banatie-service/docs/api/image-generation-advanced.md

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# Advanced Image Generation
Advanced generation features: reference images, aliases, flows, and regeneration. For basic generation, see [image-generation.md](image-generation.md).
All endpoints require Project Key authentication via `X-API-Key` header.
---
## Reference Images
Use existing images as style or content references for generation.
### Using References
Add `referenceImages` array to your generation request:
```json
{
"prompt": "A product photo with the logo in the corner",
"referenceImages": ["@brand-logo", "@product-style"]
}
```
References can be:
- **Project aliases**: `@logo`, `@brand-style`
- **Flow aliases**: `@hero` (with flowId context)
- **Technical aliases**: `@last`, `@first`, `@upload`
- **Image UUIDs**: `550e8400-e29b-41d4-a716-446655440000`
### Auto-Detection from Prompt
Aliases in the prompt are automatically detected and used as references:
```json
{
"prompt": "Create a banner using @brand-logo with blue background"
}
// @brand-logo is auto-detected and added to referenceImages
```
### Reference Limits
| Constraint | Limit |
|------------|-------|
| Max references | 3 images |
| Max file size | 5MB per image |
| Supported formats | PNG, JPEG, WebP |
### Response with References
```json
{
"data": {
"id": "550e8400-...",
"prompt": "Create a banner using @brand-logo",
"referencedImages": [
{ "imageId": "7c4ccf47-...", "alias": "@brand-logo" }
],
"referenceImages": [
{
"id": "7c4ccf47-...",
"storageUrl": "http://...",
"alias": "@brand-logo"
}
]
}
}
```
---
## Alias Assignment
Assign aliases to generated images for easy referencing.
### Project-Scoped Alias
Use `alias` parameter to assign a project-wide alias:
```json
{
"prompt": "A hero banner image",
"alias": "@hero-banner"
}
```
The output image will be accessible via `@hero-banner` anywhere in the project.
### Flow-Scoped Alias
Use `flowAlias` parameter to assign a flow-specific alias:
```json
{
"prompt": "A hero image variation",
"flowId": "550e8400-...",
"flowAlias": "@best"
}
```
The alias `@best` is only accessible within this flow's context.
### Alias Format
| Rule | Description |
|------|-------------|
| Prefix | Must start with `@` |
| Characters | Alphanumeric, underscore, hyphen |
| Pattern | `@[a-zA-Z0-9_-]+` |
| Max length | 50 characters |
| Examples | `@logo`, `@hero-bg`, `@image_1` |
### Reserved Aliases
These aliases are computed automatically and cannot be assigned:
| Alias | Description |
|-------|-------------|
| `@last` | Most recently generated image in flow |
| `@first` | First generated image in flow |
| `@upload` | Most recently uploaded image in flow |
### Override Behavior
When assigning an alias that already exists:
- The **new image gets the alias**
- The **old image loses the alias** (alias set to null)
- The old image is **not deleted**, just unlinked
---
## 3-Tier Alias Resolution
Aliases are resolved in this order of precedence:
### 1. Technical Aliases (Highest Priority)
Computed on-the-fly, require flow context:
```
GET /api/v1/images/@last?flowId=550e8400-...
```
| Alias | Returns |
|-------|---------|
| `@last` | Last generated image in flow |
| `@first` | First generated image in flow |
| `@upload` | Last uploaded image in flow |
### 2. Flow Aliases
Stored in flow's `aliases` JSONB field:
```
GET /api/v1/images/@hero?flowId=550e8400-...
```
Different flows can have the same alias pointing to different images.
### 3. Project Aliases (Lowest Priority)
Stored in image's `alias` column:
```
GET /api/v1/images/@logo
```
Global across the project, unique per project.
### Resolution Example
```
// Request with flowId
GET /api/v1/images/@hero?flowId=abc-123
// Resolution order:
// 1. Is "@hero" a technical alias? No
// 2. Does flow abc-123 have "@hero" in aliases? Check flows.aliases JSONB
// 3. Does any image have alias = "@hero"? Check images.alias column
```
---
## Flow Integration
Flows organize related generations into chains.
