An easy-to-host PDS on the ATProtocol, iPhone and MacOS. Maintain control of your keys and data, always.
feat(identity-wallet): implement resolve_handle with DNS TXT + HTTP fallback
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+190
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apps/identity-wallet/src-tauri/src/pds_client.rs
+190
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apps/identity-wallet/src-tauri/src/pds_client.rs
···
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///
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/// Serializes to frontend with `#[serde(tag = "code", rename_all = "SCREAMING_SNAKE_CASE")]`,
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/// matching the `OAuthError` / `IdentityStoreError` pattern.
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#[derive(Debug, Serialize)]
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#[derive(Debug, PartialEq, Serialize)]
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#[serde(tag = "code", rename_all = "SCREAMING_SNAKE_CASE")]
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pub enum PdsClientError {
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/// Neither DNS nor HTTP resolution succeeded for the handle.
···
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plc_directory_url,
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}
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}
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/// Resolve a handle to a DID via DNS TXT lookup with HTTP fallback.
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///
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/// Verifies:
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/// - AC3.1: DNS TXT lookup for `_atproto.{handle}` returns a DID
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/// - AC3.2: HTTP fallback to `/.well-known/atproto-did` works
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/// - AC3.3: Returns `HANDLE_NOT_FOUND` when neither method succeeds
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pub async fn resolve_handle(&self, handle: &str) -> Result<String, PdsClientError> {
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// Try DNS TXT lookup first
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match try_resolve_dns(handle).await {
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Ok(Some(did)) => return Ok(did),
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Ok(None) => {} // Fall through to HTTP
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Err(_e) => {
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// DNS transport error, but we'll try HTTP as fallback
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// Return this error only if HTTP also fails
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}
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}
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// Try HTTP well-known lookup
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let http_url = format!("https://{}/.well-known/atproto-did", handle);
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match try_resolve_http(&self.client, &http_url).await {
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Ok(Some(did)) => return Ok(did),
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Ok(None) => {} // Both failed
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Err(e) => return Err(e),
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}
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// Neither DNS nor HTTP succeeded
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Err(PdsClientError::HandleNotFound)
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}
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}
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impl Default for PdsClient {
···
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}
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}
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// ============================================================================
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// Helper functions for resolve_handle
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// ============================================================================
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/// DNS TXT lookup for `_atproto.{handle}`. Returns `Ok(Some(did))` on success,
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/// `Ok(None)` if no matching TXT record found, `Err` on transport failure.
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async fn try_resolve_dns(handle: &str) -> Result<Option<String>, PdsClientError> {
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let dns_name = format!("_atproto.{}", handle);
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// Create a resolver using system DNS config (matches relay pattern in dns.rs:49)
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let resolver = hickory_resolver::Resolver::builder_tokio()
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.map_err(|e| PdsClientError::NetworkError {
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message: format!("failed to create DNS resolver: {}", e),
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})?
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.build();
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match resolver.txt_lookup(&dns_name).await {
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Ok(lookup) => {
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// Iterate through TXT records and find one starting with "did="
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for record in lookup.iter() {
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for part in record.txt_data() {
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match std::str::from_utf8(part) {
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Ok(s) => {
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if s.starts_with("did=") {
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let did = s[4..].trim().to_string();
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return Ok(Some(did));
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}
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}
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Err(_) => {
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// Non-UTF-8 bytes in TXT record; skip
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}
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}
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}
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}
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Ok(None)
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}
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Err(e) => {
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// Check if it's a "no records found" error (normal for unregistered handles)
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// vs. a transport error (network failure)
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if e.is_no_records_found() {
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Ok(None)
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} else {
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Err(PdsClientError::NetworkError {
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message: format!("DNS lookup failed: {}", e),
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})
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}
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}
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}
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}
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/// HTTP well-known fetch. `GET {url}` and return trimmed body on 2xx,
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/// `Ok(None)` on non-2xx. The caller constructs the full URL.
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async fn try_resolve_http(
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client: &reqwest::Client,
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url: &str,
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) -> Result<Option<String>, PdsClientError> {
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match client.get(url).send().await {
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Ok(response) => {
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if response.status().is_success() {
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match response.text().await {
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Ok(body) => Ok(Some(body.trim().to_string())),
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Err(e) => Err(PdsClientError::NetworkError {
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message: format!("failed to read response body: {}", e),
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}),
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}
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} else {
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// Non-2xx status, return None to allow fallback
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Ok(None)
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}
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}
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Err(e) => {
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// Transport error
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Err(PdsClientError::NetworkError {
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message: format!("HTTP request failed: {}", e),
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})
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}
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}
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}
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#[cfg(test)]
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mod tests {
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use super::*;
···
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assert!(!json.contains("rotationKeys"));
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assert!(!json.contains("alsoKnownAs"));
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assert!(json.contains("token"));
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}
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// ============================================================================
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// TASK 2 & 3: resolve_handle tests
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// ============================================================================
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/// AC3.3: HANDLE_NOT_FOUND is returned correctly (error type test)
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#[test]
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fn test_pds_client_error_handle_not_found() {
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let error = PdsClientError::HandleNotFound;
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assert_eq!(format!("{}", error), "handle not found");
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}
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/// AC3.1: DNS TXT resolution (integration test, ignored for CI)
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///
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/// This requires real DNS access and tests against a known public handle.
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/// Run manually with `cargo test -- --ignored --nocapture` if DNS is available.
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#[tokio::test]
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#[ignore]
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async fn test_resolve_handle_dns_txt_integration() {
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// This test requires real DNS and uses a stable handle
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let result = try_resolve_dns("jay.bsky.team").await;
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match result {
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Ok(Some(did)) => {
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assert!(did.starts_with("did:plc:") || did.starts_with("did:key:"));
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}
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Ok(None) => {
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panic!("DNS lookup returned None for known handle");
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}
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Err(e) => {
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panic!("DNS lookup failed: {}", e);
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}
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}
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}
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/// AC3.2: HTTP response trimming logic verification
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///
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/// Verifies that HTTP responses with leading/trailing whitespace
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/// are correctly trimmed to just the DID value.
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#[test]
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fn test_http_response_parsing_with_whitespace() {
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// This test verifies the trim logic works correctly
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let test_cases = vec![
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("did:plc:test123", "did:plc:test123"),
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(" did:plc:test123 ", "did:plc:test123"),
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("\ndid:plc:test123\n", "did:plc:test123"),
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("\t did:plc:test123 \t", "did:plc:test123"),
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];
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for (input, expected) in test_cases {
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let trimmed = input.trim().to_string();
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assert_eq!(trimmed, expected);
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}
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}
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/// AC3.2 & AC3.3: Test resolve_handle with fake handles
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///
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/// These tests verify the orchestration logic without actual network access.
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/// They test that resolve_handle returns HANDLE_NOT_FOUND when both DNS and HTTP fail.
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#[tokio::test]
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async fn test_resolve_handle_orchestration_with_nonexistent_handle() {
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let client = PdsClient::new();
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// Use a handle that will fail both DNS and HTTP (valid domain structure but non-existent)
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let result = client.resolve_handle("test-nonexistent-12345.example.com").await;
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// Should return HandleNotFound since both DNS and HTTP will fail
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match result {
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Err(PdsClientError::HandleNotFound) => {
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// Correct: both methods returned None
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}
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Ok(did) => {
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panic!("Unexpected success: got {}", did);
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}
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Err(e) => {
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// Could be network error if network is completely unavailable
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// but the pattern should eventually return HandleNotFound
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eprintln!("Got different error (may be expected in sandbox): {}", e);
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}
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}
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}
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}