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Frank ef223ef14d added phase- Test and check and verify the functions

2026-02-27 12:00:44 +01:00

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Plan: Pluggable Character Import/Export with Microservice Adapters

This plan creates a new import package as a full-featured, extensible import/export system using Docker-based adapter microservices. The canonical CharacterImport format (from importero) becomes the system-wide interchange format (BMRT-Format), and new external formats (starting with Moam VTT) are handled by isolated adapter services. New master data is automatically flagged as personal items (house rules).

Revision Notes:

This plan uses a NEW importer/ package (not extending importero)
Incorporates comprehensive technical review feedback (security, transactions, health management)
All references to "importero as orchestration layer" are legacy - importer/ is the orchestration layer

Key Decisions:

Microservice architecture for adapters (Docker containers)
Auto-flag imported master data as personal items
Moam VTT JSON as first format
Backend-only implementation (no Vue components)
Keep transfero/ untouched (BaMoRT-to-BaMoRT transfers)
Keep importero/ untouched (legacy VTT/CSV imports)
Create new importer/ package as the adapter orchestration layer

Development Methodology:

Test Driven Development (TDD): Write failing tests first, then implement code to pass them
Keep It Small and Simple (KISS): Prefer simple, straightforward solutions over complex abstractions

1. Core Infrastructure (Backend)

1.0 Package Architecture Overview

Three Separate Concerns:

transfero/ - BaMoRT-to-BaMoRT lossless transfer (existing, untouched)
importero/ - Legacy format handlers (VTT JSON, CSV) with direct imports (existing, untouched)
importer/ - NEW microservice adapter orchestration layer

Why Keep importero Separate:

importero has working VTT/CSV imports that users depend on
importero converts directly to models.Char without adapter layer
importer/ package uses importero.CharacterImport as the canonical format
No code duplication: importer/ references importero types but doesn't modify them

Data Flow:

External Format (Moam VTT)
  ↓
Adapter Microservice
  ↓
importero.CharacterImport (BMRT-Format)
  ↓
importer/ package handlers (validation, reconciliation)
  ↓
models.Char

Benefits of New Package:

✅ Zero risk to existing importero functionality
✅ Clear separation between direct imports (importero) and microservice imports (import)
✅ Future flexibility: can migrate importero to use adapters later if desired
✅ Clean API: /api/import/* vs /api/importer/* (different purposes)
✅ Independent testing and deployment
✅ Reuses proven CharacterImport format without modification

1.1 Formalize BMRT-Format

Use importero/model.go CharacterImport as the canonical interchange format (read-only)
Create importer/bmrt.go with JSON schema validation using github.com/xeipuuv/gojsonschema
Add BmrtVersion field to new wrapper struct (start at "1.0")
Add SourceMetadata struct to track original format, adapter ID, import timestamp
Reference importero.CharacterImport internally but don't modify importero package

1.2 Database Migrations

Add new tables to models/model_character.go:

type ImportHistory struct {
    ID              uint   `gorm:"primaryKey"`
    UserID          uint   `gorm:"not null;index"`
    CharacterID     uint   `gorm:"index"`
    AdapterID       string `gorm:"type:varchar(100);not null"` // "moam-vtt-v1"
    SourceFormat    string `gorm:"type:varchar(50)"`           // "moam-vtt"
    SourceFilename  string
    SourceSnapshot  []byte `gorm:"type:MEDIUMBLOB"`            // Original file (gzip compressed)
    MappingSnapshot []byte `gorm:"type:JSON"`                  // Adapter->BMRT mappings
    BmrtVersion     string `gorm:"type:varchar(10)"`           // "1.0"
    ImportedAt      time.Time
    Status          string `gorm:"type:varchar(20)"` // "in_progress", "success", "partial", "failed"
    ErrorLog        string `gorm:"type:TEXT"`
}

type MasterDataImport struct {
    ID              uint `gorm:"primaryKey"`
    ImportHistoryID uint `gorm:"not null;index"`
    ItemType        string `gorm:"type:varchar(20)"` // "skill", "spell", "weapon", "equipment"
    ItemID          uint   `gorm:"not null"`
    ExternalName    string
    MatchType       string `gorm:"type:varchar(20)"` // "exact", "created_personal"
    CreatedAt       time.Time
}

Character Provenance (add to existing Char model):

// Add to models.Char:
ImportedFromAdapter *string    `gorm:"type:varchar(100)"` // Optional: tracks import source
ImportedAt          *time.Time // Optional: tracks when imported

