_jwk)?;
let token_hash = hex::encode(Sha256::digest(token.as_bytes())); store_credential_record(pool, backend, &space.id, subject_did, &token_hash, exp).await?;
let expires_at = chrono::DateTime::from_timestamp(exp as i64, 0) .map(|dt| dt.to_rfc3339()) .unwrap_or_default();
Ok(IssuedCredential { token, expires_at })}
async fn check_mint_policy( http: &reqwest::Client, space: &Space, subject_did: &str, client_id: Option<&str>, authority_did: &str,) -> Result<(), AppError> { match space.mint_policy { MintPolicy::Public => Ok(()), MintPolicy::MemberList => { // Caller must already be a member; verified upstream by the credential issuance route. // We trust that the delegation token proves membership was checked. Ok(()) } MintPolicy::ManagingApp => { let managing_app = space.managing_app_did.as_deref().ok_or_else(|| { AppError::Internal( "space mint_policy is managing-app but managing_app_did is not set".into(), ) })?; let space_uri = format!( "at://{}/space/{}/{}", space.did, space.type_nsid, space.skey ); let granted = check_user_access_with_managing_app( http, managing_app, &space_uri, subject_did, client_id, authority_did, ) .await?; if granted { Ok(()) } else { Err(AppError::Forbidden( "managing app denied access to this space".into(), )) } } }}
async fn check_user_access_with_managing_app( http: &reqwest::Client, managing_app: &str, space_uri: &str, user_did: &str, client_id: Option<&str>, authority_did: &str,) -> Result<bool, AppError> { // Parse DID#fragment — the fragment identifies the service endpoint in the DID doc. // For outbound callback we derive the endpoint from the DID. let (did, fragment) = if let Some(pos) = managing_app.find('#') { (&managing_app[..pos], Some(&managing_app[pos + 1..])) } else { (managing_app, None) };
if let Some(frag) = fragment && frag != "atproto_pds" { return Err(AppError::BadRequest(format!( "unsupported service fragment '#{frag}' for managing app" ))); }
// Resolve the managing app's PDS/service endpoint from its DID document. let endpoint = resolve_did_service_endpoint(http, did).await?;
let url = format!( "{}/xrpc/com.atproto.simplespace.checkUserAccess", endpoint.trim_end_matches('/') );
let mut body = serde_json::json!({ "space": space_uri, "did": user_did, }); if let Some(cid) = client_id { body["clientId"] = serde_json::Value::String(cid.to_string()); }
// Service auth: iss = authority_did, aud = managing_app DID. // We use a simple unsigned assertion here; a full implementation would sign with the space key. // For now we send the request without service auth and rely on the managing app to trust HappyView. let resp = http .post(&url) .json(&body) .header("X-Authority-Did", authority_did) .send() .await .map_err(|e| AppError::Internal(format!("checkUserAccess request failed: {e}")))?;
if resp.status() == reqwest::StatusCode::FORBIDDEN || resp.status() == reqwest::StatusCode::UNAUTHORIZED { return Ok(false); }
if !resp.status().is_success() { return Err(AppError::Internal(format!( "checkUserAccess returned unexpected status {}", resp.status() ))); }
let json: serde_json::Value = resp .json() .await .map_err(|e| AppError::Internal(format!("checkUserAccess response parse failed: {e}")))?;
Ok(json .get("granted") .and_then(|v| v.as_bool()) .unwrap_or(false))}
async fn resolve_did_service_endpoint( http: &reqwest::Client, did: &str,) -> Result<String, AppError> { let url = if did.starts_with("did:plc:") { format!("https://plc.directory/{did}") } else if did.starts_with("did:web:") { let identifier = did.strip_prefix("did:web:").unwrap(); let mut segments = identifier.split(':'); let host = segments.next().unwrap(); let path_segments: Vec<&str> = segments.collect(); if path_segments.is_empty() { format!("https://{host}/.well-known/did.json") } else { format!("https://{host}/{}/did.json", path_segments.join("/")) } } else { return Err(AppError::BadRequest(format!( "unsupported DID method for managing app: {did}" ))); };
