Changelog¶

All notable changes to traverse are documented in this file.

The format follows Keep a Changelog. traverse uses Semantic Versioning.

[0.20.0] - 2026-04-27¶

Added¶

• CreateRawAs Method (entity.go) - New generic function CreateRawAs[T]() returns raw response bytes from Create operations, complementing CreateJsonAs() and CreateXmlAs(). Useful for debugging, testing, handling non-standard OData formats, and transparently capturing both JSON and XML responses from SAP and other backends that may ignore Accept header preferences. Includes comprehensive test coverage.

Notes¶

• Fully backward compatible - all existing APIs unchanged
• Complements the Phase 10 CSRF architecture fixes in traverse v0.19.0

[0.19.0] - 2026-04-27 - Phase 10: Critical SAP CSRF Architecture Fix¶

Added¶

• Complete CSRF Token + Cookie Management - Traverse now handles SAP CSRF tokens completely transparently, including session cookie management. Fixed 7 interrelated architectural bugs that broke OData integration with SAP backends:

BUG-001 (CRITICAL) - CookieJar support in relay v0.4.0 - http.Client now automatically captures and reuses session cookies - Fixes CSRF token validation failures - Root cause of all 403 FORBIDDEN errors in enterprise SAP integrations - Fully transparent—no code changes needed

BUG-002 (CRITICAL) - Automatic cookie management via http.CookieJar - No manual cookie handling required - Cookies are captured from Set-Cookie headers - Automatically included in subsequent requests - Managed transparently by Go's standard library

BUG-003 (CRITICAL) - Token lifecycle fix - CSRF tokens are now reused for their full 30-minute validity window - Previously tokens were invalidated before every request, causing unnecessary latency - Automatic 403 recovery when tokens actually expire

BUG-004 (HIGH) - Response hooks properly connected - HandleResponse() now correctly subscribes to OnAfterResponse hook - Enables automatic 403 recovery without retry logic in application code - Invalid tokens are detected and refreshed transparently

BUG-005 (HIGH) - CSRF middleware API consistency - Hook() method signature aligns with relay's OnBeforeRequest hook system - Clean, documented API contract

BUG-006 (MEDIUM) - URL normalization - Fixed malformed URLs with multiple consecutive slashes (///sap/opu/...) - Uses url.URL struct instead of fmt.Sprintf for proper path joining - Handles edge cases: trailing slashes, no scheme, special characters, URL encoding

BUG-007 (MEDIUM) - Error diagnostics - Implemented ErrorDiagnostic with 9 error categories: - csrf_expired - token validation window expired - csrf_invalid - token format invalid - auth_failed - authentication failure - network_error - transport/connection error - service_unavailable - backend overloaded - config_error - metadata or configuration issue - And 3 others for observability - Includes suggested fixes and IsRetryable() flags for resilience

Changed¶

• ext/sap - Improved CSRF middleware initialization and token management:
• Token fetch now correctly captures and stores session cookies
• All subsequent requests automatically include both token header (X-CSRF-Token) and cookie header

• Fixes atomic CSRF+cookie validation required by SAP Gateway

• XML Support - XML struct mapping now correctly identifies response content type from Content-Type header:

• Distinguishes JSON vs XML responses from SAP backends that may ignore Accept header

• Auto-detects format without explicit type hints

• URL Construction - ext/sap/client.go uses url.URL struct for proper path joining:

• Eliminates edge cases that produced double-slash patterns
• Handles special characters and encoding correctly

Notes for Upgrade¶

• 100% backward compatible - All existing code works without changes
• Transparent CSRF handling - No application code changes needed to fix CSRF failures
• Automatic error recovery - 403 errors are automatically recovered without retry logic
• Enhanced diagnostics - Better error messages distinguish between config, auth, CSRF, and network failures

[0.4.0] - Phase C: Production Readiness¶

Added¶

• Lambda filter DSL (lambda_filter.go) - type-safe filter builder with query.Field().Gt(), query.And(), query.Any(), query.All() and full OData function support
• Deep insert (deep_insert.go) - create an entity and its related entities in a single POST, following the OData deep insert specification
• Conditional headers (conditional_headers.go) - typed IfMatch, IfNoneMatch, IfModifiedSince, IfUnmodifiedSince request modifiers with ETag type
• Stream property support (stream_property.go) - read, write, and delete OData stream properties; multipart chunked upload with progress callback

[0.3.0] - Phase B2: Code Generation¶

Added¶

• traverse-gen CLI (cmd/traverse-gen/) - reads EDMX metadata and generates typed Go client, entity structs, query builders, and enum types
• EDMX parser supporting OData v2 and v4 metadata documents
• PascalCase normalisation for entity and property names
• --include / --exclude flags for selective generation
• --nullable flag for pointer vs value types on nullable properties

[0.2.0] - Phase B: Advanced OData¶

Added¶

• Entity change tracking (change_tracking.go) - ChangeSet[T] records mutations to tracked entities and submits them as an atomic $batch request
• Deep expand (deep_expand.go) - nested $expand with per-level $select, $filter, $orderby, $top options (OData v4)
• Async operation poller (async_op.go) - AsyncPoller[T] polls 202 Accepted / Location responses with configurable interval, progress callbacks, and timeout

[0.1.0] - Phase A: Core OData Features¶

Added¶

• ETag upsert (etag_upsert.go) - upsert entity with If-Match: * or If-None-Match: * semantics for atomic create-or-replace
• Typed paginator (paginator.go) - Paginator[T] supports @odata.nextLink, $skiptoken, and $top/$skip pagination strategies
• $apply aggregation - CollectionBuilder.Apply() for server-side group-by and aggregate expressions

[0.0.1] - Initial release¶

Added¶

• Declarative OData query builder ($filter, $select, $expand, $orderby, $top, $skip, $count, $format)
• CRUD operations: List, Get, Create, Update, Replace, Delete
• OData v2 and v4 support with auto-detection
• JSON and ATOM response parsing
• Built on relay for all transport-level concerns (retries, timeouts, circuit breaker)
• Typed error types with OData error code and details