Add to models/database.go MigrateStructure() function Add to models/model_character.go migration function

Module Registration: Add to cmd/main.go:

import "bamort/import"

// In main() after other RegisterRoutes calls:
import.RegisterRoutes(protected)

1.3 Adapter Service Registry

Create importer/registry.go:

type AdapterMetadata struct {
    ID                  string   // "moam-vtt-v1"
    Name                string   // "Moam VTT Character"
    Version             string   // "1.0"
    BmrtVersions        []string // ["1.0"] - supported BMRT versions
    SupportedExtensions []string // [".json"]
    BaseURL             string   // "http://adapter-moam:8181"
    Capabilities        []string // ["import", "export", "detect"]
    Healthy             bool     // Runtime health status
    LastCheckedAt       time.Time
    LastError           string
}

type AdapterRegistry struct {
    adapters map[string]*AdapterMetadata
    mu       sync.RWMutex
}

func (r *AdapterRegistry) Register(meta AdapterMetadata) error
func (r *AdapterRegistry) Detect(data []byte, filename string) (string, float64, error) // Smart detection with short-circuit
func (r *AdapterRegistry) Import(adapterID string, data []byte) (*importero.CharacterImport, error)
func (r *AdapterRegistry) Export(adapterID string, char *importero.CharacterImport) ([]byte, error)
func (r *AdapterRegistry) HealthCheck() error // Background health checker
func (r *AdapterRegistry) GetHealthy() []*AdapterMetadata // Only healthy adapters

Load adapters from config on startup (importer/routes.go):

Environment variable IMPORT_ADAPTERS (JSON array of adapter configs)
Whitelist adapter base URLs for security (prevent SSRF)
Ping each adapter's /metadata endpoint to register
Verify BMRT version compatibility
Cache metadata in memory
Start background health checker (every 30s)

HTTP Client Configuration:

2s timeout for /detect calls (per adapter)
30s timeout for /import and /export
Disable redirects (security)
3 retry attempts with exponential backoff

1.4 Format Detection

Create importer/detector.go:

func DetectFormat(data []byte, filename string) (adapterID string, confidence float64, err error) {
    // Smart detection with short-circuit optimization:
    // 1. If user specified adapter - use it
    // 2. Extension match (SupportedExtensions) - if single match, skip detection
    // 3. Signature cache (hash of first 1KB) - check previous detections
    // 4. Full /detect fan-out to healthy adapters only (parallel, 2s timeout each)
    // 5. Return highest confidence match (threshold: 0.7 minimum)
}

Detection Cache:

type DetectionCache struct {
    signature string // SHA256 of first 1KB
    adapterID string
    ttl       time.Time
}

1.5 Validation Framework

Create importer/validator.go:

type ValidationResult struct {
    Valid    bool
    Errors   []ValidationError
    Warnings []ValidationWarning
    Source   string // "adapter", "bmrt", "gamesystem"
}

type ValidationError struct {
    Field   string
    Message string
    Source  string
}

type ValidationWarning struct {
    Field   string
    Message string
    Source  string
}

type ValidationRule interface {
    Validate(char *importero.CharacterImport) ValidationResult
}

// Validation Phases:
// Phase 1 - BMRT Structural (before game logic):
//   - RequiredFieldsRule (name, gameSystem must exist)
//   - JSONSchemaRule (valid BMRT structure)
//   - BmrtVersionRule (supported version)
//
// Phase 2 - Game System Semantic:
//   - StatsRangeRule (stats 0-100 for Midgard)
//   - ReferentialIntegrityRule (skills reference valid categories)

1.6 Master Data Reconciliation

Create importer/reconciler.go with new reconciliation functions (similar to importero's approach but independent):

func ReconcileSkill(skill Fertigkeit, importHistoryID uint) (*models.Skill, string, error) {
    // 1. Exact match by (Name + GameSystem) → "exact"
    // 2. Not found → Create with PersonalItem=true → "created_personal"
    // 3. Log to MasterDataImport table
}

Apply to all types: skills, weapon skills, spells, equipment, weapons, containers Set PersonalItem = true for all created master data Chain user's UserID to created items via CreatedByUserID (add field to GSM models)

Transaction Boundary:

func ImportCharacter(char *importero.CharacterImport, userID uint, adapterID string) (*ImportResult, error) {
    tx := database.DB.Begin()
    defer func() {
        if r := recover(); r != nil {
            tx.Rollback()
        }
    }()
    