#[derive(serde::Deserialize)] struct DidDoc { #[serde(default)] service: Vec<DidService>, } #[derive(serde::Deserialize)] #[serde(rename_all = "camelCase")] struct DidService { id: String, service_endpoint: String, }
let resp = http .get(&url) .send() .await .map_err(|e| AppError::Internal(format!("DID resolution failed for {did}: {e}")))?;
if !resp.status().is_success() { return Err(AppError::Internal(format!( "DID resolution returned {} for {did}", resp.status() ))); }
let doc: DidDoc = resp .json() .await .map_err(|e| AppError::Internal(format!("invalid DID document for {did}: {e}")))?;
doc.service .iter() .find(|s| s.id == "#atproto_pds" || s.id == format!("{did}#atproto_pds")) .map(|s| s.service_endpoint.clone()) .ok_or_else(|| AppError::Internal(format!("no #atproto_pds service in DID doc for {did}")))}
pub fn check_app_access(space: &Space, attested_client_id: Option<&str>) -> Result<(), AppError> { match &space.app_access { AppAccess::Open => Ok(()), AppAccess::AllowList { allowed } => { let client_id = attested_client_id .ok_or_else(|| AppError::Auth("space requires client attestation".into()))?; if allowed.iter().any(|id| id == client_id) { Ok(()) } else { Err(AppError::Forbidden( "this app is not authorized to access this space".into(), )) } } }}
async fn get_or_create_signing_key( pool: &sqlx::AnyPool, backend: DatabaseBackend, encryption_key: &[u8; 32], space: &Space,) -> Result<serde_json::Value, AppError> { let sql = adapt_sql( "SELECT signing_key_enc FROM happyview_space_dids WHERE space_id = ?", backend, ); let row: Option<(Vec<u8>,)> = crate::db::query_as(&sql) .bind(&space.id) .fetch_optional(pool) .await .map_err(|e| AppError::Internal(format!("failed to look up space signing key: {e}")))?;
if let Some((encrypted,)) = row { let decrypted = decrypt(encryption_key, &encrypted) .map_err(|e| AppError::Internal(format!("failed to decrypt signing key: {e}")))?; let jwk: serde_json::Value = serde_json::from_slice(&decrypted) .map_err(|e| AppError::Internal(format!("failed to parse signing key: {e}")))?; return Ok(jwk); }
let keypair = generate_space_keypair()?; let key_bytes = serde_json::to_vec(&keypair.private_jwk) .map_err(|e| AppError::Internal(format!("failed to serialize signing key: {e}")))?; let encrypted_signing = encrypt(encryption_key, &key_bytes) .map_err(|e| AppError::Internal(format!("failed to encrypt signing key: {e}")))?;
// Rotation key is a separate keypair for recovery let rotation_keypair = generate_space_keypair()?; let rotation_bytes = serde_json::to_vec(&rotation_keypair.private_jwk) .map_err(|e| AppError::Internal(format!("failed to serialize rotation key: {e}")))?; let encrypted_rotation = encrypt(encryption_key, &rotation_bytes) .map_err(|e| AppError::Internal(format!("failed to encrypt rotation key: {e}")))?;
let now = now_rfc3339(); let insert_sql = adapt_sql( "INSERT INTO happyview_space_dids (id, did, space_id, signing_key_enc, rotation_key_enc, created_by, created_at) VALUES (?, ?, ?, ?, ?, ?, ?)", backend, );
crate::db::query(&insert_sql) .bind(Uuid::new_v4().to_string()) .bind(&space.did) .bind(&space.id) .bind(&encrypted_signing) .bind(&encrypted_rotation) .bind(&space.authority_did) .bind(&now) .execute(pool) .await .map_err(|e| AppError::Internal(format!("failed to store space signing key: {e}")))?;
