The Image Edit Tool

So I want to build an real world app that helps me to learn more about rust web programming.

And for this image edit project, it will support following functions:

• To help users upload images.
• To add watermark to the images.
• To resize the images.
• Let user corp the images.
• User can compress the images into another format.
• Let user can download the images after the above operations is done.

The API Design

Since we have defined the goals of this project. then we can degisn the APIs according our requirments.

For your Rust-based backend image editing service, I'll design a RESTful API using standard HTTP methods. The backend will handle image uploads and provide endpoints for each editing feature (watermark, resize, crop, compress). To keep it simple and scalable:

• Images are uploaded and stored temporarily on the server (e.g., in a directory or database; you can use crates like actix-web for the web framework, image for processing, and uuid for IDs).
• Each uploaded image gets a unique ID.
• Edits are non-destructive: They create a new version of the image and return a new ID or direct URL to the result. This allows chaining operations (e.g., resize then watermark).
• Authentication is omitted for simplicity; add JWT or API keys if needed.
• Error handling: Standard HTTP status codes (e.g., 400 for bad requests, 404 for missing images, 500 for server errors) with JSON error bodies.
• Responses: JSON for metadata, with image data served via GET endpoints.

Assume the base URL is /api/images. All endpoints require appropriate headers (e.g., Content-Type: application/json for bodies).

Endpoints and Requests

I'll describe each endpoint with:

• Method and Path
• Description
• Request Parameters/Body
• Response
• Example Request (cURL-style)

Use tables for structured details where helpful.

1. Upload Image

This endpoint allows users to upload an image file, which is stored on the server and assigned an ID.

• Method and Path: POST /api/images/upload

• Description: Uploads an image file (supports JPEG, PNG, etc.). Returns the image ID and a URL to access it.

• Request:

  • Body: Multipart form data.

  • Required fields:

    Field Name	Type	Description
    file	binary	The image file to upload.

• Response (200 OK):

  • JSON body: { "image_id": "uuid-string", "url": "http://server/api/images/{image_id}" }

• Example Request:

  curl -X POST http://localhost:8080/api/images/upload \
  -F "file=@/path/to/image.jpg"

2. Get Image

Retrieve the original or edited image by ID.

• Method and Path: GET /api/images/{image_id}

• Description: Serves the image binary data.

• Request:

  • Path Params:

    Param	Type	Description
    image_id	string	Unique ID of the image.

• Response (200 OK):

  • Binary image data (with Content-Type: image/* header).

• Example Request:

  curl -X GET http://localhost:8080/api/images/123e4567-e89b-12d3-a456-426614174000 --output edited.jpg

3. Add Watermark

Apply a text or image watermark to the image.

• Method and Path: POST /api/images/{image_id}/watermark

• Description: Adds a watermark (text-based for simplicity; extend to image if needed). Creates a new image version.

• Request:

  • Path Params:

    Param	Type	Description
    image_id	string	ID of the source image.

  • Body: JSON.

    Field	Type	Required	Description
    text	string	Yes	Watermark text (e.g., "Copyright").
    position	string	No	Position: "top-left", "center", etc. (default: "bottom-right").
    opacity	float	No	Opacity (0.0-1.0, default: 0.5).
    font_size	integer	No	Font size in pixels (default: 20).

• Response (200 OK):

  • JSON body: { "new_image_id": "uuid-string", "url": "http://server/api/images/{new_image_id}" }

• Example Request:

  curl -X POST http://localhost:8080/api/images/123e4567-e89b-12d3-a456-426614174000/watermark \
  -H "Content-Type: application/json" \
  -d '{"text": "My Watermark", "position": "center", "opacity": 0.7, "font_size": 30}'

4. Resize Image

Resize the image to specified dimensions.

• Method and Path: POST /api/images/{image_id}/resize

• Description: Resizes the image while maintaining aspect ratio if only one dimension is provided. Creates a new version.

• Request:

  • Path Params:

    Param	Type	Description
    image_id	string	ID of the source image.

  • Body: JSON.

    Field	Type	Required	Description
    width	integer	No	New width in pixels (required if height omitted).
    height	integer	No	New height in pixels (required if width omitted).
    maintain_aspect	boolean	No	Maintain ratio? (default: true).

• Response (200 OK):

  • JSON body: { "new_image_id": "uuid-string", "url": "http://server/api/images/{new_image_id}" }

• Example Request:

  curl -X POST http://localhost:8080/api/images/123e4567-e89b-12d3-a456-426614174000/resize \
  -H "Content-Type: application/json" \
  -d '{"width": 800, "height": 600, "maintain_aspect": true}'

5. Crop Image

Crop a portion of the image.

• Method and Path: POST /api/images/{image_id}/crop

• Description: Crops based on coordinates and dimensions. Creates a new version.

• Request:

  • Path Params:

    Param	Type	Description
    image_id	string	ID of the source image.

  • Body: JSON.

    Field	Type	Required	Description
    x	integer	Yes	Starting x-coordinate (top-left=0).
    y	integer	Yes	Starting y-coordinate.
    width	integer	Yes	Crop width in pixels.
    height	integer	Yes	Crop height in pixels.

• Response (200 OK):

  • JSON body: { "new_image_id": "uuid-string", "url": "http://server/api/images/{new_image_id}" }

• Example Request:

  curl -X POST http://localhost:8080/api/images/123e4567-e89b-12d3-a456-426614174000/crop \
  -H "Content-Type: application/json" \
  -d '{"x": 100, "y": 100, "width": 400, "height": 300}'

6. Compress Image

Compress the image to reduce file size.

• Method and Path: POST /api/images/{image_id}/compress

• Description: Applies lossy compression (e.g., for JPEG). Creates a new version.

• Request:

  • Path Params:

    Param	Type	Description
    image_id	string	ID of the source image.

  • Body: JSON.

    Field	Type	Required	Description
    quality	integer	No	Compression quality (0-100, default: 80).
    format	string	No	Output format: "jpeg", "png" (default: original).

• Response (200 OK):

  • JSON body: { "new_image_id": "uuid-string", "url": "http://server/api/images/{new_image_id}" }

• Example Request:

  curl -X POST http://localhost:8080/api/images/123e4567-e89b-12d3-a456-426614174000/compress \
  -H "Content-Type: application/json" \
  -d '{"quality": 70, "format": "jpeg"}'

Implementation Notes for Rust

• Use axum for the server.
• For image processing: Crate image for resize/crop/watermark/compress.
• Storage: Save files in a ./uploads dir with UUID filenames.
• Cleanup: Implement a mechanism to delete old images (e.g., TTL).
• Security: Validate file types, sizes, and inputs to prevent attacks.
• Chaining: Frontend can call endpoints sequentially using the returned new_image_id.