    // 1. Create ImportHistory (failed status initially)
    // 2. Reconcile master data
    // 3. Create models.Char
    // 4. Update ImportHistory (success status)
    
    if err := tx.Commit().Error; err != nil {
        tx.Rollback()
        // Keep ImportHistory with failed status
        return nil, err
    }
}

1.7 Security Middleware

Create importer/security.go:

Rate Limiting Middleware:

import (
    "sync"
    "time"
    "github.com/gin-gonic/gin"
)

type RateLimiter struct {
    requests map[uint][]time.Time  // userID -> request timestamps
    mu       sync.RWMutex
    limit    int                    // requests per window
    window   time.Duration          // time window
}

func NewRateLimiter(limit int, window time.Duration) *RateLimiter {
    return &RateLimiter{
        requests: make(map[uint][]time.Time),
        limit:    limit,
        window:   window,
    }
}

func (rl *RateLimiter) Middleware() gin.HandlerFunc {
    return func(c *gin.Context) {
        userID := getUserID(c) // Extract from JWT token
        
        rl.mu.Lock()
        defer rl.mu.Unlock()
        
        now := time.Now()
        cutoff := now.Add(-rl.window)
        
        // Remove expired timestamps
        timestamps := rl.requests[userID]
        valid := make([]time.Time, 0)
        for _, t := range timestamps {
            if t.After(cutoff) {
                valid = append(valid, t)
            }
        }
        
        // Check limit
        if len(valid) >= rl.limit {
            c.JSON(429, gin.H{
                "error": "Rate limit exceeded",
                "retry_after": rl.window.Seconds(),
            })
            c.Abort()
            return
        }
        
        // Add current request
        valid = append(valid, now)
        rl.requests[userID] = valid
        
        c.Next()
    }
}

Input Validation Middleware:

import (
    "bytes"
    "encoding/json"
    "io"
)

// ValidateFileSizeMiddleware limits upload file size
func ValidateFileSizeMiddleware(maxSize int64) gin.HandlerFunc {
    return func(c *gin.Context) {
        c.Request.Body = http.MaxBytesReader(c.Writer, c.Request.Body, maxSize)
        c.Next()
    }
}

// ValidateJSONDepth prevents deeply nested JSON attacks
func ValidateJSONDepth(data []byte, maxDepth int) error {
    var depth int
    decoder := json.NewDecoder(bytes.NewReader(data))
    decoder.UseNumber() // Prevent float precision issues
    
    for {
        token, err := decoder.Token()
        if err == io.EOF {
            break
        }
        if err != nil {
            return err
        }
        
        switch token {
        case json.Delim('{'), json.Delim('['):
            depth++
            if depth > maxDepth {
                return fmt.Errorf("JSON depth exceeds maximum of %d levels", maxDepth)
            }
        case json.Delim('}'), json.Delim(']'):
            depth--
        }
    }
    
    return nil
}

SSRF Protection:

import (
    "net/url"
    "strings"
)

type SSRFProtection struct {
    allowedHosts []string  // Whitelist of adapter hosts
}

func NewSSRFProtection(allowedHosts []string) *SSRFProtection {
    return &SSRFProtection{allowedHosts: allowedHosts}
}

func (s *SSRFProtection) ValidateURL(rawURL string) error {
    parsed, err := url.Parse(rawURL)
    if err != nil {
        return fmt.Errorf("invalid URL: %w", err)
    }
    
    // Block redirects to internal networks
    if isInternalIP(parsed.Host) {
        return fmt.Errorf("internal network access forbidden")
    }
    
    // Check whitelist
    allowed := false
    for _, host := range s.allowedHosts {
        if strings.HasPrefix(parsed.Host, host) {
            allowed = true
            break
        }
    }
    
    if !allowed {
        return fmt.Errorf("host %s not in whitelist", parsed.Host)
    }
    
    return nil
}

func isInternalIP(host string) bool {
    // Remove port if present
    if idx := strings.LastIndex(host, ":"); idx != -1 {
        host = host[:idx]
    }
    
    internal := []string{
        "localhost",
        "127.",
        "10.",
        "172.16.", "172.17.", "172.18.", "172.19.", 
        "172.20.", "172.21.", "172.22.", "172.23.",
        "172.24.", "172.25.", "172.26.", "172.27.",
        "172.28.", "172.29.", "172.30.", "172.31.",
        "192.168.",
        "169.254.", // Link-local
    }
    
    for _, prefix := range internal {
        if strings.HasPrefix(host, prefix) {
            return true
        }
    }
    
    return false
}

HTTP Client with Security Settings:

import (
    "net/http"
    "time"
)

func NewSecureHTTPClient(timeout time.Duration) *http.Client {
    return &http.Client{
        Timeout: timeout,
        CheckRedirect: func(req *http.Request, via []*http.Request) error {
            return http.ErrUseLastResponse // Disable redirects
        },
        Transport: &http.Transport{
            MaxIdleConns:        10,
            MaxIdleConnsPerHost: 2,
            IdleConnTimeout:     30 * time.Second,
            DisableKeepAlives:   false,
            DisableCompression:  false,
        },
    }
}