Ok(keypair.private_jwk)}
struct SpaceKeypair { private_jwk: serde_json::Value,}
fn generate_space_keypair() -> Result<SpaceKeypair, AppError> { let mut rng_bytes = [0u8; 32]; rand::rng().fill_bytes(&mut rng_bytes);
let signing_key = SigningKey::from_slice(&rng_bytes[..]) .map_err(|e| AppError::Internal(format!("failed to generate signing key: {e}")))?;
let verifying_key = signing_key.verifying_key(); let public_point = verifying_key.to_sec1_point(false);
let x_bytes = public_point .x() .ok_or_else(|| AppError::Internal("missing x coordinate".into()))?; let y_bytes = public_point .y() .ok_or_else(|| AppError::Internal("missing y coordinate".into()))?;
let x_b64 = URL_SAFE_NO_PAD.encode(x_bytes); let y_b64 = URL_SAFE_NO_PAD.encode(y_bytes); let d_b64 = URL_SAFE_NO_PAD.encode(rng_bytes);
let private_jwk = serde_json::json!({ "kty": "EC", "crv": "P-256", "x": x_b64, "y": y_b64, "d": d_b64, });
Ok(SpaceKeypair { private_jwk })}
async fn store_credential_record( pool: &sqlx::AnyPool, backend: DatabaseBackend, space_id: &str, issued_to: &str, token_hash: &str, expires_at_epoch: u64,) -> Result<(), AppError> { let now = now_rfc3339(); let expires_at = chrono::DateTime::from_timestamp(expires_at_epoch as i64, 0) .map(|dt| dt.to_rfc3339()) .unwrap_or_default();
let sql = adapt_sql( "INSERT INTO happyview_space_credentials (id, space_id, issued_to, token_hash, expires_at, created_at) VALUES (?, ?, ?, ?, ?, ?)", backend, );
crate::db::query(&sql) .bind(Uuid::new_v4().to_string()) .bind(space_id) .bind(issued_to) .bind(token_hash) .bind(&expires_at) .bind(&now) .execute(pool) .await .map_err(|e| AppError::Internal(format!("failed to store credential record: {e}")))?;
Ok(())}
#[cfg(test)]mod tests { use super::*; use crate::spaces::types::{AppAccess, MintPolicy, Space, SpaceConfig};
fn test_space(app_access: AppAccess) -> Space { Space { id: "test-space".into(), did: "did:plc:owner".into(), authority_did: "did:plc:owner".into(), creator_did: "did:plc:owner".into(), type_nsid: "com.example.forum".into(), skey: "main".into(), display_name: None, description: None, mint_policy: MintPolicy::MemberList, app_access, managing_app_did: None, config: SpaceConfig::default(), revision: None, created_at: String::new(), updated_at: String::new(), } }
#[test] fn app_access_open_allows_any() { let space = test_space(AppAccess::Open); assert!(check_app_access(&space, Some("any-app")).is_ok()); }
#[test] fn app_access_allowlist_permits_listed() { let space = test_space(AppAccess::AllowList { allowed: vec!["good-app".into()], }); assert!(check_app_access(&space, Some("good-app")).is_ok()); assert!(check_app_access(&space, Some("other-app")).is_err()); }
#[test] fn app_access_allowlist_requires_client_id() { let space = test_space(AppAccess::AllowList { allowed: vec![] }); assert!(check_app_access(&space, None).is_err()); }
#[test] fn app_access_open_allows_none_client_id() { let space = test_space(AppAccess::Open); assert!(check_app_access(&space, None).is_ok()); }
#[test] fn app_access_empty_allowlist_rejects() { let space = test_space(AppAccess::AllowList { allowed: vec![] }); assert!(check_app_access(&space, Some("any-client")).is_err()); }
// resolve_did_service_endpoint is async and makes HTTP calls to resolve DID // documents, so it cannot be unit-tested without a mock HTTP server.
#[test] fn generate_keypair_produces_valid_jwk() { let kp = generate_space_keypair().unwrap(); assert_eq!(kp.private_jwk["kty"], "EC"); assert_eq!(kp.private_jwk["crv"], "P-256"); assert!(kp.private_jwk["d"].is_string()); assert!(kp.private_jwk["x"].is_string()); assert!(kp.private_jwk["y"].is_string()); }}