### Lazy Flow Creation
When `flowId` is not provided, a pending flow ID is generated:
```json
// Request
{
"prompt": "A red car"
// No flowId
}
// Response
{
"data": {
"id": "gen-123",
"flowId": "flow-456" // Auto-generated, flow record not created yet
}
}
```
The flow record is created when:
- A second generation uses the same `flowId`
- A `flowAlias` is assigned to any generation in the flow
### Eager Flow Creation
When `flowAlias` is provided, the flow is created immediately:
```json
{
"prompt": "A hero banner",
"flowAlias": "@hero-flow"
}
```
### No Flow Association
To explicitly create without flow association:
```json
{
"prompt": "A standalone image",
"flowId": null
}
```
### flowId Behavior Summary
| Value | Behavior |
|-------|----------|
| `undefined` (not provided) | Auto-generate pendingFlowId, lazy creation |
| `null` (explicitly null) | No flow association |
| `"uuid-string"` | Use provided ID, create flow if doesn't exist |
---
## Regeneration
### Regenerate Generation
Recreate an image using the exact same parameters:
```
POST /api/v1/generations/:id/regenerate
```
**Behavior:**
- Uses exact same prompt, aspect ratio, references
- **Preserves** output image ID and URL
- Works regardless of current status
- No request body needed
**Response:** Same as original generation with new image
### Update and Regenerate
Use PUT to modify parameters with smart regeneration:
```
PUT /api/v1/generations/:id
```
```json
{
"prompt": "A blue car instead",
"aspectRatio": "1:1"
}
```
**Smart Behavior:**
| Changed Field | Triggers Regeneration |
|---------------|----------------------|
| `prompt` | Yes |
| `aspectRatio` | Yes |
| `flowId` | No (metadata only) |
| `meta` | No (metadata only) |
### Flow Regenerate
Regenerate the most recent generation in a flow:
```
POST /api/v1/flows/:id/regenerate
```
**Behavior:**
- Finds the most recent generation in flow
- Regenerates with exact same parameters
- Returns error if flow has no generations
---
## Flow Management
### List Flows
```
GET /api/v1/flows
```
**Query Parameters:**
| Parameter | Type | Default | Description |
|-----------|------|---------|-------------|
| `limit` | number | `20` | Results per page (max: 100) |
| `offset` | number | `0` | Pagination offset |
**Response:**
```json
{
"data": [
{
"id": "flow-456",
"projectId": "project-123",
"aliases": { "@hero": "img-789", "@best": "img-abc" },
"generationCount": 5,
"imageCount": 7,
"createdAt": "2025-11-28T10:00:00.000Z"
}
],
"pagination": { "limit": 20, "offset": 0, "total": 3, "hasMore": false }
}
```
### Get Flow
```
GET /api/v1/flows/:id
```
Returns flow with computed counts and aliases.
### List Flow Generations
```
GET /api/v1/flows/:id/generations
```
Returns all generations in the flow, ordered by creation date (newest first).
### List Flow Images
```
GET /api/v1/flows/:id/images
```
Returns all images in the flow (generated and uploaded).
### Update Flow Aliases
```
PUT /api/v1/flows/:id/aliases
```
```json
{
"aliases": {
"@hero": "image-id-123",
"@best": "image-id-456"
}
}
```
**Behavior:** Merges with existing aliases (does not replace all).
### Remove Flow Alias
```
DELETE /api/v1/flows/:id/aliases/:alias
```
Example: `DELETE /api/v1/flows/flow-456/aliases/@hero`
### Delete Flow
```
DELETE /api/v1/flows/:id
```
**Cascade Behavior:**
- Flow record is **hard deleted**
- All generations in flow are **hard deleted**
- Images **without** project alias: **hard deleted** with MinIO cleanup
- Images **with** project alias: **kept**, but `flowId` set to null
---
## Full Request Example
```json
// POST /api/v1/generations
{
"prompt": "A professional product photo using @brand-style and @product-template",
"aspectRatio": "1:1",
"autoEnhance": true,
"enhancementOptions": { "template": "product" },
"flowId": "campaign-flow-123",
"alias": "@latest-product",
"flowAlias": "@hero",
"meta": { "campaign": "summer-2025" }
}
```
**What happens:**
1. `@brand-style` and `@product-template` resolved and used as references
2. Prompt enhanced using "product" template
3. Generation created in flow `campaign-flow-123`
4. Output image assigned project alias `@latest-product`
5. Output image assigned flow alias `@hero` in the flow
6. Custom metadata stored
---
## Response Fields (Additional)
| Field | Type | Description |
|-------|------|-------------|
| `flowId` | string | Associated flow UUID |
| `alias` | string | Project-scoped alias (on outputImage) |
| `referencedImages` | array | Resolved references: `[{ imageId, alias }]` |
| `referenceImages` | array | Full image details of references |
---
## Error Codes
| HTTP Status | Code | Description |
|-------------|------|-------------|
| 400 | `ALIAS_FORMAT_CHECK` | Alias must start with @ |
| 400 | `RESERVED_ALIAS` | Cannot use technical alias |
| 404 | `ALIAS_NOT_FOUND` | Referenced alias doesn't exist |
| 404 | `FLOW_NOT_FOUND` | Flow does not exist |
---
## See Also
- [Basic Generation](image-generation.md) - Simple generation
- [Image Upload](images-upload.md) - Upload with aliases
- [Live URLs](live-url.md) - CDN and live generation