Usage in Routes:

func RegisterRoutes(r *gin.RouterGroup) {
    // Rate limiters
    detectLimiter := NewRateLimiter(10, time.Minute)      // 10/min
    importLimiter := NewRateLimiter(5, time.Minute)       // 5/min
    exportLimiter := NewRateLimiter(20, time.Minute)      // 20/min
    
    // File size limit (10MB)
    maxFileSize := int64(10 << 20)
    
    importer := r.Group("/import")
    importer.Use(ValidateFileSizeMiddleware(maxFileSize))
    
    importer.POST("/detect", detectLimiter.Middleware(), DetectHandler)
    importer.POST("/import", importLimiter.Middleware(), ImportHandler)
    importer.POST("/export/:id", exportLimiter.Middleware(), ExportHandler)
    importer.GET("/adapters", ListAdaptersHandler)
    importer.GET("/history", ImportHistoryHandler)
}

2. API Endpoints (Backend)

Create importer/routes.go:

func RegisterRoutes(r *gin.RouterGroup) {
    importer := r.Group("/import")
    
    // NEW endpoints:
    importer.POST("/detect", DetectHandler)           // Upload file, returns detected format
    importer.POST("/import", ImportHandler)           // Upload + import with adapter
    importer.GET("/adapters", ListAdaptersHandler)    // List registered adapters
    importer.GET("/history", ImportHistoryHandler)    // User's import history
    importer.GET("/history/:id", ImportDetailsHandler) // Details + errors
    importer.POST("/export/:id", ExportHandler)        // Export char to original format
}

Import Result Model:

type ImportResult struct {
    CharacterID uint              `json:"character_id"`
    ImportID    uint              `json:"import_id"`
    AdapterID   string            `json:"adapter_id"`
    Warnings    []ValidationWarning `json:"warnings"`
    CreatedItems map[string]int   `json:"created_items"` // {"skills": 3, "spells": 1}
    Status      string            `json:"status"`
}

Handler Implementations in importer/handlers.go:

DetectHandler:

Accept multipart file upload
Validate file size (max 10MB)
Validate JSON depth (max 100 levels) if JSON
Save to ./uploads/detect_<uuid>
Call DetectFormat()
Return {adapter_id, confidence, suggested_adapter_name}
Clean up temp file

Security: Rate limit per user (10 requests/minute)

ImportHandler:

Accept file + optional adapter_id (from detect)
Validate file size (max 10MB)
If no adapter_id, call DetectFormat()
Call registry.Import(adapterID, fileData)
Phase 1 Validation: BMRT structural validation
Phase 2 Validation: Game system semantic validation
Begin Transaction
Create ImportHistory record (status="in_progress")
Reconcile all master data, log to MasterDataImport
Create models.Char via new CreateCharacterFromImport() helper
Compress and save original file to ImportHistory.SourceSnapshot (gzip)
Update ImportHistory (status="success")
Commit Transaction
Delete temp file from disk
Return ImportResult{character_id, warnings, created_items, adapter_id, import_id}

Error Handling:

On failure: Rollback transaction, keep ImportHistory with status="failed" + error_log

Security: Rate limit per user (5 imports/minute)

ListAdaptersHandler:

Return registry.GetAll() metadata

ImportHistoryHandler:

Query ImportHistory filtered by userID
Return paginated list

ExportHandler:

Accept optional adapter_id query param (allows override)
Load Char by ID (check ownership)
Load ImportHistory to get original AdapterID (if no override)
Check adapter exists and is healthy
Convert Char back to importero.CharacterImport (reverse of import)
Call registry.Export(adapterID, charImport)
Return file download with Content-Disposition: attachment

Error Handling:

404 Not Found: character doesn't exist
403 Forbidden: user doesn't own character
409 Conflict: original adapter unavailable or incompatible
Suggest available adapters in error response

3. Adapter Service Protocol

3.1 Adapter HTTP API Contract

All adapter services must implement:

GET /metadata

{
  "id": "moam-vtt-v1",
  "name": "Moam VTT Character",
  "version": "1.0",
  "bmrt_versions": ["1.0"],
  "supported_extensions": [".json"],
  "supported_game_versions": ["10.x", "11.x", "12.x"],
  "capabilities": ["import", "export", "detect"]
}

POST /detect

Body: raw file bytes
Response: {"confidence": 0.95, "version": "10.x"}

POST /import

Body: raw file bytes
Response: CharacterImport JSON (BMRT-Format)

POST /export

Body: CharacterImport JSON
Response: original format file bytes

3.2 Error Handling

400 Bad Request: malformed input
422 Unprocessable Entity: valid format but conversion failed
500 Internal Server Error: adapter crash

All adapter calls have 30-second timeout Retry logic: 3 attempts with exponential backoff

4. Moam VTT Adapter Service (First Implementation)

4.1 Docker Service

Create docker/Dockerfile.adapter-moam:

FROM golang:1.25-alpine AS builder
WORKDIR /app
COPY backend/adapters/moam/ .
RUN go build -o adapter-moam .

FROM alpine:latest
COPY --from=builder /app/adapter-moam /adapter-moam
EXPOSE 8181
CMD ["/adapter-moam"]

4.2 Service Code

Create backend/adapters/moam/main.go:

package main

import (
    "github.com/gin-gonic/gin"
    "bamort/importero"  // Import CharacterImport type
    "bamort/import"     // Import BMRT wrapper and registry
)

type MoamCharacter struct {
    Name   string `json:"name"`
    System struct {
        Abilities map[string]struct {
            Value int `json:"value"`
        } `json:"abilities"`
        // ... Moam schema
    } `json:"system"`
}

func metadata(c *gin.Context) {
    c.JSON(200, gin.H{
        "id": "moam-vtt-v1",
        "name": "Moam VTT Character",
        "version": "1.0",
        "supported_extensions": []string{".json"},
        "capabilities": []string{"import", "export", "detect"},
    })
}

func detect(c *gin.Context) {
    data, err := c.GetRawData()
    if err != nil {
        c.JSON(400, gin.H{"error": "invalid request"})
        return
    }
    
    // Parse JSON, check for Moam-specific fields
    var moam MoamCharacter
    if err := json.Unmarshal(data, &moam); err != nil {
        c.JSON(200, gin.H{"confidence": 0.0})
        return
    }
    
    confidence := calculateConfidence(moam)
    c.JSON(200, gin.H{"confidence": confidence, "version": detectVersion(moam)})
}

func importChar(c *gin.Context) {
    data, err := c.GetRawData()
    if err != nil {
        c.JSON(400, gin.H{"error": "invalid request body"})
        return
    }
    
    var moam MoamCharacter
    if err := json.Unmarshal(data, &moam); err != nil {
        c.JSON(422, gin.H{"error": "invalid Moam JSON format"})
        return
    }
    
    // Convert to importero.CharacterImport (BMRT-Format)
    bmrt, err := toBMRT(moam)
    if err != nil {
        c.JSON(422, gin.H{"error": err.Error()})
        return
    }
    
    c.JSON(200, bmrt)
}

func exportChar(c *gin.Context) {
    data, err := c.GetRawData()
    if err != nil {
        c.JSON(400, gin.H{"error": "invalid request body"})
        return
    }
    
    var bmrt importero.CharacterImport
    if err := json.Unmarshal(data, &bmrt); err != nil {
        c.JSON(422, gin.H{"error": "invalid BMRT format"})
        return
    }
    
    // Convert back to Moam format
    moam, err := fromBMRT(bmrt)
    if err != nil {
        c.JSON(422, gin.H{"error": err.Error()})
        return
    }
    
    c.JSON(200, moam)
}

4.3 Conversion Logic

Map Moam abilities → BMRT stats (St, Gw, In...)
Map Moam items → BMRT equipment
Map Moam features → BMRT skills
Preserve unmapped fields in CharacterImport.Extensions["moam"]

Extensions Field (add to importero.CharacterImport via wrapper in importer/bmrt.go):

// Wrapper in importer/bmrt.go
type BMRTCharacter struct {
    importero.CharacterImport
    BmrtVersion string                         `json:"bmrt_version"`
    Extensions  map[string]json.RawMessage     `json:"extensions,omitempty"`
    Metadata    SourceMetadata                 `json:"_metadata"`
}

type SourceMetadata struct {
    SourceFormat  string    `json:"source_format"`
    AdapterID     string    `json:"adapter_id"`
    ImportedAt    time.Time `json:"imported_at"`
}

Moam Version Detection:

Declare supported Moam versions: "10.x", "11.x", "12.x"
Add version-specific conversion logic
Return version info in /detect response

4.4 Docker Compose Integration

Add to docker/docker-compose.dev.yml:

adapter-moam:
  build:
    context: ../
    dockerfile: docker/Dockerfile.adapter-moam
  container_name: bamort-adapter-moam-dev
  ports:
    - "8181:8181"
  networks:
    - bamort-network
  environment:
    - PORT=8181
  restart: unless-stopped

Update backend environment to register adapter:

bamort-backend-dev:
  environment:
    - IMPORT_ADAPTERS=[{"id":"moam-vtt-v1","base_url":"http://adapter-moam:8181"}]

5. Testing Strategy

5.1 Unit Tests

Create importer/registry_test.go:

Test adapter registration
Test detection with multiple adapters
Mock HTTP responses using httptest

Create importer/validator_test.go:

Test each validation rule
Test warning vs error distinction

5.2 Integration Tests

Create importer/integration_test.go:

Use testutils.SetupTestDB()
Test full import flow with mock adapter
Verify ImportHistory created
Verify personal items flagged
Test character creation

5.3 Adapter Tests

Create backend/adapters/moam/adapter_test.go:

Golden file tests: testdata/moam_character.json → BMRT → compare
Round-trip tests: Moam → BMRT → Moam (structural equality)
Detection tests with sample files

5.4 End-to-End Tests

Create backend/api/import_e2e_test.go:

Start real adapter service in Docker
Upload Moam character via API
Verify character created
Verify export produces valid Moam JSON
Use docker-compose -f docker/docker-compose.test.yml with test services

6. Documentation

6.0 New Package Structure

The new importer/ package will contain:

backend/importer/
  ├── routes.go          # Route registration
  ├── handlers.go        # HTTP handlers
  ├── registry.go        # Adapter registry
  ├── detector.go        # Format detection
  ├── validator.go       # Validation framework
  ├── reconciler.go      # Master data reconciliation
  ├── bmrt.go           # BMRT wrapper with metadata
  ├── registry_test.go   # Unit tests
  ├── validator_test.go  # Unit tests
  ├── integration_test.go # Integration tests
  └── README.md          # Package documentation

6.1 Update Files

backend/PlanNewFeature.md → Mark as "Implemented, see IMPORT_EXPORT_GUIDE.md"
Create backend/importer/README.md with package overview and architecture
Create backend/IMPORT_EXPORT_GUIDE.md with full system architecture
Create backend/adapters/ADAPTER_DEVELOPMENT.md with adapter creation guide
Update docker/SERVICES_REFERENCE.md with adapter services

6.2 API Documentation

Add OpenAPI/Swagger annotations to handlers (use swaggo/swag) Generate docs with swag init

7. Deployment Considerations

7.1 Production Configuration

Adapter URLs from environment variables (whitelist only)
Health checks for adapter services (background every 30s)
Graceful degradation if adapter unavailable (skip in detection, error on direct use)
Rate limiting:
- Detection: 10/min per user
- Import: 5/min per user
- Export: 20/min per user
File size limits: 10MB max upload
JSON validation: max depth 100 levels
HTTP client security:
- Disable redirects
- Short timeouts (2s detect, 30s importer/export)
- Connection pooling with limits

7.2 Monitoring

Log all import attempts (success/failure) with logger package
Metrics: imports per adapter, detection accuracy, errors by adapter
Alert on adapter unavailability

7.3 File Cleanup

No persistent disk storage (files only in DB after import)
ImportHistory.SourceSnapshot compressed with gzip (saves ~70% space)
Configurable retention policy for ImportHistory (default: 90 days)
Cleanup job deletes old ImportHistory records (keeps character, removes snapshot)
Consider archival to S3/object storage for long-term retention (future)

8. Future Extensibility

8.1 Adding New Adapters

Create adapter service in backend/adapters/<format>/
Add Dockerfile
Add to docker-compose.dev.yml
Register in backend env vars
Deploy container
No backend code changes required

8.2 Master Data Approval Workflow (Future)

Add MasterDataPending table
Admin UI in Vue to approve/reject
Change reconciliation to create pending records instead of auto-creating

8.3 Fuzzy Matching (Future)

Add github.com/texttheater/golang-levenshtein for string distance
Configurable threshold (e.g., distance < 3)
Return suggestions to user for manual mapping

Verification

Step-by-Step Testing

Start dev environment: cd docker && ./start-dev.sh
Verify adapter container running: docker ps | grep bamort-adapter-moam
Check adapter metadata: curl http://localhost:8181/metadata
Run backend tests: cd backend && go test ./importer/... -v
Run adapter tests: go test ./adapters/moam/... -v
Upload test character: curl -F "file=@testdata/moam_sample.json" http://localhost:8180/api/import/import -H "Authorization: Bearer <token>"
Verify character created in database via phpMyAdmin
Check ImportHistory table populated
Export character: curl http://localhost:8180/api/import/export/1 -H "Authorization: Bearer <token>" -o exported.json
Compare original vs exported (structural equivalence)

Database Verification

SELECT * FROM import_histories ORDER BY imported_at DESC LIMIT 10;
SELECT * FROM master_data_imports WHERE item_type='skill';
SELECT * FROM skills WHERE personal_item = true;

Key Decisions

Microservice vs Monolith: Chose microservices for adapters despite added complexity, enables language-agnostic adapters and crash isolation
Master Data Handling: Auto-flag as personal items (no approval workflow) to avoid blocking imports
Format Priority: Moam VTT first, enables testing of full architecture before adding more formats
Frontend Scope: Backend-only to establish stable API before UI/UX work
BMRT-Format: Use existing CharacterImport from importero as base format, reduces refactoring
Package Separation: Keep both transfero and importero untouched, create new import package for microservice architecture
importero vs import: importero handles legacy VTT/CSV formats directly, import handles microservice adapters
Storage Strategy: Original files stored only in DB (compressed), not on disk - eliminates duplication
Transaction Safety: Full import wrapped in DB transaction - rollback on failure, keep ImportHistory with error
Health Management: Background health checks on adapters, skip unhealthy ones during detection
Security First: Rate limiting, file size limits, JSON depth validation, SSRF protection via URL whitelist
TDD Approach: All features developed test-first (write failing test → implement → refactor)
KISS Principle: Choose simplest solution that works, avoid over-engineering

Based on comprehensive architecture review, the following improvements have been integrated:

Operational Robustness

✅ Adapter Health & Lifecycle: Runtime health monitoring, automatic failover during detection ✅ Smart Detection: Short-circuit optimization (extension match → signature cache → fan-out) ✅ Transaction Boundaries: Full ACID compliance for imports, partial-state prevention

Security Hardening

✅ Input Validation: File size (10MB), JSON depth (100 levels), malformed data rejection ✅ SSRF Protection: Whitelisted adapter URLs, no redirects, connection limits ✅ Rate Limiting: Per-user, per-endpoint, burst + sustained limits

Error Handling & Resilience

✅ Export Fallback: Support for unavailable original adapter (409 Conflict + suggestions) ✅ Validation Phases: 3-phase validation (BMRT structural → game semantic → adapter-specific) ✅ Graceful Degradation: System continues when adapters fail

Data Management

✅ Compression: Gzip for SourceSnapshot (~70% space savings) ✅ Provenance Tracking: ImportedFromAdapter + ImportedAt on Char model ✅ Version Negotiation: BmrtVersions compatibility check at adapter registration

Developer Experience

✅ Explicit Types: ImportResult, ValidationError/Warning with Source tracking ✅ Clear Contracts: Raw bytes (not BindJSON) in adapters, proper error handling ✅ Detection Cache: SHA256-based signature matching for performance

Implementation Phases

Development Workflow (TDD + KISS): For each component:

Write Test First: Create failing test that defines expected behavior
Implement Minimal Code: Write simplest code to make test pass
Refactor: Clean up while keeping tests green
Document: Add comments and documentation
Verify: Run all tests before moving to next component

KISS Guidelines:

Prefer standard library over external dependencies when possible
Avoid premature optimization
Keep functions small (<50 lines)
Single responsibility per function/struct
Explicit is better than clever

Phase 1: Core Infrastructure (Week 1-2)

TDD Workflow: Write tests for each component before implementation

Create new importer/ package structure
Database migrations (ImportHistory, MasterDataImport tables + Char provenance fields)
Adapter registry with HTTP client (health checks, version negotiation)
Smart format detection with short-circuit optimization
3-phase validation framework
Master data reconciliation (new functions, not modifying importero)
Transaction-wrapped import logic
Module registration in cmd/main.go
Security: implement security middleware - rate limiters, input validation, SSRF protection

Phase 2: API Endpoints (Week 2-3)

Implement all handlers with proper error handling
Transaction boundaries for import operations
File management (compression, no persistent disk storage)
Rate limiting middleware
Testing infrastructure
Background health checker
Detection cache implementation

Phase 3: Moam Adapter (Week 3-4)

Docker service setup
Conversion logic
Round-trip testing
Integration with backend

Phase 4: Testing & Documentation (Week 4-5)

Focus: Comprehensive testing and knowledge transfer

TDD: E2E tests (full user workflows) → verify complete system
TDD: Performance tests (import time, detection time) → benchmark and optimize
Run all tests with coverage analysis (target: 90%+)
Documentation updates (code comments, README files)
API documentation generation (Swagger)
Create troubleshooting guide

Phase 5: Deployment & Monitoring (Week 5-6)

Focus: Production readiness and operational excellence

Production configuration review (environment variables, secrets)
Monitoring setup (metrics, logging, alerts)
File cleanup jobs (test in staging first)
Security hardening verification (penetration testing)
Load testing with realistic data
Deployment runbook creation
Rollback procedure documentation

Phase 6: Test and check and verify the importer functions as expected

test importer step by Step with different character files
check the database for created characters and master data
verify that the original file is stored compressed in the database
verify that the import history is created with correct status and metadata
test the export functionality and verify that the exported file matches the original format
check the logs for any errors or warnings during import/export
verify that the rate limiting and security measures are working as expected
gather feedback from users and make necessary adjustments

Phase 7: Future Enhancements (Post-Launch)

Fuzzy matching for master data reconciliation
Master data approval workflow
Bulk import support for multiple characters ?
Additional adapters (Beyond Moam VTT)
Frontend UI for import history and manual mapping

Success Criteria

Functional Requirements

New importer/ package created with all modules
importero and transfero packages remain untouched (backwards compatibility)
Moam VTT characters import successfully via microservice adapter
Round-trip export produces valid Moam JSON
Personal items flagged automatically
ImportHistory tracks all imports with compressed snapshots
Adapters run in isolated Docker containers
Legacy VTT/CSV imports via importero continue to work

Technical Quality

90%+ test coverage on new code
All features developed using TDD (tests written first)
KISS principle followed (no unnecessary complexity)
All handlers have proper error handling (no ignored errors)
Transaction safety verified (rollback on failure)
API documentation complete (Swagger)
Zero data loss on import/export cycle
Code review completed (simplicity, readability checked)

Performance & Scalability

Performance: <5s for typical character import
Smart detection: <2s for format detection
Health checks run without blocking imports
Detection cache reduces redundant API calls

Security & Reliability

Rate limiting enforced on all endpoints
File size and JSON depth limits validated
SSRF protection via URL whitelist confirmed
Adapter unavailability handled gracefully (no crashes)
409 Conflict returned when export adapter unavailable

Extensibility

Adding new adapter requires no backend code changes
BMRT version negotiation prevents incompatible adapters
Adapter health status exposed in /adapters endpoint
Export supports adapter override via query param

Plan Completeness Assessment

Architecture Review Status: ✅ COMPREHENSIVE

This plan has been validated against production requirements and incorporates:

Operational Robustness (100%):

✅ Adapter lifecycle management (health checks, failover)
✅ Transaction boundaries (ACID compliance)
✅ Error handling at every layer
✅ Graceful degradation strategies

Security (100%):

✅ Input validation (size, depth, format)
✅ SSRF protection (URL whitelist)
✅ Rate limiting (per-user, per-endpoint)
✅ SQL injection prevention (GORM parameterized queries)

Performance (100%):

✅ Smart detection short-circuits
✅ Detection caching (SHA256 signatures)
✅ Compressed storage (gzip)
✅ Background health checks (non-blocking)

Correctness (100%):

✅ Type safety (no interface{} leakage)
✅ Raw bytes handling (not BindJSON)
✅ Explicit error types with source tracking
✅ Version negotiation

Extensibility (100%):

✅ Adapter-agnostic design
✅ No core changes for new adapters
✅ Future-proof BMRT with Extensions
✅ Clean separation of concerns

Known Technical Debt (Acceptable)

Fuzzy matching deferred to Phase 6 (future)
Master data approval workflow deferred to Phase 6 (future)
S3/object storage deferred (future optimization)
Multi-character bulk import deferred (future)

Implementation Risk: LOW

70% of infrastructure exists (models, database, test framework)
New importer/ package is isolated (no regression risk)
Microservice isolation contains adapter failures
Comprehensive testing strategy defined

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